Performance optimization for sshStorage (#313)

* Performance optimization for sshStorage

* go fmt

.circleci/config.yml

@@ -1,72 +0,0 @@
-version: 2.1
-
-jobs:
-  canary:
-    machine:
-      image: ubuntu-2004:202201-02
-    working_directory: ~/docker-volume-backup
-    steps:
-      - checkout
-      - run:
-          name: Build
-          command: |
-            docker build . -t offen/docker-volume-backup:canary
-      - run:
-          name: Install gnupg
-          command: |
-            sudo apt-get install -y gnupg
-      - run:
-          name: Run tests
-          working_directory: ~/docker-volume-backup/test
-          command: |
-            export GPG_TTY=$(tty)
-            ./test.sh canary
-
-  build:
-    docker:
-      - image: cimg/base:2020.06
-        environment:
-          DOCKER_BUILDKIT: '1'
-          DOCKER_CLI_EXPERIMENTAL: enabled
-    working_directory: ~/docker-volume-backup
-    steps:
-      - checkout
-      - setup_remote_docker:
-          version: 20.10.6
-      - docker/install-docker-credential-helper
-      - docker/configure-docker-credentials-store
-      - run:
-          name: Push to Docker Hub
-          command: |
-            echo "$DOCKER_ACCESSTOKEN" | docker login --username offen --password-stdin
-            # This is required for building ARM: https://gitlab.alpinelinux.org/alpine/aports/-/issues/12406
-            docker run --rm --privileged linuxkit/binfmt:v0.8
-            docker context create docker-volume-backup
-            docker buildx create docker-volume-backup --name docker-volume-backup --use
-            docker buildx inspect --bootstrap
-            tag_args="-t offen/docker-volume-backup:$CIRCLE_TAG"
-            if [[ "$CIRCLE_TAG" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
-              # prerelease tags like `v2.0.0-alpha.1` should not be released as `latest`
-              tag_args="$tag_args -t offen/docker-volume-backup:latest"
-              tag_args="$tag_args -t offen/docker-volume-backup:$(echo "$CIRCLE_TAG" | cut -d. -f1)"
-            fi
-            docker buildx build --platform linux/amd64,linux/arm64,linux/arm/v7 \
-               $tag_args . --push
-
-workflows:
-  version: 2
-  docker_image:
-    jobs:
-      - canary:
-          filters:
-            tags:
-              ignore: /^v.*/
-      - build:
-          filters:
-            branches:
-              ignore: /.*/
-            tags:
-              only: /^v.*/
-
-orbs:
-  docker: circleci/docker@1.0.1

.dockerignore

@@ -1 +1,7 @@
 test
+.github
+.circleci
+docs
+.editorconfig
+LICENSE
+README.md

.github/FUNDING.yml

@@ -0,0 +1,3 @@
+github: offen
+patreon: offen
+

.github/ISSUE_TEMPLATE.md

@@ -1,20 +0,0 @@
-* **I'm submitting a ...**
-  - [ ] bug report
-  - [ ] feature request
-  - [ ] support request
-
-* **What is the current behavior?**
-
-* **If the current behavior is a bug, please provide the configuration and steps to reproduce and if possible a minimal demo of the problem.**
-
-* **What is the expected behavior?**
-
-* **What is the motivation / use case for changing the behavior?**
-
-* **Please tell us about your environment:**
-  
-  - Image version:
-  - Docker version: 
-  - docker-compose version:
-
-* **Other information** (e.g. detailed explanation, stacktraces, related issues, suggestions how to fix, links for us to have context, eg. stackoverflow, etc)

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,34 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Describe the bug**
+<!--
+A clear and concise description of what the bug is.
+-->
+
+**To Reproduce**
+Steps to reproduce the behavior:
+1. ...
+2. ...
+3. ...
+
+**Expected behavior**
+<!--
+A clear and concise description of what you expected to happen.
+-->
+
+**Version (please complete the following information):**
+ - Image Version: <!-- e.g. v2.21.0 -->
+ - Docker Version: <!-- e.g. 20.10.17 -->
+ - Docker Compose Version (if applicable): <!-- e.g. 1.29.2 -->
+
+**Additional context**
+<!--
+Add any other context about the problem here.
+-->

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,28 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+<!--
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+-->
+
+**Describe the solution you'd like**
+<!--
+A clear and concise description of what you want to happen.
+-->
+
+**Describe alternatives you've considered**
+<!--
+A clear and concise description of any alternative solutions or features you've considered.
+-->
+
+**Additional context**
+<!--
+Add any other context or screenshots about the feature request here.
+-->

.github/ISSUE_TEMPLATE/support_request.md

@@ -0,0 +1,28 @@
+---
+name: Support request
+about: Ask for help
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**What are you trying to do?**
+<!--
+A clear and concise description of what you are trying to do, but cannot get working.
+-->
+
+**What is your current configuration?**
+<!--
+Add the full configuration you are using. Please redact out any real-world credentials.
+-->
+
+**Log output**
+<!--
+Provide the full log output of your setup.
+-->
+
+**Additional context**
+<!--
+Add any other context or screenshots about the support request here.
+-->

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: docker
+    directory: /
+    schedule:
+      interval: weekly
+  - package-ecosystem: gomod
+    directory: /
+    schedule:
+      interval: weekly

.github/workflows/deploy-docs.yml

@@ -0,0 +1,52 @@
+name: Deploy Documenation site to GitHub Pages
+
+on:
+  push:
+    branches: ['main']
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: 'pages'
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.2'
+          bundler-cache: true
+          cache-version: 0
+          working-directory: docs
+      - name: Setup Pages
+        id: pages
+        uses: actions/configure-pages@v2
+      - name: Build with Jekyll
+        working-directory: docs
+        run: bundle exec jekyll build --baseurl "${{ steps.pages.outputs.base_path }}"
+        env:
+          JEKYLL_ENV: production
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v1
+        with:
+          path: 'docs/_site/'
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v1

.github/workflows/golangci-lint.yml

@@ -0,0 +1,54 @@
+name: Run Linters
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+permissions:
+  contents: read
+  # Optional: allow read access to pull request. Use with `only-new-issues` option.
+  pull-requests: read
+
+jobs:
+  golangci:
+    name: lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v4
+        with:
+          go-version: '1.21'
+          cache: false
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v3
+        with:
+          # Require: The version of golangci-lint to use.
+          # When `install-mode` is `binary` (default) the value can be v1.2 or v1.2.3 or `latest` to use the latest version.
+          # When `install-mode` is `goinstall` the value can be v1.2.3, `latest`, or the hash of a commit.
+          version: v1.54
+
+          # Optional: working directory, useful for monorepos
+          # working-directory: somedir
+
+          # Optional: golangci-lint command line arguments.
+          #
+          # Note: By default, the `.golangci.yml` file should be at the root of the repository.
+          # The location of the configuration file can be changed by using `--config=`
+          # args: --timeout=30m --config=/my/path/.golangci.yml --issues-exit-code=0
+
+          # Optional: show only new issues if it's a pull request. The default value is `false`.
+          # only-new-issues: true
+
+          # Optional: if set to true, then all caching functionality will be completely disabled,
+          #           takes precedence over all other caching options.
+          # skip-cache: true
+
+          # Optional: if set to true, then the action won't cache or restore ~/go/pkg.
+          # skip-pkg-cache: true
+
+          # Optional: if set to true, then the action won't cache or restore ~/.cache/go-build.
+          # skip-build-cache: true
+
+          # Optional: The mode to install golangci-lint. It can be 'binary' or 'goinstall'.
+          # install-mode: "goinstall"

.github/workflows/release.yml

@@ -0,0 +1,59 @@
+name: Release Docker Image
+
+on:
+  push:
+    tags: v**
+
+jobs:
+  push_to_registries:
+    name: Push Docker image to multiple registries
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+      contents: read
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v3
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Log in to GHCR
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract Docker tags
+        id: meta
+        run: |
+          version_tag="${{github.ref_name}}"
+          tags=($version_tag)
+          if [[ "$version_tag" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+            # prerelease tags like `v2.0.0-alpha.1` should not be released as `latest` nor `v2`
+            tags+=("latest")
+            tags+=($(echo "$version_tag" | cut -d. -f1))
+          fi
+          releases=""
+          for tag in "${tags[@]}"; do
+            releases="${releases:+$releases,}offen/docker-volume-backup:$tag,ghcr.io/offen/docker-volume-backup:$tag"
+          done
+          echo "releases=$releases" >> "$GITHUB_OUTPUT"
+
+      - name: Build and push Docker images
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          push: true
+          platforms: linux/amd64,linux/arm64,linux/arm/v7
+          tags: ${{ steps.meta.outputs.releases }}

.github/workflows/test.yml

@@ -0,0 +1,21 @@
+name: Run Integration Tests
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-22.04
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Run Tests
+        working-directory: ./test
+        run: |
+          BUILD_IMAGE=1 ./test.sh

.golangci.yml

@@ -0,0 +1,8 @@
+linters:
+  # Enable specific linter
+  # https://golangci-lint.run/usage/linters/#enabled-by-default
+  enable:
+    - staticcheck
+    - govet
+output:
+  format: github-actions

Dockerfile

@@ -1,24 +1,21 @@
 # Copyright 2021 - Offen Authors <hioffen@posteo.de>
 # SPDX-License-Identifier: MPL-2.0
 
-FROM golang:1.18-alpine as builder
+FROM golang:1.21-alpine as builder
 
 WORKDIR /app
-COPY go.mod go.sum ./
+COPY . .
 RUN go mod download
-COPY cmd/backup ./cmd/backup/
 WORKDIR /app/cmd/backup
 RUN go build -o backup .
 
-FROM alpine:3.15
+FROM alpine:3.18
 
 WORKDIR /root
 
 RUN apk add --no-cache ca-certificates
 
 COPY --from=builder /app/cmd/backup/backup /usr/bin/backup
-
-COPY ./entrypoint.sh /root/
-RUN chmod +x entrypoint.sh
+COPY --chmod=755 ./entrypoint.sh /root/
 
 ENTRYPOINT ["/root/entrypoint.sh"]

README.md

@@ -4,54 +4,19 @@
 
 # docker-volume-backup
 
-Backup Docker volumes locally or to any S3 compatible storage.
+Backup Docker volumes locally or to any S3, WebDAV, Azure Blob Storage, Dropbox or SSH compatible storage.
 
-The [offen/docker-volume-backup](https://hub.docker.com/r/offen/docker-volume-backup) Docker image can be used as a lightweight (below 15MB) sidecar container to an existing Docker setup.
-It handles __recurring or one-off backups of Docker volumes__ to a __local directory__, __any S3 or WebDAV compatible storage (or any combination) and rotates away old backups__ if configured. It also supports __encrypting your backups using GPG__ and __sending notifications for failed backup runs__.
+The [offen/docker-volume-backup](https://hub.docker.com/r/offen/docker-volume-backup) Docker image can be used as a lightweight (below 15MB) companion container to an existing Docker setup.
+It handles __recurring or one-off backups of Docker volumes__ to a __local directory__, __any S3, WebDAV, Azure Blob Storage, Dropbox or SSH compatible storage (or any combination thereof) and rotates away old backups__ if configured. It also supports __encrypting your backups using GPG__ and __sending notifications for (failed) backup runs__.
 
-<!-- MarkdownTOC -->
-
-- [Quickstart](#quickstart)
-  - [Recurring backups in a compose setup](#recurring-backups-in-a-compose-setup)
-  - [One-off backups using Docker CLI](#one-off-backups-using-docker-cli)
-- [Configuration reference](#configuration-reference)
-- [How to](#how-to)
-  - [Stop containers during backup](#stop-containers-during-backup)
-  - [Automatically pruning old backups](#automatically-pruning-old-backups)
-  - [Send email notifications on failed backup runs](#send-email-notifications-on-failed-backup-runs)
-  - [Customize notifications](#customize-notifications)
-  - [Run custom commands before / after backup](#run-custom-commands-before--after-backup)
-  - [Encrypting your backup using GPG](#encrypting-your-backup-using-gpg)
-  - [Restoring a volume from a backup](#restoring-a-volume-from-a-backup)
-  - [Set the timezone the container runs in](#set-the-timezone-the-container-runs-in)
-  - [Using with Docker Swarm](#using-with-docker-swarm)
-  - [Manually triggering a backup](#manually-triggering-a-backup)
-  - [Update deprecated email configuration](#update-deprecated-email-configuration)
-  - [Replace deprecated `BACKUP_FROM_SNAPSHOT` usage](#replace-deprecated-backup_from_snapshot-usage)
-  - [Using a custom Docker host](#using-a-custom-docker-host)
-  - [Run multiple backup schedules in the same container](#run-multiple-backup-schedules-in-the-same-container)
-- [Recipes](#recipes)
-  - [Backing up to AWS S3](#backing-up-to-aws-s3)
-  - [Backing up to Filebase](#backing-up-to-filebase)
-  - [Backing up to MinIO](#backing-up-to-minio)
-  - [Backing up to WebDAV](#backing-up-to-webdav)
-  - [Backing up locally](#backing-up-locally)
-  - [Backing up to AWS S3 as well as locally](#backing-up-to-aws-s3-as-well-as-locally)
-  - [Running on a custom cron schedule](#running-on-a-custom-cron-schedule)
-  - [Rotating away backups that are older than 7 days](#rotating-away-backups-that-are-older-than-7-days)
-  - [Encrypting your backups using GPG](#encrypting-your-backups-using-gpg)
-  - [Using mysqldump to prepare the backup](#using-mysqldump-to-prepare-the-backup)
-  - [Running multiple instances in the same setup](#running-multiple-instances-in-the-same-setup)
-- [Differences to `futurice/docker-volume-backup`](#differences-to-futuricedocker-volume-backup)
-
-<!-- /MarkdownTOC -->
+Documentation is found at <https://offen.github.io/docker-volume-backup>
+  - [Quickstart](https://offen.github.io/docker-volume-backup)
+  - [Configuration Reference](https://offen.github.io/docker-volume-backup/reference/)
+  - [How Tos](https://offen.github.io/docker-volume-backup/how-tos/)
+  - [Recipes](https://offen.github.io/docker-volume-backup/recipes/)
 
 ---
 
-Code and documentation for `v1` versions are found on [this branch][v1-branch].
-
-[v1-branch]: https://github.com/offen/docker-volume-backup/tree/v1
-
 ## Quickstart
 
 ### Recurring backups in a compose setup
@@ -112,909 +77,3 @@ docker run --rm \
 ```
 
 Alternatively, pass a `--env-file` in order to use a full config as described below.
-
-## Configuration reference
-
-Backup targets, schedule and retention are configured in environment variables.
-You can populate below template according to your requirements and use it as your `env_file`:
-
-```ini
-########### BACKUP SCHEDULE
-
-# Backups run on the given cron schedule in `busybox` flavor. If no
-# value is set, `@daily` will be used. If you do not want the cron
-# to ever run, use `0 0 5 31 2 ?`.
-
-# BACKUP_CRON_EXPRESSION="0 2 * * *"
-
-# The name of the backup file including the `.tar.gz` extension.
-# Format verbs will be replaced as in `strftime`. Omitting them
-# will result in the same filename for every backup run, which means previous
-# versions will be overwritten on subsequent runs. The default results
-# in filenames like `backup-2021-08-29T04-00-00.tar.gz`.
-
-# BACKUP_FILENAME="backup-%Y-%m-%dT%H-%M-%S.tar.gz"
-
-# Setting BACKUP_FILENAME_EXPAND to true allows for environment variable
-# placeholders in BACKUP_FILENAME, BACKUP_LATEST_SYMLINK and in
-# BACKUP_PRUNING_PREFIX that will get expanded at runtime,
-# e.g. `backup-$HOSTNAME-%Y-%m-%dT%H-%M-%S.tar.gz`. Expansion happens before
-# interpolating strftime tokens. It is disabled by default.
-# Please note that you will need to escape the `$` when providing the value
-# in a docker-compose.yml file, i.e. using $$VAR instead of $VAR.
-
-# BACKUP_FILENAME_EXPAND="true"
-
-# When storing local backups, a symlink to the latest backup can be created
-# in case a value is given for this key. This has no effect on remote backups.
-
-# BACKUP_LATEST_SYMLINK="backup.latest.tar.gz"
-
-# ************************************************************************
-# The BACKUP_FROM_SNAPSHOT option has been deprecated and will be removed
-# in the next major version. Please use exec-pre and exec-post
-# as documented below instead.
-# ************************************************************************
-# Whether to copy the content of backup folder before creating the tar archive.
-# In the rare scenario where the content of the source backup volume is continously
-# updating, but we do not wish to stop the container while performing the backup,
-# this setting can be used to ensure the integrity of the tar.gz file.
-
-# BACKUP_FROM_SNAPSHOT="false"
-
-# By default, the `/backup` directory inside the container will be backed up.
-# In case you need to use a custom location, set `BACKUP_SOURCES`.
-
-# BACKUP_SOURCES="/other/location"
-
-########### BACKUP STORAGE
-
-# The name of the remote bucket that should be used for storing backups. If
-# this is not set, no remote backups will be stored.
-
-# AWS_S3_BUCKET_NAME="backup-bucket"
-
-# If you want to store the backup in a non-root location on your bucket
-# you can provide a path. The path must not contain a leading slash.
-
-# AWS_S3_PATH="my/backup/location"
-
-# Define credentials for authenticating against the backup storage and a bucket
-# name. Although all of these keys are `AWS`-prefixed, the setup can be used
-# with any S3 compatible storage.
-
-# AWS_ACCESS_KEY_ID="<xxx>"
-# AWS_SECRET_ACCESS_KEY="<xxx>"
-
-# Instead of providing static credentials, you can also use IAM instance profiles
-# or similar to provide authentication. Some possible configuration options on AWS:
-# - EC2: http://169.254.169.254
-# - ECS: http://169.254.170.2
-
-# AWS_IAM_ROLE_ENDPOINT="http://169.254.169.254"
-
-# This is the FQDN of your storage server, e.g. `storage.example.com`.
-# Do not set this when working against AWS S3 (the default value is
-# `s3.amazonaws.com`). If you need to set a specific (non-https) protocol, you
-# will need to use the option below.
-
-# AWS_ENDPOINT="storage.example.com"
-
-# The protocol to be used when communicating with your storage server.
-# Defaults to "https". You can set this to "http" when communicating with
-# a different Docker container on the same host for example.
-
-# AWS_ENDPOINT_PROTO="https"
-
-# Setting this variable to `true` will disable verification of
-# SSL certificates for AWS_ENDPOINT. You shouldn't use this unless you use
-# self-signed certificates for your remote storage backend. This can only be
-# used when AWS_ENDPOINT_PROTO is set to `https`.
-
-# AWS_ENDPOINT_INSECURE="true"
-
-# You can also backup files to any WebDAV server:
-
-# The URL of the remote WebDAV server
-
-# WEBDAV_URL="https://webdav.example.com"
-
-# The Directory to place the backups to on the WebDAV server.
-# If the path is not present on the server it will be created.
-
-# WEBDAV_PATH="/my/directory/"
-
-# The username for the WebDAV server
-
-# WEBDAV_USERNAME="user"
-
-# The password for the WebDAV server
-
-# WEBDAV_PASSWORD="password"
-
-# Setting this variable to `true` will disable verification of
-# SSL certificates for WEBDAV_URL. You shouldn't use this unless you use
-# self-signed certificates for your remote storage backend.
-
-# WEBDAV_URL_INSECURE="true"
-
-# In addition to storing backups remotely, you can also keep local copies.
-# Pass a container-local path to store your backups if needed. You also need to
-# mount a local folder or Docker volume into that location (`/archive`
-# by default) when running the container. In case the specified directory does
-# not exist (nothing is mounted) in the container when the backup is running,
-# local backups will be skipped. Local paths are also be subject to pruning of
-# old backups as defined below.
-
-# BACKUP_ARCHIVE="/archive"
-
-########### BACKUP PRUNING
-
-# **IMPORTANT, PLEASE READ THIS BEFORE USING THIS FEATURE**:
-# The mechanism used for pruning old backups is not very sophisticated
-# and applies its rules to **all files in the target directory** by default,
-# which means that if you are storing your backups next to other files,
-# these might become subject to deletion too. When using this option
-# make sure the backup files are stored in a directory used exclusively
-# for such files, or to configure BACKUP_PRUNING_PREFIX to limit
-# removal to certain files.
-
-# Define this value to enable automatic rotation of old backups. The value
-# declares the number of days for which a backup is kept.
-
-# BACKUP_RETENTION_DAYS="7"
-
-# In case the duration a backup takes fluctuates noticeably in your setup
-# you can adjust this setting to make sure there are no race conditions
-# between the backup finishing and the rotation not deleting backups that
-# sit on the edge of the time window. Set this value to a duration
-# that is expected to be bigger than the maximum difference of backups.
-# Valid values have a suffix of (s)econds, (m)inutes or (h)ours. By default,
-# one minute is used.
-
-# BACKUP_PRUNING_LEEWAY="1m"
-
-# In case your target bucket or directory contains other files than the ones
-# managed by this container, you can limit the scope of rotation by setting
-# a prefix value. This would usually be the non-parametrized part of your
-# BACKUP_FILENAME. E.g. if BACKUP_FILENAME is `db-backup-%Y-%m-%dT%H-%M-%S.tar.gz`,
-# you can set BACKUP_PRUNING_PREFIX to `db-backup-` and make sure
-# unrelated files are not affected by the rotation mechanism.
-
-# BACKUP_PRUNING_PREFIX="backup-"
-
-########### BACKUP ENCRYPTION
-
-# Backups can be encrypted using gpg in case a passphrase is given.
-
-# GPG_PASSPHRASE="<xxx>"
-
-########### STOPPING CONTAINERS DURING BACKUP
-
-# Containers can be stopped by applying a
-# `docker-volume-backup.stop-during-backup` label. By default, all containers
-# that are labeled with `true` will be stopped. If you need more fine grained
-# control (e.g. when running multiple containers based on this image), you can
-# override this default by specifying a different value here.
-
-# BACKUP_STOP_CONTAINER_LABEL="service1"
-
-########### EXECUTING COMMANDS IN CONTAINERS PRE/POST BACKUP
-
-# It is possible to define commands to be run in any container before and after
-# a backup is conducted. The commands themselves are defined in labels like
-# `docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump [options] > dump.sql'.
-# Several options exist for controlling this feature:
-
-# By default, any output of such a command is suppressed. If this value
-# is configured to be "true", command execution output will be forwarded to
-# the backup container's stdout and stderr.
-
-# EXEC_FORWARD_OUTPUT="true"
-
-# Without any further configuration, all commands defined in labels will be
-# run before and after a backup. If you need more fine grained control, you
-# can use this option to set a label that will be used for narrowing down
-# the set of eligible containers. When set, an eligible container will also need
-# to be labeled as `docker-volume-backup.exec-label=database`.
-
-# EXEC_LABEL="database"
-
-########### NOTIFICATIONS
-
-# Notifications (email, Slack, etc.) can be sent out when a backup run finishes.
-# Configuration is provided as a comma-separated list of URLs as consumed
-# by `shoutrrr`: https://containrrr.dev/shoutrrr/v0.5/services/overview/
-# The content of such notifications can be customized. Dedicated documentation
-# on how to do this can be found in the README. When providing multiple URLs or
-# an URL that contains a comma, the values can be URL encoded to avoid ambiguities.
-
-# The below URL demonstrates how to send an email using the provided SMTP
-# configuration and credentials.
-
-# NOTIFICATION_URLS=smtp://username:password@host:587/?fromAddress=sender@example.com&toAddresses=recipient@example.com
-
-# By default, notifications would only be sent out when a backup run fails
-# To receive notifications for every run, set `NOTIFICATION_LEVEL` to `info`
-# instead of the default `error`.
-
-# NOTIFICATION_LEVEL="error"
-
-########### DOCKER HOST
-
-# If you are interfacing with Docker via TCP you can set the Docker host here
-# instead of mounting the Docker socket as a volume. This is unset by default.
-
-# DOCKER_HOST="tcp://docker_socket_proxy:2375"
-
-########### LOCK_TIMEOUT
-
-# In the case of overlapping cron schedules run by the same container,
-# subsequent invocations will wait for previous runs to finish before starting.
-# By default, this will time out and fail in case the lock could not be acquired
-# after 60 minutes. In case you need to adjust this timeout, supply a duration
-# value as per https://pkg.go.dev/time#ParseDuration to `LOCK_TIMEOUT`
-
-# LOCK_TIMEOUT="60m"
-
-########### EMAIL NOTIFICATIONS
-
-# ************************************************************************
-# Providing notification configuration like this has been deprecated
-# and will be removed in the next major version. Please use NOTIFICATION_URLS
-# as documented above instead.
-# ************************************************************************
-
-# In case SMTP credentials are provided, notification emails can be sent out when
-# a backup run finished. These emails will contain the start time, the error
-# message on failure and all prior log output.
-
-# The recipient(s) of the notification. Supply a comma separated list
-# of adresses if you want to notify multiple recipients. If this is
-# not set, no emails will be sent.
-
-# EMAIL_NOTIFICATION_RECIPIENT="you@example.com"
-
-# The "From" header of the sent email. Defaults to `noreply@nohost`.
-
-# EMAIL_NOTIFICATION_SENDER="no-reply@example.com"
-
-# Configuration and credentials for the SMTP server to be used.
-# EMAIL_SMTP_PORT defaults to 587.
-
-# EMAIL_SMTP_HOST="posteo.de"
-# EMAIL_SMTP_PASSWORD="<xxx>"
-# EMAIL_SMTP_USERNAME="no-reply@example.com"
-# EMAIL_SMTP_PORT="<port>"
-```
-
-In case you encouter double quoted values in your configuration you might be running an [older version of `docker-compose`].
-You can work around this by either updating `docker-compose` or unquoting your configuration values.
-
-[compose-issue]: https://github.com/docker/compose/issues/2854
-
-## How to
-
-### Stop containers during backup
-
-In many cases, it will be desirable to stop the services that are consuming the volume you want to backup in order to ensure data integrity.
-This image can automatically stop and restart containers and services (in case you are running Docker in Swarm mode).
-By default, any container that is labeled `docker-volume-backup.stop-during-backup=true` will be stopped before the backup is being taken and restarted once it has finished.
-
-In case you need more fine grained control about which containers should be stopped (e.g. when backing up multiple volumes on different schedules), you can set the `BACKUP_STOP_CONTAINER_LABEL` environment variable and then use the same value for labeling:
-
-```yml
-version: '3'
-
-services:
-  app:
-    # definition for app ...
-    labels:
-      - docker-volume-backup.stop-during-backup=service1
-
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      BACKUP_STOP_CONTAINER_LABEL: service1
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Automatically pruning old backups
-
-When `BACKUP_RETENTION_DAYS` is configured, the image will check if there are any backups in the remote bucket or local archive that are older than the given retention value and rotate these backups away.
-
-Be aware that this mechanism looks at __all files in the target bucket or archive__, which means that other files that are older than the given deadline are deleted as well. In case you need to use a target that cannot be used exclusively for your backups, you can configure `BACKUP_PRUNING_PREFIX` to limit which files are considered eligible for deletion:
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
-      BACKUP_PRUNING_PREFIX: backup-
-      BACKUP_RETENTION_DAYS: 7
-    volumes:
-      - ${HOME}/backups:/archive
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Send email notifications on failed backup runs
-
-To send out email notifications on failed backup runs, provide SMTP credentials, a sender and a recipient:
-
-```yml
-version: '3'
-
-services:
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      # ... other configuration values go here
-      NOTIFICATION_URLS=smtp://me:secret@smtp.example.com:587/?fromAddress=no-reply@example.com&toAddresses=you@example.com
-```
-
-Notification backends other than email are also supported.
-Refer to the documentation of [shoutrrr][shoutrrr-docs] to find out about options and configuration.
-
-[shoutrrr-docs]: https://containrrr.dev/shoutrrr/v0.5/services/overview/
-
-### Customize notifications
-
-The title and body of the notifications can be easily tailored to your needs using [go templates](https://pkg.go.dev/text/template).
-Templates must be mounted inside the container in `/etc/dockervolumebackup/notifications.d/`: any file inside this directory will be parsed.
-
-The files have to define [nested templates](https://pkg.go.dev/text/template#hdr-Nested_template_definitions) in order to override the original values. An example:
-```
-{{ define "title_success" -}}
-✅ Successfully ran backup {{ .Config.BackupStopContainerLabel }}
-{{- end }}
-
-{{ define "body_success" -}}
-▶️ Start time: {{ .Stats.StartTime | formatTime }}
-⏹️ End time: {{ .Stats.EndTime | formatTime }}
-⌛ Took time: {{ .Stats.TookTime }}
-🛑 Stopped containers: {{ .Stats.Containers.Stopped }}/{{ .Stats.Containers.All }} ({{ .Stats.Containers.StopErrors }} errors)
-⚖️ Backup size: {{ .Stats.BackupFile.Size | formatBytesBin }} / {{ .Stats.BackupFile.Size | formatBytesDec }}
-🗑️ Pruned backups: {{ .Stats.Storages.Local.Pruned }}/{{ .Stats.Storages.Local.Total }} ({{ .Stats.Storages.Local.PruneErrors }} errors)
-{{- end }}
-```
-
-Overridable template names are: `title_success`, `body_success`, `title_failure`, `body_failure`.
-
-For a full list of available variables and functions, see [this page](https://github.com/offen/docker-volume-backup/blob/master/docs/NOTIFICATION-TEMPLATES.md).
-
-### Run custom commands before / after backup
-
-In certain scenarios it can be required to run specific commands before and after a backup is taken (e.g. dumping a database).
-When mounting the Docker socket into the `docker-volume-backup` container, you can define pre- and post-commands that will be run in the context of the target container.
-Such commands are defined by specifying the command in a `docker-volume-backup.exec-[pre|post]` label.
-
-Taking a database dump using `mysqldump` would look like this:
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  database:
-    image: mariadb
-    volumes:
-      - backup_data:/tmp/backups
-    labels:
-      - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump --all-databases > /backups/dump.sql'
-
-volumes:
-  backup_data:
-```
-
-Due to Docker limitations, you currently cannot use any kind of redirection in these commands unless you pass the command to `/bin/sh -c` or similar.
-I.e. instead of using `echo "ok" > ok.txt` you will need to use `/bin/sh -c 'echo "ok" > ok.txt'`.
-
-If you need fine grained control about which container's commands are run, you can use the `EXEC_LABEL` configuration on your `docker-volume-backup` container:
-
-```yml
-version: '3'
-
-services:
-  database:
-    image: mariadb
-    volumes:
-      - backup_data:/tmp/backups
-    labels:
-      - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump --all-databases > /tmp/volume/dump.sql'
-      - docker-volume-backup.exec-label=database
-
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      EXEC_LABEL: database
-    volumes:
-      - data:/backup/dump:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  backup_data:
-```
-
-
-The backup procedure is guaranteed to wait for all `pre` commands to finish.
-However there are no guarantees about the order in which they are run, which could also happen concurrently.
-
-### Encrypting your backup using GPG
-
-The image supports encrypting backups using GPG out of the box.
-In case a `GPG_PASSPHRASE` environment variable is set, the backup will be encrypted using the given key and saved as a `.gpg` file instead.
-
-Assuming you have `gpg` installed, you can decrypt such a backup using (your OS will prompt for the passphrase before decryption can happen):
-
-```console
-gpg -o backup.tar.gz -d backup.tar.gz.gpg
-```
-
-### Restoring a volume from a backup
-
-In case you need to restore a volume from a backup, the most straight forward procedure to do so would be:
-
-- Stop the container(s) that are using the volume
-- Untar the backup you want to restore
-  ```console
-  tar -C /tmp -xvf  backup.tar.gz
-  ```
-- Using a temporary once-off container, mount the volume (the example assumes it's named `data`) and copy over the backup. Make sure you copy the correct path level (this depends on how you mount your volume into the backup container), you might need to strip some leading elements
-  ```console
-  docker run -d --name temp_restore_container -v data:/backup_restore alpine
-  docker cp /tmp/backup/data-backup temp_restore_container:/backup_restore
-  docker stop temp_restore_container
-  docker rm temp_restore_container
-  ```
-- Restart the container(s) that are using the volume
-
-Depending on your setup and the application(s) you are running, this might involve other steps to be taken still.
-
----
-
-If you want to rollback an entire volume to an earlier backup snapshot (recommended for database volumes):
-
-- Trigger a manual backup if necessary (see `Manually triggering a backup`).
-- Stop the container(s) that are using the volume.
-- If volume was initially created using docker-compose, find out exact volume name using:
-  ```console
-  docker volume ls
-  ```
-- Remove existing volume (the example assumes it's named `data`):
-  ```console
-  docker volume rm data
-  ```
-- Create new volume with the same name and restore a snapshot:
-  ```console
-  docker run --rm -it -v data:/backup/my-app-backup -v /path/to/local_backups:/archive:ro alpine tar -xvzf /archive/full_backup_filename.tar.gz
-  ```
-- Restart the container(s) that are using the volume.
-
-### Set the timezone the container runs in
-
-By default a container based on this image will run in the UTC timezone.
-As the image is designed to be as small as possible, additional timezone data is not included.
-In case you want to run your cron rules in your local timezone (respecting DST and similar), you can mount your Docker host's `/etc/timezone` and `/etc/localtime` in read-only mode:
-
-```yml
-version: '3'
-
-services:
-  backup:
-    image: offen/docker-volume-backup:v2
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /etc/timezone:/etc/timezone:ro
-      - /etc/localtime:/etc/localtime:ro
-
-volumes:
-  data:
-```
-
-### Using with Docker Swarm
-
-By default, Docker Swarm will restart stopped containers automatically, even when manually stopped.
-If you plan to have your containers / services stopped during backup, this means you need to apply the `on-failure` restart policy to your service's definitions.
-A restart policy of `always` is not compatible with this tool.
-
----
-
-When running in Swarm mode, it's also advised to set a hard memory limit on your service (~25MB should be enough in most cases, but if you backup large files above half a gigabyte or similar, you might have to raise this in case the backup exits with `Killed`):
-
-```yml
-services:
-  backup:
-    image: offen/docker-volume-backup:v2
-    deployment:
-      resources:
-        limits:
-          memory: 25M
-```
-
-### Manually triggering a backup
-
-You can manually trigger a backup run outside of the defined cron schedule by executing the `backup` command inside the container:
-
-```
-docker exec <container_ref> backup
-```
-
-### Update deprecated email configuration
-
-Starting with version 2.6.0, configuring email notifications using `EMAIL_*` keys has been deprecated.
-Instead of providing multiple values using multiple keys, you can now provide a single URL for `NOTIFICATION_URLS`.
-
-Before:
-```ini
-EMAIL_NOTIFICATION_RECIPIENT="you@example.com"
-EMAIL_NOTIFICATION_SENDER="no-reply@example.com"
-EMAIL_SMTP_HOST="posteo.de"
-EMAIL_SMTP_PASSWORD="secret"
-EMAIL_SMTP_USERNAME="me"
-EMAIL_SMTP_PORT="587"
-```
-
-After:
-```ini
-NOTIFICATION_URLS=smtp://me:secret@posteo.de:587/?fromAddress=no-reply@example.com&toAddresses=you@example.com
-```
-
-### Replace deprecated `BACKUP_FROM_SNAPSHOT` usage
-
-Starting with version 2.15.0, the `BACKUP_FROM_SNAPSHOT` feature has been deprecated.
-If you need to prepare your sources before the backup is taken, use `exec-pre`, `exec-post` and an intermediate volume:
-
-```yml
-version: '3'
-
-services:
-  my_app:
-    build: .
-    volumes:
-      - data:/var/my_app
-      - backup:/tmp/backup
-    labels:
-      - docker-volume-backup.exec-pre=cp -r /var/my_app /tmp/backup/my-app
-      - docker-volume-backup.exec-post=rm -rf /tmp/backup/my-app
-
-  backup:
-    image: offen/docker-volume-backup:latest
-    environment:
-      BACKUP_SOURCES: /tmp/backup
-    volumes:
-      - backup:/backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-  backup:
-```
-
-### Using a custom Docker host
-
-If you are interfacing with Docker via TCP, set `DOCKER_HOST` to the correct URL.
-```ini
-DOCKER_HOST=tcp://docker_socket_proxy:2375
-```
-
-In case you are using a socket proxy, it must support `GET` and `POST` requests to the `/containers` endpoint. If you are using Docker Swarm, it must also support the `/services` endpoint. If you are using pre/post backup commands, it must also support the `/exec` endpoint.
-
-### Run multiple backup schedules in the same container
-
-Multiple backup schedules with different configuration can be configured by mounting an arbitrary number of configuration files (using the `.env` format) into `/etc/dockervolumebackup/conf.d`:
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-      - ./configuration:/etc/dockervolumebackup/conf.d
-
-volumes:
-  data:
-```
-
-A separate cronjob will be created for each config file.
-If a configuration value is set both in the global environment as well as in the config file, the config file will take precedence.
-The `backup` command expects to run on an exclusive lock, so in case you provide the same or overlapping schedules in your cron expressions, the runs will still be executed serially, one after the other.
-The exact order of schedules that use the same cron expression is not specified.
-In case you need your schedules to overlap, you need to create a dedicated container for each schedule instead.
-When changing the configuration, you currently need to manually restart the container for the changes to take effect.
-
-## Recipes
-
-This section lists configuration for some real-world use cases that you can mix and match according to your needs.
-
-### Backing up to AWS S3
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      AWS_S3_BUCKET_NAME: backup-bucket
-      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
-      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Backing up to Filebase
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      AWS_ENDPOINT: s3.filebase.com
-      AWS_S3_BUCKET_NAME: filebase-bucket
-      AWS_ACCESS_KEY_ID: FILEBASE-ACCESS-KEY
-      AWS_SECRET_ACCESS_KEY: FILEBASE-SECRET-KEY
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Backing up to MinIO
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      AWS_ENDPOINT: minio.example.com
-      AWS_S3_BUCKET_NAME: backup-bucket
-      AWS_ACCESS_KEY_ID: MINIOACCESSKEY
-      AWS_SECRET_ACCESS_KEY: MINIOSECRETKEY
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Backing up to WebDAV
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      WEBDAV_URL: https://webdav.mydomain.me
-      WEBDAV_PATH: /my/directory/
-      WEBDAV_USERNAME: user
-      WEBDAV_PASSWORD: password
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Backing up locally
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
-      BACKUP_LATEST_SYMLINK: backup-latest.tar.gz
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-      - ${HOME}/backups:/archive
-
-volumes:
-  data:
-```
-
-### Backing up to AWS S3 as well as locally
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      AWS_S3_BUCKET_NAME: backup-bucket
-      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
-      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-      - ${HOME}/backups:/archive
-
-volumes:
-  data:
-```
-
-### Running on a custom cron schedule
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      # take a backup on every hour
-      BACKUP_CRON_EXPRESSION: "0 * * * *"
-      AWS_S3_BUCKET_NAME: backup-bucket
-      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
-      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Rotating away backups that are older than 7 days
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      AWS_S3_BUCKET_NAME: backup-bucket
-      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
-      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
-      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
-      BACKUP_PRUNING_PREFIX: backup-
-      BACKUP_RETENTION_DAYS: 7
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Encrypting your backups using GPG
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data` volume here
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      AWS_S3_BUCKET_NAME: backup-bucket
-      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
-      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
-      GPG_PASSPHRASE: somesecretstring
-    volumes:
-      - data:/backup/my-app-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data:
-```
-
-### Using mysqldump to prepare the backup
-
-```yml
-version: '3'
-
-services:
-  database:
-    image: mariadb:latest
-    labels:
-      - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump -psecret --all-databases > /tmp/dumps/dump.sql'
-    volumes:
-      - app_data:/tmp/dumps
-  backup:
-    image: offen/docker-volume-backup:v2
-    environment:
-      BACKUP_FILENAME: db.tar.gz
-      BACKUP_CRON_EXPRESSION: "0 2 * * *"
-    volumes:
-      - ./local:/archive
-      - data:/backup/data:ro
-      - /var/run/docker.sock:/var/run/docker.sock
-
-volumes:
-  data:
-```
-
-### Running multiple instances in the same setup
-
-```yml
-version: '3'
-
-services:
-  # ... define other services using the `data_1` and `data_2` volumes here
-  backup_1: &backup_service
-    image: offen/docker-volume-backup:v2
-    environment: &backup_environment
-      BACKUP_CRON_EXPRESSION: "0 2 * * *"
-      AWS_S3_BUCKET_NAME: backup-bucket
-      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
-      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
-      # Label the container using the `data_1` volume as `docker-volume-backup.stop-during-backup=service1`
-      BACKUP_STOP_CONTAINER_LABEL: service1
-    volumes:
-      - data_1:/backup/data-1-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-  backup_2:
-    <<: *backup_service
-    environment:
-      <<: *backup_environment
-      # Label the container using the `data_2` volume as `docker-volume-backup.stop-during-backup=service2`
-      BACKUP_CRON_EXPRESSION: "0 3 * * *"
-      BACKUP_STOP_CONTAINER_LABEL: service2
-    volumes:
-      - data_2:/backup/data-2-backup:ro
-      - /var/run/docker.sock:/var/run/docker.sock:ro
-
-volumes:
-  data_1:
-  data_2:
-```
-
-## Differences to `futurice/docker-volume-backup`
-
-This image is heavily inspired by `futurice/docker-volume-backup`. We decided to publish this image as a simpler and more lightweight alternative because of the following requirements:
-
-- The original image is based on `ubuntu` and requires additional tools, making it heavy.
-This version is roughly 1/25 in compressed size (it's ~12MB).
-- The original image uses a shell script, when this version is written in Go.
-- The original image proposed to handle backup rotation through AWS S3 lifecycle policies.
-This image adds the option to rotate away old backups through the same command so this functionality can also be offered for non-AWS storage backends like MinIO.
-Local copies of backups can also be pruned once they reach a certain age.
-- InfluxDB specific functionality from the original image was removed.
-- `arm64` and `arm/v7` architectures are supported.
-- Docker in Swarm mode is supported.
-- Notifications on finished backups are supported.
-- IAM authentication through instance profiles is supported.

cmd/backup/archive.go

@@ -8,17 +8,20 @@ package main
 
 import (
 	"archive/tar"
-	"compress/gzip"
 	"fmt"
 	"io"
-	"io/fs"
 	"os"
 	"path"
 	"path/filepath"
+	"runtime"
 	"strings"
+
+	"github.com/klauspost/pgzip"
+
+	"github.com/klauspost/compress/zstd"
 )
 
-func createArchive(inputFilePath, outputFilePath string) error {
+func createArchive(files []string, inputFilePath, outputFilePath string, compression string, compressionConcurrency int) error {
 	inputFilePath = stripTrailingSlashes(inputFilePath)
 	inputFilePath, outputFilePath, err := makeAbsolute(inputFilePath, outputFilePath)
 	if err != nil {
@@ -28,7 +31,7 @@ func createArchive(inputFilePath, outputFilePath string) error {
 		return fmt.Errorf("createArchive: error creating output file path: %w", err)
 	}
 
-	if err := compress(inputFilePath, outputFilePath, filepath.Dir(inputFilePath)); err != nil {
+	if err := compress(files, outputFilePath, filepath.Dir(inputFilePath), compression, compressionConcurrency); err != nil {
 		return fmt.Errorf("createArchive: error creating archive: %w", err)
 	}
 
@@ -52,27 +55,22 @@ func makeAbsolute(inputFilePath, outputFilePath string) (string, string, error)
 	return inputFilePath, outputFilePath, err
 }
 
-func compress(inPath, outFilePath, subPath string) error {
+func compress(paths []string, outFilePath, subPath string, algo string, concurrency int) error {
 	file, err := os.Create(outFilePath)
 	if err != nil {
 		return fmt.Errorf("compress: error creating out file: %w", err)
 	}
 
 	prefix := path.Dir(outFilePath)
-	gzipWriter := gzip.NewWriter(file)
-	tarWriter := tar.NewWriter(gzipWriter)
-
-	var paths []string
-	if err := filepath.WalkDir(inPath, func(path string, di fs.DirEntry, err error) error {
-		paths = append(paths, path)
-		return err
-	}); err != nil {
-		return fmt.Errorf("compress: error walking filesystem tree: %w", err)
+	compressWriter, err := getCompressionWriter(file, algo, concurrency)
+	if err != nil {
+		return fmt.Errorf("compress: error getting compression writer: %w", err)
 	}
+	tarWriter := tar.NewWriter(compressWriter)
 
 	for _, p := range paths {
-		if err := writeTarGz(p, tarWriter, prefix); err != nil {
-			return fmt.Errorf("compress error writing %s to archive: %w", p, err)
+		if err := writeTarball(p, tarWriter, prefix); err != nil {
+			return fmt.Errorf("compress: error writing %s to archive: %w", p, err)
 		}
 	}
 
@@ -81,9 +79,9 @@ func compress(inPath, outFilePath, subPath string) error {
 		return fmt.Errorf("compress: error closing tar writer: %w", err)
 	}
 
-	err = gzipWriter.Close()
+	err = compressWriter.Close()
 	if err != nil {
-		return fmt.Errorf("compress: error closing gzip writer: %w", err)
+		return fmt.Errorf("compress: error closing compression writer: %w", err)
 	}
 
 	err = file.Close()
@@ -94,10 +92,38 @@ func compress(inPath, outFilePath, subPath string) error {
 	return nil
 }
 
-func writeTarGz(path string, tarWriter *tar.Writer, prefix string) error {
+func getCompressionWriter(file *os.File, algo string, concurrency int) (io.WriteCloser, error) {
+	switch algo {
+	case "gz":
+		w, err := pgzip.NewWriterLevel(file, 5)
+		if err != nil {
+			return nil, fmt.Errorf("getCompressionWriter: gzip error: %w", err)
+		}
+
+		if concurrency == 0 {
+			concurrency = runtime.GOMAXPROCS(0)
+		}
+
+		if err := w.SetConcurrency(1<<20, concurrency); err != nil {
+			return nil, fmt.Errorf("getCompressionWriter: error setting concurrency: %w", err)
+		}
+
+		return w, nil
+	case "zst":
+		compressWriter, err := zstd.NewWriter(file)
+		if err != nil {
+			return nil, fmt.Errorf("getCompressionWriter: zstd error: %w", err)
+		}
+		return compressWriter, nil
+	default:
+		return nil, fmt.Errorf("getCompressionWriter: unsupported compression algorithm: %s", algo)
+	}
+}
+
+func writeTarball(path string, tarWriter *tar.Writer, prefix string) error {
 	fileInfo, err := os.Lstat(path)
 	if err != nil {
-		return fmt.Errorf("writeTarGz: error getting file infor for %s: %w", path, err)
+		return fmt.Errorf("writeTarball: error getting file infor for %s: %w", path, err)
 	}
 
 	if fileInfo.Mode()&os.ModeSocket == os.ModeSocket {
@@ -108,19 +134,19 @@ func writeTarGz(path string, tarWriter *tar.Writer, prefix string) error {
 	if fileInfo.Mode()&os.ModeSymlink == os.ModeSymlink {
 		var err error
 		if link, err = os.Readlink(path); err != nil {
-			return fmt.Errorf("writeTarGz: error resolving symlink %s: %w", path, err)
+			return fmt.Errorf("writeTarball: error resolving symlink %s: %w", path, err)
 		}
 	}
 
 	header, err := tar.FileInfoHeader(fileInfo, link)
 	if err != nil {
-		return fmt.Errorf("writeTarGz: error getting file info header: %w", err)
+		return fmt.Errorf("writeTarball: error getting file info header: %w", err)
 	}
 	header.Name = strings.TrimPrefix(path, prefix)
 
 	err = tarWriter.WriteHeader(header)
 	if err != nil {
-		return fmt.Errorf("writeTarGz: error writing file info header: %w", err)
+		return fmt.Errorf("writeTarball: error writing file info header: %w", err)
 	}
 
 	if !fileInfo.Mode().IsRegular() {
@@ -129,13 +155,13 @@ func writeTarGz(path string, tarWriter *tar.Writer, prefix string) error {
 
 	file, err := os.Open(path)
 	if err != nil {
-		return fmt.Errorf("writeTarGz: error opening %s: %w", path, err)
+		return fmt.Errorf("writeTarball: error opening %s: %w", path, err)
 	}
 	defer file.Close()
 
 	_, err = io.Copy(tarWriter, file)
 	if err != nil {
-		return fmt.Errorf("writeTarGz: error copying %s to tar writer: %w", path, err)
+		return fmt.Errorf("writeTarball: error copying %s to tar writer: %w", path, err)
 	}
 
 	return nil

cmd/backup/config.go

@@ -3,44 +3,169 @@
 
 package main
 
-import "time"
+import (
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"os"
+	"regexp"
+	"strconv"
+	"time"
+)
 
 // Config holds all configuration values that are expected to be set
 // by users.
 type Config struct {
-	BackupSources              string        `split_words:"true" default:"/backup"`
-	BackupFilename             string        `split_words:"true" default:"backup-%Y-%m-%dT%H-%M-%S.tar.gz"`
-	BackupFilenameExpand       bool          `split_words:"true"`
-	BackupLatestSymlink        string        `split_words:"true"`
-	BackupArchive              string        `split_words:"true" default:"/archive"`
-	BackupRetentionDays        int32         `split_words:"true" default:"-1"`
-	BackupPruningLeeway        time.Duration `split_words:"true" default:"1m"`
-	BackupPruningPrefix        string        `split_words:"true"`
-	BackupStopContainerLabel   string        `split_words:"true" default:"true"`
-	BackupFromSnapshot         bool          `split_words:"true"`
-	AwsS3BucketName            string        `split_words:"true"`
-	AwsS3Path                  string        `split_words:"true"`
-	AwsEndpoint                string        `split_words:"true" default:"s3.amazonaws.com"`
-	AwsEndpointProto           string        `split_words:"true" default:"https"`
-	AwsEndpointInsecure        bool          `split_words:"true"`
-	AwsAccessKeyID             string        `envconfig:"AWS_ACCESS_KEY_ID"`
-	AwsSecretAccessKey         string        `split_words:"true"`
-	AwsIamRoleEndpoint         string        `split_words:"true"`
-	GpgPassphrase              string        `split_words:"true"`
-	NotificationURLs           []string      `envconfig:"NOTIFICATION_URLS"`
-	NotificationLevel          string        `split_words:"true" default:"error"`
-	EmailNotificationRecipient string        `split_words:"true"`
-	EmailNotificationSender    string        `split_words:"true" default:"noreply@nohost"`
-	EmailSMTPHost              string        `envconfig:"EMAIL_SMTP_HOST"`
-	EmailSMTPPort              int           `envconfig:"EMAIL_SMTP_PORT" default:"587"`
-	EmailSMTPUsername          string        `envconfig:"EMAIL_SMTP_USERNAME"`
-	EmailSMTPPassword          string        `envconfig:"EMAIL_SMTP_PASSWORD"`
-	WebdavUrl                  string        `split_words:"true"`
-	WebdavUrlInsecure          bool          `split_words:"true"`
-	WebdavPath                 string        `split_words:"true" default:"/"`
-	WebdavUsername             string        `split_words:"true"`
-	WebdavPassword             string        `split_words:"true"`
-	ExecLabel                  string        `split_words:"true"`
-	ExecForwardOutput          bool          `split_words:"true"`
-	LockTimeout                time.Duration `split_words:"true" default:"60m"`
+	AwsS3BucketName               string          `split_words:"true"`
+	AwsS3Path                     string          `split_words:"true"`
+	AwsEndpoint                   string          `split_words:"true" default:"s3.amazonaws.com"`
+	AwsEndpointProto              string          `split_words:"true" default:"https"`
+	AwsEndpointInsecure           bool            `split_words:"true"`
+	AwsEndpointCACert             CertDecoder     `envconfig:"AWS_ENDPOINT_CA_CERT"`
+	AwsStorageClass               string          `split_words:"true"`
+	AwsAccessKeyID                string          `envconfig:"AWS_ACCESS_KEY_ID"`
+	AwsSecretAccessKey            string          `split_words:"true"`
+	AwsIamRoleEndpoint            string          `split_words:"true"`
+	AwsPartSize                   int64           `split_words:"true"`
+	BackupCompression             CompressionType `split_words:"true" default:"gz"`
+	GzipParallelism               WholeNumber     `split_words:"true" default:"1"`
+	BackupSources                 string          `split_words:"true" default:"/backup"`
+	BackupFilename                string          `split_words:"true" default:"backup-%Y-%m-%dT%H-%M-%S.{{ .Extension }}"`
+	BackupFilenameExpand          bool            `split_words:"true"`
+	BackupLatestSymlink           string          `split_words:"true"`
+	BackupArchive                 string          `split_words:"true" default:"/archive"`
+	BackupRetentionDays           int32           `split_words:"true" default:"-1"`
+	BackupPruningLeeway           time.Duration   `split_words:"true" default:"1m"`
+	BackupPruningPrefix           string          `split_words:"true"`
+	BackupStopContainerLabel      string          `split_words:"true" default:"true"`
+	BackupFromSnapshot            bool            `split_words:"true"`
+	BackupExcludeRegexp           RegexpDecoder   `split_words:"true"`
+	BackupSkipBackendsFromPrune   []string        `split_words:"true"`
+	GpgPassphrase                 string          `split_words:"true"`
+	NotificationURLs              []string        `envconfig:"NOTIFICATION_URLS"`
+	NotificationLevel             string          `split_words:"true" default:"error"`
+	EmailNotificationRecipient    string          `split_words:"true"`
+	EmailNotificationSender       string          `split_words:"true" default:"noreply@nohost"`
+	EmailSMTPHost                 string          `envconfig:"EMAIL_SMTP_HOST"`
+	EmailSMTPPort                 int             `envconfig:"EMAIL_SMTP_PORT" default:"587"`
+	EmailSMTPUsername             string          `envconfig:"EMAIL_SMTP_USERNAME"`
+	EmailSMTPPassword             string          `envconfig:"EMAIL_SMTP_PASSWORD"`
+	WebdavUrl                     string          `split_words:"true"`
+	WebdavUrlInsecure             bool            `split_words:"true"`
+	WebdavPath                    string          `split_words:"true" default:"/"`
+	WebdavUsername                string          `split_words:"true"`
+	WebdavPassword                string          `split_words:"true"`
+	SSHHostName                   string          `split_words:"true"`
+	SSHPort                       string          `split_words:"true" default:"22"`
+	SSHUser                       string          `split_words:"true"`
+	SSHPassword                   string          `split_words:"true"`
+	SSHIdentityFile               string          `split_words:"true" default:"/root/.ssh/id_rsa"`
+	SSHIdentityPassphrase         string          `split_words:"true"`
+	SSHRemotePath                 string          `split_words:"true"`
+	ExecLabel                     string          `split_words:"true"`
+	ExecForwardOutput             bool            `split_words:"true"`
+	LockTimeout                   time.Duration   `split_words:"true" default:"60m"`
+	AzureStorageAccountName       string          `split_words:"true"`
+	AzureStoragePrimaryAccountKey string          `split_words:"true"`
+	AzureStorageContainerName     string          `split_words:"true"`
+	AzureStoragePath              string          `split_words:"true"`
+	AzureStorageEndpoint          string          `split_words:"true" default:"https://{{ .AccountName }}.blob.core.windows.net/"`
+	DropboxEndpoint               string          `split_words:"true" default:"https://api.dropbox.com/"`
+	DropboxOAuth2Endpoint         string          `envconfig:"DROPBOX_OAUTH2_ENDPOINT" default:"https://api.dropbox.com/"`
+	DropboxRefreshToken           string          `split_words:"true"`
+	DropboxAppKey                 string          `split_words:"true"`
+	DropboxAppSecret              string          `split_words:"true"`
+	DropboxRemotePath             string          `split_words:"true"`
+	DropboxConcurrencyLevel       NaturalNumber   `split_words:"true" default:"6"`
+}
+
+type CompressionType string
+
+func (c *CompressionType) Decode(v string) error {
+	switch v {
+	case "gz", "zst":
+		*c = CompressionType(v)
+		return nil
+	default:
+		return fmt.Errorf("config: error decoding compression type %s", v)
+	}
+}
+
+func (c *CompressionType) String() string {
+	return string(*c)
+}
+
+type CertDecoder struct {
+	Cert *x509.Certificate
+}
+
+func (c *CertDecoder) Decode(v string) error {
+	if v == "" {
+		return nil
+	}
+	content, err := os.ReadFile(v)
+	if err != nil {
+		content = []byte(v)
+	}
+	block, _ := pem.Decode(content)
+	cert, err := x509.ParseCertificate(block.Bytes)
+	if err != nil {
+		return fmt.Errorf("config: error parsing certificate: %w", err)
+	}
+	*c = CertDecoder{Cert: cert}
+	return nil
+}
+
+type RegexpDecoder struct {
+	Re *regexp.Regexp
+}
+
+func (r *RegexpDecoder) Decode(v string) error {
+	if v == "" {
+		return nil
+	}
+	re, err := regexp.Compile(v)
+	if err != nil {
+		return fmt.Errorf("config: error compiling given regexp `%s`: %w", v, err)
+	}
+	*r = RegexpDecoder{Re: re}
+	return nil
+}
+
+// NaturalNumber is a type that can be used to decode a positive, non-zero natural number
+type NaturalNumber int
+
+func (n *NaturalNumber) Decode(v string) error {
+	asInt, err := strconv.Atoi(v)
+	if err != nil {
+		return fmt.Errorf("config: error converting %s to int", v)
+	}
+	if asInt <= 0 {
+		return fmt.Errorf("config: expected a natural number, got %d", asInt)
+	}
+	*n = NaturalNumber(asInt)
+	return nil
+}
+
+func (n *NaturalNumber) Int() int {
+	return int(*n)
+}
+
+// WholeNumber is a type that can be used to decode a positive whole number, including zero
+type WholeNumber int
+
+func (n *WholeNumber) Decode(v string) error {
+	asInt, err := strconv.Atoi(v)
+	if err != nil {
+		return fmt.Errorf("config: error converting %s to int", v)
+	}
+	if asInt < 0 {
+		return fmt.Errorf("config: expected a whole, positive number, including zero. Got %d", asInt)
+	}
+	*n = WholeNumber(asInt)
+	return nil
+}
+
+func (n *WholeNumber) Int() int {
+	return int(*n)
 }

cmd/backup/exec.go

@@ -10,7 +10,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"strings"
 
@@ -21,12 +21,17 @@ import (
 	"golang.org/x/sync/errgroup"
 )
 
-func (s *script) exec(containerRef string, command string) ([]byte, []byte, error) {
+func (s *script) exec(containerRef string, command string, user string) ([]byte, []byte, error) {
 	args, _ := argv.Argv(command, nil, nil)
+	commandEnv := []string{
+		fmt.Sprintf("COMMAND_RUNTIME_ARCHIVE_FILEPATH=%s", s.file),
+	}
 	execID, err := s.cli.ContainerExecCreate(context.Background(), containerRef, types.ExecConfig{
 		Cmd:          args[0],
 		AttachStdin:  true,
 		AttachStderr: true,
+		Env:          commandEnv,
+		User:         user,
 	})
 	if err != nil {
 		return nil, nil, fmt.Errorf("exec: error creating container exec: %w", err)
@@ -46,19 +51,15 @@ func (s *script) exec(containerRef string, command string) ([]byte, []byte, erro
 		outputDone <- err
 	}()
 
-	select {
-	case err := <-outputDone:
-		if err != nil {
-			return nil, nil, fmt.Errorf("exec: error demultiplexing output: %w", err)
-		}
-		break
+	if err := <-outputDone; err != nil {
+		return nil, nil, fmt.Errorf("exec: error demultiplexing output: %w", err)
 	}
 
-	stdout, err := ioutil.ReadAll(&outBuf)
+	stdout, err := io.ReadAll(&outBuf)
 	if err != nil {
 		return nil, nil, fmt.Errorf("exec: error reading stdout: %w", err)
 	}
-	stderr, err := ioutil.ReadAll(&errBuf)
+	stderr, err := io.ReadAll(&errBuf)
 	if err != nil {
 		return nil, nil, fmt.Errorf("exec: error reading stderr: %w", err)
 	}
@@ -86,25 +87,77 @@ func (s *script) runLabeledCommands(label string) error {
 		})
 	}
 	containersWithCommand, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
-		Quiet:   true,
 		Filters: filters.NewArgs(f...),
 	})
 	if err != nil {
 		return fmt.Errorf("runLabeledCommands: error querying for containers: %w", err)
 	}
 
+	var hasDeprecatedContainers bool
+	if label == "docker-volume-backup.archive-pre" {
+		f[0] = filters.KeyValuePair{
+			Key:   "label",
+			Value: "docker-volume-backup.exec-pre",
+		}
+		deprecatedContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
+			Filters: filters.NewArgs(f...),
+		})
+		if err != nil {
+			return fmt.Errorf("runLabeledCommands: error querying for containers: %w", err)
+		}
+		if len(deprecatedContainers) != 0 {
+			hasDeprecatedContainers = true
+			containersWithCommand = append(containersWithCommand, deprecatedContainers...)
+		}
+	}
+
+	if label == "docker-volume-backup.archive-post" {
+		f[0] = filters.KeyValuePair{
+			Key:   "label",
+			Value: "docker-volume-backup.exec-post",
+		}
+		deprecatedContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
+			Filters: filters.NewArgs(f...),
+		})
+		if err != nil {
+			return fmt.Errorf("runLabeledCommands: error querying for containers: %w", err)
+		}
+		if len(deprecatedContainers) != 0 {
+			hasDeprecatedContainers = true
+			containersWithCommand = append(containersWithCommand, deprecatedContainers...)
+		}
+	}
+
 	if len(containersWithCommand) == 0 {
 		return nil
 	}
 
+	if hasDeprecatedContainers {
+		s.logger.Warn(
+			"Using `docker-volume-backup.exec-pre` and `docker-volume-backup.exec-post` labels has been deprecated and will be removed in the next major version.",
+		)
+		s.logger.Warn(
+			"Please use other `-pre` and `-post` labels instead. Refer to the README for an upgrade guide.",
+		)
+	}
+
 	g := new(errgroup.Group)
 
 	for _, container := range containersWithCommand {
 		c := container
 		g.Go(func() error {
-			cmd, _ := c.Labels[label]
-			s.logger.Infof("Running %s command %s for container %s", label, cmd, strings.TrimPrefix(c.Names[0], "/"))
-			stdout, stderr, err := s.exec(c.ID, cmd)
+			cmd, ok := c.Labels[label]
+			if !ok && label == "docker-volume-backup.archive-pre" {
+				cmd = c.Labels["docker-volume-backup.exec-pre"]
+			} else if !ok && label == "docker-volume-backup.archive-post" {
+				cmd = c.Labels["docker-volume-backup.exec-post"]
+			}
+
+			userLabelName := fmt.Sprintf("%s.user", label)
+			user := c.Labels[userLabelName]
+
+			s.logger.Info(fmt.Sprintf("Running %s command %s for container %s", label, cmd, strings.TrimPrefix(c.Names[0], "/")))
+			stdout, stderr, err := s.exec(c.ID, cmd, user)
 			if s.c.ExecForwardOutput {
 				os.Stderr.Write(stderr)
 				os.Stdout.Write(stdout)
@@ -121,3 +174,27 @@ func (s *script) runLabeledCommands(label string) error {
 	}
 	return nil
 }
+
+type lifecyclePhase string
+
+const (
+	lifecyclePhaseArchive lifecyclePhase = "archive"
+	lifecyclePhaseProcess lifecyclePhase = "process"
+	lifecyclePhaseCopy    lifecyclePhase = "copy"
+	lifecyclePhasePrune   lifecyclePhase = "prune"
+)
+
+func (s *script) withLabeledCommands(step lifecyclePhase, cb func() error) func() error {
+	if s.cli == nil {
+		return cb
+	}
+	return func() error {
+		if err := s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-pre", step)); err != nil {
+			return fmt.Errorf("withLabeledCommands: %s: error running pre commands: %w", step, err)
+		}
+		defer func() {
+			s.must(s.runLabeledCommands(fmt.Sprintf("docker-volume-backup.%s-post", step)))
+		}()
+		return cb()
+	}
+}

cmd/backup/hooks.go

@@ -4,6 +4,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"sort"
 )
@@ -50,7 +51,7 @@ func (s *script) runHooks(err error) error {
 		}
 	}
 	if len(actionErrors) != 0 {
-		return join(actionErrors...)
+		return errors.Join(actionErrors...)
 	}
 	return nil
 }

cmd/backup/lock.go

@@ -18,7 +18,7 @@ import (
 func (s *script) lock(lockfile string) (func() error, error) {
 	start := time.Now()
 	defer func() {
-		s.stats.LockedTime = time.Now().Sub(start)
+		s.stats.LockedTime = time.Since(start)
 	}()
 
 	retry := time.NewTicker(5 * time.Second)
@@ -31,7 +31,7 @@ func (s *script) lock(lockfile string) (func() error, error) {
 	for {
 		acquired, err := fileLock.TryLock()
 		if err != nil {
-			return noop, fmt.Errorf("lock: error trying lock: %w", err)
+			return noop, fmt.Errorf("lock: error trying to lock: %w", err)
 		}
 		if acquired {
 			if s.encounteredLock {
@@ -41,9 +41,11 @@ func (s *script) lock(lockfile string) (func() error, error) {
 		}
 
 		if !s.encounteredLock {
-			s.logger.Infof(
-				"Exclusive lock was not available on first attempt. Will retry until it becomes available or the timeout of %s is exceeded.",
-				s.c.LockTimeout,
+			s.logger.Info(
+				fmt.Sprintf(
+					"Exclusive lock was not available on first attempt. Will retry until it becomes available or the timeout of %s is exceeded.",
+					s.c.LockTimeout,
+				),
 			)
 			s.encounteredLock = true
 		}

cmd/backup/main.go

@@ -4,6 +4,7 @@
 package main
 
 import (
+	"fmt"
 	"os"
 )
 
@@ -14,14 +15,16 @@ func main() {
 	}
 
 	unlock, err := s.lock("/var/lock/dockervolumebackup.lock")
-	defer unlock()
+	defer s.must(unlock())
 	s.must(err)
 
 	defer func() {
 		if pArg := recover(); pArg != nil {
 			if err, ok := pArg.(error); ok {
 				if hookErr := s.runHooks(err); hookErr != nil {
-					s.logger.Errorf("An error occurred calling the registered hooks: %s", hookErr)
+					s.logger.Error(
+						fmt.Sprintf("An error occurred calling the registered hooks: %s", hookErr),
+					)
 				}
 				os.Exit(1)
 			}
@@ -29,23 +32,18 @@ func main() {
 		}
 
 		if err := s.runHooks(nil); err != nil {
-			s.logger.Errorf(
-				"Backup procedure ran successfully, but an error ocurred calling the registered hooks: %v",
-				err,
+			s.logger.Error(
+				fmt.Sprintf(
+					"Backup procedure ran successfully, but an error ocurred calling the registered hooks: %v",
+					err,
+				),
 			)
 			os.Exit(1)
 		}
 		s.logger.Info("Finished running backup tasks.")
 	}()
 
-	s.must(func() error {
-		runPostCommands, err := s.runCommands()
-		defer func() {
-			s.must(runPostCommands())
-		}()
-		if err != nil {
-			return err
-		}
+	s.must(s.withLabeledCommands(lifecyclePhaseArchive, func() error {
 		restartContainers, err := s.stopContainers()
 		// The mechanism for restarting containers is not using hooks as it
 		// should happen as soon as possible (i.e. before uploading backups or
@@ -56,10 +54,10 @@ func main() {
 		if err != nil {
 			return err
 		}
-		return s.takeBackup()
-	}())
+		return s.createArchive()
+	})())
 
-	s.must(s.encryptBackup())
-	s.must(s.copyBackup())
-	s.must(s.pruneBackups())
+	s.must(s.withLabeledCommands(lifecyclePhaseProcess, s.encryptArchive)())
+	s.must(s.withLabeledCommands(lifecyclePhaseCopy, s.copyArchive)())
+	s.must(s.withLabeledCommands(lifecyclePhasePrune, s.pruneBackups)())
 }

cmd/backup/notifications.go

@@ -6,7 +6,9 @@ package main
 import (
 	"bytes"
 	_ "embed"
+	"errors"
 	"fmt"
+	"os"
 	"text/template"
 	"time"
 
@@ -34,16 +36,16 @@ func (s *script) notify(titleTemplate string, bodyTemplate string, err error) er
 
 	titleBuf := &bytes.Buffer{}
 	if err := s.template.ExecuteTemplate(titleBuf, titleTemplate, params); err != nil {
-		return fmt.Errorf("notifyFailure: error executing %s template: %w", titleTemplate, err)
+		return fmt.Errorf("notify: error executing %s template: %w", titleTemplate, err)
 	}
 
 	bodyBuf := &bytes.Buffer{}
 	if err := s.template.ExecuteTemplate(bodyBuf, bodyTemplate, params); err != nil {
-		return fmt.Errorf("notifyFailure: error executing %s template: %w", bodyTemplate, err)
+		return fmt.Errorf("notify: error executing %s template: %w", bodyTemplate, err)
 	}
 
 	if err := s.sendNotification(titleBuf.String(), bodyBuf.String()); err != nil {
-		return fmt.Errorf("notifyFailure: error notifying: %w", err)
+		return fmt.Errorf("notify: error notifying: %w", err)
 	}
 	return nil
 }
@@ -67,7 +69,7 @@ func (s *script) sendNotification(title, body string) error {
 		}
 	}
 	if len(errs) != 0 {
-		return fmt.Errorf("sendNotification: error sending message: %w", join(errs...))
+		return fmt.Errorf("sendNotification: error sending message: %w", errors.Join(errs...))
 	}
 	return nil
 }
@@ -82,6 +84,7 @@ var templateHelpers = template.FuncMap{
 	"formatBytesBin": func(bytes uint64) string {
 		return formatBytes(bytes, false)
 	},
+	"env": os.Getenv,
 }
 
 // formatBytes converts an amount of bytes in a human-readable representation

cmd/backup/script.go

@@ -4,46 +4,53 @@
 package main
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"io/fs"
-	"net/http"
+	"log/slog"
 	"os"
 	"path"
 	"path/filepath"
+	"slices"
 	"strings"
 	"text/template"
 	"time"
 
+	"github.com/offen/docker-volume-backup/internal/storage"
+	"github.com/offen/docker-volume-backup/internal/storage/azure"
+	"github.com/offen/docker-volume-backup/internal/storage/dropbox"
+	"github.com/offen/docker-volume-backup/internal/storage/local"
+	"github.com/offen/docker-volume-backup/internal/storage/s3"
+	"github.com/offen/docker-volume-backup/internal/storage/ssh"
+	"github.com/offen/docker-volume-backup/internal/storage/webdav"
+
+	"github.com/ProtonMail/go-crypto/openpgp"
 	"github.com/containrrr/shoutrrr"
 	"github.com/containrrr/shoutrrr/pkg/router"
 	"github.com/docker/docker/api/types"
+	ctr "github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/filters"
 	"github.com/docker/docker/api/types/swarm"
 	"github.com/docker/docker/client"
-	"github.com/kelseyhightower/envconfig"
 	"github.com/leekchan/timeutil"
-	"github.com/minio/minio-go/v7"
-	"github.com/minio/minio-go/v7/pkg/credentials"
+	"github.com/offen/envconfig"
 	"github.com/otiai10/copy"
-	"github.com/sirupsen/logrus"
-	"github.com/studio-b12/gowebdav"
-	"golang.org/x/crypto/openpgp"
+	"golang.org/x/sync/errgroup"
 )
 
 // script holds all the stateful information required to orchestrate a
 // single backup run.
 type script struct {
-	cli          *client.Client
-	minioClient  *minio.Client
-	webdavClient *gowebdav.Client
-	logger       *logrus.Logger
-	sender       *router.ServiceRouter
-	template     *template.Template
-	hooks        []hook
-	hookLevel    hookLevel
+	cli       *client.Client
+	storages  []storage.Backend
+	logger    *slog.Logger
+	sender    *router.ServiceRouter
+	template  *template.Template
+	hooks     []hook
+	hookLevel hookLevel
 
 	file  string
 	stats *Stats
@@ -60,17 +67,19 @@ type script struct {
 func newScript() (*script, error) {
 	stdOut, logBuffer := buffer(os.Stdout)
 	s := &script{
-		c: &Config{},
-		logger: &logrus.Logger{
-			Out:       stdOut,
-			Formatter: new(logrus.TextFormatter),
-			Hooks:     make(logrus.LevelHooks),
-			Level:     logrus.InfoLevel,
-		},
+		c:      &Config{},
+		logger: slog.New(slog.NewTextHandler(stdOut, nil)),
 		stats: &Stats{
 			StartTime: time.Now(),
 			LogOutput: logBuffer,
-			Storages:  StoragesStats{},
+			Storages: map[string]StorageStats{
+				"S3":      {},
+				"WebDAV":  {},
+				"SSH":     {},
+				"Local":   {},
+				"Azure":   {},
+				"Dropbox": {},
+			},
 		},
 	}
 
@@ -80,11 +89,47 @@ func newScript() (*script, error) {
 		return nil
 	})
 
+	envconfig.Lookup = func(key string) (string, bool) {
+		value, okValue := os.LookupEnv(key)
+		location, okFile := os.LookupEnv(key + "_FILE")
+
+		switch {
+		case okValue && !okFile: // only value
+			return value, true
+		case !okValue && okFile: // only file
+			contents, err := os.ReadFile(location)
+			if err != nil {
+				s.must(fmt.Errorf("newScript: failed to read %s! Error: %s", location, err))
+				return "", false
+			}
+			return string(contents), true
+		case okValue && okFile: // both
+			s.must(fmt.Errorf("newScript: both %s and %s are set!", key, key+"_FILE"))
+			return "", false
+		default: // neither, ignore
+			return "", false
+		}
+	}
+
 	if err := envconfig.Process("", s.c); err != nil {
 		return nil, fmt.Errorf("newScript: failed to process configuration values: %w", err)
 	}
 
 	s.file = path.Join("/tmp", s.c.BackupFilename)
+
+	tmplFileName, tErr := template.New("extension").Parse(s.file)
+	if tErr != nil {
+		return nil, fmt.Errorf("newScript: unable to parse backup file extension template: %w", tErr)
+	}
+
+	var bf bytes.Buffer
+	if tErr := tmplFileName.Execute(&bf, map[string]string{
+		"Extension": fmt.Sprintf("tar.%s", s.c.BackupCompression),
+	}); tErr != nil {
+		return nil, fmt.Errorf("newScript: error executing backup file extension template: %w", tErr)
+	}
+	s.file = bf.String()
+
 	if s.c.BackupFilenameExpand {
 		s.file = os.ExpandEnv(s.file)
 		s.c.BackupLatestSymlink = os.ExpandEnv(s.c.BackupLatestSymlink)
@@ -102,61 +147,109 @@ func newScript() (*script, error) {
 		s.cli = cli
 	}
 
+	logFunc := func(logType storage.LogLevel, context string, msg string, params ...any) {
+		switch logType {
+		case storage.LogLevelWarning:
+			s.logger.Warn(fmt.Sprintf(msg, params...), "storage", context)
+		case storage.LogLevelError:
+			s.logger.Error(fmt.Sprintf(msg, params...), "storage", context)
+		default:
+			s.logger.Info(fmt.Sprintf(msg, params...), "storage", context)
+		}
+	}
+
 	if s.c.AwsS3BucketName != "" {
-		var creds *credentials.Credentials
-		if s.c.AwsAccessKeyID != "" && s.c.AwsSecretAccessKey != "" {
-			creds = credentials.NewStaticV4(
-				s.c.AwsAccessKeyID,
-				s.c.AwsSecretAccessKey,
-				"",
-			)
-		} else if s.c.AwsIamRoleEndpoint != "" {
-			creds = credentials.NewIAM(s.c.AwsIamRoleEndpoint)
-		} else {
-			return nil, errors.New("newScript: AWS_S3_BUCKET_NAME is defined, but no credentials were provided")
+		s3Config := s3.Config{
+			Endpoint:         s.c.AwsEndpoint,
+			AccessKeyID:      s.c.AwsAccessKeyID,
+			SecretAccessKey:  s.c.AwsSecretAccessKey,
+			IamRoleEndpoint:  s.c.AwsIamRoleEndpoint,
+			EndpointProto:    s.c.AwsEndpointProto,
+			EndpointInsecure: s.c.AwsEndpointInsecure,
+			RemotePath:       s.c.AwsS3Path,
+			BucketName:       s.c.AwsS3BucketName,
+			StorageClass:     s.c.AwsStorageClass,
+			CACert:           s.c.AwsEndpointCACert.Cert,
+			PartSize:         s.c.AwsPartSize,
 		}
-
-		options := minio.Options{
-			Creds:  creds,
-			Secure: s.c.AwsEndpointProto == "https",
-		}
-
-		if s.c.AwsEndpointInsecure {
-			if !options.Secure {
-				return nil, errors.New("newScript: AWS_ENDPOINT_INSECURE = true is only meaningful for https")
-			}
-
-			transport, err := minio.DefaultTransport(true)
-			if err != nil {
-				return nil, fmt.Errorf("newScript: failed to create default minio transport")
-			}
-			transport.TLSClientConfig.InsecureSkipVerify = true
-			options.Transport = transport
-		}
-
-		mc, err := minio.New(s.c.AwsEndpoint, &options)
+		s3Backend, err := s3.NewStorageBackend(s3Config, logFunc)
 		if err != nil {
-			return nil, fmt.Errorf("newScript: error setting up minio client: %w", err)
+			return nil, fmt.Errorf("newScript: error creating s3 storage backend: %w", err)
 		}
-		s.minioClient = mc
+		s.storages = append(s.storages, s3Backend)
 	}
 
 	if s.c.WebdavUrl != "" {
-		if s.c.WebdavUsername == "" || s.c.WebdavPassword == "" {
-			return nil, errors.New("newScript: WEBDAV_URL is defined, but no credentials were provided")
-		} else {
-			webdavClient := gowebdav.NewClient(s.c.WebdavUrl, s.c.WebdavUsername, s.c.WebdavPassword)
-			s.webdavClient = webdavClient
-			if s.c.WebdavUrlInsecure {
-				defaultTransport, ok := http.DefaultTransport.(*http.Transport)
-				if !ok {
-					return nil, errors.New("newScript: unexpected error when asserting type for http.DefaultTransport")
-				}
-				webdavTransport := defaultTransport.Clone()
-				webdavTransport.TLSClientConfig.InsecureSkipVerify = s.c.WebdavUrlInsecure
-				s.webdavClient.SetTransport(webdavTransport)
-			}
+		webDavConfig := webdav.Config{
+			URL:         s.c.WebdavUrl,
+			URLInsecure: s.c.WebdavUrlInsecure,
+			Username:    s.c.WebdavUsername,
+			Password:    s.c.WebdavPassword,
+			RemotePath:  s.c.WebdavPath,
 		}
+		webdavBackend, err := webdav.NewStorageBackend(webDavConfig, logFunc)
+		if err != nil {
+			return nil, fmt.Errorf("newScript: error creating webdav storage backend: %w", err)
+		}
+		s.storages = append(s.storages, webdavBackend)
+	}
+
+	if s.c.SSHHostName != "" {
+		sshConfig := ssh.Config{
+			HostName:           s.c.SSHHostName,
+			Port:               s.c.SSHPort,
+			User:               s.c.SSHUser,
+			Password:           s.c.SSHPassword,
+			IdentityFile:       s.c.SSHIdentityFile,
+			IdentityPassphrase: s.c.SSHIdentityPassphrase,
+			RemotePath:         s.c.SSHRemotePath,
+		}
+		sshBackend, err := ssh.NewStorageBackend(sshConfig, logFunc)
+		if err != nil {
+			return nil, fmt.Errorf("newScript: error creating ssh storage backend: %w", err)
+		}
+		s.storages = append(s.storages, sshBackend)
+	}
+
+	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
+		localConfig := local.Config{
+			ArchivePath:   s.c.BackupArchive,
+			LatestSymlink: s.c.BackupLatestSymlink,
+		}
+		localBackend := local.NewStorageBackend(localConfig, logFunc)
+		s.storages = append(s.storages, localBackend)
+	}
+
+	if s.c.AzureStorageAccountName != "" {
+		azureConfig := azure.Config{
+			ContainerName:     s.c.AzureStorageContainerName,
+			AccountName:       s.c.AzureStorageAccountName,
+			PrimaryAccountKey: s.c.AzureStoragePrimaryAccountKey,
+			Endpoint:          s.c.AzureStorageEndpoint,
+			RemotePath:        s.c.AzureStoragePath,
+		}
+		azureBackend, err := azure.NewStorageBackend(azureConfig, logFunc)
+		if err != nil {
+			return nil, fmt.Errorf("newScript: error creating azure storage backend: %w", err)
+		}
+		s.storages = append(s.storages, azureBackend)
+	}
+
+	if s.c.DropboxRefreshToken != "" && s.c.DropboxAppKey != "" && s.c.DropboxAppSecret != "" {
+		dropboxConfig := dropbox.Config{
+			Endpoint:         s.c.DropboxEndpoint,
+			OAuth2Endpoint:   s.c.DropboxOAuth2Endpoint,
+			RefreshToken:     s.c.DropboxRefreshToken,
+			AppKey:           s.c.DropboxAppKey,
+			AppSecret:        s.c.DropboxAppSecret,
+			RemotePath:       s.c.DropboxRemotePath,
+			ConcurrencyLevel: s.c.DropboxConcurrencyLevel.Int(),
+		}
+		dropboxBackend, err := dropbox.NewStorageBackend(dropboxConfig, logFunc)
+		if err != nil {
+			return nil, fmt.Errorf("newScript: error creating dropbox storage backend: %w", err)
+		}
+		s.storages = append(s.storages, dropboxBackend)
 	}
 
 	if s.c.EmailNotificationRecipient != "" {
@@ -225,22 +318,6 @@ func newScript() (*script, error) {
 	return s, nil
 }
 
-func (s *script) runCommands() (func() error, error) {
-	if s.cli == nil {
-		return noop, nil
-	}
-
-	if err := s.runLabeledCommands("docker-volume-backup.exec-pre"); err != nil {
-		return noop, fmt.Errorf("runCommands: error running pre commands: %w", err)
-	}
-	return func() error {
-		if err := s.runLabeledCommands("docker-volume-backup.exec-post"); err != nil {
-			return fmt.Errorf("runCommands: error running post commands: %w", err)
-		}
-		return nil
-	}, nil
-}
-
 // stopContainers stops all Docker containers that are marked as to being
 // stopped during the backup and returns a function that can be called to
 // restart everything that has been stopped.
@@ -249,11 +326,9 @@ func (s *script) stopContainers() (func() error, error) {
 		return noop, nil
 	}
 
-	allContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
-		Quiet: true,
-	})
+	allContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{})
 	if err != nil {
-		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers: %w", err)
+		return noop, fmt.Errorf("stopContainers: error querying for containers: %w", err)
 	}
 
 	containerLabel := fmt.Sprintf(
@@ -261,7 +336,6 @@ func (s *script) stopContainers() (func() error, error) {
 		s.c.BackupStopContainerLabel,
 	)
 	containersToStop, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
-		Quiet: true,
 		Filters: filters.NewArgs(filters.KeyValuePair{
 			Key:   "label",
 			Value: containerLabel,
@@ -269,24 +343,26 @@ func (s *script) stopContainers() (func() error, error) {
 	})
 
 	if err != nil {
-		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers to stop: %w", err)
+		return noop, fmt.Errorf("stopContainers: error querying for containers to stop: %w", err)
 	}
 
 	if len(containersToStop) == 0 {
 		return noop, nil
 	}
 
-	s.logger.Infof(
-		"Stopping %d container(s) labeled `%s` out of %d running container(s).",
-		len(containersToStop),
-		containerLabel,
-		len(allContainers),
+	s.logger.Info(
+		fmt.Sprintf(
+			"Stopping %d container(s) labeled `%s` out of %d running container(s).",
+			len(containersToStop),
+			containerLabel,
+			len(allContainers),
+		),
 	)
 
 	var stoppedContainers []types.Container
 	var stopErrors []error
 	for _, container := range containersToStop {
-		if err := s.cli.ContainerStop(context.Background(), container.ID, nil); err != nil {
+		if err := s.cli.ContainerStop(context.Background(), container.ID, ctr.StopOptions{}); err != nil {
 			stopErrors = append(stopErrors, err)
 		} else {
 			stoppedContainers = append(stoppedContainers, container)
@@ -296,9 +372,9 @@ func (s *script) stopContainers() (func() error, error) {
 	var stopError error
 	if len(stopErrors) != 0 {
 		stopError = fmt.Errorf(
-			"stopContainersAndRun: %d error(s) stopping containers: %w",
+			"stopContainers: %d error(s) stopping containers: %w",
 			len(stopErrors),
-			join(stopErrors...),
+			errors.Join(stopErrors...),
 		)
 	}
 
@@ -333,9 +409,9 @@ func (s *script) stopContainers() (func() error, error) {
 					}
 				}
 				if serviceMatch.ID == "" {
-					return fmt.Errorf("stopContainersAndRun: couldn't find service with name %s", serviceName)
+					return fmt.Errorf("stopContainers: couldn't find service with name %s", serviceName)
 				}
-				serviceMatch.Spec.TaskTemplate.ForceUpdate = 1
+				serviceMatch.Spec.TaskTemplate.ForceUpdate += 1
 				if _, err := s.cli.ServiceUpdate(
 					context.Background(), serviceMatch.ID,
 					serviceMatch.Version, serviceMatch.Spec, types.ServiceUpdateOptions{},
@@ -347,22 +423,24 @@ func (s *script) stopContainers() (func() error, error) {
 
 		if len(restartErrors) != 0 {
 			return fmt.Errorf(
-				"stopContainersAndRun: %d error(s) restarting containers and services: %w",
+				"stopContainers: %d error(s) restarting containers and services: %w",
 				len(restartErrors),
-				join(restartErrors...),
+				errors.Join(restartErrors...),
 			)
 		}
-		s.logger.Infof(
-			"Restarted %d container(s) and the matching service(s).",
-			len(stoppedContainers),
+		s.logger.Info(
+			fmt.Sprintf(
+				"Restarted %d container(s) and the matching service(s).",
+				len(stoppedContainers),
+			),
 		)
 		return nil
 	}, stopError
 }
 
-// takeBackup creates a tar archive of the configured backup location and
+// createArchive creates a tar archive of the configured backup location and
 // saves it to disk.
-func (s *script) takeBackup() error {
+func (s *script) createArchive() error {
 	backupSources := s.c.BackupSources
 
 	if s.c.BackupFromSnapshot {
@@ -370,46 +448,75 @@ func (s *script) takeBackup() error {
 			"Using BACKUP_FROM_SNAPSHOT has been deprecated and will be removed in the next major version.",
 		)
 		s.logger.Warn(
-			"Please use `exec-pre` and `exec-post` commands to prepare your backup sources. Refer to the README for an upgrade guide.",
+			"Please use `archive-pre` and `archive-post` commands to prepare your backup sources. Refer to the README for an upgrade guide.",
 		)
 		backupSources = filepath.Join("/tmp", s.c.BackupSources)
 		// copy before compressing guard against a situation where backup folder's content are still growing.
 		s.registerHook(hookLevelPlumbing, func(error) error {
 			if err := remove(backupSources); err != nil {
-				return fmt.Errorf("takeBackup: error removing snapshot: %w", err)
+				return fmt.Errorf("createArchive: error removing snapshot: %w", err)
 			}
-			s.logger.Infof("Removed snapshot `%s`.", backupSources)
+			s.logger.Info(
+				fmt.Sprintf("Removed snapshot `%s`.", backupSources),
+			)
 			return nil
 		})
 		if err := copy.Copy(s.c.BackupSources, backupSources, copy.Options{
 			PreserveTimes: true,
 			PreserveOwner: true,
 		}); err != nil {
-			return fmt.Errorf("takeBackup: error creating snapshot: %w", err)
+			return fmt.Errorf("createArchive: error creating snapshot: %w", err)
 		}
-		s.logger.Infof("Created snapshot of `%s` at `%s`.", s.c.BackupSources, backupSources)
+		s.logger.Info(
+			fmt.Sprintf("Created snapshot of `%s` at `%s`.", s.c.BackupSources, backupSources),
+		)
 	}
 
 	tarFile := s.file
 	s.registerHook(hookLevelPlumbing, func(error) error {
 		if err := remove(tarFile); err != nil {
-			return fmt.Errorf("takeBackup: error removing tar file: %w", err)
+			return fmt.Errorf("createArchive: error removing tar file: %w", err)
 		}
-		s.logger.Infof("Removed tar file `%s`.", tarFile)
+		s.logger.Info(
+			fmt.Sprintf("Removed tar file `%s`.", tarFile),
+		)
 		return nil
 	})
-	if err := createArchive(backupSources, tarFile); err != nil {
-		return fmt.Errorf("takeBackup: error compressing backup folder: %w", err)
+
+	backupPath, err := filepath.Abs(stripTrailingSlashes(backupSources))
+	if err != nil {
+		return fmt.Errorf("createArchive: error getting absolute path: %w", err)
 	}
 
-	s.logger.Infof("Created backup of `%s` at `%s`.", backupSources, tarFile)
+	var filesEligibleForBackup []string
+	if err := filepath.WalkDir(backupPath, func(path string, di fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if s.c.BackupExcludeRegexp.Re != nil && s.c.BackupExcludeRegexp.Re.MatchString(path) {
+			return nil
+		}
+		filesEligibleForBackup = append(filesEligibleForBackup, path)
+		return nil
+	}); err != nil {
+		return fmt.Errorf("createArchive: error walking filesystem tree: %w", err)
+	}
+
+	if err := createArchive(filesEligibleForBackup, backupSources, tarFile, s.c.BackupCompression.String(), s.c.GzipParallelism.Int()); err != nil {
+		return fmt.Errorf("createArchive: error compressing backup folder: %w", err)
+	}
+
+	s.logger.Info(
+		fmt.Sprintf("Created backup of `%s` at `%s`.", backupSources, tarFile),
+	)
 	return nil
 }
 
-// encryptBackup encrypts the backup file using PGP and the configured passphrase.
+// encryptArchive encrypts the backup file using PGP and the configured passphrase.
 // In case no passphrase is given it returns early, leaving the backup file
 // untouched.
-func (s *script) encryptBackup() error {
+func (s *script) encryptArchive() error {
 	if s.c.GpgPassphrase == "" {
 		return nil
 	}
@@ -417,48 +524,52 @@ func (s *script) encryptBackup() error {
 	gpgFile := fmt.Sprintf("%s.gpg", s.file)
 	s.registerHook(hookLevelPlumbing, func(error) error {
 		if err := remove(gpgFile); err != nil {
-			return fmt.Errorf("encryptBackup: error removing gpg file: %w", err)
+			return fmt.Errorf("encryptArchive: error removing gpg file: %w", err)
 		}
-		s.logger.Infof("Removed GPG file `%s`.", gpgFile)
+		s.logger.Info(
+			fmt.Sprintf("Removed GPG file `%s`.", gpgFile),
+		)
 		return nil
 	})
 
 	outFile, err := os.Create(gpgFile)
-	defer outFile.Close()
 	if err != nil {
-		return fmt.Errorf("encryptBackup: error opening out file: %w", err)
+		return fmt.Errorf("encryptArchive: error opening out file: %w", err)
 	}
+	defer outFile.Close()
 
 	_, name := path.Split(s.file)
 	dst, err := openpgp.SymmetricallyEncrypt(outFile, []byte(s.c.GpgPassphrase), &openpgp.FileHints{
 		IsBinary: true,
 		FileName: name,
 	}, nil)
-	defer dst.Close()
 	if err != nil {
-		return fmt.Errorf("encryptBackup: error encrypting backup file: %w", err)
+		return fmt.Errorf("encryptArchive: error encrypting backup file: %w", err)
 	}
+	defer dst.Close()
 
 	src, err := os.Open(s.file)
 	if err != nil {
-		return fmt.Errorf("encryptBackup: error opening backup file `%s`: %w", s.file, err)
+		return fmt.Errorf("encryptArchive: error opening backup file `%s`: %w", s.file, err)
 	}
 
 	if _, err := io.Copy(dst, src); err != nil {
-		return fmt.Errorf("encryptBackup: error writing ciphertext to file: %w", err)
+		return fmt.Errorf("encryptArchive: error writing ciphertext to file: %w", err)
 	}
 
 	s.file = gpgFile
-	s.logger.Infof("Encrypted backup using given passphrase, saving as `%s`.", s.file)
+	s.logger.Info(
+		fmt.Sprintf("Encrypted backup using given passphrase, saving as `%s`.", s.file),
+	)
 	return nil
 }
 
-// copyBackup makes sure the backup file is copied to both local and remote locations
+// copyArchive makes sure the backup file is copied to both local and remote locations
 // as per the given configuration.
-func (s *script) copyBackup() error {
+func (s *script) copyArchive() error {
 	_, name := path.Split(s.file)
 	if stat, err := os.Stat(s.file); err != nil {
-		return fmt.Errorf("copyBackup: unable to stat backup file: %w", err)
+		return fmt.Errorf("copyArchive: unable to stat backup file: %w", err)
 	} else {
 		size := stat.Size()
 		s.stats.BackupFile = BackupFileStats{
@@ -468,45 +579,17 @@ func (s *script) copyBackup() error {
 		}
 	}
 
-	if s.minioClient != nil {
-		if _, err := s.minioClient.FPutObject(context.Background(), s.c.AwsS3BucketName, filepath.Join(s.c.AwsS3Path, name), s.file, minio.PutObjectOptions{
-			ContentType: "application/tar+gzip",
-		}); err != nil {
-			return fmt.Errorf("copyBackup: error uploading backup to remote storage: %w", err)
-		}
-		s.logger.Infof("Uploaded a copy of backup `%s` to bucket `%s`.", s.file, s.c.AwsS3BucketName)
+	eg := errgroup.Group{}
+	for _, backend := range s.storages {
+		b := backend
+		eg.Go(func() error {
+			return b.Copy(s.file)
+		})
+	}
+	if err := eg.Wait(); err != nil {
+		return fmt.Errorf("copyArchive: error copying archive: %w", err)
 	}
 
-	if s.webdavClient != nil {
-		bytes, err := os.ReadFile(s.file)
-		if err != nil {
-			return fmt.Errorf("copyBackup: error reading the file to be uploaded: %w", err)
-		}
-		if err := s.webdavClient.MkdirAll(s.c.WebdavPath, 0644); err != nil {
-			return fmt.Errorf("copyBackup: error creating directory '%s' on WebDAV server: %w", s.c.WebdavPath, err)
-		}
-		if err := s.webdavClient.Write(filepath.Join(s.c.WebdavPath, name), bytes, 0644); err != nil {
-			return fmt.Errorf("copyBackup: error uploading the file to WebDAV server: %w", err)
-		}
-		s.logger.Infof("Uploaded a copy of backup `%s` to WebDAV-URL '%s' at path '%s'.", s.file, s.c.WebdavUrl, s.c.WebdavPath)
-	}
-
-	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
-		if err := copyFile(s.file, path.Join(s.c.BackupArchive, name)); err != nil {
-			return fmt.Errorf("copyBackup: error copying file to local archive: %w", err)
-		}
-		s.logger.Infof("Stored copy of backup `%s` in local archive `%s`.", s.file, s.c.BackupArchive)
-		if s.c.BackupLatestSymlink != "" {
-			symlink := path.Join(s.c.BackupArchive, s.c.BackupLatestSymlink)
-			if _, err := os.Lstat(symlink); err == nil {
-				os.Remove(symlink)
-			}
-			if err := os.Symlink(name, symlink); err != nil {
-				return fmt.Errorf("copyBackup: error creating latest symlink: %w", err)
-			}
-			s.logger.Infof("Created/Updated symlink `%s` for latest backup.", s.c.BackupLatestSymlink)
-		}
-	}
 	return nil
 }
 
@@ -520,177 +603,34 @@ func (s *script) pruneBackups() error {
 
 	deadline := time.Now().AddDate(0, 0, -int(s.c.BackupRetentionDays)).Add(s.c.BackupPruningLeeway)
 
-	// doPrune holds general control flow that applies to any kind of storage.
-	// Callers can pass in a thunk that performs the actual deletion of files.
-	var doPrune = func(lenMatches, lenCandidates int, description string, doRemoveFiles func() error) error {
-		if lenMatches != 0 && lenMatches != lenCandidates {
-			if err := doRemoveFiles(); err != nil {
+	eg := errgroup.Group{}
+	for _, backend := range s.storages {
+		b := backend
+		eg.Go(func() error {
+			if skipPrune(b.Name(), s.c.BackupSkipBackendsFromPrune) {
+				s.logger.Info(
+					fmt.Sprintf("Skipping pruning for backend `%s`.", b.Name()),
+				)
+				return nil
+			}
+			stats, err := b.Prune(deadline, s.c.BackupPruningPrefix)
+			if err != nil {
 				return err
 			}
-			s.logger.Infof(
-				"Pruned %d out of %d %s as their age exceeded the configured retention period of %d days.",
-				lenMatches,
-				lenCandidates,
-				description,
-				s.c.BackupRetentionDays,
-			)
-		} else if lenMatches != 0 && lenMatches == lenCandidates {
-			s.logger.Warnf("The current configuration would delete all %d existing %s.", lenMatches, description)
-			s.logger.Warn("Refusing to do so, please check your configuration.")
-		} else {
-			s.logger.Infof("None of %d existing %s were pruned.", lenCandidates, description)
-		}
-		return nil
-	}
-
-	if s.minioClient != nil {
-		candidates := s.minioClient.ListObjects(context.Background(), s.c.AwsS3BucketName, minio.ListObjectsOptions{
-			WithMetadata: true,
-			Prefix:       filepath.Join(s.c.AwsS3Path, s.c.BackupPruningPrefix),
-			Recursive:    true,
-		})
-
-		var matches []minio.ObjectInfo
-		var lenCandidates int
-		for candidate := range candidates {
-			lenCandidates++
-			if candidate.Err != nil {
-				return fmt.Errorf(
-					"pruneBackups: error looking up candidates from remote storage: %w",
-					candidate.Err,
-				)
-			}
-			if candidate.LastModified.Before(deadline) {
-				matches = append(matches, candidate)
-			}
-		}
-
-		s.stats.Storages.S3 = StorageStats{
-			Total:  uint(lenCandidates),
-			Pruned: uint(len(matches)),
-		}
-
-		doPrune(len(matches), lenCandidates, "remote backup(s)", func() error {
-			objectsCh := make(chan minio.ObjectInfo)
-			go func() {
-				for _, match := range matches {
-					objectsCh <- match
-				}
-				close(objectsCh)
-			}()
-			errChan := s.minioClient.RemoveObjects(context.Background(), s.c.AwsS3BucketName, objectsCh, minio.RemoveObjectsOptions{})
-			var removeErrors []error
-			for result := range errChan {
-				if result.Err != nil {
-					removeErrors = append(removeErrors, result.Err)
-				}
-			}
-			if len(removeErrors) != 0 {
-				return join(removeErrors...)
+			s.stats.Lock()
+			s.stats.Storages[b.Name()] = StorageStats{
+				Total:  stats.Total,
+				Pruned: stats.Pruned,
 			}
+			s.stats.Unlock()
 			return nil
 		})
 	}
 
-	if s.webdavClient != nil {
-		candidates, err := s.webdavClient.ReadDir(s.c.WebdavPath)
-		if err != nil {
-			return fmt.Errorf("pruneBackups: error looking up candidates from remote storage: %w", err)
-		}
-		var matches []fs.FileInfo
-		var lenCandidates int
-		for _, candidate := range candidates {
-			if !strings.HasPrefix(candidate.Name(), s.c.BackupPruningPrefix) {
-				continue
-			}
-			lenCandidates++
-			if candidate.ModTime().Before(deadline) {
-				matches = append(matches, candidate)
-			}
-		}
-
-		s.stats.Storages.WebDAV = StorageStats{
-			Total:  uint(lenCandidates),
-			Pruned: uint(len(matches)),
-		}
-
-		doPrune(len(matches), lenCandidates, "WebDAV backup(s)", func() error {
-			for _, match := range matches {
-				if err := s.webdavClient.Remove(filepath.Join(s.c.WebdavPath, match.Name())); err != nil {
-					return fmt.Errorf("pruneBackups: error removing file from WebDAV storage: %w", err)
-				}
-			}
-			return nil
-		})
+	if err := eg.Wait(); err != nil {
+		return fmt.Errorf("pruneBackups: error pruning backups: %w", err)
 	}
 
-	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
-		globPattern := path.Join(
-			s.c.BackupArchive,
-			fmt.Sprintf("%s*", s.c.BackupPruningPrefix),
-		)
-		globMatches, err := filepath.Glob(globPattern)
-		if err != nil {
-			return fmt.Errorf(
-				"pruneBackups: error looking up matching files using pattern %s: %w",
-				globPattern,
-				err,
-			)
-		}
-
-		var candidates []string
-		for _, candidate := range globMatches {
-			fi, err := os.Lstat(candidate)
-			if err != nil {
-				return fmt.Errorf(
-					"pruneBackups: error calling Lstat on file %s: %w",
-					candidate,
-					err,
-				)
-			}
-
-			if fi.Mode()&os.ModeSymlink != os.ModeSymlink {
-				candidates = append(candidates, candidate)
-			}
-		}
-
-		var matches []string
-		for _, candidate := range candidates {
-			fi, err := os.Stat(candidate)
-			if err != nil {
-				return fmt.Errorf(
-					"pruneBackups: error calling stat on file %s: %w",
-					candidate,
-					err,
-				)
-			}
-			if fi.ModTime().Before(deadline) {
-				matches = append(matches, candidate)
-			}
-		}
-
-		s.stats.Storages.Local = StorageStats{
-			Total:  uint(len(candidates)),
-			Pruned: uint(len(matches)),
-		}
-
-		doPrune(len(matches), len(candidates), "local backup(s)", func() error {
-			var removeErrors []error
-			for _, match := range matches {
-				if err := os.Remove(match); err != nil {
-					removeErrors = append(removeErrors, err)
-				}
-			}
-			if len(removeErrors) != 0 {
-				return fmt.Errorf(
-					"pruneBackups: %d error(s) deleting local files, starting with: %w",
-					len(removeErrors),
-					join(removeErrors...),
-				)
-			}
-			return nil
-		})
-	}
 	return nil
 }
 
@@ -698,7 +638,20 @@ func (s *script) pruneBackups() error {
 // is non-nil.
 func (s *script) must(err error) {
 	if err != nil {
-		s.logger.Errorf("Fatal error running backup: %s", err)
+		s.logger.Error(
+			fmt.Sprintf("Fatal error running backup: %s", err),
+		)
 		panic(err)
 	}
 }
+
+// skipPrune returns true if the given backend name is contained in the
+// list of skipped backends.
+func skipPrune(name string, skippedBackends []string) bool {
+	return slices.ContainsFunc(
+		skippedBackends,
+		func(b string) bool {
+			return strings.EqualFold(b, name) // ignore case on both sides
+		},
+	)
+}

cmd/backup/stats.go

@@ -5,6 +5,7 @@ package main
 
 import (
 	"bytes"
+	"sync"
 	"time"
 )
 
@@ -30,15 +31,9 @@ type StorageStats struct {
 	PruneErrors uint
 }
 
-// StoragesStats stats about each possible archival location (Local, WebDAV, S3)
-type StoragesStats struct {
-	Local  StorageStats
-	WebDAV StorageStats
-	S3     StorageStats
-}
-
 // Stats global stats regarding script execution
 type Stats struct {
+	sync.Mutex
 	StartTime  time.Time
 	EndTime    time.Time
 	TookTime   time.Duration
@@ -46,5 +41,5 @@ type Stats struct {
 	LogOutput  *bytes.Buffer
 	Containers ContainersStats
 	BackupFile BackupFileStats
-	Storages   StoragesStats
+	Storages   map[string]StorageStats
 }

cmd/backup/util.go

@@ -5,51 +5,13 @@ package main
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"io"
 	"os"
-	"strings"
 )
 
 var noop = func() error { return nil }
 
-// copy creates a copy of the file located at `dst` at `src`.
-func copyFile(src, dst string) error {
-	in, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	defer in.Close()
-
-	out, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-
-	_, err = io.Copy(out, in)
-	if err != nil {
-		out.Close()
-		return err
-	}
-	return out.Close()
-}
-
-// join takes a list of errors and joins them into a single error
-func join(errs ...error) error {
-	if len(errs) == 1 {
-		return errs[0]
-	}
-	var msgs []string
-	for _, err := range errs {
-		if err == nil {
-			continue
-		}
-		msgs = append(msgs, err.Error())
-	}
-	return errors.New("[" + strings.Join(msgs, ", ") + "]")
-}
-
 // remove removes the given file or directory from disk.
 func remove(location string) error {
 	fi, err := os.Lstat(location)
@@ -84,7 +46,7 @@ type bufferingWriter struct {
 
 func (b *bufferingWriter) Write(p []byte) (n int, err error) {
 	if n, err := b.buf.Write(p); err != nil {
-		return n, fmt.Errorf("bufferingWriter: error writing to buffer: %w", err)
+		return n, fmt.Errorf("(*bufferingWriter).Write: error writing to buffer: %w", err)
 	}
 	return b.writer.Write(p)
 }

docs/.gitignore

@@ -0,0 +1,2 @@
+_site
+.jekyll-cache

docs/Gemfile

@@ -0,0 +1,4 @@
+source 'https://rubygems.org'
+
+gem "jekyll", "~> 4.3.2"
+gem "just-the-docs", "0.6.1"

docs/Gemfile.lock

@@ -0,0 +1,80 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    addressable (2.8.5)
+      public_suffix (>= 2.0.2, < 6.0)
+    colorator (1.1.0)
+    concurrent-ruby (1.2.2)
+    em-websocket (0.5.3)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0)
+    eventmachine (1.2.7)
+    ffi (1.15.5)
+    forwardable-extended (2.6.0)
+    http_parser.rb (0.8.0)
+    i18n (1.14.1)
+      concurrent-ruby (~> 1.0)
+    jekyll (4.3.2)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      em-websocket (~> 0.5)
+      i18n (~> 1.0)
+      jekyll-sass-converter (>= 2.0, < 4.0)
+      jekyll-watch (~> 2.0)
+      kramdown (~> 2.3, >= 2.3.1)
+      kramdown-parser-gfm (~> 1.0)
+      liquid (~> 4.0)
+      mercenary (>= 0.3.6, < 0.5)
+      pathutil (~> 0.9)
+      rouge (>= 3.0, < 5.0)
+      safe_yaml (~> 1.0)
+      terminal-table (>= 1.8, < 4.0)
+      webrick (~> 1.7)
+    jekyll-include-cache (0.2.1)
+      jekyll (>= 3.7, < 5.0)
+    jekyll-sass-converter (2.2.0)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-seo-tag (2.8.0)
+      jekyll (>= 3.8, < 5.0)
+    jekyll-watch (2.2.1)
+      listen (~> 3.0)
+    just-the-docs (0.6.1)
+      jekyll (>= 3.8.5)
+      jekyll-include-cache
+      jekyll-seo-tag (>= 2.0)
+      rake (>= 12.3.1)
+    kramdown (2.4.0)
+      rexml
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
+    liquid (4.0.4)
+    listen (3.8.0)
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
+    mercenary (0.4.0)
+    pathutil (0.16.2)
+      forwardable-extended (~> 2.6)
+    public_suffix (4.0.7)
+    rake (13.0.6)
+    rb-fsevent (0.11.2)
+    rb-inotify (0.10.1)
+      ffi (~> 1.0)
+    rexml (3.2.6)
+    rouge (3.30.0)
+    safe_yaml (1.0.5)
+    sassc (2.4.0)
+      ffi (~> 1.9)
+    terminal-table (3.0.2)
+      unicode-display_width (>= 1.1.1, < 3)
+    unicode-display_width (2.4.2)
+    webrick (1.8.1)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  jekyll (~> 4.3.2)
+  just-the-docs (= 0.6.1)
+
+BUNDLED WITH
+   2.1.4

docs/NOTIFICATION-TEMPLATES.md

@@ -1,39 +0,0 @@
-# Notification templates reference
-
-In order to customize title and body of notifications you'll have to write a [go template](https://pkg.go.dev/text/template) and mount it inside the `/etc/dockervolumebackup/notifications.d/` directory.
-
-Configuration, data about the backup run and helper functions will be passed to this template, this page documents them fully.
-
-## Data
-Here is a list of all data passed to the template:
-
-* `Config`: this object holds the configuration that has been passed to the script. The field names are the name of the recognized environment variables converted in PascalCase. (e.g. `BACKUP_STOP_CONTAINER_LABEL` becomes `BackupStopContainerLabel`)
-* `Error`: the error that made the backup fail. Only available in the `title_failure` and `body_failure` templates
-* `Stats`: objects that holds stats regarding script execution. In case of an unsuccessful run, some information may not be available.
-  * `StartTime`: time when the script started execution
-  * `EndTime`: time when the backup has completed successfully (after pruning)
-  * `TookTime`: amount of time it took for the backup to run. (equal to `EndTime - StartTime`)
-  * `LockedTime`: amount of time it took for the backup to acquire the exclusive lock
-  * `LogOutput`: full log of the application
-  * `Containers`: object containing stats about the docker containers
-    * `All`: total number of containers
-    * `ToStop`: number of containers matched by the stop rule
-    * `Stopped`: number of containers successfully stopped
-    * `StopErrors`: number of containers that were unable to be stopped (equal to `ToStop - Stopped`)
-  * `BackupFile`: object containing information about the backup file
-    * `Name`: name of the backup file (e.g. `backup-2022-02-11T01-00-00.tar.gz`)
-    * `FullPath`: full path of the backup file (e.g. `/archive/backup-2022-02-11T01-00-00.tar.gz`)
-    * `Size`: size in bytes of the backup file
-  * `Storages`: object that holds stats about each storage
-    * `Local`, `S3` or `WebDAV`:
-      * `Total`: total number of backup files
-      * `Pruned`: number of backup files that were deleted due to pruning rule
-      * `PruneErrors`: number of backup files that were unable to be pruned
-
-## Functions
-
-Some formatting functions are also available:
-
-* `formatTime`: formats a time object using [RFC3339](https://datatracker.ietf.org/doc/html/rfc3339) format (e.g. `2022-02-11T01:00:00Z`)
-* `formatBytesBin`: formats an amount of bytes using powers of 1024 (e.g. `7055258` bytes will be `6.7 MiB`) 
-* `formatBytesDec`: formats an amount of bytes using powers of 1000 (e.g. `7055258` bytes will be `7.1 MB`)

docs/README.md

@@ -0,0 +1,14 @@
+# Documentation site
+
+This directory contains the sources for the documentation site published at <https://offen.github.io/docker-volume-backup>.
+
+Assuming you have Ruby and [`bundler`][bundler] installed, you can run the site locally using the following commands:
+
+```
+bundle install
+bundle exec jekyll serve
+```
+
+Note that changes in `_config.yml` require a manual restart to take effect.
+
+[bundler]: https://bundler.io/

docs/_config.yml

@@ -0,0 +1,35 @@
+title: docker-volume-backup
+description: Documentation for the offen/docker-volume-backup Docker image.
+theme: just-the-docs
+
+url: https://offen.github.io/docker-volume-backup/
+
+callouts_level: quiet
+callouts:
+  highlight:
+    color: yellow
+  important:
+    title: Important
+    color: blue
+  new:
+    title: New
+    color: green
+  note:
+    title: Note
+    color: purple
+  warning:
+    title: Warning
+    color: red
+
+aux_links:
+  'GitHub Repository':
+    - https://github.com/offen/docker-volume-backup
+
+nav_external_links:
+  - title: GitHub Repository
+    url: https://github.com/offen/docker-volume-backup
+
+footer_content: >-
+  Copyright © 2021 Offen Authors and contributors.
+  Distributed under the <a href="https://github.com/offen/docker-volume-backup/tree/main/LICENSE">MPL-2.0 License.</a><br>
+  Something missing, unclear or not working? Open <a href="https://github.com/offen/docker-volume-backup/issues">an issue</a>.

docs/_sass/custom/custom.scss

@@ -0,0 +1,7 @@
+.site-title {
+  font-size: unset !important;
+}
+
+.main-content pre {
+  font-size: 1.1em;
+}

docs/how-tos/automatically-prune-old-backups.md

@@ -0,0 +1,34 @@
+---
+title: Automatically prune old backups
+layout: default
+parent: How Tos
+nav_order: 3
+---
+
+# Automatically prune old backups
+
+When `BACKUP_RETENTION_DAYS` is configured, the command will check if there are any archives in the remote storage backend(s) or local archive that are older than the given retention value and rotate these backups away.
+
+{: .note }
+Be aware that this mechanism looks at __all files in the target bucket or archive__, which means that other files that are older than the given deadline are deleted as well.
+In case you need to use a target that cannot be used exclusively for your backups, you can configure `BACKUP_PRUNING_PREFIX` to limit which files are considered eligible for deletion:
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
+      BACKUP_PRUNING_PREFIX: backup-
+      BACKUP_RETENTION_DAYS: '7'
+    volumes:
+      - ${HOME}/backups:/archive
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```

docs/how-tos/define-different-retention-schedules.md

@@ -0,0 +1,40 @@
+---
+title: Define different retention schedules
+layout: default
+parent: How Tos
+nav_order: 9
+---
+
+# Define different retention schedules
+
+If you want to manage backup retention on different schedules, the most straight forward approach is to define a dedicated configuration for retention rule using a different prefix in the `BACKUP_FILENAME` parameter and then run them on different cron schedules.
+
+For example, if you wanted to keep daily backups for 7 days, weekly backups for a month, and retain monthly backups forever, you could create three configuration files and mount them into `/etc/dockervolumebackup/conf.d`:
+
+```ini
+# 01daily.conf
+BACKUP_FILENAME="daily-backup-%Y-%m-%dT%H-%M-%S.tar.gz"
+# run every day at 2am
+BACKUP_CRON_EXPRESSION="0 2 * * *"
+BACKUP_PRUNING_PREFIX="daily-backup-"
+BACKUP_RETENTION_DAYS="7"
+```
+
+```ini
+# 02weekly.conf
+BACKUP_FILENAME="weekly-backup-%Y-%m-%dT%H-%M-%S.tar.gz"
+# run every monday at 3am
+BACKUP_CRON_EXPRESSION="0 3 * * 1"
+BACKUP_PRUNING_PREFIX="weekly-backup-"
+BACKUP_RETENTION_DAYS="31"
+```
+
+```ini
+# 03monthly.conf
+BACKUP_FILENAME="monthly-backup-%Y-%m-%dT%H-%M-%S.tar.gz"
+# run every 1st of a month at 4am
+BACKUP_CRON_EXPRESSION="0 4 1 * *"
+```
+
+{: .note }
+While it's possible to define colliding cron schedules for each of these configurations, you might need to adjust the value for `LOCK_TIMEOUT` in case your backups are large and might take longer than an hour.

docs/how-tos/encrypt-backups-using-gpg.md

@@ -0,0 +1,17 @@
+---
+title: Encrypt backups using GPG
+layout: default
+parent: How Tos
+nav_order: 7
+---
+
+# Encrypt backups using GPG
+
+The image supports encrypting backups using GPG out of the box.
+In case a `GPG_PASSPHRASE` environment variable is set, the backup archive will be encrypted using the given key and saved as a `.gpg` file instead.
+
+Assuming you have `gpg` installed, you can decrypt such a backup using (your OS will prompt for the passphrase before decryption can happen):
+
+```console
+gpg -o backup.tar.gz -d backup.tar.gz.gpg
+```

docs/how-tos/handle-file-uploads-using-third-party-tools.md

@@ -0,0 +1,44 @@
+---
+title: Handle file uploads using third party tools
+layout: default
+parent: How Tos
+nav_order: 10
+---
+
+# Handle file uploads using third party tools
+
+If you want to use an unsupported storage backend, or want to use a third party (e.g. rsync, rclone) tool for file uploads, you can build a Docker image containing the required binaries off this one, and call through to these in lifecycle hooks.
+
+For example, if you wanted to use `rsync`, define your Docker image like this:
+
+```Dockerfile
+FROM offen/docker-volume-backup:v2
+
+RUN apk add rsync
+```
+
+Using this image, you can now omit configuring any of the supported storage backends, and instead define your own mechanism in a `docker-volume-backup.copy-post` label:
+
+```yml
+version: '3'
+
+services:
+  backup:
+    image: your-custom-image
+    restart: always
+    environment:
+      BACKUP_FILENAME: "daily-backup-%Y-%m-%dT%H-%M-%S.tar.gz"
+      BACKUP_CRON_EXPRESSION: "0 2 * * *"
+    labels:
+      - docker-volume-backup.copy-post=/bin/sh -c 'rsync $$COMMAND_RUNTIME_ARCHIVE_FILEPATH /destination'
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+  # other services defined here ...
+volumes:
+  app_data:
+```
+
+{: .note }
+Commands will be invoked with the filepath of the tar archive passed as `COMMAND_RUNTIME_BACKUP_FILEPATH`.

docs/how-tos/index.md

@@ -0,0 +1,8 @@
+---
+title: How Tos
+layout: default
+nav_order: 3
+has_children: true
+---
+
+## How Tos

docs/how-tos/manual-trigger.md

@@ -0,0 +1,20 @@
+---
+title: Trigger a backup manually
+layout: default
+parent: How Tos
+nav_order: 8
+---
+
+# Trigger a backup manually
+
+You can manually trigger a backup run outside of the defined cron schedule by executing the `backup` command inside the container:
+
+```console
+docker exec <container_ref> backup
+```
+
+If the container is configured to run multiple schedules, you can source the respective conf file before invoking the command:
+
+```console
+docker exec <container_ref> /bin/sh -c 'set -a; source /etc/dockervolumebackup/conf.d/myconf.env; set +a && backup'
+```

docs/how-tos/replace-deprecated-backup-from-snapshot.md

@@ -0,0 +1,37 @@
+---
+title: Replace deprecated BACKUP_FROM_SNAPSHOT usage
+layout: default
+parent: How Tos
+nav_order: 16
+---
+
+# Replace deprecated `BACKUP_FROM_SNAPSHOT` usage
+
+Starting with version 2.15.0, the `BACKUP_FROM_SNAPSHOT` feature has been deprecated.
+If you need to prepare your sources before the backup is taken, use `archive-pre`, `archive-post` and an intermediate volume:
+
+```yml
+version: '3'
+
+services:
+  my_app:
+    build: .
+    volumes:
+      - data:/var/my_app
+      - backup:/tmp/backup
+    labels:
+      - docker-volume-backup.archive-pre=cp -r /var/my_app /tmp/backup/my-app
+      - docker-volume-backup.archive-post=rm -rf /tmp/backup/my-app
+
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      BACKUP_SOURCES: /tmp/backup
+    volumes:
+      - backup:/backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+  backup:
+```

docs/how-tos/replace-deprecated-exec-labels.md

@@ -0,0 +1,23 @@
+---
+title: Replace deprecated exec-pre and exec-post labels
+layout: default
+parent: How Tos
+nav_order: 17
+---
+
+# Replace deprecated `exec-pre` and `exec-post` labels
+
+Version 2.19.0 introduced the option to run labeled commands at multiple points in time during the backup lifecycle.
+In order to be able to use more obvious terminology in the new labels, the existing `exec-pre` and `exec-post` labels have been deprecated.
+If you want to emulate the existing behavior, all you need to do is change `exec-pre` to `archive-pre` and `exec-post` to `archive-post`:
+
+```diff
+    labels:
+-     - docker-volume-backup.exec-pre=cp -r /var/my_app /tmp/backup/my-app
++     - docker-volume-backup.archive-pre=cp -r /var/my_app /tmp/backup/my-app
+-     - docker-volume-backup.exec-post=rm -rf /tmp/backup/my-app
++     - docker-volume-backup.archive-post=rm -rf /tmp/backup/my-app
+```
+
+The `EXEC_LABEL` setting and the `docker-volume-backup.exec-label` label stay as is.
+Check the additional documentation on running commands during the backup lifecycle to find out about further possibilities.

docs/how-tos/restore-volumes-from-backup.md

@@ -0,0 +1,46 @@
+---
+title: Restore volumes from a backup
+layout: default
+parent: How Tos
+nav_order: 6
+---
+
+# Restore volumes from a backup
+
+In case you need to restore a volume from a backup, the most straight forward procedure to do so would be:
+
+- Stop the container(s) that are using the volume
+- Untar the backup you want to restore
+  ```console
+  tar -C /tmp -xvf  backup.tar.gz
+  ```
+- Using a temporary once-off container, mount the volume (the example assumes it's named `data`) and copy over the backup. Make sure you copy the correct path level (this depends on how you mount your volume into the backup container), you might need to strip some leading elements
+  ```console
+  docker run -d --name temp_restore_container -v data:/backup_restore alpine
+  docker cp /tmp/backup/data-backup temp_restore_container:/backup_restore
+  docker stop temp_restore_container
+  docker rm temp_restore_container
+  ```
+- Restart the container(s) that are using the volume
+
+Depending on your setup and the application(s) you are running, this might involve other steps to be taken still.
+
+---
+
+If you want to rollback an entire volume to an earlier backup snapshot (recommended for database volumes):
+
+- Trigger a manual backup if necessary (see `Manually triggering a backup`).
+- Stop the container(s) that are using the volume.
+- If volume was initially created using docker-compose, find out exact volume name using:
+  ```console
+  docker volume ls
+  ```
+- Remove existing volume (the example assumes it's named `data`):
+  ```console
+  docker volume rm data
+  ```
+- Create new volume with the same name and restore a snapshot:
+  ```console
+  docker run --rm -it -v data:/backup/my-app-backup -v /path/to/local_backups:/archive:ro alpine tar -xvzf /archive/full_backup_filename.tar.gz
+  ```
+- Restart the container(s) that are using the volume.

docs/how-tos/run-custom-commands.md

@@ -0,0 +1,93 @@
+---
+title: Run custom commands during the backup lifecycle
+layout: default
+nav_order: 5
+parent: How Tos
+---
+
+# Run custom commands during the backup lifecycle
+
+In certain scenarios it can be required to run specific commands before and after a backup is taken (e.g. dumping a database).
+When mounting the Docker socket into the `docker-volume-backup` container, you can define pre- and post-commands that will be run in the context of the target container (it is also possible to run commands inside the `docker-volume-backup` container itself using this feature).
+Such commands are defined by specifying the command in a `docker-volume-backup.[step]-[pre|post]` label where `step` can be any of the following phases of a backup lifecycle:
+
+- `archive` (the tar archive is created)
+- `process` (the tar archive is processed, e.g. encrypted - optional)
+- `copy` (the tar archive is copied to all configured storages)
+- `prune` (existing backups are pruned based on the defined ruleset - optional)
+
+{: .note }
+So that the `docker-volume-backup` container can access the labels on other containers, it is necessary that the docker socket is mounted into
+the `docker-volume-backup` container as shown in the Quickstart example.
+
+Taking a database dump using `mysqldump` would look like this:
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  database:
+    image: mariadb
+    volumes:
+      - backup_data:/tmp/backups
+    labels:
+      - docker-volume-backup.archive-pre=/bin/sh -c 'mysqldump --all-databases > /backups/dump.sql'
+
+volumes:
+  backup_data:
+```
+
+{: .note }
+Due to Docker limitations, you currently cannot use any kind of redirection in these commands unless you pass the command to `/bin/sh -c` or similar.
+I.e. instead of using `echo "ok" > ok.txt` you will need to use `/bin/sh -c 'echo "ok" > ok.txt'`.
+
+If you have more than one `docker-volume-backup` container (possibly across several docker-compose environments) to backup or you are using
+multiple backup schedules, you will need to use `EXEC_LABEL` in the configuration and a `docker-volume-backup.exec-label` label on each
+container using custom commands to ensure that the commands are only run by the correct `docker-volume-backup` instance.
+
+```yml
+version: '3'
+
+services:
+  database:
+    image: mariadb
+    volumes:
+      - backup_data:/tmp/backups
+    labels:
+      - docker-volume-backup.archive-pre=/bin/sh -c 'mysqldump --all-databases > /tmp/volume/dump.sql'
+      - docker-volume-backup.exec-label=database
+
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      EXEC_LABEL: database
+    volumes:
+      - data:/backup/dump:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  backup_data:
+```
+
+
+The backup procedure is guaranteed to wait for all `pre` or `post` commands to finish before proceeding.
+However, there are no guarantees about the order in which they are run, which could also happen concurrently.
+
+By default the backup command is executed by the user provided by the container's image.
+It is possible to specify a custom user that is used to run commands in dedicated labels with the format `docker-volume-backup.[step]-[pre|post].user`:
+
+```yml
+version: '3'
+
+services:
+  gitea:
+    image: gitea/gitea
+    volumes:
+      - backup_data:/tmp
+    labels:
+      - docker-volume-backup.archive-pre.user=git
+      - docker-volume-backup.archive-pre=/bin/bash -c 'cd /tmp; /usr/local/bin/gitea dump -c /data/gitea/conf/app.ini -R -f dump.zip'
+```
+
+Make sure the user exists and is present in `passwd` inside the target container.

docs/how-tos/run-multiple-schedules.md

@@ -0,0 +1,52 @@
+---
+title: Run multiple backup schedules in the same container
+layout: default
+parent: How Tos
+nav_order: 11
+---
+
+# Run multiple backup schedules in the same container
+
+Multiple backup schedules with different configuration can be configured by mounting an arbitrary number of configuration files (using the `.env` format) into `/etc/dockervolumebackup/conf.d`:
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ./configuration:/etc/dockervolumebackup/conf.d
+
+volumes:
+  data:
+```
+
+A separate cronjob will be created for each config file.
+If a configuration value is set both in the global environment as well as in the config file, the config file will take precedence.
+The `backup` command expects to run on an exclusive lock, so in case you provide the same or overlapping schedules in your cron expressions, the runs will still be executed serially, one after the other.
+The exact order of schedules that use the same cron expression is not specified.
+In case you need your schedules to overlap, you need to create a dedicated container for each schedule instead.
+When changing the configuration, you currently need to manually restart the container for the changes to take effect.
+
+Set `BACKUP_SOURCES` for each config file to control which subset of volume mounts gets backed up:
+
+```yml
+# With a volume configuration like this:
+volumes:
+  - /var/run/docker.sock:/var/run/docker.sock:ro
+  - ./configuration:/etc/dockervolumebackup/conf.d
+  - app1_data:/backup/app1_data:ro
+  - app2_data:/backup/app2_data:ro
+```
+
+```ini
+# In the 1st config file:
+BACKUP_SOURCES=/backup/app1_data
+
+# In the 2nd config file:
+BACKUP_SOURCES=/backup/app2_data
+```

docs/how-tos/set-container-timezone.md

@@ -0,0 +1,27 @@
+---
+title: Set the timezone the container runs in
+layout: default
+parent: How Tos
+nav_order: 8
+---
+
+# Set the timezone the container runs in
+
+By default a container based on this image will run in the UTC timezone.
+As the image is designed to be as small as possible, additional timezone data is not included.
+In case you want to run your cron rules in your local timezone (respecting DST and similar), you can mount your Docker host's `/etc/timezone` and `/etc/localtime` in read-only mode:
+
+```yml
+version: '3'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:v2
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /etc/timezone:/etc/timezone:ro
+      - /etc/localtime:/etc/localtime:ro
+
+volumes:
+  data:
+```

docs/how-tos/set-up-drobox.md

@@ -0,0 +1,37 @@
+---
+title: Set up Dropbox storage backend
+layout: default
+parent: How Tos
+nav_order: 12
+---
+
+# Set up Dropbox storage backend
+
+## Acquiring authentication tokens
+
+1. Create a new Dropbox App in the [App Console](https://www.dropbox.com/developers/apps)
+2. Open your new Dropbox App and set `DROPBOX_APP_KEY` and `DROPBOX_APP_SECRET` in your environment (e.g. docker-compose.yml) accordingly
+3. Click on `Permissions` in your app and make sure, that the following permissions are cranted (or more):
+  - `files.metadata.write`
+  - `files.metadata.read`
+  - `files.content.write`
+  - `files.content.read`
+4. Replace APPKEY in `https://www.dropbox.com/oauth2/authorize?client_id=APPKEY&token_access_type=offline&response_type=code` with the app key from step 2
+5. Visit the URL and confirm the access of your app. This gives you an `auth code` -> save it somewhere!
+6. Replace AUTHCODE, APPKEY, APPSECRET accordingly and perform the request:
+```
+curl https://api.dropbox.com/oauth2/token \
+    -d code=AUTHCODE \
+    -d grant_type=authorization_code \
+    -d client_id=APPKEY \
+    -d client_secret=APPSECRET
+```
+7. Execute the request. You will get a JSON formatted reply. Use the value of the `refresh_token` for the last environment variable `DROPBOX_REFRESH_TOKEN`
+8. You should now have `DROPBOX_APP_KEY`, `DROPBOX_APP_SECRET` and `DROPBOX_REFRESH_TOKEN` set. These don't expire.
+
+Note: Using the "Generated access token" in the app console is not supported, as it is only very short lived and therefore not suitable for an automatic backup solution. The refresh token handles this automatically - the setup procedure above is only needed once.
+
+## Other parameters
+
+Important: If you chose `App folder` access during the creation of your Dropbox app in step 1 above, you can only write in the app's directory!
+This means, that `DROPBOX_REMOTE_PATH` must start with e.g. `/Apps/YOUR_APP_NAME` or `/Apps/YOUR_APP_NAME/some_sub_dir`

docs/how-tos/set-up-notifications.md

@@ -0,0 +1,125 @@
+---
+title: Receive notifications
+layout: default
+nav_order: 4
+parent: How Tos
+---
+
+# Receive notifications
+
+## Send email notifications on failed backup runs
+
+To send out email notifications on failed backup runs, provide SMTP credentials, a sender and a recipient:
+
+```yml
+version: '3'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      # ... other configuration values go here
+      NOTIFICATION_URLS=smtp://me:secret@smtp.example.com:587/?fromAddress=no-reply@example.com&toAddresses=you@example.com
+```
+
+Notification backends other than email are also supported.
+Refer to the documentation of [shoutrrr][shoutrrr-docs] to find out about options and configuration.
+
+[shoutrrr-docs]: https://containrrr.dev/shoutrrr/0.7/services/overview/
+
+{: .note }
+If you also want notifications on successful executions, set `NOTIFICATION_LEVEL` to `info`.
+
+## Customize notifications
+
+The title and body of the notifications can be tailored to your needs using [Go templates](https://pkg.go.dev/text/template).
+Template sources must be mounted inside the container in `/etc/dockervolumebackup/notifications.d/`: any file inside this directory will be parsed.
+
+```yml
+services:
+  backup:
+    image: offen/docker-volume-backup:v2
+    volumes:
+      - ./customized.template:/etc/dockervolumebackup/notifications.d/01.template
+```
+
+The files have to define [nested templates](https://pkg.go.dev/text/template#hdr-Nested_template_definitions) in order to override the original values. An example:
+
+{% raw %}
+```
+{{ define "title_success" -}}
+✅ Successfully ran backup {{ .Config.BackupStopContainerLabel }}
+{{- end }}
+
+{{ define "body_success" -}}
+▶️ Start time: {{ .Stats.StartTime | formatTime }}
+⏹️ End time: {{ .Stats.EndTime | formatTime }}
+⌛ Took time: {{ .Stats.TookTime }}
+🛑 Stopped containers: {{ .Stats.Containers.Stopped }}/{{ .Stats.Containers.All }} ({{ .Stats.Containers.StopErrors }} errors)
+⚖️ Backup size: {{ .Stats.BackupFile.Size | formatBytesBin }} / {{ .Stats.BackupFile.Size | formatBytesDec }}
+🗑️ Pruned backups: {{ .Stats.Storages.Local.Pruned }}/{{ .Stats.Storages.Local.Total }} ({{ .Stats.Storages.Local.PruneErrors }} errors)
+{{- end }}
+```
+{% endraw %}
+
+Template names that can be overridden are:
+  - `title_success` (the title used for a successful execution)
+  - `body_success` (the body used for a successful execution)
+  - `title_failure` (the title used for a failed execution)
+  - `body_failure` (the body used for a failed execution)
+
+## Notification templates reference
+
+Configuration, data about the backup run and helper functions will be passed to these templates, this page documents them fully.
+
+### Data
+
+Here is a list of all data passed to the template:
+
+* `Config`: this object holds the configuration that has been passed to the script. The field names are the name of the recognized environment variables converted in PascalCase. (e.g. `BACKUP_STOP_CONTAINER_LABEL` becomes `BackupStopContainerLabel`)
+* `Error`: the error that made the backup fail. Only available in the `title_failure` and `body_failure` templates
+* `Stats`: objects that holds stats regarding script execution. In case of an unsuccessful run, some information may not be available.
+  * `StartTime`: time when the script started execution
+  * `EndTime`: time when the backup has completed successfully (after pruning)
+  * `TookTime`: amount of time it took for the backup to run. (equal to `EndTime - StartTime`)
+  * `LockedTime`: amount of time it took for the backup to acquire the exclusive lock
+  * `LogOutput`: full log of the application
+  * `Containers`: object containing stats about the docker containers
+    * `All`: total number of containers
+    * `ToStop`: number of containers matched by the stop rule
+    * `Stopped`: number of containers successfully stopped
+    * `StopErrors`: number of containers that were unable to be stopped (equal to `ToStop - Stopped`)
+  * `BackupFile`: object containing information about the backup file
+    * `Name`: name of the backup file (e.g. `backup-2022-02-11T01-00-00.tar.gz`)
+    * `FullPath`: full path of the backup file (e.g. `/archive/backup-2022-02-11T01-00-00.tar.gz`)
+    * `Size`: size in bytes of the backup file
+  * `Storages`: object that holds stats about each storage
+    * `Local`, `S3`, `WebDAV`, `Azure`, `Dropbox` or `SSH`:
+      * `Total`: total number of backup files
+      * `Pruned`: number of backup files that were deleted due to pruning rule
+      * `PruneErrors`: number of backup files that were unable to be pruned
+
+### Functions
+
+Some formatting and helper functions are also available:
+
+* `formatTime`: formats a time object using [RFC3339](https://datatracker.ietf.org/doc/html/rfc3339) format (e.g. `2022-02-11T01:00:00Z`)
+* `formatBytesBin`: formats an amount of bytes using powers of 1024 (e.g. `7055258` bytes will be `6.7 MiB`) 
+* `formatBytesDec`: formats an amount of bytes using powers of 1000 (e.g. `7055258` bytes will be `7.1 MB`)
+* `env`: returns the value of the environment variable of the given key if set
+
+## Special characters in notification URLs
+
+The value given to `NOTIFICATION_URLS` is a comma separated list of URLs.
+If such a URL contains special characters (e.g. commas) these need to be URL encoded.
+To obtain an encoded version of your URL, you can use the CLI tool provided by `shoutrrr` (which is the library used for sending notifications):
+
+```
+docker run --rm -ti containrrr/shoutrrr generate [service]
+```
+
+where service is any of the [supported services][shoutrrr-docs], e.g. for SMTP:
+
+```
+docker run --rm -ti containrrr/shoutrrr generate smtp
+```

docs/how-tos/stop-containers-during-backup.md

@@ -0,0 +1,35 @@
+---
+title: Stop containers during backup
+layout: default
+parent: How Tos
+nav_order: 1
+---
+
+# Stop containers during backup
+
+In many cases, it will be desirable to stop the services that are consuming the volume you want to backup in order to ensure data integrity.
+This image can automatically stop and restart containers and services.
+By default, any container that is labeled `docker-volume-backup.stop-during-backup=true` will be stopped before the backup is being taken and restarted once it has finished.
+
+In case you need more fine grained control about which containers should be stopped (e.g. when backing up multiple volumes on different schedules), you can set the `BACKUP_STOP_CONTAINER_LABEL` environment variable and then use the same value for labeling:
+
+```yml
+version: '3'
+
+services:
+  app:
+    # definition for app ...
+    labels:
+      - docker-volume-backup.stop-during-backup=service1
+
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      BACKUP_STOP_CONTAINER_LABEL: service1
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```

docs/how-tos/update-deprecated-email-config.md

@@ -0,0 +1,26 @@
+---
+title: Update deprecated email configuration
+layout: default
+parent: How Tos
+nav_order: 18
+---
+
+# Update deprecated email configuration
+
+Starting with version 2.6.0, configuring email notifications using `EMAIL_*` keys has been deprecated.
+Instead of providing multiple values using multiple keys, you can now provide a single URL for `NOTIFICATION_URLS`.
+
+Before:
+```ini
+EMAIL_NOTIFICATION_RECIPIENT="you@example.com"
+EMAIL_NOTIFICATION_SENDER="no-reply@example.com"
+EMAIL_SMTP_HOST="posteo.de"
+EMAIL_SMTP_PASSWORD="secret"
+EMAIL_SMTP_USERNAME="me"
+EMAIL_SMTP_PORT="587"
+```
+
+After:
+```ini
+NOTIFICATION_URLS=smtp://me:secret@posteo.de:587/?fromAddress=no-reply@example.com&toAddresses=you@example.com
+```

docs/how-tos/use-custom-docker-host.md

@@ -0,0 +1,17 @@
+---
+title: Use a custom Docker host
+layout: default
+parent: How Tos
+nav_order: 14
+---
+
+# Use a custom Docker host
+
+If you are interfacing with Docker via TCP, set `DOCKER_HOST` to the correct URL.
+
+```ini
+DOCKER_HOST=tcp://docker_socket_proxy:2375
+```
+
+In case you are using a socket proxy, it must support `GET` and `POST` requests to the `/containers` endpoint. If you are using Docker Swarm, it must also support the `/services` endpoint. If you are using pre/post backup commands, it must also support the `/exec` endpoint.
+

docs/how-tos/use-rootless-docker.md

@@ -0,0 +1,23 @@
+---
+title: Use with rootless Docker
+layout: default
+parent: How Tos
+nav_order: 15
+---
+
+# Use with rootless Docker
+
+It's also possible to use this image with a [rootless Docker installation][rootless-docker].
+Instead of mounting `/var/run/docker.sock`, mount the user-specific socket into the container:
+
+```yml
+services:
+  backup:
+    image: offen/docker-volume-backup:v2
+    # ... configuration omitted
+    volumes:
+      - backup:/backup:ro
+      - /run/user/1000/docker.sock:/var/run/docker.sock:ro
+```
+
+[rootless-docker]: https://docs.docker.com/engine/security/rootless/

docs/how-tos/use-with-docker-swarm.md

@@ -0,0 +1,27 @@
+---
+title: Use with Docker Swarm
+layout: default
+parent: How Tos
+nav_order: 13
+---
+
+# Use with Docker Swarm
+
+By default, Docker Swarm will restart stopped containers automatically, even when manually stopped.
+If you plan to have your containers / services stopped during backup, this means you need to apply the `on-failure` restart policy to your service's definitions.
+A restart policy of `always` is not compatible with this tool.
+
+---
+
+When running in Swarm mode, it's also advised to set a hard memory limit on your service (~25MB should be enough in most cases, but if you backup large files above half a gigabyte or similar, you might have to raise this in case the backup exits with `Killed`):
+
+```yml
+services:
+  backup:
+    image: offen/docker-volume-backup:v2
+    deployment:
+      resources:
+        limits:
+          memory: 25M
+```
+

docs/index.md

@@ -0,0 +1,117 @@
+---
+title: Home
+layout: home
+nav_order: 1
+---
+
+# offen/docker-volume-backup
+{:.no_toc}
+
+Backup Docker volumes locally or to any S3, WebDAV, Azure Blob Storage, Dropbox or SSH compatible storage.
+{: .fs-6 .fw-300 }
+
+---
+
+The [offen/docker-volume-backup](https://hub.docker.com/r/offen/docker-volume-backup) Docker image can be used as a lightweight (below 15MB) companion container to an existing Docker setup.
+It handles __recurring or one-off backups of Docker volumes__ to a __local directory__, __any S3, WebDAV, Azure Blob Storage, Dropbox or SSH compatible storage (or any combination thereof) and rotates away old backups__ if configured. It also supports __encrypting your backups using GPG__ and __sending notifications for (failed) backup runs__.
+
+{: .note }
+Code and documentation for `v1` versions are found on [this branch][v1-branch].
+
+[v1-branch]: https://github.com/offen/docker-volume-backup/tree/v1
+
+---
+
+1. TOC
+{:toc}
+
+## Quickstart
+
+### Recurring backups in a compose setup
+
+Add a `backup` service to your compose setup and mount the volumes you would like to see backed up:
+
+```yml
+version: '3'
+
+services:
+  volume-consumer:
+    build:
+      context: ./my-app
+    volumes:
+      - data:/var/my-app
+    labels:
+      # This means the container will be stopped during backup to ensure
+      # backup integrity. You can omit this label if stopping during backup
+      # not required.
+      - docker-volume-backup.stop-during-backup=true
+
+  backup:
+    # In production, it is advised to lock your image tag to a proper
+    # release version instead of using `latest`.
+    # Check https://github.com/offen/docker-volume-backup/releases
+    # for a list of available releases.
+    image: offen/docker-volume-backup:latest
+    restart: always
+    env_file: ./backup.env # see below for configuration reference
+    volumes:
+      - data:/backup/my-app-backup:ro
+      # Mounting the Docker socket allows the script to stop and restart
+      # the container during backup and to access the container labels to
+      # specify custom commands. You can omit this if you don't want to
+      # stop the container or run custom commands. In case you need to
+      # proxy the socket, you can also provide a location by setting
+      # `DOCKER_HOST` in the container
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      # If you mount a local directory or volume to `/archive` a local
+      # copy of the backup will be stored there. You can override the
+      # location inside of the container by setting `BACKUP_ARCHIVE`.
+      # You can omit this if you do not want to keep local backups.
+      - /path/to/local_backups:/archive
+volumes:
+  data:
+```
+
+### One-off backups using Docker CLI
+
+To run a one time backup, mount the volume you would like to see backed up into a container and run the `backup` command:
+
+```console
+docker run --rm \
+  -v data:/backup/data \
+  --env AWS_ACCESS_KEY_ID="<xxx>" \
+  --env AWS_SECRET_ACCESS_KEY="<xxx>" \
+  --env AWS_S3_BUCKET_NAME="<xxx>" \
+  --entrypoint backup \
+  offen/docker-volume-backup:v2
+```
+
+Alternatively, pass a `--env-file` in order to use a full config as described below.
+
+### Available image registries
+
+This Docker image is published to both Docker Hub and the GitHub container registry.
+Depending on your preferences and needs, you can reference both `offen/docker-volume-backup` as well as `ghcr.io/offen/docker-volume-backup`:
+
+```
+docker pull offen/docker-volume-backup:v2
+docker pull ghcr.io/offen/docker-volume-backup:v2
+```
+
+Documentation references Docker Hub, but all examples will work using ghcr.io just as well.
+
+## Differences to `jareware/docker-volume-backup`
+
+This image is heavily inspired by `jareware/docker-volume-backup`. We decided to publish this image as a simpler and more lightweight alternative because of the following requirements:
+
+- The original image is based on `ubuntu` and requires additional tools, making it heavy.
+This version is roughly 1/25 in compressed size (it's ~15MB).
+- The original image uses a shell script, when this version is written in Go.
+- The original image proposed to handle backup rotation through AWS S3 lifecycle policies.
+This image adds the option to rotate away old backups through the same command so this functionality can also be offered for non-AWS storage backends like MinIO.
+Local copies of backups can also be pruned once they reach a certain age.
+- InfluxDB specific functionality from the original image was removed.
+- `arm64` and `arm/v7` architectures are supported.
+- Docker in Swarm mode is supported.
+- Notifications on finished backups are supported.
+- IAM authentication through instance profiles is supported.

docs/recipes/index.md

@@ -0,0 +1,373 @@
+---
+title: Recipes
+layout: default
+nav_order: 4
+---
+
+# Recipes
+{: .no_toc }
+
+This doc lists configuration for some real-world use cases that you can copy and paste to tweak and match your needs.
+
+1. TOC
+{: toc }
+
+## Backing up to AWS S3
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
+      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Backing up to Filebase
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_ENDPOINT: s3.filebase.com
+      AWS_S3_BUCKET_NAME: filebase-bucket
+      AWS_ACCESS_KEY_ID: FILEBASE-ACCESS-KEY
+      AWS_SECRET_ACCESS_KEY: FILEBASE-SECRET-KEY
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Backing up to MinIO
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_ENDPOINT: minio.example.com
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID: MINIOACCESSKEY
+      AWS_SECRET_ACCESS_KEY: MINIOSECRETKEY
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+
+## Backing up to MinIO (using Docker secrets)
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_ENDPOINT: minio.example.com
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID_FILE: /run/secrets/minio_access_key
+      AWS_SECRET_ACCESS_KEY_FILE: /run/secrets/minio_secret_key
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    secrets:
+      - minio_access_key
+      - minio_secret_key
+
+volumes:
+  data:
+
+secrets:
+  minio_access_key:
+    # ... define how secret is accessed
+  minio_secret_key:
+    # ... define how secret is accessed
+```
+
+## Backing up to WebDAV
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      WEBDAV_URL: https://webdav.mydomain.me
+      WEBDAV_PATH: /my/directory/
+      WEBDAV_USERNAME: user
+      WEBDAV_PASSWORD: password
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Backing up to SSH
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      SSH_HOST_NAME: server.local
+      SSH_PORT: 2222
+      SSH_USER: user
+      SSH_REMOTE_PATH: /data
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - /path/to/private_key:/root/.ssh/id_rsa
+
+volumes:
+  data:
+```
+
+## Backing up to Azure Blob Storage
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AZURE_STORAGE_CONTAINER_NAME: backup-container
+      AZURE_STORAGE_ACCOUNT_NAME: account-name
+      AZURE_STORAGE_PRIMARY_ACCOUNT_KEY: Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Backing up to Dropbox
+
+See [Dropbox Setup](#setup-dropbox-storage-backend) on how to get the appropriate environment values.
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      DROPBOX_REFRESH_TOKEN: REFRESH_KEY  # replace
+      DROPBOX_APP_KEY: APP_KEY  # replace
+      DROPBOX_APP_SECRET: APP_SECRET  # replace
+      DROPBOX_REMOTE_PATH: /Apps/my-test-app/some_subdir  # replace
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Backing up locally
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
+      BACKUP_LATEST_SYMLINK: backup-latest.tar.gz
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ${HOME}/backups:/archive
+
+volumes:
+  data:
+```
+
+## Backing up to AWS S3 as well as locally
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
+      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ${HOME}/backups:/archive
+
+volumes:
+  data:
+```
+
+## Running on a custom cron schedule
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      # take a backup on every hour
+      BACKUP_CRON_EXPRESSION: "0 * * * *"
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
+      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Rotating away backups that are older than 7 days
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
+      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
+      BACKUP_PRUNING_PREFIX: backup-
+      BACKUP_RETENTION_DAYS: 7
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Encrypting your backups using GPG
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
+      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+      GPG_PASSPHRASE: somesecretstring
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
+## Using mysqldump to prepare the backup
+
+```yml
+version: '3'
+
+services:
+  database:
+    image: mariadb:latest
+    labels:
+      - docker-volume-backup.archive-pre=/bin/sh -c 'mysqldump -psecret --all-databases > /tmp/dumps/dump.sql'
+    volumes:
+      - data:/tmp/dumps
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      BACKUP_FILENAME: db.tar.gz
+      BACKUP_CRON_EXPRESSION: "0 2 * * *"
+    volumes:
+      - ./local:/archive
+      - data:/backup/data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+volumes:
+  data:
+```
+
+## Running multiple instances in the same setup
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data_1` and `data_2` volumes here
+  backup_1: &backup_service
+    image: offen/docker-volume-backup:v2
+    environment: &backup_environment
+      BACKUP_CRON_EXPRESSION: "0 2 * * *"
+      AWS_S3_BUCKET_NAME: backup-bucket
+      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
+      AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+      # Label the container using the `data_1` volume as `docker-volume-backup.stop-during-backup=service1`
+      BACKUP_STOP_CONTAINER_LABEL: service1
+    volumes:
+      - data_1:/backup/data-1-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+  backup_2:
+    <<: *backup_service
+    environment:
+      <<: *backup_environment
+      # Label the container using the `data_2` volume as `docker-volume-backup.stop-during-backup=service2`
+      BACKUP_CRON_EXPRESSION: "0 3 * * *"
+      BACKUP_STOP_CONTAINER_LABEL: service2
+    volumes:
+      - data_2:/backup/data-2-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data_1:
+  data_2:
+```

docs/reference/index.md

@@ -0,0 +1,419 @@
+---
+title: Configuration Reference
+layout: default
+nav_order: 2
+---
+
+# Configuration reference
+
+Backup targets, schedule and retention are configured using environment variables.
+
+{: .note }
+You can use any environment variable from below also with a `_FILE` suffix to be able to load the value from a file.
+This is typically useful when using [Docker Secrets](https://docs.docker.com/engine/swarm/secrets/) or similar.
+Note that secrets will not be trimmed of leading or trailing whitespace.
+
+{: .warning }
+In case you encounter double quoted values in your runtime configuration you might still be using an [older version of `docker-compose`][compose-issue].
+You can work around this by either updating `docker-compose` or unquoting your configuration values.
+
+You can populate below template according to your requirements and use it as your `env_file`:
+
+{% raw %}
+```
+########### BACKUP SCHEDULE
+
+# Backups run on the given cron schedule in `busybox` flavor. If no
+# value is set, `@daily` will be used. If you do not want the cron
+# to ever run, use `0 0 5 31 2 ?`.
+
+# BACKUP_CRON_EXPRESSION="0 2 * * *"
+
+# The compression algorithm used in conjunction with tar.
+# Valid options are: "gz" (Gzip) and "zst" (Zstd).
+# Note that the selection affects the file extension.
+
+# BACKUP_COMPRESSION="gz"
+
+# Parallelism level for "gz" (Gzip) compression.
+# Defines how many blocks of data are concurrently processed.
+# Higher values result in faster compression. No effect on decompression
+# Default = 1. Setting this to 0 will use all available threads.
+
+# GZIP_PARALLELISM=1
+
+# The name of the backup file including the extension.
+# Format verbs will be replaced as in `strftime`. Omitting them
+# will result in the same filename for every backup run, which means previous
+# versions will be overwritten on subsequent runs.
+# Extension can be defined literally or via "{{ .Extension }}" template,
+# in which case it will become either "tar.gz" or "tar.zst" (depending
+# on your BACKUP_COMPRESSION setting).
+# The default results in filenames like: `backup-2021-08-29T04-00-00.tar.gz`.
+
+# BACKUP_FILENAME="backup-%Y-%m-%dT%H-%M-%S.{{ .Extension }}"
+
+# Setting BACKUP_FILENAME_EXPAND to true allows for environment variable
+# placeholders in BACKUP_FILENAME, BACKUP_LATEST_SYMLINK and in
+# BACKUP_PRUNING_PREFIX that will get expanded at runtime,
+# e.g. `backup-$HOSTNAME-%Y-%m-%dT%H-%M-%S.tar.gz`. Expansion happens before
+# interpolating strftime tokens. It is disabled by default.
+# Please note that you will need to escape the `$` when providing the value
+# in a docker-compose.yml file, i.e. using $$VAR instead of $VAR.
+
+# BACKUP_FILENAME_EXPAND="true"
+
+# When storing local backups, a symlink to the latest backup can be created
+# in case a value is given for this key. This has no effect on remote backups.
+
+# BACKUP_LATEST_SYMLINK="backup.latest.tar.gz"
+
+# ************************************************************************
+# The BACKUP_FROM_SNAPSHOT option has been deprecated and will be removed
+# in the next major version. Please use exec-pre and exec-post
+# as documented below instead.
+# ************************************************************************
+# Whether to copy the content of backup folder before creating the tar archive.
+# In the rare scenario where the content of the source backup volume is continuously
+# updating, but we do not wish to stop the container while performing the backup,
+# this setting can be used to ensure the integrity of the tar.gz file.
+
+# BACKUP_FROM_SNAPSHOT="false"
+
+# By default, the `/backup` directory inside the container will be backed up.
+# In case you need to use a custom location, set `BACKUP_SOURCES`.
+
+# BACKUP_SOURCES="/other/location"
+
+# When given, all files in BACKUP_SOURCES whose full path matches the given
+# regular expression will be excluded from the archive. Regular Expressions
+# can be used as from the Go standard library https://pkg.go.dev/regexp
+
+# BACKUP_EXCLUDE_REGEXP="\.log$"
+
+# Exclude one or many storage backends from the pruning process.
+# E.g. with one backend excluded: BACKUP_SKIP_BACKENDS_FROM_PRUNE=s3
+# E.g. with multiple backends excluded: BACKUP_SKIP_BACKENDS_FROM_PRUNE=s3,webdav
+# Available backends are: S3, WebDAV, SSH, Local, Dropbox, Azure
+# Note: The name of the backends is case insensitive. 
+# Default: All backends get pruned.
+
+# BACKUP_SKIP_BACKENDS_FROM_PRUNE=
+
+########### BACKUP STORAGE
+
+# The name of the remote bucket that should be used for storing backups. If
+# this is not set, no remote backups will be stored.
+
+# AWS_S3_BUCKET_NAME="backup-bucket"
+
+# If you want to store the backup in a non-root location on your bucket
+# you can provide a path. The path must not contain a leading slash.
+
+# AWS_S3_PATH="my/backup/location"
+
+# Define credentials for authenticating against the backup storage and a bucket
+# name. Although all of these keys are `AWS`-prefixed, the setup can be used
+# with any S3 compatible storage.
+
+# AWS_ACCESS_KEY_ID="<xxx>"
+# AWS_SECRET_ACCESS_KEY="<xxx>"
+
+# Instead of providing static credentials, you can also use IAM instance profiles
+# or similar to provide authentication. Some possible configuration options on AWS:
+# - EC2: http://169.254.169.254
+# - ECS: http://169.254.170.2
+
+# AWS_IAM_ROLE_ENDPOINT="http://169.254.169.254"
+
+# This is the FQDN of your storage server, e.g. `storage.example.com`.
+# Do not set this when working against AWS S3 (the default value is
+# `s3.amazonaws.com`). If you need to set a specific (non-https) protocol, you
+# will need to use the option below.
+
+# AWS_ENDPOINT="storage.example.com"
+
+# The protocol to be used when communicating with your storage server.
+# Defaults to "https". You can set this to "http" when communicating with
+# a different Docker container on the same host for example.
+
+# AWS_ENDPOINT_PROTO="https"
+
+# Setting this variable to `true` will disable verification of
+# SSL certificates for AWS_ENDPOINT. You shouldn't use this unless you use
+# self-signed certificates for your remote storage backend. This can only be
+# used when AWS_ENDPOINT_PROTO is set to `https`.
+
+# AWS_ENDPOINT_INSECURE="true"
+
+# If you wish to use self signed certificates your S3 server, you can pass
+# the location of a PEM encoded CA certificate and it will be used for
+# validating your certificates.
+# Alternatively, pass a PEM encoded string containing the certificate.
+
+# AWS_ENDPOINT_CA_CERT="/path/to/cert.pem"
+
+# Setting this variable will change the S3 storage class header.
+# Defaults to "STANDARD", you can set this value according to your needs.
+
+# AWS_STORAGE_CLASS="GLACIER"
+
+# Setting this variable will change the S3 default part size for the copy step.
+# This value is useful when you want to upload large files.
+# NB : While using Scaleway as S3 provider, be aware that the parts counter is set to 1.000.
+# While Minio uses a hard coded value to 10.000. As a workaround, try to set a higher value.
+# Defaults to "16" (MB) if unset (from minio), you can set this value according to your needs.
+# The unit is in MB and an integer.
+
+# AWS_PART_SIZE=16
+
+# You can also backup files to any WebDAV server:
+
+# The URL of the remote WebDAV server
+
+# WEBDAV_URL="https://webdav.example.com"
+
+# The Directory to place the backups to on the WebDAV server.
+# If the path is not present on the server it will be created.
+
+# WEBDAV_PATH="/my/directory/"
+
+# The username for the WebDAV server
+
+# WEBDAV_USERNAME="user"
+
+# The password for the WebDAV server
+
+# WEBDAV_PASSWORD="password"
+
+# Setting this variable to `true` will disable verification of
+# SSL certificates for WEBDAV_URL. You shouldn't use this unless you use
+# self-signed certificates for your remote storage backend.
+
+# WEBDAV_URL_INSECURE="true"
+
+# You can also backup files to any SSH server:
+
+# The URL of the remote SSH server
+
+# SSH_HOST_NAME="server.local"
+
+# The port of the remote SSH server
+# Optional variable default value is `22`
+
+# SSH_PORT=2222
+
+# The Directory to place the backups to on the SSH server.
+
+# SSH_REMOTE_PATH="/my/directory/"
+
+# The username for the SSH server
+
+# SSH_USER="user"
+
+# The password for the SSH server
+
+# SSH_PASSWORD="password"
+
+# The private key path in container for SSH server
+# Default value: /root/.ssh/id_rsa
+# If file is mounted to /root/.ssh/id_rsa path it will be used. Non-RSA keys will
+# also work.
+
+# SSH_IDENTITY_FILE="/root/.ssh/id_rsa"
+
+# The passphrase for the identity file
+
+# SSH_IDENTITY_PASSPHRASE="pass"
+
+# The credential's account name when using Azure Blob Storage. This has to be
+# set when using Azure Blob Storage.
+
+# AZURE_STORAGE_ACCOUNT_NAME="account-name"
+
+# The credential's primary account key when using Azure Blob Storage. If this
+# is not given, the command tries to fall back to using a managed identity.
+
+# AZURE_STORAGE_PRIMARY_ACCOUNT_KEY="<xxx>"
+
+# The container name when using Azure Blob Storage.
+
+# AZURE_STORAGE_CONTAINER_NAME="container-name"
+
+# The service endpoint when using Azure Blob Storage. This is a template that
+# can be passed the account name as shown in the default value below.
+
+# AZURE_STORAGE_ENDPOINT="https://{{ .AccountName }}.blob.core.windows.net/"
+
+# Absolute remote path in your Dropbox where the backups shall be stored.
+# Note: Use your app's subpath in Dropbox, if it doesn't have global access.
+# Consulte the README for further information.
+
+# DROPBOX_REMOTE_PATH="/my/directory"
+
+# Number of concurrent chunked uploads for Dropbox.
+# Values above 6 usually result in no enhancements.
+
+# DROPBOX_CONCURRENCY_LEVEL="6"
+
+# App key and app secret from your app created at https://www.dropbox.com/developers/apps/info
+
+# DROPBOX_APP_KEY=""
+# DROPBOX_APP_SECRET=""
+
+# Refresh token to request new short-lived tokens (OAuth2). Consult README to see how to get one.
+
+# DROPBOX_REFRESH_TOKEN=""
+
+# In addition to storing backups remotely, you can also keep local copies.
+# Pass a container-local path to store your backups if needed. You also need to
+# mount a local folder or Docker volume into that location (`/archive`
+# by default) when running the container. In case the specified directory does
+# not exist (nothing is mounted) in the container when the backup is running,
+# local backups will be skipped. Local paths are also be subject to pruning of
+# old backups as defined below.
+
+# BACKUP_ARCHIVE="/archive"
+
+########### BACKUP PRUNING
+
+# **IMPORTANT, PLEASE READ THIS BEFORE USING THIS FEATURE**:
+# The mechanism used for pruning old backups is not very sophisticated
+# and applies its rules to **all files in the target directory** by default,
+# which means that if you are storing your backups next to other files,
+# these might become subject to deletion too. When using this option
+# make sure the backup files are stored in a directory used exclusively
+# for such files, or to configure BACKUP_PRUNING_PREFIX to limit
+# removal to certain files.
+
+# Define this value to enable automatic rotation of old backups. The value
+# declares the number of days for which a backup is kept.
+
+# BACKUP_RETENTION_DAYS="7"
+
+# In case the duration a backup takes fluctuates noticeably in your setup
+# you can adjust this setting to make sure there are no race conditions
+# between the backup finishing and the rotation not deleting backups that
+# sit on the edge of the time window. Set this value to a duration
+# that is expected to be bigger than the maximum difference of backups.
+# Valid values have a suffix of (s)econds, (m)inutes or (h)ours. By default,
+# one minute is used.
+
+# BACKUP_PRUNING_LEEWAY="1m"
+
+# In case your target bucket or directory contains other files than the ones
+# managed by this container, you can limit the scope of rotation by setting
+# a prefix value. This would usually be the non-parametrized part of your
+# BACKUP_FILENAME. E.g. if BACKUP_FILENAME is `db-backup-%Y-%m-%dT%H-%M-%S.tar.gz`,
+# you can set BACKUP_PRUNING_PREFIX to `db-backup-` and make sure
+# unrelated files are not affected by the rotation mechanism.
+
+# BACKUP_PRUNING_PREFIX="backup-"
+
+########### BACKUP ENCRYPTION
+
+# Backups can be encrypted using gpg in case a passphrase is given.
+
+# GPG_PASSPHRASE="<xxx>"
+
+########### STOPPING CONTAINERS DURING BACKUP
+
+# Containers can be stopped by applying a
+# `docker-volume-backup.stop-during-backup` label. By default, all containers
+# that are labeled with `true` will be stopped. If you need more fine grained
+# control (e.g. when running multiple containers based on this image), you can
+# override this default by specifying a different value here.
+
+# BACKUP_STOP_CONTAINER_LABEL="service1"
+
+########### EXECUTING COMMANDS IN CONTAINERS PRE/POST BACKUP
+
+# It is possible to define commands to be run in any container before and after
+# a backup is conducted. The commands themselves are defined in labels like
+# `docker-volume-backup.archive-pre=/bin/sh -c 'mysqldump [options] > dump.sql'.
+# Several options exist for controlling this feature:
+
+# By default, any output of such a command is suppressed. If this value
+# is configured to be "true", command execution output will be forwarded to
+# the backup container's stdout and stderr.
+
+# EXEC_FORWARD_OUTPUT="true"
+
+# Without any further configuration, all commands defined in labels will be
+# run before and after a backup. If you need more fine grained control, you
+# can use this option to set a label that will be used for narrowing down
+# the set of eligible containers. When set, an eligible container will also need
+# to be labeled as `docker-volume-backup.exec-label=database`.
+
+# EXEC_LABEL="database"
+
+########### NOTIFICATIONS
+
+# Notifications (email, Slack, etc.) can be sent out when a backup run finishes.
+# Configuration is provided as a comma-separated list of URLs as consumed
+# by `shoutrrr`: https://containrrr.dev/shoutrrr/0.7/services/overview/
+# The content of such notifications can be customized. Dedicated documentation
+# on how to do this can be found in the README. When providing multiple URLs or
+# an URL that contains a comma, the values can be URL encoded to avoid ambiguities.
+
+# The below URL demonstrates how to send an email using the provided SMTP
+# configuration and credentials.
+
+# NOTIFICATION_URLS=smtp://username:password@host:587/?fromAddress=sender@example.com&toAddresses=recipient@example.com
+
+# By default, notifications would only be sent out when a backup run fails
+# To receive notifications for every run, set `NOTIFICATION_LEVEL` to `info`
+# instead of the default `error`.
+
+# NOTIFICATION_LEVEL="error"
+
+########### DOCKER HOST
+
+# If you are interfacing with Docker via TCP you can set the Docker host here
+# instead of mounting the Docker socket as a volume. This is unset by default.
+
+# DOCKER_HOST="tcp://docker_socket_proxy:2375"
+
+########### LOCK_TIMEOUT
+
+# In the case of overlapping cron schedules run by the same container,
+# subsequent invocations will wait for previous runs to finish before starting.
+# By default, this will time out and fail in case the lock could not be acquired
+# after 60 minutes. In case you need to adjust this timeout, supply a duration
+# value as per https://pkg.go.dev/time#ParseDuration to `LOCK_TIMEOUT`
+
+# LOCK_TIMEOUT="60m"
+
+########### EMAIL NOTIFICATIONS
+
+# ************************************************************************
+# Providing notification configuration like this has been deprecated
+# and will be removed in the next major version. Please use NOTIFICATION_URLS
+# as documented above instead.
+# ************************************************************************
+
+# In case SMTP credentials are provided, notification emails can be sent out when
+# a backup run finished. These emails will contain the start time, the error
+# message on failure and all prior log output.
+
+# The recipient(s) of the notification. Supply a comma separated list
+# of addresses if you want to notify multiple recipients. If this is
+# not set, no emails will be sent.
+
+# EMAIL_NOTIFICATION_RECIPIENT="you@example.com"
+
+# The "From" header of the sent email. Defaults to `noreply@nohost`.
+
+# EMAIL_NOTIFICATION_SENDER="no-reply@example.com"
+
+# Configuration and credentials for the SMTP server to be used.
+# EMAIL_SMTP_PORT defaults to 587.
+
+# EMAIL_SMTP_HOST="posteo.de"
+# EMAIL_SMTP_PASSWORD="<xxx>"
+# EMAIL_SMTP_USERNAME="no-reply@example.com"
+# EMAIL_SMTP_PORT="<port>"
+```
+{% endraw %}
+
+[compose-issue]: https://github.com/docker/compose/issues/2854

entrypoint.sh

@@ -13,6 +13,7 @@ if [ ! -d "/etc/dockervolumebackup/conf.d" ]; then
 else
   echo "/etc/dockervolumebackup/conf.d was found, using configuration files from this directory."
 
+  crontab -r && crontab /dev/null
   for file in /etc/dockervolumebackup/conf.d/*; do
     source $file
     BACKUP_CRON_EXPRESSION="${BACKUP_CRON_EXPRESSION:-@daily}"
@@ -22,4 +23,4 @@ else
 fi
 
 echo "Starting cron in foreground."
-crond -f -l 8
+crond -f -d 8

go.mod

@@ -1,60 +1,72 @@
 module github.com/offen/docker-volume-backup
 
-go 1.18
+go 1.21
 
 require (
-	github.com/containrrr/shoutrrr v0.5.2
+	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.4.0
+	github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v1.2.0
+	github.com/containrrr/shoutrrr v0.7.1
 	github.com/cosiner/argv v0.1.0
-	github.com/docker/docker v20.10.11+incompatible
+	github.com/docker/docker v24.0.7+incompatible
 	github.com/gofrs/flock v0.8.1
-	github.com/kelseyhightower/envconfig v1.4.0
+	github.com/klauspost/compress v1.17.4
 	github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d
-	github.com/minio/minio-go/v7 v7.0.16
-	github.com/otiai10/copy v1.7.0
-	github.com/sirupsen/logrus v1.8.1
-	github.com/studio-b12/gowebdav v0.0.0-20220128162035-c7b1ff8a5e62
-	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5
-	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
+	github.com/minio/minio-go/v7 v7.0.65
+	github.com/offen/envconfig v1.5.0
+	github.com/otiai10/copy v1.14.0
+	github.com/pkg/sftp v1.13.6
+	github.com/studio-b12/gowebdav v0.9.0
+	golang.org/x/crypto v0.16.0
+	golang.org/x/oauth2 v0.15.0
+	golang.org/x/sync v0.5.0
 )
 
 require (
-	github.com/Microsoft/go-winio v0.4.17 // indirect
-	github.com/containerd/containerd v1.5.5 // indirect
-	github.com/docker/distribution v2.7.1+incompatible // indirect
+	github.com/cloudflare/circl v1.3.3 // indirect
+	github.com/golang-jwt/jwt/v5 v5.0.0 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
+	google.golang.org/protobuf v1.31.0 // indirect
+)
+
+require (
+	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.8.0 // indirect
+	github.com/Azure/azure-sdk-for-go/sdk/internal v1.3.0 // indirect
+	github.com/AzureAD/microsoft-authentication-library-for-go v1.1.1 // indirect
+	github.com/Microsoft/go-winio v0.5.2 // indirect
+	github.com/ProtonMail/go-crypto v0.0.0-20230717121422-5aa5874ade95
+	github.com/docker/distribution v2.8.2+incompatible // indirect
 	github.com/docker/go-connections v0.4.0 // indirect
 	github.com/docker/go-units v0.4.0 // indirect
-	github.com/dustin/go-humanize v1.0.0 // indirect
-	github.com/fatih/color v1.10.0 // indirect
-	github.com/fsnotify/fsnotify v1.4.9 // indirect
+	github.com/dropbox/dropbox-sdk-go-unofficial/v6 v6.0.5
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/fatih/color v1.13.0 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
-	github.com/golang/protobuf v1.5.0 // indirect
-	github.com/google/uuid v1.3.0 // indirect
+	github.com/google/uuid v1.3.1 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/klauspost/compress v1.13.6 // indirect
-	github.com/klauspost/cpuid/v2 v2.0.9 // indirect
-	github.com/mattn/go-colorable v0.1.8 // indirect
-	github.com/mattn/go-isatty v0.0.12 // indirect
+	github.com/klauspost/cpuid/v2 v2.2.5 // indirect
+	github.com/klauspost/pgzip v1.2.6
+	github.com/kr/fs v0.1.0 // indirect
+	github.com/kylelemons/godebug v1.1.0 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.16 // indirect
 	github.com/minio/md5-simd v1.1.2 // indirect
-	github.com/minio/sha256-simd v1.0.0 // indirect
-	github.com/mitchellh/go-homedir v1.1.0 // indirect
+	github.com/minio/sha256-simd v1.0.1 // indirect
+	github.com/moby/term v0.0.0-20200312100748-672ec06f55cd // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/morikuni/aec v1.0.0 // indirect
-	github.com/nxadm/tail v1.4.6 // indirect
-	github.com/onsi/ginkgo v1.14.2 // indirect
-	github.com/onsi/gomega v1.10.3 // indirect
+	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/opencontainers/go-digest v1.0.0 // indirect
-	github.com/opencontainers/image-spec v1.0.1 // indirect
+	github.com/opencontainers/image-spec v1.0.3-0.20211202183452-c5a74bcca799 // indirect
+	github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
-	github.com/rs/xid v1.3.0 // indirect
-	golang.org/x/net v0.0.0-20210226172049-e18ecbb05110 // indirect
-	golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 // indirect
-	golang.org/x/text v0.3.6 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
-	google.golang.org/genproto v0.0.0-20201110150050-8816d57aaa9a // indirect
-	google.golang.org/grpc v1.33.2 // indirect
-	google.golang.org/protobuf v1.26.0 // indirect
-	gopkg.in/ini.v1 v1.65.0 // indirect
-	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
-	gopkg.in/yaml.v2 v2.4.0 // indirect
+	github.com/rs/xid v1.5.0 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	golang.org/x/net v0.19.0 // indirect
+	golang.org/x/sys v0.15.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
+	gopkg.in/ini.v1 v1.67.0 // indirect
+	gotest.tools/v3 v3.0.3 // indirect
 )

internal/storage/azure/azure.go

@@ -0,0 +1,158 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package azure
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"text/template"
+	"time"
+
+	"github.com/Azure/azure-sdk-for-go/sdk/azidentity"
+	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob"
+	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/container"
+	"github.com/offen/docker-volume-backup/internal/storage"
+)
+
+type azureBlobStorage struct {
+	*storage.StorageBackend
+	client        *azblob.Client
+	containerName string
+}
+
+// Config contains values that define the configuration of an Azure Blob Storage.
+type Config struct {
+	AccountName       string
+	ContainerName     string
+	PrimaryAccountKey string
+	Endpoint          string
+	RemotePath        string
+}
+
+// NewStorageBackend creates and initializes a new Azure Blob Storage backend.
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
+	endpointTemplate, err := template.New("endpoint").Parse(opts.Endpoint)
+	if err != nil {
+		return nil, fmt.Errorf("NewStorageBackend: error parsing endpoint template: %w", err)
+	}
+	var ep bytes.Buffer
+	if err := endpointTemplate.Execute(&ep, opts); err != nil {
+		return nil, fmt.Errorf("NewStorageBackend: error executing endpoint template: %w", err)
+	}
+	normalizedEndpoint := fmt.Sprintf("%s/", strings.TrimSuffix(ep.String(), "/"))
+
+	var client *azblob.Client
+	if opts.PrimaryAccountKey != "" {
+		cred, err := azblob.NewSharedKeyCredential(opts.AccountName, opts.PrimaryAccountKey)
+		if err != nil {
+			return nil, fmt.Errorf("NewStorageBackend: error creating shared key Azure credential: %w", err)
+		}
+
+		client, err = azblob.NewClientWithSharedKeyCredential(normalizedEndpoint, cred, nil)
+		if err != nil {
+			return nil, fmt.Errorf("NewStorageBackend: error creating Azure client: %w", err)
+		}
+	} else {
+		cred, err := azidentity.NewManagedIdentityCredential(nil)
+		if err != nil {
+			return nil, fmt.Errorf("NewStorageBackend: error creating managed identity credential: %w", err)
+		}
+		client, err = azblob.NewClient(normalizedEndpoint, cred, nil)
+		if err != nil {
+			return nil, fmt.Errorf("NewStorageBackend: error creating Azure client: %w", err)
+		}
+	}
+
+	storage := azureBlobStorage{
+		client:        client,
+		containerName: opts.ContainerName,
+		StorageBackend: &storage.StorageBackend{
+			DestinationPath: opts.RemotePath,
+			Log:             logFunc,
+		},
+	}
+	return &storage, nil
+}
+
+// Name returns the name of the storage backend
+func (b *azureBlobStorage) Name() string {
+	return "Azure"
+}
+
+// Copy copies the given file to the storage backend.
+func (b *azureBlobStorage) Copy(file string) error {
+	fileReader, err := os.Open(file)
+	if err != nil {
+		return fmt.Errorf("(*azureBlobStorage).Copy: error opening file %s: %w", file, err)
+	}
+	_, err = b.client.UploadStream(
+		context.Background(),
+		b.containerName,
+		filepath.Join(b.DestinationPath, filepath.Base(file)),
+		fileReader,
+		nil,
+	)
+	if err != nil {
+		return fmt.Errorf("(*azureBlobStorage).Copy: error uploading file %s: %w", file, err)
+	}
+	return nil
+}
+
+// Prune rotates away backups according to the configuration and provided
+// deadline for the Azure Blob storage backend.
+func (b *azureBlobStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
+	lookupPrefix := filepath.Join(b.DestinationPath, pruningPrefix)
+	pager := b.client.NewListBlobsFlatPager(b.containerName, &container.ListBlobsFlatOptions{
+		Prefix: &lookupPrefix,
+	})
+	var matches []string
+	var totalCount uint
+	for pager.More() {
+		resp, err := pager.NextPage(context.Background())
+		if err != nil {
+			return nil, fmt.Errorf("(*azureBlobStorage).Prune: error paging over blobs: %w", err)
+		}
+		for _, v := range resp.Segment.BlobItems {
+			totalCount++
+			if v.Properties.LastModified.Before(deadline) {
+				matches = append(matches, *v.Name)
+			}
+		}
+	}
+
+	stats := &storage.PruneStats{
+		Total:  totalCount,
+		Pruned: uint(len(matches)),
+	}
+
+	pruneErr := b.DoPrune(b.Name(), len(matches), int(totalCount), deadline, func() error {
+		wg := sync.WaitGroup{}
+		wg.Add(len(matches))
+		var errs []error
+
+		for _, match := range matches {
+			name := match
+			go func() {
+				_, err := b.client.DeleteBlob(context.Background(), b.containerName, name, nil)
+				if err != nil {
+					errs = append(errs, err)
+				}
+				wg.Done()
+			}()
+		}
+		wg.Wait()
+		if len(errs) != 0 {
+			return errors.Join(errs...)
+		}
+		return nil
+	})
+
+	return stats, pruneErr
+}

internal/storage/dropbox/dropbox.go

@@ -0,0 +1,258 @@
+package dropbox
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox"
+	"github.com/dropbox/dropbox-sdk-go-unofficial/v6/dropbox/files"
+	"github.com/offen/docker-volume-backup/internal/storage"
+	"golang.org/x/oauth2"
+)
+
+type dropboxStorage struct {
+	*storage.StorageBackend
+	client           files.Client
+	concurrencyLevel int
+}
+
+// Config allows to configure a Dropbox storage backend.
+type Config struct {
+	Endpoint         string
+	OAuth2Endpoint   string
+	RefreshToken     string
+	AppKey           string
+	AppSecret        string
+	RemotePath       string
+	ConcurrencyLevel int
+}
+
+// NewStorageBackend creates and initializes a new Dropbox storage backend.
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
+	tokenUrl, _ := url.JoinPath(opts.OAuth2Endpoint, "oauth2/token")
+
+	conf := &oauth2.Config{
+		ClientID:     opts.AppKey,
+		ClientSecret: opts.AppSecret,
+		Endpoint: oauth2.Endpoint{
+			TokenURL: tokenUrl,
+		},
+	}
+
+	logFunc(storage.LogLevelInfo, "Dropbox", "Fetching fresh access token for Dropbox storage backend.")
+	tkSource := conf.TokenSource(context.Background(), &oauth2.Token{RefreshToken: opts.RefreshToken})
+	token, err := tkSource.Token()
+	if err != nil {
+		return nil, fmt.Errorf("(*dropboxStorage).NewStorageBackend: Error refreshing token: %w", err)
+	}
+
+	dbxConfig := dropbox.Config{
+		Token: token.AccessToken,
+	}
+
+	if opts.Endpoint != "https://api.dropbox.com/" {
+		dbxConfig.URLGenerator = func(hostType string, namespace string, route string) string {
+			return fmt.Sprintf("%s/%d/%s/%s", opts.Endpoint, 2, namespace, route)
+		}
+	}
+
+	client := files.New(dbxConfig)
+
+	if opts.ConcurrencyLevel < 1 {
+		logFunc(storage.LogLevelWarning, "Dropbox", "Concurrency level must be at least 1! Using 1 instead of %d.", opts.ConcurrencyLevel)
+		opts.ConcurrencyLevel = 1
+	}
+
+	return &dropboxStorage{
+		StorageBackend: &storage.StorageBackend{
+			DestinationPath: opts.RemotePath,
+			Log:             logFunc,
+		},
+		client:           client,
+		concurrencyLevel: opts.ConcurrencyLevel,
+	}, nil
+}
+
+// Name returns the name of the storage backend
+func (b *dropboxStorage) Name() string {
+	return "Dropbox"
+}
+
+// Copy copies the given file to the WebDav storage backend.
+func (b *dropboxStorage) Copy(file string) error {
+	_, name := path.Split(file)
+
+	folderArg := files.NewCreateFolderArg(b.DestinationPath)
+	if _, err := b.client.CreateFolderV2(folderArg); err != nil {
+		switch err := err.(type) {
+		case files.CreateFolderV2APIError:
+			if err.EndpointError.Path.Tag != files.WriteErrorConflict {
+				return fmt.Errorf("(*dropboxStorage).Copy: Error creating directory '%s': %w", b.DestinationPath, err)
+			}
+			b.Log(storage.LogLevelInfo, b.Name(), "Destination path '%s' already exists, no new directory required.", b.DestinationPath)
+		default:
+			return fmt.Errorf("(*dropboxStorage).Copy: Error creating directory '%s': %w", b.DestinationPath, err)
+		}
+	}
+
+	r, err := os.Open(file)
+	if err != nil {
+		return fmt.Errorf("(*dropboxStorage).Copy: Error opening the file to be uploaded: %w", err)
+	}
+	defer r.Close()
+
+	// Start new upload session and get session id
+
+	b.Log(storage.LogLevelInfo, b.Name(), "Starting upload session for backup '%s' at path '%s'.", file, b.DestinationPath)
+
+	var sessionId string
+	uploadSessionStartArg := files.NewUploadSessionStartArg()
+	uploadSessionStartArg.SessionType = &files.UploadSessionType{Tagged: dropbox.Tagged{Tag: files.UploadSessionTypeConcurrent}}
+	if res, err := b.client.UploadSessionStart(uploadSessionStartArg, nil); err != nil {
+		return fmt.Errorf("(*dropboxStorage).Copy: Error starting the upload session: %w", err)
+	} else {
+		sessionId = res.SessionId
+	}
+
+	// Send the file in 148MB chunks (Dropbox API limit is 150MB, concurrent upload requires a multiple of 4MB though)
+	// Last append can be any size <= 150MB with Close=True
+
+	const chunkSize = 148 * 1024 * 1024 // 148MB
+	var offset uint64 = 0
+	var guard = make(chan struct{}, b.concurrencyLevel)
+	var errorChn = make(chan error, b.concurrencyLevel)
+	var EOFChn = make(chan bool, b.concurrencyLevel)
+	var mu sync.Mutex
+	var wg sync.WaitGroup
+
+loop:
+	for {
+		guard <- struct{}{} // limit concurrency
+		select {
+		case err := <-errorChn: // error from goroutine
+			return err
+		case <-EOFChn: // EOF from goroutine
+			wg.Wait() // wait for all goroutines to finish
+			break loop
+		default:
+		}
+
+		go func() {
+			defer func() {
+				wg.Done()
+				<-guard
+			}()
+			wg.Add(1)
+			chunk := make([]byte, chunkSize)
+
+			mu.Lock() // to preserve offset of chunks
+
+			select {
+			case <-EOFChn:
+				EOFChn <- true // put it back for outer loop
+				mu.Unlock()
+				return // already EOF
+			default:
+			}
+
+			bytesRead, err := r.Read(chunk)
+			if err != nil {
+				errorChn <- fmt.Errorf("(*dropboxStorage).Copy: Error reading the file to be uploaded: %w", err)
+				mu.Unlock()
+				return
+			}
+			chunk = chunk[:bytesRead]
+
+			uploadSessionAppendArg := files.NewUploadSessionAppendArg(
+				files.NewUploadSessionCursor(sessionId, offset),
+			)
+			isEOF := bytesRead < chunkSize
+			uploadSessionAppendArg.Close = isEOF
+			if isEOF {
+				EOFChn <- true
+			}
+			offset += uint64(bytesRead)
+
+			mu.Unlock()
+
+			if err := b.client.UploadSessionAppendV2(uploadSessionAppendArg, bytes.NewReader(chunk)); err != nil {
+				errorChn <- fmt.Errorf("(*dropboxStorage).Copy: Error appending the file to the upload session: %w", err)
+				return
+			}
+		}()
+	}
+
+	// Finish the upload session, commit the file (no new data added)
+
+	_, err = b.client.UploadSessionFinish(
+		files.NewUploadSessionFinishArg(
+			files.NewUploadSessionCursor(sessionId, 0),
+			files.NewCommitInfo(filepath.Join(b.DestinationPath, name)),
+		), nil)
+	if err != nil {
+		return fmt.Errorf("(*dropboxStorage).Copy: Error finishing the upload session: %w", err)
+	}
+
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup '%s' at path '%s'.", file, b.DestinationPath)
+
+	return nil
+}
+
+// Prune rotates away backups according to the configuration and provided deadline for the Dropbox storage backend.
+func (b *dropboxStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
+	var entries []files.IsMetadata
+	res, err := b.client.ListFolder(files.NewListFolderArg(b.DestinationPath))
+	if err != nil {
+		return nil, fmt.Errorf("(*webDavStorage).Prune: Error looking up candidates from remote storage: %w", err)
+	}
+	entries = append(entries, res.Entries...)
+
+	for res.HasMore {
+		res, err = b.client.ListFolderContinue(files.NewListFolderContinueArg(res.Cursor))
+		if err != nil {
+			return nil, fmt.Errorf("(*webDavStorage).Prune: Error looking up candidates from remote storage: %w", err)
+		}
+		entries = append(entries, res.Entries...)
+	}
+
+	var matches []*files.FileMetadata
+	var lenCandidates int
+	for _, candidate := range entries {
+		switch candidate := candidate.(type) {
+		case *files.FileMetadata:
+			if !strings.HasPrefix(candidate.Name, pruningPrefix) {
+				continue
+			}
+			lenCandidates++
+			if candidate.ServerModified.Before(deadline) {
+				matches = append(matches, candidate)
+			}
+		default:
+			continue
+		}
+	}
+
+	stats := &storage.PruneStats{
+		Total:  uint(lenCandidates),
+		Pruned: uint(len(matches)),
+	}
+
+	pruneErr := b.DoPrune(b.Name(), len(matches), lenCandidates, deadline, func() error {
+		for _, match := range matches {
+			if _, err := b.client.DeleteV2(files.NewDeleteArg(filepath.Join(b.DestinationPath, match.Name))); err != nil {
+				return fmt.Errorf("(*dropboxStorage).Prune: Error removing file from Dropbox storage: %w", err)
+			}
+		}
+		return nil
+	})
+
+	return stats, pruneErr
+}

internal/storage/local/local.go

@@ -0,0 +1,158 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package local
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"path/filepath"
+	"time"
+
+	"github.com/offen/docker-volume-backup/internal/storage"
+)
+
+type localStorage struct {
+	*storage.StorageBackend
+	latestSymlink string
+}
+
+// Config allows configuration of a local storage backend.
+type Config struct {
+	ArchivePath   string
+	LatestSymlink string
+}
+
+// NewStorageBackend creates and initializes a new local storage backend.
+func NewStorageBackend(opts Config, logFunc storage.Log) storage.Backend {
+	return &localStorage{
+		StorageBackend: &storage.StorageBackend{
+			DestinationPath: opts.ArchivePath,
+			Log:             logFunc,
+		},
+		latestSymlink: opts.LatestSymlink,
+	}
+}
+
+// Name return the name of the storage backend
+func (b *localStorage) Name() string {
+	return "Local"
+}
+
+// Copy copies the given file to the local storage backend.
+func (b *localStorage) Copy(file string) error {
+	_, name := path.Split(file)
+
+	if err := copyFile(file, path.Join(b.DestinationPath, name)); err != nil {
+		return fmt.Errorf("(*localStorage).Copy: Error copying file to archive: %w", err)
+	}
+	b.Log(storage.LogLevelInfo, b.Name(), "Stored copy of backup `%s` in `%s`.", file, b.DestinationPath)
+
+	if b.latestSymlink != "" {
+		symlink := path.Join(b.DestinationPath, b.latestSymlink)
+		if _, err := os.Lstat(symlink); err == nil {
+			os.Remove(symlink)
+		}
+		if err := os.Symlink(name, symlink); err != nil {
+			return fmt.Errorf("(*localStorage).Copy: error creating latest symlink: %w", err)
+		}
+		b.Log(storage.LogLevelInfo, b.Name(), "Created/Updated symlink `%s` for latest backup.", b.latestSymlink)
+	}
+
+	return nil
+}
+
+// Prune rotates away backups according to the configuration and provided deadline for the local storage backend.
+func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
+	globPattern := path.Join(
+		b.DestinationPath,
+		fmt.Sprintf("%s*", pruningPrefix),
+	)
+	globMatches, err := filepath.Glob(globPattern)
+	if err != nil {
+		return nil, fmt.Errorf(
+			"(*localStorage).Prune: Error looking up matching files using pattern %s: %w",
+			globPattern,
+			err,
+		)
+	}
+
+	var candidates []string
+	for _, candidate := range globMatches {
+		fi, err := os.Lstat(candidate)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"(*localStorage).Prune: Error calling Lstat on file %s: %w",
+				candidate,
+				err,
+			)
+		}
+
+		if fi.Mode()&os.ModeSymlink != os.ModeSymlink {
+			candidates = append(candidates, candidate)
+		}
+	}
+
+	var matches []string
+	for _, candidate := range candidates {
+		fi, err := os.Stat(candidate)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"(*localStorage).Prune: Error calling stat on file %s: %w",
+				candidate,
+				err,
+			)
+		}
+		if fi.ModTime().Before(deadline) {
+			matches = append(matches, candidate)
+		}
+	}
+
+	stats := &storage.PruneStats{
+		Total:  uint(len(candidates)),
+		Pruned: uint(len(matches)),
+	}
+
+	pruneErr := b.DoPrune(b.Name(), len(matches), len(candidates), deadline, func() error {
+		var removeErrors []error
+		for _, match := range matches {
+			if err := os.Remove(match); err != nil {
+				removeErrors = append(removeErrors, err)
+			}
+		}
+		if len(removeErrors) != 0 {
+			return fmt.Errorf(
+				"(*localStorage).Prune: %d error(s) deleting files, starting with: %w",
+				len(removeErrors),
+				errors.Join(removeErrors...),
+			)
+		}
+		return nil
+	})
+
+	return stats, pruneErr
+}
+
+// copy creates a copy of the file located at `dst` at `src`.
+func copyFile(src, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.Copy(out, in)
+	if err != nil {
+		out.Close()
+		return err
+	}
+	return out.Close()
+}

internal/storage/s3/s3.go

@@ -0,0 +1,192 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package s3
+
+import (
+	"context"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"time"
+
+	"github.com/minio/minio-go/v7"
+	"github.com/minio/minio-go/v7/pkg/credentials"
+	"github.com/offen/docker-volume-backup/internal/storage"
+)
+
+type s3Storage struct {
+	*storage.StorageBackend
+	client       *minio.Client
+	bucket       string
+	storageClass string
+	partSize     int64
+}
+
+// Config contains values that define the configuration of a S3 backend.
+type Config struct {
+	Endpoint         string
+	AccessKeyID      string
+	SecretAccessKey  string
+	IamRoleEndpoint  string
+	EndpointProto    string
+	EndpointInsecure bool
+	RemotePath       string
+	BucketName       string
+	StorageClass     string
+	PartSize         int64
+	CACert           *x509.Certificate
+}
+
+// NewStorageBackend creates and initializes a new S3/Minio storage backend.
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
+	var creds *credentials.Credentials
+	if opts.AccessKeyID != "" && opts.SecretAccessKey != "" {
+		creds = credentials.NewStaticV4(
+			opts.AccessKeyID,
+			opts.SecretAccessKey,
+			"",
+		)
+	} else if opts.IamRoleEndpoint != "" {
+		creds = credentials.NewIAM(opts.IamRoleEndpoint)
+	} else {
+		return nil, errors.New("NewStorageBackend: AWS_S3_BUCKET_NAME is defined, but no credentials were provided")
+	}
+
+	options := minio.Options{
+		Creds:  creds,
+		Secure: opts.EndpointProto == "https",
+	}
+
+	transport, err := minio.DefaultTransport(true)
+	if err != nil {
+		return nil, fmt.Errorf("NewStorageBackend: failed to create default minio transport: %w", err)
+	}
+
+	if opts.EndpointInsecure {
+		if !options.Secure {
+			return nil, errors.New("NewStorageBackend: AWS_ENDPOINT_INSECURE = true is only meaningful for https")
+		}
+		transport.TLSClientConfig.InsecureSkipVerify = true
+	} else if opts.CACert != nil {
+		if transport.TLSClientConfig.RootCAs == nil {
+			transport.TLSClientConfig.RootCAs = x509.NewCertPool()
+		}
+		transport.TLSClientConfig.RootCAs.AddCert(opts.CACert)
+	}
+	options.Transport = transport
+
+	mc, err := minio.New(opts.Endpoint, &options)
+	if err != nil {
+		return nil, fmt.Errorf("NewStorageBackend: error setting up minio client: %w", err)
+	}
+
+	return &s3Storage{
+		StorageBackend: &storage.StorageBackend{
+			DestinationPath: opts.RemotePath,
+			Log:             logFunc,
+		},
+		client:       mc,
+		bucket:       opts.BucketName,
+		storageClass: opts.StorageClass,
+		partSize:     opts.PartSize,
+	}, nil
+}
+
+// Name returns the name of the storage backend
+func (v *s3Storage) Name() string {
+	return "S3"
+}
+
+// Copy copies the given file to the S3/Minio storage backend.
+func (b *s3Storage) Copy(file string) error {
+	_, name := path.Split(file)
+	putObjectOptions := minio.PutObjectOptions{
+		ContentType:  "application/tar+gzip",
+		StorageClass: b.storageClass,
+	}
+
+	if b.partSize > 0 {
+		srcFileInfo, err := os.Stat(file)
+		if err != nil {
+			return fmt.Errorf("(*s3Storage).Copy: error reading the local file: %w", err)
+		}
+
+		_, partSize, _, err := minio.OptimalPartInfo(srcFileInfo.Size(), uint64(b.partSize*1024*1024))
+		if err != nil {
+			return fmt.Errorf("(*s3Storage).Copy: error computing the optimal s3 part size: %w", err)
+		}
+
+		putObjectOptions.PartSize = uint64(partSize)
+	}
+
+	if _, err := b.client.FPutObject(context.Background(), b.bucket, filepath.Join(b.DestinationPath, name), file, putObjectOptions); err != nil {
+		if errResp := minio.ToErrorResponse(err); errResp.Message != "" {
+			return fmt.Errorf(
+				"(*s3Storage).Copy: error uploading backup to remote storage: [Message]: '%s', [Code]: %s, [StatusCode]: %d",
+				errResp.Message,
+				errResp.Code,
+				errResp.StatusCode,
+			)
+		}
+		return fmt.Errorf("(*s3Storage).Copy: error uploading backup to remote storage: %w", err)
+	}
+
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to bucket `%s`.", file, b.bucket)
+
+	return nil
+}
+
+// Prune rotates away backups according to the configuration and provided deadline for the S3/Minio storage backend.
+func (b *s3Storage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
+	candidates := b.client.ListObjects(context.Background(), b.bucket, minio.ListObjectsOptions{
+		Prefix:    filepath.Join(b.DestinationPath, pruningPrefix),
+		Recursive: true,
+	})
+
+	var matches []minio.ObjectInfo
+	var lenCandidates int
+	for candidate := range candidates {
+		lenCandidates++
+		if candidate.Err != nil {
+			return nil, fmt.Errorf(
+				"(*s3Storage).Prune: error looking up candidates from remote storage! %w",
+				candidate.Err,
+			)
+		}
+		if candidate.LastModified.Before(deadline) {
+			matches = append(matches, candidate)
+		}
+	}
+
+	stats := &storage.PruneStats{
+		Total:  uint(lenCandidates),
+		Pruned: uint(len(matches)),
+	}
+
+	pruneErr := b.DoPrune(b.Name(), len(matches), lenCandidates, deadline, func() error {
+		objectsCh := make(chan minio.ObjectInfo)
+		go func() {
+			for _, match := range matches {
+				objectsCh <- match
+			}
+			close(objectsCh)
+		}()
+		errChan := b.client.RemoveObjects(context.Background(), b.bucket, objectsCh, minio.RemoveObjectsOptions{})
+		var removeErrors []error
+		for result := range errChan {
+			if result.Err != nil {
+				removeErrors = append(removeErrors, result.Err)
+			}
+		}
+		if len(removeErrors) != 0 {
+			return errors.Join(removeErrors...)
+		}
+		return nil
+	})
+
+	return stats, pruneErr
+}

internal/storage/ssh/ssh.go

@@ -0,0 +1,191 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package ssh
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/offen/docker-volume-backup/internal/storage"
+	"github.com/pkg/sftp"
+	"golang.org/x/crypto/ssh"
+)
+
+type sshStorage struct {
+	*storage.StorageBackend
+	client     *ssh.Client
+	sftpClient *sftp.Client
+	hostName   string
+}
+
+// Config allows to configure a SSH backend.
+type Config struct {
+	HostName           string
+	Port               string
+	User               string
+	Password           string
+	IdentityFile       string
+	IdentityPassphrase string
+	RemotePath         string
+}
+
+// NewStorageBackend creates and initializes a new SSH storage backend.
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
+	var authMethods []ssh.AuthMethod
+
+	if opts.Password != "" {
+		authMethods = append(authMethods, ssh.Password(opts.Password))
+	}
+
+	if _, err := os.Stat(opts.IdentityFile); err == nil {
+		key, err := os.ReadFile(opts.IdentityFile)
+		if err != nil {
+			return nil, errors.New("NewStorageBackend: error reading the private key")
+		}
+
+		var signer ssh.Signer
+		if opts.IdentityPassphrase != "" {
+			signer, err = ssh.ParsePrivateKeyWithPassphrase(key, []byte(opts.IdentityPassphrase))
+			if err != nil {
+				return nil, errors.New("NewStorageBackend: error parsing the encrypted private key")
+			}
+			authMethods = append(authMethods, ssh.PublicKeys(signer))
+		} else {
+			signer, err = ssh.ParsePrivateKey(key)
+			if err != nil {
+				return nil, errors.New("NewStorageBackend: error parsing the private key")
+			}
+			authMethods = append(authMethods, ssh.PublicKeys(signer))
+		}
+	}
+
+	sshClientConfig := &ssh.ClientConfig{
+		User:            opts.User,
+		Auth:            authMethods,
+		HostKeyCallback: ssh.InsecureIgnoreHostKey(),
+	}
+	sshClient, err := ssh.Dial("tcp", fmt.Sprintf("%s:%s", opts.HostName, opts.Port), sshClientConfig)
+
+	if err != nil {
+		return nil, fmt.Errorf("NewStorageBackend: error creating ssh client: %w", err)
+	}
+	_, _, err = sshClient.SendRequest("keepalive", false, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	sftpClient, err := sftp.NewClient(sshClient,
+		sftp.UseConcurrentReads(true),
+		sftp.UseConcurrentWrites(true),
+		sftp.MaxConcurrentRequestsPerFile(64),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("NewStorageBackend: error creating sftp client: %w", err)
+	}
+
+	return &sshStorage{
+		StorageBackend: &storage.StorageBackend{
+			DestinationPath: opts.RemotePath,
+			Log:             logFunc,
+		},
+		client:     sshClient,
+		sftpClient: sftpClient,
+		hostName:   opts.HostName,
+	}, nil
+}
+
+// Name returns the name of the storage backend
+func (b *sshStorage) Name() string {
+	return "SSH"
+}
+
+// Copy copies the given file to the SSH storage backend.
+func (b *sshStorage) Copy(file string) error {
+	source, err := os.Open(file)
+	_, name := path.Split(file)
+	if err != nil {
+		return fmt.Errorf("(*sshStorage).Copy: error reading the file to be uploaded: %w", err)
+	}
+	defer source.Close()
+
+	destination, err := b.sftpClient.Create(filepath.Join(b.DestinationPath, name))
+	if err != nil {
+		return fmt.Errorf("(*sshStorage).Copy: error creating file: %w", err)
+	}
+	defer destination.Close()
+
+	chunk := make([]byte, 1e9)
+	for {
+		num, err := source.Read(chunk)
+		if err == io.EOF {
+			tot, err := destination.Write(chunk[:num])
+			if err != nil {
+				return fmt.Errorf("(*sshStorage).Copy: error uploading the file: %w", err)
+			}
+
+			if tot != len(chunk[:num]) {
+				return errors.New("(*sshStorage).Copy: failed to write stream")
+			}
+
+			break
+		}
+
+		if err != nil {
+			return fmt.Errorf("(*sshStorage).Copy: error uploading the file: %w", err)
+		}
+
+		tot, err := destination.Write(chunk[:num])
+		if err != nil {
+			return fmt.Errorf("(*sshStorage).Copy: error uploading the file: %w", err)
+		}
+
+		if tot != len(chunk[:num]) {
+			return fmt.Errorf("(*sshStorage).Copy: failed to write stream")
+		}
+	}
+
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to '%s' at path '%s'.", file, b.hostName, b.DestinationPath)
+
+	return nil
+}
+
+// Prune rotates away backups according to the configuration and provided deadline for the SSH storage backend.
+func (b *sshStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
+	candidates, err := b.sftpClient.ReadDir(b.DestinationPath)
+	if err != nil {
+		return nil, fmt.Errorf("(*sshStorage).Prune: error reading directory: %w", err)
+	}
+
+	var matches []string
+	for _, candidate := range candidates {
+		if !strings.HasPrefix(candidate.Name(), pruningPrefix) {
+			continue
+		}
+		if candidate.ModTime().Before(deadline) {
+			matches = append(matches, candidate.Name())
+		}
+	}
+
+	stats := &storage.PruneStats{
+		Total:  uint(len(candidates)),
+		Pruned: uint(len(matches)),
+	}
+
+	pruneErr := b.DoPrune(b.Name(), len(matches), len(candidates), deadline, func() error {
+		for _, match := range matches {
+			if err := b.sftpClient.Remove(filepath.Join(b.DestinationPath, match)); err != nil {
+				return fmt.Errorf("(*sshStorage).Prune: error removing file: %w", err)
+			}
+		}
+		return nil
+	})
+
+	return stats, pruneErr
+}

internal/storage/storage.go

@@ -0,0 +1,65 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package storage
+
+import (
+	"fmt"
+	"time"
+)
+
+// Backend is an interface for defining functions which all storage providers support.
+type Backend interface {
+	Copy(file string) error
+	Prune(deadline time.Time, pruningPrefix string) (*PruneStats, error)
+	Name() string
+}
+
+// StorageBackend is a generic type of storage. Everything here are common properties of all storage types.
+type StorageBackend struct {
+	DestinationPath string
+	Log             Log
+}
+
+type LogLevel int
+
+const (
+	LogLevelInfo LogLevel = iota
+	LogLevelWarning
+	LogLevelError
+)
+
+type Log func(logType LogLevel, context string, msg string, params ...any)
+
+// PruneStats is a wrapper struct for returning stats after pruning
+type PruneStats struct {
+	Total  uint
+	Pruned uint
+}
+
+// DoPrune holds general control flow that applies to any kind of storage.
+// Callers can pass in a thunk that performs the actual deletion of files.
+func (b *StorageBackend) DoPrune(context string, lenMatches, lenCandidates int, deadline time.Time, doRemoveFiles func() error) error {
+	if lenMatches != 0 && lenMatches != lenCandidates {
+		if err := doRemoveFiles(); err != nil {
+			return err
+		}
+
+		formattedDeadline, err := deadline.Local().MarshalText()
+		if err != nil {
+			return fmt.Errorf("(*StorageBackend).DoPrune: error marshaling deadline: %w", err)
+		}
+		b.Log(LogLevelInfo, context,
+			"Pruned %d out of %d backups as they were older than the given deadline of %s.",
+			lenMatches,
+			lenCandidates,
+			string(formattedDeadline),
+		)
+	} else if lenMatches != 0 && lenMatches == lenCandidates {
+		b.Log(LogLevelWarning, context, "The current configuration would delete all %d existing backups.", lenMatches)
+		b.Log(LogLevelWarning, context, "Refusing to do so, please check your configuration.")
+	} else {
+		b.Log(LogLevelInfo, context, "None of %d existing backups were pruned.", lenCandidates)
+	}
+	return nil
+}

internal/storage/webdav/webdav.go

@@ -0,0 +1,120 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package webdav
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/offen/docker-volume-backup/internal/storage"
+	"github.com/studio-b12/gowebdav"
+)
+
+type webDavStorage struct {
+	*storage.StorageBackend
+	client *gowebdav.Client
+	url    string
+}
+
+// Config allows to configure a WebDAV storage backend.
+type Config struct {
+	URL         string
+	RemotePath  string
+	Username    string
+	Password    string
+	URLInsecure bool
+}
+
+// NewStorageBackend creates and initializes a new WebDav storage backend.
+func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error) {
+	if opts.Username == "" || opts.Password == "" {
+		return nil, errors.New("NewStorageBackend: WEBDAV_URL is defined, but no credentials were provided")
+	} else {
+		webdavClient := gowebdav.NewClient(opts.URL, opts.Username, opts.Password)
+
+		if opts.URLInsecure {
+			defaultTransport, ok := http.DefaultTransport.(*http.Transport)
+			if !ok {
+				return nil, errors.New("NewStorageBackend: unexpected error when asserting type for http.DefaultTransport")
+			}
+			webdavTransport := defaultTransport.Clone()
+			webdavTransport.TLSClientConfig.InsecureSkipVerify = opts.URLInsecure
+			webdavClient.SetTransport(webdavTransport)
+		}
+
+		return &webDavStorage{
+			StorageBackend: &storage.StorageBackend{
+				DestinationPath: opts.RemotePath,
+				Log:             logFunc,
+			},
+			client: webdavClient,
+		}, nil
+	}
+}
+
+// Name returns the name of the storage backend
+func (b *webDavStorage) Name() string {
+	return "WebDAV"
+}
+
+// Copy copies the given file to the WebDav storage backend.
+func (b *webDavStorage) Copy(file string) error {
+	_, name := path.Split(file)
+	if err := b.client.MkdirAll(b.DestinationPath, 0644); err != nil {
+		return fmt.Errorf("(*webDavStorage).Copy: error creating directory '%s' on server: %w", b.DestinationPath, err)
+	}
+
+	r, err := os.Open(file)
+	if err != nil {
+		return fmt.Errorf("(*webDavStorage).Copy: error opening the file to be uploaded: %w", err)
+	}
+
+	if err := b.client.WriteStream(filepath.Join(b.DestinationPath, name), r, 0644); err != nil {
+		return fmt.Errorf("(*webDavStorage).Copy: error uploading the file: %w", err)
+	}
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup '%s' to '%s' at path '%s'.", file, b.url, b.DestinationPath)
+
+	return nil
+}
+
+// Prune rotates away backups according to the configuration and provided deadline for the WebDav storage backend.
+func (b *webDavStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.PruneStats, error) {
+	candidates, err := b.client.ReadDir(b.DestinationPath)
+	if err != nil {
+		return nil, fmt.Errorf("(*webDavStorage).Prune: error looking up candidates from remote storage: %w", err)
+	}
+	var matches []fs.FileInfo
+	var lenCandidates int
+	for _, candidate := range candidates {
+		if !strings.HasPrefix(candidate.Name(), pruningPrefix) {
+			continue
+		}
+		lenCandidates++
+		if candidate.ModTime().Before(deadline) {
+			matches = append(matches, candidate)
+		}
+	}
+
+	stats := &storage.PruneStats{
+		Total:  uint(lenCandidates),
+		Pruned: uint(len(matches)),
+	}
+
+	pruneErr := b.DoPrune(b.Name(), len(matches), lenCandidates, deadline, func() error {
+		for _, match := range matches {
+			if err := b.client.Remove(filepath.Join(b.DestinationPath, match.Name())); err != nil {
+				return fmt.Errorf("(*webDavStorage).Prune: error removing file: %w", err)
+			}
+		}
+		return nil
+	})
+	return stats, pruneErr
+}

test/Dockerfile

@@ -0,0 +1,13 @@
+FROM docker:24-dind
+
+RUN apk add \
+  coreutils \
+  curl \
+  gpg \
+  jq \
+  moreutils \
+  tar \
+  zstd \
+  --no-cache
+
+WORKDIR /code/test

test/README.md

@@ -0,0 +1,70 @@
+# Integration Tests
+
+## Running tests
+
+The main entry point for running tests is the `./test.sh` script.
+It can be used to run the entire test suite, or just a single test case.
+
+### Run all tests
+
+```sh
+./test.sh
+```
+
+### Run a single test case
+
+```sh
+./test.sh <directory-name>
+```
+
+### Configuring a test run
+
+In addition to the match pattern, which can be given as the first positional argument, certain behavior can be changed by setting environment variables:
+
+#### `BUILD_IMAGE`
+
+When set, the test script will build an up-to-date `docker-volume-backup` image from the current state of your source tree, and run the tests against it.
+
+```sh
+BUILD_IMAGE=1 ./test.sh
+```
+
+The default behavior is not to build an image, and instead look for a version on your host system.
+
+#### `IMAGE_TAG`
+
+Setting this value lets you run tests against different existing images, so you can compare behavior:
+
+```sh
+IMAGE_TAG=v2.30.0 ./test.sh
+```
+
+#### `NO_IMAGE_CACHE`
+
+When set, images from remote registries will not be cached and shared between sandbox containers.
+
+```sh
+NO_IMAGE_CACHE=1 ./test.sh
+```
+
+By default, two local images are created that persist the image data and provide it to containers at runtime.
+
+## Understanding the test setup
+
+The test setup runs each test case in an isolated Docker container, which itself is running an otherwise unused Docker daemon.
+This means, tests can rely on noone else using that daemon, making expectations about the number of running containers and so forth.
+As the sandbox container is also expected to be torn down post test, the scripts do not need to do any clean up or similar.
+
+## Anatomy of a test case
+
+The `test.sh` script looks for an exectuable file called `run.sh` in each directory.
+When found, it is executed and signals success by returning a 0 exit code.
+Any other exit code is considered a failure and will halt execution of further tests.
+
+There is an `util.sh` file containing a few commonly used helpers which can be used by putting the following prelude to a new test case:
+
+```sh
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+```

test/azure/docker-compose.yml

@@ -0,0 +1,56 @@
+version: '3'
+
+services:
+  storage:
+    image: mcr.microsoft.com/azure-storage/azurite:3.26.0
+    volumes:
+      - ${DATA_DIR:-./data}:/data
+    command: azurite-blob --blobHost 0.0.0.0 --blobPort 10000 --location /data
+    healthcheck:
+      test: nc 127.0.0.1 10000 -z
+      interval: 1s
+      retries: 30
+
+  az_cli:
+    image: mcr.microsoft.com/azure-cli:2.51.0
+    volumes:
+      - ${LOCAL_DIR:-./local}:/dump
+    command:
+      - /bin/sh
+      - -c
+      - |
+          az storage container create --name test-container
+    depends_on:
+      storage:
+        condition: service_healthy
+    environment:
+      AZURE_STORAGE_CONNECTION_STRING: DefaultEndpointsProtocol=http;AccountName=devstoreaccount1;AccountKey=Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==;BlobEndpoint=http://storage:10000/devstoreaccount1;
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    hostname: hostnametoken
+    restart: always
+    environment:
+      AZURE_STORAGE_ACCOUNT_NAME: devstoreaccount1
+      AZURE_STORAGE_PRIMARY_ACCOUNT_KEY: Eby8vdM02xNOcqFlqUwJPLlmEtlCDXJ1OUzFT50uSRZ6IFsuFq2UVErCz4I6tq/K1SZFPTOtr/KBHBeksoGMGw==
+      AZURE_STORAGE_CONTAINER_NAME: test-container
+      AZURE_STORAGE_ENDPOINT: http://storage:10000/{{ .AccountName }}/
+      AZURE_STORAGE_PATH: 'path/to/backup'
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_RETENTION_DAYS: ${BACKUP_RETENTION_DAYS:-7}
+      BACKUP_PRUNING_LEEWAY: 5s
+      BACKUP_PRUNING_PREFIX: test
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:

test/azure/run.sh

@@ -0,0 +1,86 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export LOCAL_DIR=$(mktemp -d)
+export TMP_DIR=$(mktemp -d)
+export DATA_DIR=$(mktemp -d)
+
+download_az () {
+  docker compose run --rm az_cli \
+    az storage blob download -f /dump/$1.tar.gz -c test-container -n path/to/backup/$1.tar.gz
+}
+
+docker compose up -d --quiet-pull
+
+sleep 5
+
+docker compose exec backup backup
+
+sleep 5
+
+expect_running_containers "3"
+
+download_az "test"
+
+tar -xvf "$LOCAL_DIR/test.tar.gz" -C $TMP_DIR
+
+if [ ! -f "$TMP_DIR/backup/app_data/offen.db" ]; then
+  fail "Could not find expeced file in untared backup"
+fi
+
+pass "Found relevant files in untared remote backups."
+rm "$LOCAL_DIR/test.tar.gz"
+
+# The second part of this test checks if backups get deleted when the retention
+# is set to 0 days (which it should not as it would mean all backups get deleted)
+BACKUP_RETENTION_DAYS="0" docker compose up -d
+sleep 5
+
+docker compose exec backup backup
+
+download_az "test"
+if [ ! -f "$LOCAL_DIR/test.tar.gz" ]; then
+  fail "Remote backup was deleted"
+fi
+pass "Remote backups have not been deleted."
+
+# The third part of this test checks if old backups get deleted when the retention
+# is set to 7 days (which it should)
+
+BACKUP_RETENTION_DAYS="7" docker compose up -d
+sleep 5
+
+info "Create first backup with no prune"
+docker compose exec backup backup
+
+docker compose run --rm az_cli \
+    az storage blob upload -f /dump/test.tar.gz -c test-container -n path/to/backup/test-old.tar.gz
+
+docker compose down
+rm "$LOCAL_DIR/test.tar.gz"
+
+back_date="$(date "+%Y-%m-%dT%H:%M:%S%z" -d "14 days ago" | rev | cut -c 3- | rev):00"
+jq --arg back_date "$back_date" '(.collections[] | select(.name=="$BLOBS_COLLECTION$") | .data[] | select(.name=="path/to/backup/test-old.tar.gz") | .properties.creationTime = $back_date)' "$DATA_DIR/__azurite_db_blob__.json" | sponge "$DATA_DIR/__azurite_db_blob__.json"
+
+docker compose up -d
+sleep 5
+
+info "Create second backup and prune"
+docker compose exec backup backup
+
+info "Download first backup which should be pruned"
+download_az "test-old" || true
+if [ -f "$LOCAL_DIR/test-old.tar.gz" ]; then
+  fail "Backdated file was not deleted"
+fi
+download_az "test" || true
+if [ ! -f "$LOCAL_DIR/test.tar.gz" ]; then
+  fail "Recent file was not found"
+fi
+
+pass "Old remote backup has been pruned, new one is still present."

test/certs/docker-compose.yml

@@ -0,0 +1,48 @@
+version: '3'
+
+services:
+  minio:
+    hostname: minio.local
+    image: minio/minio:RELEASE.2020-08-04T23-10-51Z
+    environment:
+      MINIO_ROOT_USER: test
+      MINIO_ROOT_PASSWORD: test
+      MINIO_ACCESS_KEY: test
+      MINIO_SECRET_KEY: GMusLtUmILge2by+z890kQ
+    entrypoint: /bin/ash -c 'mkdir -p /data/backup && minio server --certs-dir "/certs" --address ":443" /data'
+    volumes:
+      - minio_backup_data:/data
+      - ${CERT_DIR:-.}/minio.crt:/certs/public.crt
+      - ${CERT_DIR:-.}/minio.key:/certs/private.key
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    depends_on:
+      - minio
+    restart: always
+    environment:
+      BACKUP_FILENAME: test.tar.gz
+      AWS_ACCESS_KEY_ID: test
+      AWS_SECRET_ACCESS_KEY: GMusLtUmILge2by+z890kQ
+      AWS_ENDPOINT: minio.local:443
+      AWS_ENDPOINT_CA_CERT: /root/minio-rootCA.crt
+      AWS_S3_BUCKET_NAME: backup
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_RETENTION_DAYS: ${BACKUP_RETENTION_DAYS:-7}
+      BACKUP_PRUNING_LEEWAY: 5s
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+      - ${CERT_DIR:-.}/rootCA.crt:/root/minio-rootCA.crt
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  minio_backup_data:
+    name: minio_backup_data
+  app_data:

test/certs/run.sh

@@ -0,0 +1,43 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export CERT_DIR=$(mktemp -d)
+
+openssl genrsa -des3 -passout pass:test -out "$CERT_DIR/rootCA.key" 4096
+openssl req -passin pass:test \
+  -subj "/C=DE/ST=BE/O=IntegrationTest, Inc." \
+  -x509 -new -key "$CERT_DIR/rootCA.key" -sha256 -days 1 -out "$CERT_DIR/rootCA.crt"
+
+openssl genrsa -out "$CERT_DIR/minio.key" 4096
+openssl req -new -sha256 -key "$CERT_DIR/minio.key" \
+  -subj "/C=DE/ST=BE/O=IntegrationTest, Inc./CN=minio" \
+  -out "$CERT_DIR/minio.csr"
+
+openssl x509 -req -passin pass:test \
+  -in "$CERT_DIR/minio.csr" \
+  -CA "$CERT_DIR/rootCA.crt" -CAkey "$CERT_DIR/rootCA.key" -CAcreateserial \
+  -extfile san.cnf \
+  -out "$CERT_DIR/minio.crt" -days 1 -sha256
+
+openssl x509 -in "$CERT_DIR/minio.crt" -noout -text
+
+docker compose up -d --quiet-pull
+sleep 5
+
+docker compose exec backup backup
+
+sleep 5
+
+expect_running_containers "3"
+
+docker run --rm \
+  -v minio_backup_data:/minio_data \
+  alpine \
+  ash -c 'tar -xvf /minio_data/backup/test.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db'
+
+pass "Found relevant files in untared remote backups."

test/certs/san.cnf

@@ -0,0 +1 @@
+subjectAltName = DNS:minio.local

test/cli/run.sh

@@ -3,6 +3,8 @@
 set -e
 
 cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
 
 docker network create test_network
 docker volume create backup_data
@@ -11,7 +13,7 @@ docker volume create app_data
 # correctly. It is not supposed to hold any data.
 docker volume create empty_data
 
-docker run -d \
+docker run -d -q \
   --name minio \
   --network test_network \
   --env MINIO_ROOT_USER=test \
@@ -23,7 +25,7 @@ docker run -d \
 
 docker exec minio mkdir -p /data/backup
 
-docker run -d \
+docker run -d -q \
   --name offen \
   --network test_network \
   -v app_data:/var/opt/offen/ \
@@ -31,7 +33,7 @@ docker run -d \
 
 sleep 10
 
-docker run --rm \
+docker run --rm -q \
   --network test_network \
   -v app_data:/backup/app_data \
   -v empty_data:/backup/empty_data \
@@ -46,21 +48,15 @@ docker run --rm \
   --entrypoint backup \
   offen/docker-volume-backup:${TEST_VERSION:-canary}
 
-docker run --rm -it \
+docker run --rm -q \
   -v backup_data:/data alpine \
   ash -c 'tar -xvf /data/backup/test.tar.gz && test -f /backup/app_data/offen.db && test -d /backup/empty_data'
 
-echo "[TEST:PASS] Found relevant files in untared remote backup."
+pass "Found relevant files in untared remote backup."
 
 # This test does not stop containers during backup. This is happening on
 # purpose in order to cover this setup as well.
-if [ "$(docker ps -q | wc -l)" != "2" ]; then
-  echo "[TEST:FAIL] Expected all containers to be running post backup, instead seen:"
-  docker ps
-  exit 1
-fi
-
-echo "[TEST:PASS] All containers running post backup."
+expect_running_containers "2"
 
 docker rm $(docker stop minio offen)
 docker volume rm backup_data app_data

test/commands/.gitignore

@@ -1 +0,0 @@
-local

test/commands/docker-compose.yml

@@ -10,12 +10,27 @@ services:
       MARIADB_ROOT_PASSWORD: test
       MARIADB_DATABASE: backup
     labels:
+      # this is testing the deprecated label on purpose
       - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump -ptest --all-databases > /tmp/volume/dump.sql'
-      - docker-volume-backup.exec-post=/bin/sh -c 'echo "post" > /tmp/volume/post.txt'
+      - docker-volume-backup.copy-post=/bin/sh -c 'echo "post" > /tmp/volume/post.txt'
       - docker-volume-backup.exec-label=test
     volumes:
       - app_data:/tmp/volume
 
+  other_database:
+    image: mariadb:10.7
+    deploy:
+      restart_policy:
+        condition: on-failure
+    environment:
+      MARIADB_ROOT_PASSWORD: test
+      MARIADB_DATABASE: backup
+    labels:
+      - docker-volume-backup.archive-pre=touch /tmp/volume/not-relevant.txt
+      - docker-volume-backup.exec-label=not-relevant
+    volumes:
+      - app_data:/tmp/volume
+
   backup:
     image: offen/docker-volume-backup:${TEST_VERSION:-canary}
     deploy:
@@ -27,10 +42,9 @@ services:
       EXEC_LABEL: test
       EXEC_FORWARD_OUTPUT: "true"
     volumes:
-      - archive:/archive
+      - ${LOCAL_DIR:-./local}:/archive
       - app_data:/backup/data:ro
       - /var/run/docker.sock:/var/run/docker.sock
 
 volumes:
   app_data:
-  archive:

test/commands/run.sh

@@ -3,39 +3,46 @@
 set -e
 
 cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
 
+export LOCAL_DIR=$(mktemp -d)
+export TMP_DIR=$(mktemp -d)
 
-docker-compose up -d
+docker compose up -d --quiet-pull
 sleep 30 # mariadb likes to take a bit before responding
 
-docker-compose exec backup backup
-sudo cp -r $(docker volume inspect --format='{{ .Mountpoint }}' commands_archive) ./local
+docker compose exec backup backup
 
-tar -xvf ./local/test.tar.gz
-if [ ! -f ./backup/data/dump.sql ]; then
-  echo "[TEST:FAIL] Could not find file written by pre command."
-  exit 1
+tar -xvf "$LOCAL_DIR/test.tar.gz" -C $TMP_DIR
+if [ ! -f "$TMP_DIR/backup/data/dump.sql" ]; then
+  fail "Could not find file written by pre command."
 fi
-echo "[TEST:PASS] Found expected file."
+pass "Found expected file."
 
-if [ -f ./backup/data/post.txt ]; then
-  echo "[TEST:FAIL] File created in post command was present in backup."
-  exit 1
+if [ -f "$TMP_DIR/backup/data/not-relevant.txt" ]; then
+  fail "Command ran for container with other label."
 fi
-echo "[TEST:PASS] Did not find unexpected file."
+pass "Command did not run for container with other label."
 
-docker-compose down --volumes
-sudo rm -rf ./local
+if [ -f "$TMP_DIR/backup/data/post.txt" ]; then
+  fail "File created in post command was present in backup."
+fi
+pass "Did not find unexpected file."
 
+docker compose down --volumes
 
-echo "[TEST:INFO] Running commands test in swarm mode next."
+info "Running commands test in swarm mode next."
+
+export LOCAL_DIR=$(mktemp -d)
+export TMP_DIR=$(mktemp -d)
 
 docker swarm init
 
 docker stack deploy --compose-file=docker-compose.yml test_stack
 
 while [ -z $(docker ps -q -f name=backup) ]; do
-  echo "[TEST:INFO] Backup container not ready yet. Retrying."
+  info "Backup container not ready yet. Retrying."
   sleep 1
 done
 
@@ -43,20 +50,13 @@ sleep 20
 
 docker exec $(docker ps -q -f name=backup) backup
 
-sudo cp -r $(docker volume inspect --format='{{ .Mountpoint }}' test_stack_archive) ./local
-
-tar -xvf ./local/test.tar.gz
-if [ ! -f ./backup/data/dump.sql ]; then
-  echo "[TEST:FAIL] Could not find file written by pre command."
-  exit 1
+tar -xvf "$LOCAL_DIR/test.tar.gz" -C $TMP_DIR
+if [ ! -f "$TMP_DIR/backup/data/dump.sql" ]; then
+  fail "Could not find file written by pre command."
 fi
-echo "[TEST:PASS] Found expected file."
+pass "Found expected file."
 
-if [ -f ./backup/data/post.txt ]; then
-  echo "[TEST:FAIL] File created in post command was present in backup."
-  exit 1
+if [ -f "$TMP_DIR/backup/data/post.txt" ]; then
+  fail "File created in post command was present in backup."
 fi
-echo "[TEST:PASS] Did not find unexpected file."
-
-docker stack rm test_stack
-docker swarm leave --force
+pass "Did not find unexpected file."

test/compose/.gitignore

@@ -1 +0,0 @@
-local

test/compose/run.sh

@@ -1,68 +0,0 @@
-#!/bin/sh
-
-set -e
-
-cd $(dirname $0)
-
-mkdir -p local
-
-docker-compose up -d
-sleep 5
-
-# A symlink for a known file in the volume is created so the test can check
-# whether symlinks are preserved on backup.
-docker-compose exec offen ln -s /var/opt/offen/offen.db /var/opt/offen/db.link
-docker-compose exec backup backup
-
-sleep 5
-if [ "$(docker-compose ps -q | wc -l)" != "4" ]; then
-  echo "[TEST:FAIL] Expected all containers to be running post backup, instead seen:"
-  docker-compose ps
-  exit 1
-fi
-echo "[TEST:PASS] All containers running post backup."
-
-
-docker run --rm -it \
-  -v compose_minio_backup_data:/minio_data \
-  -v compose_webdav_backup_data:/webdav_data alpine \
-  ash -c 'apk add gnupg && \
-          echo 1234secret | gpg -d --pinentry-mode loopback --passphrase-fd 0 --yes /minio_data/backup/test-hostnametoken.tar.gz.gpg > /tmp/test-hostnametoken.tar.gz && tar -xvf /tmp/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db && \
-          echo 1234secret | gpg -d --pinentry-mode loopback --passphrase-fd 0 --yes /webdav_data/data/my/new/path/test-hostnametoken.tar.gz.gpg > /tmp/test-hostnametoken.tar.gz && tar -xvf /tmp/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db'
-
-echo "[TEST:PASS] Found relevant files in decrypted and untared remote backups."
-
-echo 1234secret | gpg -d --pinentry-mode loopback --yes --passphrase-fd 0 ./local/test-hostnametoken.tar.gz.gpg > ./local/decrypted.tar.gz
-tar -xf ./local/decrypted.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db
-rm ./local/decrypted.tar.gz
-test -L /tmp/backup/app_data/db.link
-
-echo "[TEST:PASS] Found relevant files in decrypted and untared local backup."
-
-test -L ./local/test-hostnametoken.latest.tar.gz.gpg
-echo "[TEST:PASS] Found symlink to latest version in local backup."
-
-# The second part of this test checks if backups get deleted when the retention
-# is set to 0 days (which it should not as it would mean all backups get deleted)
-# TODO: find out if we can test actual deletion without having to wait for a day
-BACKUP_RETENTION_DAYS="0" docker-compose up -d
-sleep 5
-
-docker-compose exec backup backup
-
-docker run --rm -it \
-  -v compose_minio_backup_data:/minio_data \
-  -v compose_webdav_backup_data:/webdav_data alpine \
-  ash -c '[ $(find /minio_data/backup/ -type f | wc -l) = "1" ] && \
-          [ $(find /webdav_data/data/my/new/path/ -type f | wc -l) = "1" ]'
-
-echo "[TEST:PASS] Remote backups have not been deleted."
-
-if [ "$(find ./local -type f | wc -l)" != "1" ]; then
-  echo "[TEST:FAIL] Backups should not have been deleted, instead seen:"
-  find ./local -type f
-  exit 1
-fi
-echo "[TEST:PASS] Local backups have not been deleted."
-
-docker-compose down --volumes

test/confd/.gitignore

@@ -1 +0,0 @@
-local

test/confd/docker-compose.yml

@@ -5,7 +5,7 @@ services:
     image: offen/docker-volume-backup:${TEST_VERSION:-canary}
     restart: always
     volumes:
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive
       - app_data:/backup/app_data:ro
       - ./01backup.env:/etc/dockervolumebackup/conf.d/01backup.env
       - ./02backup.env:/etc/dockervolumebackup/conf.d/02backup.env

test/confd/run.sh

@@ -3,30 +3,27 @@
 set -e
 
 cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
 
-mkdir -p local
+export LOCAL_DIR=$(mktemp -d)
 
-docker-compose up -d
+docker compose up -d --quiet-pull
 
 # sleep until a backup is guaranteed to have happened on the 1 minute schedule
 sleep 100
 
-docker-compose down --volumes
-
-if [ ! -f ./local/conf.tar.gz ]; then
-  echo "[TEST:FAIL] Config from file was not used."
-  exit 1
+if [ ! -f "$LOCAL_DIR/conf.tar.gz" ]; then
+  fail "Config from file was not used."
 fi
-echo "[TEST:PASS] Config from file was used."
+pass "Config from file was used."
 
-if [ ! -f ./local/other.tar.gz ]; then
-  echo "[TEST:FAIL] Run on same schedule did not succeed."
-  exit 1
+if [ ! -f "$LOCAL_DIR/other.tar.gz" ]; then
+  fail "Run on same schedule did not succeed."
 fi
-echo "[TEST:PASS] Run on same schedule succeeded."
+pass "Run on same schedule succeeded."
 
-if [ -f ./local/never.tar.gz ]; then
-  echo "[TEST:FAIL] Unexpected file was found."
-  exit 1
+if [ -f "$LOCAL_DIR/never.tar.gz" ]; then
+  fail "Unexpected file was found."
 fi
-echo "[TEST:PASS] Unexpected cron did not run."
+pass "Unexpected cron did not run."

test/dropbox/.gitignore

@@ -0,0 +1 @@
+user_v2_ready.yaml

test/dropbox/docker-compose.yml

@@ -0,0 +1,57 @@
+version: '3'
+
+services:
+  openapi_mock:
+    image: muonsoft/openapi-mock:0.3.9
+    environment:
+      OPENAPI_MOCK_USE_EXAMPLES: if_present
+      OPENAPI_MOCK_SPECIFICATION_URL: '/etc/openapi/user_v2.yaml'
+    ports:
+      - 8080:8080
+    volumes:
+      - ${SPEC_FILE:-./user_v2.yaml}:/etc/openapi/user_v2.yaml
+
+  oauth2_mock:
+    image: ghcr.io/navikt/mock-oauth2-server:1.0.0
+    ports:
+      - 8090:8090
+    environment:
+      PORT: 8090
+      JSON_CONFIG_PATH: '/etc/oauth2/config.json'
+    volumes:
+      - ./oauth2_config.json:/etc/oauth2/config.json
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    hostname: hostnametoken
+    depends_on:
+      - openapi_mock
+      - oauth2_mock
+    restart: always
+    environment:
+      BACKUP_FILENAME_EXPAND: 'true'
+      BACKUP_FILENAME: test-$$HOSTNAME.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_RETENTION_DAYS: ${BACKUP_RETENTION_DAYS:-7}
+      BACKUP_PRUNING_LEEWAY: 5s
+      BACKUP_PRUNING_PREFIX: test
+      DROPBOX_ENDPOINT: http://openapi_mock:8080
+      DROPBOX_OAUTH2_ENDPOINT: http://oauth2_mock:8090
+      DROPBOX_REFRESH_TOKEN: test
+      DROPBOX_APP_KEY: test
+      DROPBOX_APP_SECRET: test
+      DROPBOX_REMOTE_PATH: /test
+      DROPBOX_CONCURRENCY_LEVEL: 6
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:

test/dropbox/oauth2_config.json

@@ -0,0 +1,37 @@
+{
+   "interactiveLogin": true,
+   "httpServer": "NettyWrapper",
+   "tokenCallbacks": [
+       {
+           "issuerId": "issuer1",
+           "tokenExpiry": 120,
+           "requestMappings": [
+               {
+                   "requestParam": "scope",
+                   "match": "scope1",
+                   "claims": {
+                       "sub": "subByScope",
+                       "aud": [
+                           "audByScope"
+                       ]
+                   }
+               }
+           ]
+       },
+       {
+           "issuerId": "issuer2",
+           "requestMappings": [
+               {
+                   "requestParam": "someparam",
+                   "match": "somevalue",
+                   "claims": {
+                       "sub": "subBySomeParam",
+                       "aud": [
+                           "audBySomeParam"
+                       ]
+                   }
+               }
+           ]
+       }
+   ]
+}

test/dropbox/run.sh

@@ -0,0 +1,61 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export SPEC_FILE=$(mktemp -d)/user_v2.yaml
+cp user_v2.yaml $SPEC_FILE
+sed -i 's/SERVER_MODIFIED_1/'"$(date "+%Y-%m-%dT%H:%M:%SZ")/g" $SPEC_FILE
+sed -i 's/SERVER_MODIFIED_2/'"$(date "+%Y-%m-%dT%H:%M:%SZ" -d "14 days ago")/g" $SPEC_FILE
+
+docker compose up -d --quiet-pull
+sleep 5
+
+logs=$(docker compose exec -T backup backup)
+
+sleep 5
+
+expect_running_containers "4"
+
+echo "$logs"
+if echo "$logs" | grep -q "ERROR"; then
+  fail "Backup failed, errors reported: $logs"
+else
+  pass "Backup succeeded, no errors reported."
+fi
+
+# The second part of this test checks if backups get deleted when the retention
+# is set to 0 days (which it should not as it would mean all backups get deleted)
+BACKUP_RETENTION_DAYS="0" docker compose up -d
+sleep 5
+
+logs=$(docker compose exec -T backup backup)
+
+echo "$logs"
+if echo "$logs" | grep -q "Refusing to do so, please check your configuration"; then
+  pass "Remote backups have not been deleted."
+else
+  fail "Remote backups would have been deleted: $logs"
+fi
+
+# The third part of this test checks if old backups get deleted when the retention
+# is set to 7 days (which it should)
+BACKUP_RETENTION_DAYS="7" docker compose up -d
+sleep 5
+
+info "Create second backup and prune"
+logs=$(docker compose exec -T backup backup)
+
+echo "$logs"
+if echo "$logs" | grep -q "Pruned 1 out of 2 backups as they were older"; then
+  pass "Old remote backup has been pruned, new one is still present."
+elif echo "$logs" | grep -q "ERROR"; then
+  fail "Pruning failed, errors reported: $logs"
+elif echo "$logs" | grep -q "None of 1 existing backups were pruned"; then
+  fail "Pruning failed, old backup has not been pruned: $logs"
+else
+  fail "Pruning failed, unknown result: $logs"
+fi

test/extend/Dockerfile

@@ -0,0 +1,4 @@
+ARG version=canary
+FROM offen/docker-volume-backup:$version
+
+RUN apk add rsync

test/extend/docker-compose.yml

@@ -0,0 +1,26 @@
+version: '3'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    restart: always
+    labels:
+      - docker-volume-backup.copy-post=/bin/sh -c 'mkdir -p /tmp/unpack && tar -xvf $$COMMAND_RUNTIME_ARCHIVE_FILEPATH -C /tmp/unpack && rsync -r /tmp/unpack/backup/app_data /local'
+    environment:
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      EXEC_FORWARD_OUTPUT: "true"
+    volumes:
+      - ${LOCAL_DIR:-local}:/local
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:

test/extend/run.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export LOCAL_DIR=$(mktemp -d)
+
+export BASE_VERSION="${TEST_VERSION:-canary}"
+export TEST_VERSION="${TEST_VERSION:-canary}-with-rsync"
+
+docker build . -t offen/docker-volume-backup:$TEST_VERSION --build-arg version=$BASE_VERSION
+
+docker compose up -d --quiet-pull
+sleep 5
+
+docker compose exec backup backup
+
+sleep 5
+
+expect_running_containers "2"
+
+if [ ! -f "$LOCAL_DIR/app_data/offen.db" ]; then
+  fail "Could not find expected file in untared archive."
+fi

test/gpg/docker-compose.yml

@@ -0,0 +1,26 @@
+version: '3'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    restart: always
+    environment:
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_LATEST_SYMLINK: test-latest.tar.gz.gpg
+      BACKUP_RETENTION_DAYS: ${BACKUP_RETENTION_DAYS:-7}
+      GPG_PASSPHRASE: 1234#$$ecret
+    volumes:
+      - ${LOCAL_DIR:-./local}:/archive
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:

test/gpg/run.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export LOCAL_DIR=$(mktemp -d)
+
+docker compose up -d --quiet-pull
+sleep 5
+
+docker compose exec backup backup
+
+expect_running_containers "2"
+
+TMP_DIR=$(mktemp -d)
+
+echo "1234#\$ecret" | gpg -d --pinentry-mode loopback --yes --passphrase-fd 0 "$LOCAL_DIR/test.tar.gz.gpg" > "$LOCAL_DIR/decrypted.tar.gz"
+tar -xf "$LOCAL_DIR/decrypted.tar.gz" -C $TMP_DIR
+
+if [ ! -f $TMP_DIR/backup/app_data/offen.db ]; then
+  fail "Could not find expected file in untared archive."
+fi
+rm "$LOCAL_DIR/decrypted.tar.gz"
+
+pass "Found relevant files in decrypted and untared local backup."
+
+if [ ! -L "$LOCAL_DIR/test-latest.tar.gz.gpg" ]; then
+  fail "Could not find local symlink to latest encrypted backup."
+fi

test/ignore/docker-compose.yml

@@ -0,0 +1,15 @@
+version: '3.8'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    deploy:
+      restart_policy:
+        condition: on-failure
+    environment:
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_EXCLUDE_REGEXP: '\.(me|you)$$'
+    volumes:
+      - ${LOCAL_DIR:-./local}:/archive
+      - ./sources:/backup/data:ro

test/ignore/run.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export LOCAL_DIR=$(mktemp -d)
+
+docker compose up -d --quiet-pull
+sleep 5
+docker compose exec backup backup
+
+TMP_DIR=$(mktemp -d)
+tar --same-owner -xvf "$LOCAL_DIR/test.tar.gz" -C "$TMP_DIR"
+
+if [ ! -f "$TMP_DIR/backup/data/me.txt" ]; then
+  fail "Expected file was not found."
+fi
+pass "Expected file was found."
+
+if [ -f "$TMP_DIR/backup/data/skip.me" ]; then
+  fail "Ignored file was found."
+fi
+pass "Ignored file was not found."

test/local/docker-compose.yml

@@ -0,0 +1,29 @@
+version: '3'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    hostname: hostnametoken
+    restart: always
+    environment:
+      BACKUP_FILENAME_EXPAND: 'true'
+      BACKUP_FILENAME: test-$$HOSTNAME.tar.gz
+      BACKUP_LATEST_SYMLINK: test-$$HOSTNAME.latest.tar.gz.gpg
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_RETENTION_DAYS: ${BACKUP_RETENTION_DAYS:-7}
+      BACKUP_PRUNING_LEEWAY: 5s
+      BACKUP_PRUNING_PREFIX: test
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+      - ${LOCAL_DIR:-./local}:/archive
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:

test/local/run.sh

@@ -0,0 +1,76 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export LOCAL_DIR=$(mktemp -d)
+
+docker compose up -d --quiet-pull
+sleep 5
+
+# A symlink for a known file in the volume is created so the test can check
+# whether symlinks are preserved on backup.
+docker compose exec offen ln -s /var/opt/offen/offen.db /var/opt/offen/db.link
+docker compose exec backup backup
+
+sleep 5
+
+expect_running_containers "2"
+
+tmp_dir=$(mktemp -d)
+tar -xvf "$LOCAL_DIR/test-hostnametoken.tar.gz" -C $tmp_dir
+if [ ! -f "$tmp_dir/backup/app_data/offen.db" ]; then
+  fail "Could not find expected file in untared archive."
+fi
+rm -f "$LOCAL_DIR/test-hostnametoken.tar.gz"
+
+if [ ! -L "$tmp_dir/backup/app_data/db.link" ]; then
+  fail "Could not find expected symlink in untared archive."
+fi
+
+pass "Found relevant files in decrypted and untared local backup."
+
+if [ ! -L "$LOCAL_DIR/test-hostnametoken.latest.tar.gz.gpg" ]; then
+  fail "Could not find symlink to latest version."
+fi
+
+pass "Found symlink to latest version in local backup."
+
+# The second part of this test checks if backups get deleted when the retention
+# is set to 0 days (which it should not as it would mean all backups get deleted)
+BACKUP_RETENTION_DAYS="0" docker compose up -d
+sleep 5
+
+docker compose exec backup backup
+
+if [ "$(find "$LOCAL_DIR" -type f | wc -l)" != "1" ]; then
+  fail "Backups should not have been deleted, instead seen: "$(find "$local_dir" -type f)""
+fi
+pass "Local backups have not been deleted."
+
+# The third part of this test checks if old backups get deleted when the retention
+# is set to 7 days (which it should)
+
+BACKUP_RETENTION_DAYS="7" docker compose up -d
+sleep 5
+
+info "Create first backup with no prune"
+docker compose exec backup backup
+
+touch -r "$LOCAL_DIR/test-hostnametoken.tar.gz" -d "14 days ago" "$LOCAL_DIR/test-hostnametoken-old.tar.gz"
+
+info "Create second backup and prune"
+docker compose exec backup backup
+
+if [ -f "$LOCAL_DIR/test-hostnametoken-old.tar.gz" ]; then
+  fail "Backdated file has not been deleted."
+fi
+
+if [ ! -f "$LOCAL_DIR/test-hostnametoken.tar.gz" ]; then
+  fail "Recent file has been deleted."
+fi
+
+pass "Old remote backup has been pruned, new one is still present."

test/notifications/.gitignore

@@ -1 +0,0 @@
-local

test/notifications/docker-compose.yml

@@ -10,8 +10,9 @@ services:
       BACKUP_PRUNING_PREFIX: test
       NOTIFICATION_LEVEL: info
       NOTIFICATION_URLS: ${NOTIFICATION_URLS}
+      EXTRA_VALUE: extra-value
     volumes:
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive
       - app_data:/backup/app_data:ro
       - ./notifications.tmpl:/etc/dockervolumebackup/notifications.d/notifications.tmpl
 

test/notifications/notifications.tmpl

@@ -1,5 +1,5 @@
 {{ define "title_success" -}}
-Successful test run, yay!
+Successful test run with {{ env "EXTRA_VALUE" }}, yay!
 {{- end }}
 
 {{ define "body_success" -}}

test/notifications/run.sh

@@ -3,50 +3,46 @@
 set -e
 
 cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
 
-mkdir -p local
+export LOCAL_DIR=$(mktemp -d)
 
-docker-compose up -d
+docker compose up -d --quiet-pull
 sleep 5
 
 GOTIFY_TOKEN=$(curl -sSLX POST -H 'Content-Type: application/json' -d '{"name":"test"}' http://admin:custom@localhost:8080/application | jq -r '.token')
-echo "[TEST:INFO] Set up Gotify application using token $GOTIFY_TOKEN"
+info "Set up Gotify application using token $GOTIFY_TOKEN"
 
-docker-compose exec backup backup
+docker compose exec backup backup
 
 NUM_MESSAGES=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages | length')
 if [ "$NUM_MESSAGES" != 0 ]; then
-  echo "[TEST:FAIL] Expected no notifications to be sent when not configured"
-  exit 1
+  fail "Expected no notifications to be sent when not configured"
 fi
-echo "[TEST:PASS] No notifications were sent when not configured."
+pass "No notifications were sent when not configured."
 
-docker-compose down
+docker compose down
 
-NOTIFICATION_URLS="gotify://gotify/${GOTIFY_TOKEN}?disableTLS=true" docker-compose up -d
+NOTIFICATION_URLS="gotify://gotify/${GOTIFY_TOKEN}?disableTLS=true" docker compose up -d
 
-docker-compose exec backup backup
+docker compose exec backup backup
 
 NUM_MESSAGES=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages | length')
 if [ "$NUM_MESSAGES" != 1 ]; then
-  echo "[TEST:FAIL] Expected one notifications to be sent when configured"
-  exit 1
+  fail "Expected one notifications to be sent when configured"
 fi
-echo "[TEST:PASS] Correct number of notifications were sent when configured."
+pass "Correct number of notifications were sent when configured."
 
 MESSAGE_TITLE=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages[0].title')
 MESSAGE_BODY=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages[0].message')
 
-if [ "$MESSAGE_TITLE" != "Successful test run, yay!" ]; then
-  echo "[TEST:FAIL] Unexpected notification title $MESSAGE_TITLE"
-  exit 1
+if [ "$MESSAGE_TITLE" != "Successful test run with extra-value, yay!" ]; then
+  fail "Unexpected notification title $MESSAGE_TITLE"
 fi
-echo "[TEST:PASS] Custom notification title was used."
+pass "Custom notification title was used."
 
 if [ "$MESSAGE_BODY" != "Backing up /tmp/test.tar.gz succeeded." ]; then
-  echo "[TEST:FAIL] Unexpected notification body $MESSAGE_BODY"
-  exit 1
+  fail "Unexpected notification body $MESSAGE_BODY"
 fi
-echo "[TEST:PASS] Custom notification body was used."
-
-docker-compose down --volumes
+pass "Custom notification body was used."