Replace Gzip with PGzip (#266 )

* Replace Gzip with optimized PGzip. Add concurrency option. * Add shortened timeout for 'dc down' too. * Add NaturalNumberZero to allow zero. * Add test for concurrency=0 * Rename to GZIP_PARALLELISM * Fix block size. Fix compression level. Fix CI. * Refactor compression writer fetching. Renamed WholeNumber
Run tests Docker in Docker (#261 )
2025-12-05 09:08:02 +01:00 · 2023-09-03 16:49:52 +02:00 · 2023-09-02 15:17:46 +02:00 · 2023-08-30 20:14:24 +02:00 · 2023-08-28 20:42:45 +02:00 · 2023-08-27 19:19:11 +02:00
73 changed files with 15603 additions and 731 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,75 +0,0 @@
-version: 2.1
-
-jobs:
-  canary:
-    machine:
-      image: ubuntu-2004:202201-02
-    working_directory: ~/docker-volume-backup
-    resource_class: large
-    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=$(tty)
-            ./test.sh canary
-
-  build:
-    docker:
-      - image: cimg/base:2020.06
-        environment:
-          DOCKER_BUILDKIT: '1'
-          DOCKER_CLI_EXPERIMENTAL: enabled
-    working_directory: ~/docker-volume-backup
-    resource_class: large
-    steps:
-      - checkout
-      - setup_remote_docker:
-          version: 20.10.6
-      - docker/install-docker-credential-helper:
-          release-tag: v0.6.4
-      - docker/configure-docker-credentials-store
-      - run:
-          name: Push to Docker Hub
-          command: |
-            echo "$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@2.1.4
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: docker
+    directory: /
+    schedule:
+      interval: weekly
+  - package-ecosystem: gomod
+    directory: /
+    schedule:
+      interval: weekly
--- a/.github/workflows/golangci-lint.yml
+++ b/.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"
--- a/.github/workflows/release.yml
+++ b/.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 }}
--- a/.github/workflows/test.yml
+++ b/.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
--- a/.golangci.yml
+++ b/.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
--- a/8
+++ b/8
@@ -1,7 +1,7 @@
 # Copyright 2021 - Offen Authors <hioffen@posteo.de>
 # SPDX-License-Identifier: MPL-2.0

-FROM golang:1.20-alpine as builder
+FROM golang:1.21-alpine as builder

 WORKDIR /app
 COPY . .
@@ -9,15 +9,13 @@ RUN go mod download
 WORKDIR /app/cmd/backup
 RUN go build -o backup .

-FROM alpine:3.17
+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"]
--- a/README.md
+++ b/README.md
@@ -4,16 +4,17 @@

 # docker-volume-backup

-Backup Docker volumes locally or to any S3, WebDAV, Azure Blob Storage or SSH 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, WebDAV, Azure Blob Storage or SSH 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__.
+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) 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)
+  - [Available image registries](#available-image-registries)
 - [Configuration reference](#configuration-reference)
 - [How to](#how-to)
  - [Stop containers during backup](#stop-containers-during-backup)
@@ -30,10 +31,12 @@ It handles __recurring or one-off backups of Docker volumes__ to a __local direc
  - [Replace deprecated `BACKUP_FROM_SNAPSHOT` usage](#replace-deprecated-backup_from_snapshot-usage)
  - [Replace deprecated `exec-pre` and `exec-post` labels](#replace-deprecated-exec-pre-and-exec-post-labels)
  - [Using a custom Docker host](#using-a-custom-docker-host)
+  - [Use with rootless Docker](#use-with-rootless-docker)
  - [Run multiple backup schedules in the same container](#run-multiple-backup-schedules-in-the-same-container)
  - [Define different retention schedules](#define-different-retention-schedules)
  - [Use special characters in notification URLs](#use-special-characters-in-notification-urls)
  - [Handle file uploads using third party tools](#handle-file-uploads-using-third-party-tools)
+  - [Setup Dropbox storage backend](#setup-dropbox-storage-backend)
 - [Recipes](#recipes)
  - [Backing up to AWS S3](#backing-up-to-aws-s3)
  - [Backing up to Filebase](#backing-up-to-filebase)
@@ -42,6 +45,7 @@ It handles __recurring or one-off backups of Docker volumes__ to a __local direc
  - [Backing up to WebDAV](#backing-up-to-webdav)
  - [Backing up to SSH](#backing-up-to-ssh)
  - [Backing up to Azure Blob Storage](#backing-up-to-azure-blob-storage)
+  - [Backing up to Dropbox](#backing-up-to-dropbox)
  - [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)
@@ -120,9 +124,24 @@ docker run --rm \

 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.
+
 ## Configuration reference

 Backup targets, schedule and retention are configured in 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 usually useful when using [Docker Secrets](https://docs.docker.com/engine/swarm/secrets/) or similar.
+
 You can populate below template according to your requirements and use it as your `env_file`:

 ```ini
@@ -134,13 +153,29 @@ You can populate below template according to your requirements and use it as you

 # BACKUP_CRON_EXPRESSION="0 2 * * *"

-# The name of the backup file including the `.tar.gz` extension.
+# 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. The default results
-# in filenames like `backup-2021-08-29T04-00-00.tar.gz`.
+# 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.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
@@ -180,6 +215,15 @@ You can populate below template according to your requirements and use it as you

 # 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
@@ -199,14 +243,6 @@ You can populate below template according to your requirements and use it as you
 # AWS_ACCESS_KEY_ID="<xxx>"
 # AWS_SECRET_ACCESS_KEY="<xxx>"

-# It is possible to provide the keys in files, allowing to hide the sensitive data.
-# These values have a higher priority than the ones above, meaning if both are set
-# the values from the files will be used.
-# This option is most useful with Docker [secrets](https://docs.docker.com/engine/swarm/secrets/).
-
-# AWS_ACCESS_KEY_ID_FILE="/path/to/file"
-# AWS_SECRET_ACCESS_KEY_FILE="/path/to/file"
-
 # 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
@@ -246,6 +282,15 @@ You can populate below template according to your requirements and use it as you

 # 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
@@ -324,6 +369,26 @@ You can populate below template according to your requirements and use it as you

 # 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`
@@ -410,7 +475,7 @@ You can populate below template according to your requirements and use it as you

 # 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/
+# 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.
@@ -554,7 +619,7 @@ services:
 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/
+[shoutrrr-docs]: https://containrrr.dev/shoutrrr/0.7/services/overview/

 ### Customize notifications

@@ -643,6 +708,24 @@ volumes:
 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.
+
 ### Encrypting your backup using GPG

 The image supports encrypting backups using GPG out of the box.
@@ -782,7 +865,7 @@ services:
      - docker-volume-backup.archive-post=rm -rf /tmp/backup/my-app

  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      BACKUP_SOURCES: /tmp/backup
    volumes:
@@ -820,6 +903,23 @@ 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.

+### 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/
+
 ### 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`:
@@ -870,7 +970,7 @@ BACKUP_SOURCES=/backup/app2_data

 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.d`:
+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
@@ -953,6 +1053,37 @@ volumes:

 Commands will be invoked with the filepath of the tar archive passed as `COMMAND_RUNTIME_BACKUP_FILEPATH`.

+### Setup Dropbox storage backend
+
+#### Auth-Setup:
+
+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`
+
 ## Recipes

 This section lists configuration for some real-world use cases that you can mix and match according to your needs.
@@ -1120,6 +1251,30 @@ 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
--- a/cmd/backup/archive.go
+++ b/cmd/backup/archive.go
@@ -8,16 +8,20 @@ package main

 import (
 	"archive/tar"
-	"compress/gzip"
 	"fmt"
 	"io"
 	"os"
 	"path"
 	"path/filepath"
+	"runtime"
 	"strings"
+
+	"github.com/klauspost/pgzip"
+
+	"github.com/klauspost/compress/zstd"
 )

-func createArchive(files []string, 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 {
@@ -27,7 +31,7 @@ func createArchive(files []string, inputFilePath, outputFilePath string) error {
 		return fmt.Errorf("createArchive: error creating output file path: %w", err)
 	}

-	if err := compress(files, 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)
 	}

@@ -51,18 +55,21 @@ func makeAbsolute(inputFilePath, outputFilePath string) (string, string, error)
 	return inputFilePath, outputFilePath, err
 }

-func compress(paths []string, 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)
+	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 {
+		if err := writeTarball(p, tarWriter, prefix); err != nil {
 			return fmt.Errorf("compress: error writing %s to archive: %w", p, err)
 		}
 	}
@@ -72,9 +79,9 @@ func compress(paths []string, 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()
@@ -85,10 +92,38 @@ func compress(paths []string, 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 {
@@ -99,19 +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() {
@@ -120,13 +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
--- a/cmd/backup/config.go
+++ b/cmd/backup/config.go
@@ -7,78 +7,92 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"regexp"
+	"strconv"
 	"time"
 )

 // Config holds all configuration values that are expected to be set
 // by users.
 type Config struct {
-	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"`
-	AwsAccessKeyIDFile            string        `envconfig:"AWS_ACCESS_KEY_ID_FILE"`
-	AwsSecretAccessKey            string        `split_words:"true"`
-	AwsSecretAccessKeyFile        string        `split_words:"true"`
-	AwsIamRoleEndpoint            string        `split_words:"true"`
-	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"`
-	BackupExcludeRegexp           RegexpDecoder `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/"`
+	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"`
 }

-func (c *Config) resolveSecret(envVar string, secretPath string) (string, error) {
-	if secretPath == "" {
-		return envVar, nil
+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)
 	}
-	data, err := os.ReadFile(secretPath)
-	if err != nil {
-		return "", fmt.Errorf("resolveSecret: error reading secret path: %w", err)
-	}
-	return string(data), nil
+}
+
+func (c *CompressionType) String() string {
+	return string(*c)
 }

 type CertDecoder struct {
@@ -89,7 +103,7 @@ func (c *CertDecoder) Decode(v string) error {
 	if v == "" {
 		return nil
 	}
-	content, err := ioutil.ReadFile(v)
+	content, err := os.ReadFile(v)
 	if err != nil {
 		content = []byte(v)
 	}
@@ -117,3 +131,41 @@ func (r *RegexpDecoder) Decode(v string) error {
 	*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)
+}
--- a/cmd/backup/exec.go
+++ b/cmd/backup/exec.go
@@ -10,7 +10,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"strings"

@@ -21,7 +21,7 @@ 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),
@@ -31,6 +31,7 @@ func (s *script) exec(containerRef string, command string) ([]byte, []byte, erro
 		AttachStdin:  true,
 		AttachStderr: true,
 		Env:          commandEnv,
+		User:         user,
 	})
 	if err != nil {
 		return nil, nil, fmt.Errorf("exec: error creating container exec: %w", err)
@@ -50,19 +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 <-outputDone != 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)
 	}
@@ -90,7 +87,6 @@ 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 {
@@ -104,7 +100,6 @@ func (s *script) runLabeledCommands(label string) error {
 			Value: "docker-volume-backup.exec-pre",
 		}
 		deprecatedContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
-			Quiet:   true,
 			Filters: filters.NewArgs(f...),
 		})
 		if err != nil {
@@ -122,7 +117,6 @@ func (s *script) runLabeledCommands(label string) error {
 			Value: "docker-volume-backup.exec-post",
 		}
 		deprecatedContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
-			Quiet:   true,
 			Filters: filters.NewArgs(f...),
 		})
 		if err != nil {
@@ -154,13 +148,16 @@ func (s *script) runLabeledCommands(label string) error {
 		g.Go(func() error {
 			cmd, ok := c.Labels[label]
 			if !ok && label == "docker-volume-backup.archive-pre" {
-				cmd, _ = c.Labels["docker-volume-backup.exec-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"]
+				cmd = c.Labels["docker-volume-backup.exec-post"]
 			}

-			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)
+			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)
--- a/cmd/backup/lock.go
+++ b/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)
@@ -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
 		}
--- a/cmd/backup/main.go
+++ b/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)
 			}
@@ -29,9 +32,11 @@ 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)
 		}
--- a/cmd/backup/script.go
+++ b/cmd/backup/script.go
@@ -4,35 +4,40 @@
 package main

 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"io"
 	"io/fs"
+	"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/offen/envconfig"
 	"github.com/otiai10/copy"
-	"github.com/sirupsen/logrus"
-	"golang.org/x/crypto/openpgp"
 	"golang.org/x/sync/errgroup"
 )

@@ -41,7 +46,7 @@ import (
 type script struct {
 	cli       *client.Client
 	storages  []storage.Backend
-	logger    *logrus.Logger
+	logger    *slog.Logger
 	sender    *router.ServiceRouter
 	template  *template.Template
 	hooks     []hook
@@ -62,22 +67,18 @@ 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: map[string]StorageStats{
-				"S3":     {},
-				"WebDAV": {},
-				"SSH":    {},
-				"Local":  {},
-				"Azure":  {},
+				"S3":      {},
+				"WebDAV":  {},
+				"SSH":     {},
+				"Local":   {},
+				"Azure":   {},
+				"Dropbox": {},
 			},
 		},
 	}
@@ -88,11 +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)
@@ -110,31 +147,22 @@ func newScript() (*script, error) {
 		s.cli = cli
 	}

-	logFunc := func(logType storage.LogLevel, context string, msg string, params ...interface{}) {
+	logFunc := func(logType storage.LogLevel, context string, msg string, params ...any) {
 		switch logType {
 		case storage.LogLevelWarning:
-			s.logger.Warnf("["+context+"] "+msg, params...)
+			s.logger.Warn(fmt.Sprintf(msg, params...), "storage", context)
 		case storage.LogLevelError:
-			s.logger.Errorf("["+context+"] "+msg, params...)
-		case storage.LogLevelInfo:
+			s.logger.Error(fmt.Sprintf(msg, params...), "storage", context)
 		default:
-			s.logger.Infof("["+context+"] "+msg, params...)
+			s.logger.Info(fmt.Sprintf(msg, params...), "storage", context)
 		}
 	}

 	if s.c.AwsS3BucketName != "" {
-		accessKeyID, err := s.c.resolveSecret(s.c.AwsAccessKeyID, s.c.AwsAccessKeyIDFile)
-		if err != nil {
-			return nil, fmt.Errorf("newScript: error resolving AwsAccessKeyID: %w", err)
-		}
-		secretAccessKey, err := s.c.resolveSecret(s.c.AwsSecretAccessKey, s.c.AwsSecretAccessKeyFile)
-		if err != nil {
-			return nil, fmt.Errorf("newScript: error resolving AwsSecretAccessKey: %w", err)
-		}
 		s3Config := s3.Config{
 			Endpoint:         s.c.AwsEndpoint,
-			AccessKeyID:      accessKeyID,
-			SecretAccessKey:  secretAccessKey,
+			AccessKeyID:      s.c.AwsAccessKeyID,
+			SecretAccessKey:  s.c.AwsSecretAccessKey,
 			IamRoleEndpoint:  s.c.AwsIamRoleEndpoint,
 			EndpointProto:    s.c.AwsEndpointProto,
 			EndpointInsecure: s.c.AwsEndpointInsecure,
@@ -142,9 +170,10 @@ func newScript() (*script, error) {
 			BucketName:       s.c.AwsS3BucketName,
 			StorageClass:     s.c.AwsStorageClass,
 			CACert:           s.c.AwsEndpointCACert.Cert,
+			PartSize:         s.c.AwsPartSize,
 		}
 		if s3Backend, err := s3.NewStorageBackend(s3Config, logFunc); err != nil {
-			return nil, err
+			return nil, fmt.Errorf("newScript: error creating s3 storage backend: %w", err)
 		} else {
 			s.storages = append(s.storages, s3Backend)
 		}
@@ -159,7 +188,7 @@ func newScript() (*script, error) {
 			RemotePath:  s.c.WebdavPath,
 		}
 		if webdavBackend, err := webdav.NewStorageBackend(webDavConfig, logFunc); err != nil {
-			return nil, err
+			return nil, fmt.Errorf("newScript: error creating webdav storage backend: %w", err)
 		} else {
 			s.storages = append(s.storages, webdavBackend)
 		}
@@ -176,7 +205,7 @@ func newScript() (*script, error) {
 			RemotePath:         s.c.SSHRemotePath,
 		}
 		if sshBackend, err := ssh.NewStorageBackend(sshConfig, logFunc); err != nil {
-			return nil, err
+			return nil, fmt.Errorf("newScript: error creating ssh storage backend: %w", err)
 		} else {
 			s.storages = append(s.storages, sshBackend)
 		}
@@ -201,11 +230,28 @@ func newScript() (*script, error) {
 		}
 		azureBackend, err := azure.NewStorageBackend(azureConfig, logFunc)
 		if err != nil {
-			return nil, err
+			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 != "" {
 		emailURL := fmt.Sprintf(
 			"smtp://%s:%s@%s:%d/?from=%s&to=%s",
@@ -280,9 +326,7 @@ 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("stopContainers: error querying for containers: %w", err)
 	}
@@ -292,7 +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,
@@ -307,17 +350,19 @@ func (s *script) stopContainers() (func() error, error) {
 		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)
@@ -366,7 +411,7 @@ func (s *script) stopContainers() (func() error, error) {
 				if serviceMatch.ID == "" {
 					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{},
@@ -383,9 +428,11 @@ func (s *script) stopContainers() (func() error, error) {
 				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
@@ -409,7 +456,9 @@ func (s *script) createArchive() error {
 			if err := remove(backupSources); err != nil {
 				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{
@@ -418,7 +467,9 @@ func (s *script) createArchive() error {
 		}); err != nil {
 			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
@@ -426,7 +477,9 @@ func (s *script) createArchive() error {
 		if err := remove(tarFile); err != nil {
 			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
 	})

@@ -450,11 +503,13 @@ func (s *script) createArchive() error {
 		return fmt.Errorf("createArchive: error walking filesystem tree: %w", err)
 	}

-	if err := createArchive(filesEligibleForBackup, backupSources, tarFile); err != nil {
+	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.Infof("Created backup of `%s` at `%s`.", backupSources, tarFile)
+	s.logger.Info(
+		fmt.Sprintf("Created backup of `%s` at `%s`.", backupSources, tarFile),
+	)
 	return nil
 }

@@ -471,7 +526,9 @@ func (s *script) encryptArchive() error {
 		if err := remove(gpgFile); err != nil {
 			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
 	})

@@ -501,7 +558,9 @@ func (s *script) encryptArchive() error {
 	}

 	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
 }

@@ -548,6 +607,12 @@ func (s *script) pruneBackups() error {
 	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
@@ -573,7 +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
+		},
+	)
+}
--- a/docs/NOTIFICATION-TEMPLATES.md
+++ b/docs/NOTIFICATION-TEMPLATES.md
@@ -25,7 +25,7 @@ Here is a list of all data passed to the template:
    * `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` or `SSH`:
+    * `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
--- a/go.mod
+++ b/go.mod
@@ -1,74 +1,72 @@
 module github.com/offen/docker-volume-backup

-go 1.19
+go 1.21

 require (
-	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.2.0
-	github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v0.6.1
-	github.com/containrrr/shoutrrr v0.5.2
+	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.3.0
+	github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v1.1.0
+	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 v24.0.5+incompatible
 	github.com/gofrs/flock v0.8.1
-	github.com/kelseyhightower/envconfig v1.4.0
+	github.com/klauspost/compress v1.16.7
 	github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d
-	github.com/minio/minio-go/v7 v7.0.44
-	github.com/otiai10/copy v1.7.0
-	github.com/pkg/sftp v1.13.5
-	github.com/sirupsen/logrus v1.9.0
-	github.com/studio-b12/gowebdav v0.0.0-20220128162035-c7b1ff8a5e62
-	golang.org/x/crypto v0.3.0
-	golang.org/x/sync v0.0.0-20220601150217-0de741cfad7f
+	github.com/minio/minio-go/v7 v7.0.62
+	github.com/offen/envconfig v1.5.0
+	github.com/otiai10/copy v1.11.0
+	github.com/pkg/sftp v1.13.6
+	github.com/studio-b12/gowebdav v0.9.0
+	golang.org/x/crypto v0.12.0
+	golang.org/x/oauth2 v0.0.0-20221014153046-6fdb5e3db783
+	golang.org/x/sync v0.3.0
 )

 require (
-	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.1.4 // indirect
-	github.com/Azure/azure-sdk-for-go/sdk/internal v1.0.1 // indirect
-	github.com/AzureAD/microsoft-authentication-library-for-go v0.7.0 // indirect
+	github.com/cloudflare/circl v1.3.3 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+)
+
+require (
+	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.6.0 // indirect
+	github.com/Azure/azure-sdk-for-go/sdk/internal v1.3.0 // indirect
+	github.com/AzureAD/microsoft-authentication-library-for-go v1.0.0 // indirect
 	github.com/Microsoft/go-winio v0.5.2 // indirect
-	github.com/containerd/containerd v1.6.6 // indirect
-	github.com/docker/distribution v2.7.1+incompatible // 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-jwt/jwt/v4 v4.4.2 // indirect
-	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/golang-jwt/jwt/v4 v4.5.0 // indirect
 	github.com/google/uuid v1.3.0 // indirect
-	github.com/gorilla/mux v1.7.3 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
-	github.com/klauspost/compress v1.15.12 // indirect
-	github.com/klauspost/cpuid/v2 v2.2.1 // 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/kr/text v0.2.0 // indirect
 	github.com/kylelemons/godebug v1.1.0 // indirect
-	github.com/mattn/go-colorable v0.1.8 // indirect
-	github.com/mattn/go-isatty v0.0.12 // 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/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/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // 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/opencontainers/go-digest v1.0.0 // indirect
 	github.com/opencontainers/image-spec v1.0.3-0.20211202183452-c5a74bcca799 // indirect
-	github.com/pkg/browser v0.0.0-20210115035449-ce105d075bb4 // indirect
+	github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
-	github.com/rs/xid v1.4.0 // indirect
-	golang.org/x/net v0.2.0 // indirect
-	golang.org/x/sys v0.2.0 // indirect
-	golang.org/x/text v0.4.0 // indirect
-	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
-	google.golang.org/genproto v0.0.0-20220602131408-e326c6e8e9c8 // indirect
-	google.golang.org/grpc v1.47.0 // indirect
-	google.golang.org/protobuf v1.28.0 // indirect
+	github.com/rs/xid v1.5.0 // indirect
+	github.com/sirupsen/logrus v1.9.3 // indirect
+	golang.org/x/net v0.14.0 // indirect
+	golang.org/x/sys v0.11.0 // indirect
+	golang.org/x/text v0.12.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20200227125254-8fa46927fb4f // indirect
 	gopkg.in/ini.v1 v1.67.0 // indirect
-	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
-	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gotest.tools/v3 v3.0.3 // indirect
 )
--- a/go.sum
+++ b/go.sum
--- a/internal/storage/azure/azure.go
+++ b/internal/storage/azure/azure.go
@@ -132,7 +132,7 @@ func (b *azureBlobStorage) Prune(deadline time.Time, pruningPrefix string) (*sto
 		Pruned: uint(len(matches)),
 	}

-	if err := b.DoPrune(b.Name(), len(matches), int(totalCount), "Azure Blob Storage backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), int(totalCount), func() error {
 		wg := sync.WaitGroup{}
 		wg.Add(len(matches))
 		var errs []error
--- a/internal/storage/dropbox/dropbox.go
+++ b/internal/storage/dropbox/dropbox.go
@@ -0,0 +1,260 @@
+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)),
+	}
+
+	if err := b.DoPrune(b.Name(), len(matches), lenCandidates, 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
+	}); err != nil {
+		return stats, err
+	}
+
+	return stats, nil
+}
--- a/internal/storage/local/local.go
+++ b/internal/storage/local/local.go
@@ -47,9 +47,9 @@ 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 local archive: %w", err)
+		return fmt.Errorf("(*localStorage).Copy: Error copying file to archive: %w", err)
 	}
-	b.Log(storage.LogLevelInfo, b.Name(), "Stored copy of backup `%s` in local archive `%s`.", file, b.DestinationPath)
+	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)
@@ -116,7 +116,7 @@ func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage
 		Pruned: uint(len(matches)),
 	}

-	if err := b.DoPrune(b.Name(), len(matches), len(candidates), "local backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), len(candidates), func() error {
 		var removeErrors []error
 		for _, match := range matches {
 			if err := os.Remove(match); err != nil {
@@ -125,7 +125,7 @@ func (b *localStorage) Prune(deadline time.Time, pruningPrefix string) (*storage
 		}
 		if len(removeErrors) != 0 {
 			return fmt.Errorf(
-				"(*localStorage).Prune: %d error(s) deleting local files, starting with: %w",
+				"(*localStorage).Prune: %d error(s) deleting files, starting with: %w",
 				len(removeErrors),
 				errors.Join(removeErrors...),
 			)
--- a/internal/storage/s3/s3.go
+++ b/internal/storage/s3/s3.go
@@ -8,6 +8,7 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
+	"os"
 	"path"
 	"path/filepath"
 	"time"
@@ -22,6 +23,7 @@ type s3Storage struct {
 	client       *minio.Client
 	bucket       string
 	storageClass string
+	partSize     int64
 }

 // Config contains values that define the configuration of a S3 backend.
@@ -35,6 +37,7 @@ type Config struct {
 	RemotePath       string
 	BucketName       string
 	StorageClass     string
+	PartSize         int64
 	CACert           *x509.Certificate
 }

@@ -89,6 +92,7 @@ func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error
 		client:       mc,
 		bucket:       opts.BucketName,
 		storageClass: opts.StorageClass,
+		partSize:     opts.PartSize,
 	}, nil
 }

@@ -100,16 +104,37 @@ func (v *s3Storage) Name() string {
 // Copy copies the given file to the S3/Minio storage backend.
 func (b *s3Storage) Copy(file string) error {
 	_, name := path.Split(file)
-
-	if _, err := b.client.FPutObject(context.Background(), b.bucket, filepath.Join(b.DestinationPath, name), file, minio.PutObjectOptions{
+	putObjectOptions := minio.PutObjectOptions{
 		ContentType:  "application/tar+gzip",
 		StorageClass: b.storageClass,
-	}); err != nil {
+	}
+
+	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: [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
@@ -128,7 +153,7 @@ func (b *s3Storage) Prune(deadline time.Time, pruningPrefix string) (*storage.Pr
 		lenCandidates++
 		if candidate.Err != nil {
 			return nil, fmt.Errorf(
-				"(*s3Storage).Prune: Error looking up candidates from remote storage! %w",
+				"(*s3Storage).Prune: error looking up candidates from remote storage! %w",
 				candidate.Err,
 			)
 		}
@@ -142,7 +167,7 @@ func (b *s3Storage) Prune(deadline time.Time, pruningPrefix string) (*storage.Pr
 		Pruned: uint(len(matches)),
 	}

-	if err := b.DoPrune(b.Name(), len(matches), lenCandidates, "remote backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), lenCandidates, func() error {
 		objectsCh := make(chan minio.ObjectInfo)
 		go func() {
 			for _, match := range matches {
--- a/internal/storage/ssh/ssh.go
+++ b/internal/storage/ssh/ssh.go
@@ -7,7 +7,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path"
 	"path/filepath"
@@ -46,7 +45,7 @@ func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error
 	}

 	if _, err := os.Stat(opts.IdentityFile); err == nil {
-		key, err := ioutil.ReadFile(opts.IdentityFile)
+		key, err := os.ReadFile(opts.IdentityFile)
 		if err != nil {
 			return nil, errors.New("NewStorageBackend: error reading the private key")
 		}
@@ -75,7 +74,7 @@ func NewStorageBackend(opts Config, logFunc storage.Log) (storage.Backend, error
 	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)
+		return nil, fmt.Errorf("NewStorageBackend: error creating ssh client: %w", err)
 	}
 	_, _, err = sshClient.SendRequest("keepalive", false, nil)
 	if err != nil {
@@ -108,13 +107,13 @@ 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)
+		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 on SSH storage: %w", err)
+		return fmt.Errorf("(*sshStorage).Copy: error creating file: %w", err)
 	}
 	defer destination.Close()

@@ -124,7 +123,7 @@ func (b *sshStorage) Copy(file string) error {
 		if err == io.EOF {
 			tot, err := destination.Write(chunk[:num])
 			if err != nil {
-				return fmt.Errorf("(*sshStorage).Copy: Error uploading the file to SSH storage: %w", err)
+				return fmt.Errorf("(*sshStorage).Copy: error uploading the file: %w", err)
 			}

 			if tot != len(chunk[:num]) {
@@ -135,12 +134,12 @@ func (b *sshStorage) Copy(file string) error {
 		}

 		if err != nil {
-			return fmt.Errorf("(*sshStorage).Copy: Error uploading the file to SSH storage: %w", err)
+			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 to SSH storage: %w", err)
+			return fmt.Errorf("(*sshStorage).Copy: error uploading the file: %w", err)
 		}

 		if tot != len(chunk[:num]) {
@@ -148,7 +147,7 @@ func (b *sshStorage) Copy(file string) error {
 		}
 	}

-	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to SSH storage '%s' at path '%s'.", file, b.hostName, b.DestinationPath)
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup `%s` to '%s' at path '%s'.", file, b.hostName, b.DestinationPath)

 	return nil
 }
@@ -157,7 +156,7 @@ func (b *sshStorage) Copy(file string) error {
 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 from SSH storage: %w", err)
+		return nil, fmt.Errorf("(*sshStorage).Prune: error reading directory: %w", err)
 	}

 	var matches []string
@@ -175,10 +174,10 @@ func (b *sshStorage) Prune(deadline time.Time, pruningPrefix string) (*storage.P
 		Pruned: uint(len(matches)),
 	}

-	if err := b.DoPrune(b.Name(), len(matches), len(candidates), "SSH backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), len(candidates), 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 from SSH storage: %w", err)
+				return fmt.Errorf("(*sshStorage).Prune: error removing file: %w", err)
 			}
 		}
 		return nil
--- a/internal/storage/storage.go
+++ b/internal/storage/storage.go
@@ -29,7 +29,7 @@ const (
 	LogLevelError
 )

-type Log func(logType LogLevel, context string, msg string, params ...interface{})
+type Log func(logType LogLevel, context string, msg string, params ...any)

 // PruneStats is a wrapper struct for returning stats after pruning
 type PruneStats struct {
@@ -39,23 +39,22 @@ type PruneStats struct {

 // 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, description string, doRemoveFiles func() error) error {
+func (b *StorageBackend) DoPrune(context string, lenMatches, lenCandidates int, doRemoveFiles func() error) error {
 	if lenMatches != 0 && lenMatches != lenCandidates {
 		if err := doRemoveFiles(); err != nil {
 			return err
 		}
 		b.Log(LogLevelInfo, context,
-			"Pruned %d out of %d %s as their age exceeded the configured retention period of %d days.",
+			"Pruned %d out of %d backups as their age exceeded the configured retention period of %d days.",
 			lenMatches,
 			lenCandidates,
-			description,
 			b.RetentionDays,
 		)
 	} else if lenMatches != 0 && lenMatches == lenCandidates {
-		b.Log(LogLevelWarning, context, "The current configuration would delete all %d existing %s.", lenMatches, description)
+		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 %s were pruned.", lenCandidates, description)
+		b.Log(LogLevelInfo, context, "None of %d existing backups were pruned.", lenCandidates)
 	}
 	return nil
 }
--- a/internal/storage/webdav/webdav.go
+++ b/internal/storage/webdav/webdav.go
@@ -69,18 +69,18 @@ func (b *webDavStorage) Name() string {
 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 WebDAV server: %w", b.DestinationPath, err)
+		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)
+		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 to WebDAV server: %w", err)
+		return fmt.Errorf("(*webDavStorage).Copy: error uploading the file: %w", err)
 	}
-	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup '%s' to WebDAV URL '%s' at path '%s'.", file, b.url, b.DestinationPath)
+	b.Log(storage.LogLevelInfo, b.Name(), "Uploaded a copy of backup '%s' to '%s' at path '%s'.", file, b.url, b.DestinationPath)

 	return nil
 }
@@ -89,7 +89,7 @@ func (b *webDavStorage) Copy(file string) error {
 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)
+		return nil, fmt.Errorf("(*webDavStorage).Prune: error looking up candidates from remote storage: %w", err)
 	}
 	var matches []fs.FileInfo
 	var lenCandidates int
@@ -108,10 +108,10 @@ func (b *webDavStorage) Prune(deadline time.Time, pruningPrefix string) (*storag
 		Pruned: uint(len(matches)),
 	}

-	if err := b.DoPrune(b.Name(), len(matches), lenCandidates, "WebDAV backup(s)", func() error {
+	if err := b.DoPrune(b.Name(), len(matches), lenCandidates, 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 from WebDAV storage: %w", err)
+				return fmt.Errorf("(*webDavStorage).Prune: error removing file: %w", err)
 			}
 		}
 		return nil
--- a/test/Dockerfile
+++ b/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
--- a/test/README.md
+++ b/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))
+```
--- a/test/azure/docker-compose.yml
+++ b/test/azure/docker-compose.yml
@@ -2,19 +2,19 @@ version: '3'

 services:
  storage:
-    image: mcr.microsoft.com/azure-storage/azurite
+    image: mcr.microsoft.com/azure-storage/azurite:3.26.0
    volumes:
-      - azurite_backup_data:/data
+      - ${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
+      test: nc 127.0.0.1 10000 -z
+      interval: 1s
+      retries: 30

  az_cli:
-    image: mcr.microsoft.com/azure-cli
+    image: mcr.microsoft.com/azure-cli:2.51.0
    volumes:
-      - ./local:/dump
+      - ${LOCAL_DIR:-./local}:/dump
    command:
      - /bin/sh
      - -c
@@ -53,6 +53,4 @@ services:
      - app_data:/var/opt/offen

 volumes:
-  azurite_backup_data:
-    name: azurite_backup_data
  app_data:
--- a/test/azure/run.sh
+++ b/test/azure/run.sh
@@ -6,35 +6,81 @@ cd "$(dirname "$0")"
 . ../util.sh
 current_test=$(basename $(pwd))

-docker-compose up -d
+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

-# 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 backup backup
+docker compose exec backup backup

 sleep 5

 expect_running_containers "3"

-docker-compose run --rm az_cli \
-  az storage blob download -f /dump/test.tar.gz -c test-container -n path/to/backup/test.tar.gz
-tar -xvf ./local/test.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db
+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)
-# TODO: find out if we can test actual deletion without having to wait for a day
-BACKUP_RETENTION_DAYS="0" docker-compose up -d
+BACKUP_RETENTION_DAYS="0" docker compose up -d
 sleep 5

-docker-compose exec backup backup
-
-docker-compose run --rm az_cli \
-  az storage blob download -f /dump/test.tar.gz -c test-container -n path/to/backup/test.tar.gz
-test -f ./local/test.tar.gz
+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."

-docker-compose down --volumes
+# 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."
--- a/test/certs/docker-compose.yml
+++ b/test/certs/docker-compose.yml
@@ -12,8 +12,8 @@ services:
    entrypoint: /bin/ash -c 'mkdir -p /data/backup && minio server --certs-dir "/certs" --address ":443" /data'
    volumes:
      - minio_backup_data:/data
-      - ./minio.crt:/certs/public.crt
-      - ./minio.key:/certs/private.key
+      - ${CERT_DIR:-.}/minio.crt:/certs/public.crt
+      - ${CERT_DIR:-.}/minio.key:/certs/private.key

  backup:
    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
@@ -33,7 +33,7 @@ services:
    volumes:
      - app_data:/backup/app_data:ro
      - /var/run/docker.sock:/var/run/docker.sock
-      - ./rootCA.crt:/root/minio-rootCA.crt
+      - ${CERT_DIR:-.}/rootCA.crt:/root/minio-rootCA.crt

  offen:
    image: offen/offen:latest
--- a/test/certs/run.sh
+++ b/test/certs/run.sh
@@ -6,25 +6,27 @@ cd "$(dirname "$0")"
 . ../util.sh
 current_test=$(basename $(pwd))

-openssl genrsa -des3 -passout pass:test -out rootCA.key 4096
+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 rootCA.key -sha256 -days 1 -out rootCA.crt
+  -x509 -new -key "$CERT_DIR/rootCA.key" -sha256 -days 1 -out "$CERT_DIR/rootCA.crt"

-openssl genrsa -out minio.key 4096
-openssl req -new -sha256 -key minio.key \
+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 minio.csr
+  -out "$CERT_DIR/minio.csr"

 openssl x509 -req -passin pass:test \
-  -in minio.csr \
-  -CA rootCA.crt -CAkey rootCA.key -CAcreateserial \
+  -in "$CERT_DIR/minio.csr" \
+  -CA "$CERT_DIR/rootCA.crt" -CAkey "$CERT_DIR/rootCA.key" -CAcreateserial \
  -extfile san.cnf \
-  -out minio.crt -days 1 -sha256
+  -out "$CERT_DIR/minio.crt" -days 1 -sha256

-openssl x509 -in minio.crt -noout -text
+openssl x509 -in "$CERT_DIR/minio.crt" -noout -text

-docker compose up -d
+docker compose up -d --quiet-pull
 sleep 5

 docker compose exec backup backup
@@ -33,11 +35,9 @@ sleep 5

 expect_running_containers "3"

-docker run --rm -it \
+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."
-
-docker compose down --volumes
--- a/test/cli/run.sh
+++ b/test/cli/run.sh
@@ -13,7 +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 \
@@ -25,7 +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/ \
@@ -33,7 +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 \
@@ -48,7 +48,7 @@ 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'

--- a/test/commands/.gitignore
+++ b/test/commands/.gitignore
@@ -1 +0,0 @@
-local
--- a/test/commands/docker-compose.yml
+++ b/test/commands/docker-compose.yml
@@ -42,10 +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:
--- a/test/commands/run.sh
+++ b/test/commands/run.sh
@@ -6,34 +6,37 @@ cd $(dirname $0)
 . ../util.sh
 current_test=$(basename $(pwd))

-docker compose up -d
+export LOCAL_DIR=$(mktemp -d)
+export TMP_DIR=$(mktemp -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

-tar -xvf ./local/test.tar.gz
-if [ ! -f ./backup/data/dump.sql ]; then
+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
 pass "Found expected file."

-if [ -f ./backup/data/not-relevant.txt ]; then
+if [ -f "$TMP_DIR/backup/data/not-relevant.txt" ]; then
  fail "Command ran for container with other label."
 fi
 pass "Command did not run for container with other label."

-if [ -f ./backup/data/post.txt ]; then
+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
-sudo rm -rf ./local
-

 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
@@ -47,18 +50,13 @@ sleep 20

 docker exec $(docker ps -q -f name=backup) backup

-sudo cp -r $(docker volume inspect --format='{{ .Mountpoint }}' test_stack_archive) ./local
-
-tar -xvf ./local/test.tar.gz
-if [ ! -f ./backup/data/dump.sql ]; then
+tar -xvf "$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
 pass "Found expected file."

-if [ -f ./backup/data/post.txt ]; then
+if [ -f "$TMP_DIR/backup/data/post.txt" ]; then
  fail "File created in post command was present in backup."
 fi
 pass "Did not find unexpected file."
-
-docker stack rm test_stack
-docker swarm leave --force
--- a/test/confd/.gitignore
+++ b/test/confd/.gitignore
@@ -1 +0,0 @@
-local
--- a/test/confd/docker-compose.yml
+++ b/test/confd/docker-compose.yml
@@ -5,7 +5,7 @@ services:
    image: offen/docker-volume-backup:${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
--- a/test/confd/run.sh
+++ b/test/confd/run.sh
@@ -6,26 +6,24 @@ 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
+if [ ! -f "$LOCAL_DIR/conf.tar.gz" ]; then
  fail "Config from file was not used."
 fi
 pass "Config from file was used."

-if [ ! -f ./local/other.tar.gz ]; then
+if [ ! -f "$LOCAL_DIR/other.tar.gz" ]; then
  fail "Run on same schedule did not succeed."
 fi
 pass "Run on same schedule succeeded."

-if [ -f ./local/never.tar.gz ]; then
+if [ -f "$LOCAL_DIR/never.tar.gz" ]; then
  fail "Unexpected file was found."
 fi
 pass "Unexpected cron did not run."
--- a/test/dropbox/.gitignore
+++ b/test/dropbox/.gitignore
@@ -0,0 +1 @@
+user_v2_ready.yaml
--- a/test/dropbox/docker-compose.yml
+++ b/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: ${BACKUP_RETENTION_DAYS:-7}
+      BACKUP_PRUNING_LEEWAY: 5s
+      BACKUP_PRUNING_PREFIX: test
+      DROPBOX_ENDPOINT: http://openapi_mock:8080
+      DROPBOX_OAUTH2_ENDPOINT: http://oauth2_mock:8090
+      DROPBOX_REFRESH_TOKEN: test
+      DROPBOX_APP_KEY: test
+      DROPBOX_APP_SECRET: test
+      DROPBOX_REMOTE_PATH: /test
+      DROPBOX_CONCURRENCY_LEVEL: 6
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:
--- a/test/dropbox/oauth2_config.json
+++ b/test/dropbox/oauth2_config.json
@@ -0,0 +1,37 @@
+{
+   "interactiveLogin": true,
+   "httpServer": "NettyWrapper",
+   "tokenCallbacks": [
+       {
+           "issuerId": "issuer1",
+           "tokenExpiry": 120,
+           "requestMappings": [
+               {
+                   "requestParam": "scope",
+                   "match": "scope1",
+                   "claims": {
+                       "sub": "subByScope",
+                       "aud": [
+                           "audByScope"
+                       ]
+                   }
+               }
+           ]
+       },
+       {
+           "issuerId": "issuer2",
+           "requestMappings": [
+               {
+                   "requestParam": "someparam",
+                   "match": "somevalue",
+                   "claims": {
+                       "sub": "subBySomeParam",
+                       "aud": [
+                           "audBySomeParam"
+                       ]
+                   }
+               }
+           ]
+       }
+   ]
+}
--- a/test/dropbox/run.sh
+++ b/test/dropbox/run.sh
@@ -0,0 +1,61 @@
+#!/bin/sh
+
+set -e
+
+cd "$(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 their age exceeded the configured retention period"; 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
--- a/test/dropbox/user_v2.yaml
+++ b/test/dropbox/user_v2.yaml
--- a/test/extend/docker-compose.yml
+++ b/test/extend/docker-compose.yml
@@ -11,7 +11,7 @@ services:
      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
      EXEC_FORWARD_OUTPUT: "true"
    volumes:
-      - ./local:/local
+      - ${LOCAL_DIR:-local}:/local
      - app_data:/backup/app_data:ro
      - /var/run/docker.sock:/var/run/docker.sock

--- a/test/extend/run.sh
+++ b/test/extend/run.sh
@@ -6,13 +6,14 @@ cd "$(dirname "$0")"
 . ../util.sh
 current_test=$(basename $(pwd))

-mkdir -p local
+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:$TEST_VERSION
+docker build . -t offen/docker-volume-backup:$TEST_VERSION --build-arg version=$BASE_VERSION

-docker compose up -d
+docker compose up -d --quiet-pull
 sleep 5

 docker compose exec backup backup
@@ -21,8 +22,6 @@ sleep 5

 expect_running_containers "2"

-if [ ! -f "./local/app_data/offen.db" ]; then
+if [ ! -f "$LOCAL_DIR/app_data/offen.db" ]; then
  fail "Could not find expected file in untared archive."
 fi
-
-docker compose down --volumes
--- a/test/gpg/.gitignore
+++ b/test/gpg/.gitignore
@@ -1 +0,0 @@
-local
--- a/test/gpg/docker-compose.yml
+++ b/test/gpg/docker-compose.yml
@@ -11,7 +11,7 @@ services:
      BACKUP_RETENTION_DAYS: ${BACKUP_RETENTION_DAYS:-7}
      GPG_PASSPHRASE: 1234#$$ecret
    volumes:
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive
      - app_data:/backup/app_data:ro
      - /var/run/docker.sock:/var/run/docker.sock

--- a/test/gpg/run.sh
+++ b/test/gpg/run.sh
@@ -6,28 +6,27 @@ 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

 docker compose exec backup backup

 expect_running_containers "2"

-tmp_dir=$(mktemp -d)
+TMP_DIR=$(mktemp -d)

-echo "1234#\$ecret" | gpg -d --pinentry-mode loopback --yes --passphrase-fd 0 ./local/test.tar.gz.gpg > ./local/decrypted.tar.gz
-tar -xf ./local/decrypted.tar.gz -C $tmp_dir
-if [ ! -f $tmp_dir/backup/app_data/offen.db ]; then
+echo "1234#\$ecret" | gpg -d --pinentry-mode loopback --yes --passphrase-fd 0 "$LOCAL_DIR/test.tar.gz.gpg" > "$LOCAL_DIR/decrypted.tar.gz"
+tar -xf "$LOCAL_DIR/decrypted.tar.gz" -C $TMP_DIR
+
+if [ ! -f $TMP_DIR/backup/app_data/offen.db ]; then
  fail "Could not find expected file in untared archive."
 fi
-rm ./local/decrypted.tar.gz
+rm "$LOCAL_DIR/decrypted.tar.gz"

 pass "Found relevant files in decrypted and untared local backup."

-if [ ! -L ./local/test-latest.tar.gz.gpg ]; then
+if [ ! -L "$LOCAL_DIR/test-latest.tar.gz.gpg" ]; then
  fail "Could not find local symlink to latest encrypted backup."
 fi
-
-docker compose down --volumes
--- a/test/ignore/.gitignore
+++ b/test/ignore/.gitignore
@@ -1 +0,0 @@
-local
--- a/test/ignore/docker-compose.yml
+++ b/test/ignore/docker-compose.yml
@@ -11,5 +11,5 @@ services:
      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
      BACKUP_EXCLUDE_REGEXP: '\.(me|you)$$'
    volumes:
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive
      - ./sources:/backup/data:ro
--- a/test/ignore/run.sh
+++ b/test/ignore/run.sh
@@ -6,23 +6,21 @@ 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
 docker compose exec backup backup

-docker compose down --volumes
+TMP_DIR=$(mktemp -d)
+tar --same-owner -xvf "$LOCAL_DIR/test.tar.gz" -C "$TMP_DIR"

-out=$(mktemp -d)
-sudo tar --same-owner -xvf ./local/test.tar.gz -C "$out"
-
-if [ ! -f "$out/backup/data/me.txt" ]; then
+if [ ! -f "$TMP_DIR/backup/data/me.txt" ]; then
  fail "Expected file was not found."
 fi
 pass "Expected file was found."

-if [ -f "$out/backup/data/skip.me" ]; then
+if [ -f "$TMP_DIR/backup/data/skip.me" ]; then
  fail "Ignored file was found."
 fi
 pass "Ignored file was not found."
--- a/test/local/.gitignore
+++ b/test/local/.gitignore
@@ -1 +0,0 @@
-local
--- a/test/local/docker-compose.yml
+++ b/test/local/docker-compose.yml
@@ -16,7 +16,7 @@ services:
    volumes:
      - app_data:/backup/app_data:ro
      - /var/run/docker.sock:/var/run/docker.sock
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive

  offen:
    image: offen/offen:latest
--- a/test/local/run.sh
+++ b/test/local/run.sh
@@ -6,9 +6,9 @@ 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

 # A symlink for a known file in the volume is created so the test can check
@@ -21,11 +21,11 @@ sleep 5
 expect_running_containers "2"

 tmp_dir=$(mktemp -d)
-tar -xvf ./local/test-hostnametoken.tar.gz -C $tmp_dir
+tar -xvf "$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/test-hostnametoken.tar.gz
+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."
@@ -33,7 +33,7 @@ fi

 pass "Found relevant files in decrypted and untared local backup."

-if [ ! -L ./local/test-hostnametoken.latest.tar.gz.gpg ]; then
+if [ ! -L "$LOCAL_DIR/test-hostnametoken.latest.tar.gz.gpg" ]; then
  fail "Could not find symlink to latest version."
 fi

@@ -41,15 +41,36 @@ 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

-if [ "$(find ./local -type f | wc -l)" != "1" ]; then
-  fail "Backups should not have been deleted, instead seen: "$(find ./local -type f)""
+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."

-docker compose down --volumes
+# 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."
--- a/test/notifications/.gitignore
+++ b/test/notifications/.gitignore
@@ -1 +0,0 @@
-local
--- a/test/notifications/docker-compose.yml
+++ b/test/notifications/docker-compose.yml
@@ -12,7 +12,7 @@ services:
      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

--- a/test/notifications/run.sh
+++ b/test/notifications/run.sh
@@ -6,9 +6,9 @@ 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=$(curl -sSLX POST -H 'Content-Type: application/json' -d '{"name":"test"}' http://admin:custom@localhost:8080/application | jq -r '.token')
@@ -46,5 +46,3 @@ if [ "$MESSAGE_BODY" != "Backing up /tmp/test.tar.gz succeeded." ]; then
  fail "Unexpected notification body $MESSAGE_BODY"
 fi
 pass "Custom notification body was used."
-
-docker compose down --volumes
--- a/test/ownership/.gitignore
+++ b/test/ownership/.gitignore
@@ -1 +0,0 @@
-local
--- a/test/ownership/docker-compose.yml
+++ b/test/ownership/docker-compose.yml
@@ -9,9 +9,9 @@ services:
    volumes:
      - postgres_data:/var/lib/postgresql/data
    environment:
-      - POSTGRES_PASSWORD=1FHJMSwt0yhIN1zS7I4DilGUhThBKq0x
-      - POSTGRES_USER=test
-      - POSTGRES_DB=test
+      POSTGRES_PASSWORD: 1FHJMSwt0yhIN1zS7I4DilGUhThBKq0x
+      POSTGRES_USER: test
+      POSTGRES_DB: test

  backup:
    image: offen/docker-volume-backup:${TEST_VERSION}
@@ -21,7 +21,7 @@ services:
    volumes:
      - postgres_data:/backup/postgres:ro
      - /var/run/docker.sock:/var/run/docker.sock:ro
-      - ./local:/archive
+      - ${LOCAL_DIR:-./local}:/archive

 volumes:
  postgres_data:
--- a/test/ownership/run.sh
+++ b/test/ownership/run.sh
@@ -7,24 +7,22 @@ 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

 docker compose exec backup backup

-tmp_dir=$(mktemp -d)
-sudo tar --same-owner -xvf ./local/backup.tar.gz -C $tmp_dir
+TMP_DIR=$(mktemp -d)
+tar --same-owner -xvf "$LOCAL_DIR/backup.tar.gz" -C $TMP_DIR

-sudo find $tmp_dir/backup/postgres > /dev/null
+find $TMP_DIR/backup/postgres > /dev/null
 pass "Backup contains files at expected location"

-for file in $(sudo find $tmp_dir/backup/postgres); do
-  if [ "$(sudo stat -c '%u:%g' $file)" != "70:70" ]; then
-    fail "Unexpected file ownership for $file: $(sudo stat -c '%u:%g' $file)"
+for file in $(find $TMP_DIR/backup/postgres); do
+  if [ "$(stat -c '%u:%g' $file)" != "70:70" ]; then
+    fail "Unexpected file ownership for $file: $(stat -c '%u:%g' $file)"
  fi
 done
 pass "All files and directories in backup preserved their ownership."
-
-docker compose down --volumes
--- a/test/pgzip/run.sh
+++ b/test/pgzip/run.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
+
+docker network create test_network
+docker volume create app_data
+
+LOCAL_DIR=$(mktemp -d)
+
+docker run -d -q \
+  --name offen \
+  --network test_network \
+  -v app_data:/var/opt/offen/ \
+  offen/offen:latest
+
+sleep 5
+
+docker run --rm -q \
+  --network test_network \
+  -v app_data:/backup/app_data \
+  -v $LOCAL_DIR:/archive \
+  -v /var/run/docker.sock:/var/run/docker.sock \
+  --env BACKUP_COMPRESSION=gz \
+  --env GZIP_PARALLELISM=0 \
+  --env BACKUP_FILENAME='test.{{ .Extension }}' \
+  --entrypoint backup \
+  offen/docker-volume-backup:${TEST_VERSION:-canary}
+
+tmp_dir=$(mktemp -d)
+tar -xvf "$LOCAL_DIR/test.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
+pass "Found relevant files in untared local backup."
+
+# This test does not stop containers during backup. This is happening on
+# purpose in order to cover this setup as well.
+expect_running_containers "1"
--- a/test/pruning/docker-compose.yml
+++ b/test/pruning/docker-compose.yml
@@ -0,0 +1,50 @@
+version: '3'
+
+services:
+  minio:
+    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 /data'
+    volumes:
+      - minio_backup_data:/data
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    hostname: hostnametoken
+    depends_on:
+      - minio
+    restart: always
+    environment:
+      AWS_ACCESS_KEY_ID: test
+      AWS_SECRET_ACCESS_KEY: GMusLtUmILge2by+z890kQ
+      AWS_ENDPOINT: minio:9000
+      AWS_ENDPOINT_PROTO: http
+      AWS_S3_BUCKET_NAME: backup
+      BACKUP_FILENAME_EXPAND: 'true'
+      BACKUP_FILENAME: test-$$HOSTNAME.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_RETENTION_DAYS: 7
+      BACKUP_PRUNING_LEEWAY: 5s
+      BACKUP_PRUNING_PREFIX: test
+      BACKUP_LATEST_SYMLINK: test-$$HOSTNAME.latest.tar.gz
+      BACKUP_SKIP_BACKENDS_FROM_PRUNE: 's3'
+    volumes:
+      - app_data:/backup/app_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+      - ./local:/archive
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+volumes:
+  app_data:
+  minio_backup_data:
+    name: minio_backup_data
--- a/test/pruning/run.sh
+++ b/test/pruning/run.sh
@@ -0,0 +1,70 @@
+#!/bin/sh
+
+# Tests prune-skipping with multiple backends (local, s3)
+# Pruning itself is tested individually for each storage backend
+
+set -e
+
+cd "$(dirname "$0")"
+. ../util.sh
+current_test=$(basename $(pwd))
+
+mkdir -p local
+
+docker compose up -d --quiet-pull
+sleep 5
+
+docker compose exec backup backup
+
+sleep 5
+
+expect_running_containers "3"
+
+touch -r ./local/test-hostnametoken.tar.gz -d "14 days ago" ./local/test-hostnametoken-old.tar.gz
+
+docker run --rm \
+  -v minio_backup_data:/minio_data \
+  alpine \
+  ash -c 'touch -d@$(( $(date +%s) - 1209600 )) /minio_data/backup/test-hostnametoken-old.tar.gz'
+
+# Skip s3 backend from prune
+
+docker compose up -d
+sleep 5
+
+info "Create backup with no prune for s3 backend"
+docker compose exec backup backup
+
+info "Check if old backup has been pruned (local)"
+test ! -f ./local/test-hostnametoken-old.tar.gz
+
+info "Check if old backup has NOT been pruned (s3)"
+docker run --rm \
+  -v minio_backup_data:/minio_data \
+  alpine \
+  ash -c 'test -f /minio_data/backup/test-hostnametoken-old.tar.gz'
+
+pass "Old remote backup has been pruned locally, skipped S3 backend is untouched."
+
+# Skip local and s3 backend from prune (all backends)
+
+touch -r ./local/test-hostnametoken.tar.gz -d "14 days ago" ./local/test-hostnametoken-old.tar.gz
+
+docker compose up -d
+sleep 5
+
+info "Create backup with no prune for both backends"
+docker compose exec -e BACKUP_SKIP_BACKENDS_FROM_PRUNE="s3,local" backup backup
+
+info "Check if old backup has NOT been pruned (local)"
+if [ ! -f ./local/test-hostnametoken-old.tar.gz ]; then
+  fail "Backdated file has not been deleted"
+fi
+
+info "Check if old backup has NOT been pruned (s3)"
+docker run --rm \
+  -v minio_backup_data:/minio_data \
+  alpine \
+  ash -c 'test -f /minio_data/backup/test-hostnametoken-old.tar.gz'
+
+pass "Skipped all backends while pruning."
--- a/test/s3/run.sh
+++ b/test/s3/run.sh
@@ -6,18 +6,16 @@ cd "$(dirname "$0")"
 . ../util.sh
 current_test=$(basename $(pwd))

-docker compose up -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 backup backup

 sleep 5

 expect_running_containers "3"

-docker run --rm -it \
+docker run --rm \
  -v minio_backup_data:/minio_data \
  alpine \
  ash -c 'tar -xvf /minio_data/backup/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db'
@@ -26,17 +24,38 @@ pass "Found relevant files in untared remote backups."

 # 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 \
+docker run --rm \
  -v minio_backup_data:/minio_data \
  alpine \
  ash -c '[ $(find /minio_data/backup/ -type f | wc -l) = "1" ]'

 pass "Remote backups have not been deleted."

-docker compose down --volumes
+# 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 run --rm \
+  -v minio_backup_data:/minio_data \
+  alpine \
+  ash -c 'touch -d@$(( $(date +%s) - 1209600 )) /minio_data/backup/test-hostnametoken-old.tar.gz'
+
+info "Create second backup and prune"
+docker compose exec backup backup
+
+docker run --rm \
+  -v minio_backup_data:/minio_data \
+  alpine \
+  ash -c 'test ! -f /minio_data/backup/test-hostnametoken-old.tar.gz && test -f /minio_data/backup/test-hostnametoken.tar.gz'
+
+pass "Old remote backup has been pruned, new one is still present."
--- a/test/secrets/run.sh
+++ b/test/secrets/run.sh
@@ -22,7 +22,7 @@ sleep 20

 docker exec $(docker ps -q -f name=backup) backup

-docker run --rm -it \
+docker run --rm \
  -v backup_data:/data alpine \
  ash -c 'tar -xf /data/backup/test.tar.gz && test -f /backup/pg_data/PG_VERSION'

@@ -31,14 +31,12 @@ pass "Found relevant files in untared backup."
 sleep 5
 expect_running_containers "5"

-docker stack rm test_stack
+docker exec -e AWS_ACCESS_KEY_ID=test $(docker ps -q -f name=backup) backup \
+  && fail "Backup should have failed due to duplicate env variables."

-docker secret rm minio_root_password
-docker secret rm minio_root_user
+pass "Backup failed due to duplicate env variables."

-docker swarm leave --force
+docker exec -e AWS_ACCESS_KEY_ID_FILE=/tmp/nonexistant $(docker ps -q -f name=backup) backup \
+  && fail "Backup should have failed due to non existing file env variable."

-sleep 10
-
-docker volume rm backup_data
-docker volume rm pg_data
+pass "Backup failed due to non existing file env variable."
--- a/test/ssh/docker-compose.yml
+++ b/test/ssh/docker-compose.yml
@@ -8,7 +8,7 @@ services:
      - PGID=1000
      - USER_NAME=test
    volumes:
-      - ./id_rsa.pub:/config/.ssh/authorized_keys
+      - ${KEY_DIR:-.}/id_rsa.pub:/config/.ssh/authorized_keys
      - ssh_backup_data:/tmp

  backup:
@@ -30,7 +30,7 @@ services:
      SSH_REMOTE_PATH: /tmp
      SSH_IDENTITY_PASSPHRASE: test1234
    volumes:
-      - ./id_rsa:/root/.ssh/id_rsa
+      - ${KEY_DIR:-.}/id_rsa:/root/.ssh/id_rsa
      - app_data:/backup/app_data:ro
      - /var/run/docker.sock:/var/run/docker.sock

--- a/test/ssh/run.sh
+++ b/test/ssh/run.sh
@@ -6,9 +6,11 @@ cd "$(dirname "$0")"
 . ../util.sh
 current_test=$(basename $(pwd))

-ssh-keygen -t rsa -m pem -b 4096 -N "test1234" -f id_rsa -C "docker-volume-backup@local"
+export KEY_DIR=$(mktemp -d)

-docker compose up -d
+ssh-keygen -t rsa -m pem -b 4096 -N "test1234" -f "$KEY_DIR/id_rsa" -C "docker-volume-backup@local"
+
+docker compose up -d --quiet-pull
 sleep 5

 docker compose exec backup backup
@@ -17,7 +19,7 @@ sleep 5

 expect_running_containers 3

-docker run --rm -it \
+docker run --rm \
  -v ssh_backup_data:/ssh_data \
  alpine \
  ash -c 'tar -xvf /ssh_data/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db'
@@ -26,18 +28,40 @@ pass "Found relevant files in decrypted and untared remote backups."

 # 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 \
+docker run --rm \
  -v ssh_backup_data:/ssh_data \
  alpine \
  ash -c '[ $(find /ssh_data/ -type f | wc -l) = "1" ]'

 pass "Remote backups have not been deleted."

-docker compose down --volumes
-rm -f id_rsa id_rsa.pub
+# 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
+
+# Set the modification date of the old backup to 14 days ago
+docker run --rm \
+  -v ssh_backup_data:/ssh_data \
+  --user 1000 \
+  alpine \
+  ash -c 'touch -d@$(( $(date +%s) - 1209600 )) /ssh_data/test-hostnametoken-old.tar.gz'
+
+info "Create second backup and prune"
+docker compose exec backup backup
+
+docker run --rm \
+  -v ssh_backup_data:/ssh_data \
+  alpine \
+  ash -c 'test ! -f /ssh_data/test-hostnametoken-old.tar.gz && test -f /ssh_data/test-hostnametoken.tar.gz'
+
+pass "Old remote backup has been pruned, new one is still present."
--- a/test/swarm/run.sh
+++ b/test/swarm/run.sh
@@ -19,7 +19,7 @@ sleep 20

 docker exec $(docker ps -q -f name=backup) backup

-docker run --rm -it \
+docker run --rm \
  -v backup_data:/data alpine \
  ash -c 'tar -xf /data/backup/test.tar.gz && test -f /backup/pg_data/PG_VERSION'

@@ -27,11 +27,3 @@ pass "Found relevant files in untared backup."

 sleep 5
 expect_running_containers "5"
-
-docker stack rm test_stack
-docker swarm leave --force
-
-sleep 10
-
-docker volume rm backup_data
-docker volume rm pg_data
--- a/test/test.sh
+++ b/test/test.sh
@@ -2,15 +2,69 @@

 set -e

-TEST_VERSION=${1:-canary}
+MATCH_PATTERN=$1
+IMAGE_TAG=${IMAGE_TAG:-canary}

-for dir in $(ls -d -- */); do
-  test="${dir}run.sh"
+sandbox="docker_volume_backup_test_sandbox"
+tarball="$(mktemp -d)/image.tar.gz"
+
+trap finish EXIT INT TERM
+
+finish () {
+  rm -rf $(dirname $tarball)
+  if [ ! -z $(docker ps -aq --filter=name=$sandbox) ]; then
+    docker rm -f $(docker stop $sandbox)
+  fi
+  if [ ! -z $(docker volume ls -q --filter=name="^${sandbox}\$") ]; then
+    docker volume rm $sandbox
+  fi
+}
+
+docker build -t offen/docker-volume-backup:test-sandbox .
+
+if [ ! -z "$BUILD_IMAGE" ]; then
+  docker build -t offen/docker-volume-backup:$IMAGE_TAG $(dirname $(pwd))
+fi
+
+docker save offen/docker-volume-backup:$IMAGE_TAG -o $tarball
+
+find_args="-mindepth 1 -maxdepth 1 -type d"
+if [ ! -z "$MATCH_PATTERN" ]; then
+  find_args="$find_args -name $MATCH_PATTERN"
+fi
+
+for dir in $(find $find_args | sort); do
+  dir=$(echo $dir | cut -c 3-)
  echo "################################################"
-  echo "Now running $test"
+  echo "Now running ${dir}"
  echo "################################################"
  echo ""
-  TEST_VERSION=$TEST_VERSION /bin/sh $test
+
+  test="${dir}/run.sh"
+  docker_run_args="--name "$sandbox" --detach \
+    --privileged \
+    -v $(dirname $(pwd)):/code \
+    -v $tarball:/cache/image.tar.gz \
+    -v $sandbox:/var/lib/docker"
+
+  if [ -z "$NO_IMAGE_CACHE" ]; then
+    docker_run_args="$docker_run_args \
+    -v "${sandbox}_image":/var/lib/docker/image \
+    -v "${sandbox}_overlay2":/var/lib/docker/overlay2"
+  fi
+
+  docker run $docker_run_args offen/docker-volume-backup:test-sandbox
+
+  until docker exec $sandbox /bin/sh -c 'docker info' > /dev/null 2>&1; do
+    sleep 0.5
+  done
+  sleep 0.5
+
+  docker exec $sandbox /bin/sh -c "docker load -i /cache/image.tar.gz"
+  docker exec -e TEST_VERSION=$IMAGE_TAG $sandbox /bin/sh -c "/code/test/$test"
+
+  docker rm $(docker stop $sandbox)
+  docker volume rm $sandbox
  echo ""
  echo "$test passed"
  echo ""
--- a/test/user/docker-compose.yml
+++ b/test/user/docker-compose.yml
@@ -0,0 +1,29 @@
+version: '2.4'
+
+services:
+  alpine:
+    image: alpine:3.17.3
+    tty: true 
+    volumes:
+      - app_data:/tmp
+    labels:
+      - docker-volume-backup.archive-pre.user=testuser
+      - docker-volume-backup.archive-pre=/bin/sh -c 'whoami > /tmp/whoami.txt'
+
+  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 ?
+      EXEC_FORWARD_OUTPUT: "true"
+    volumes:
+      - ${LOCAL_DIR:-./local}:/archive
+      - app_data:/backup/data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+volumes:
+  app_data:
+  archive:
--- a/test/user/run.sh
+++ b/test/user/run.sh
@@ -0,0 +1,30 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export LOCAL_DIR=$(mktemp -d)
+export TMP_DIR=$(mktemp -d)
+
+echo "LOCAL_DIR $LOCAL_DIR"
+echo "TMP_DIR $TMP_DIR"
+
+docker compose up -d --quiet-pull
+user_name=testuser
+docker exec user-alpine-1 adduser --disabled-password "$user_name"
+
+docker compose exec backup backup
+
+tar -xvf "$LOCAL_DIR/test.tar.gz" -C "$TMP_DIR"
+if [ ! -f "$TMP_DIR/backup/data/whoami.txt" ]; then
+  fail "Could not find file written by pre command."
+fi
+pass "Found expected file."
+
+if [ "$(cat $TMP_DIR/backup/data/whoami.txt)" != "$user_name" ]; then
+  fail "Could not find expected user name."
+fi
+pass "Found expected user."
--- a/test/util.sh
+++ b/test/util.sh
@@ -15,9 +15,34 @@ fail () {
  exit 1
 }

+skip () {
+  echo "[test:${current_test:-none}:skip] "$1""
+  exit 0
+}
+
 expect_running_containers () {
  if [ "$(docker ps -q | wc -l)" != "$1" ]; then
    fail "Expected $1 containers to be running, instead seen: "$(docker ps -a | wc -l)""
  fi
  pass "$1 containers running."
 }
+
+docker() {
+  case $1 in
+    compose)
+      shift
+      case $1 in
+        up)
+          shift
+          command docker compose up --timeout 3 "$@";;
+        down)
+          shift
+          command docker compose down --timeout 3 "$@";;
+        *)
+          command docker compose "$@";;
+      esac
+      ;;
+    *)
+      command docker "$@";;
+  esac
+}
--- a/test/webdav/run.sh
+++ b/test/webdav/run.sh
@@ -6,7 +6,7 @@ cd "$(dirname "$0")"
 . ../util.sh
 current_test=$(basename $(pwd))

-docker compose up -d
+docker compose up -d --quiet-pull
 sleep 5

 docker compose exec backup backup
@@ -15,7 +15,7 @@ sleep 5

 expect_running_containers "3"

-docker run --rm -it \
+docker run --rm \
  -v webdav_backup_data:/webdav_data \
  alpine \
  ash -c 'tar -xvf /webdav_data/data/my/new/path/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db'
@@ -24,17 +24,40 @@ pass "Found relevant files in untared remote 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 \
+docker run --rm \
  -v webdav_backup_data:/webdav_data \
  alpine \
  ash -c '[ $(find /webdav_data/data/my/new/path/ -type f | wc -l) = "1" ]'

 pass "Remote backups have not been deleted."

-docker compose down --volumes
+# 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
+
+# Set the modification date of the old backup to 14 days ago
+docker run --rm \
+  -v webdav_backup_data:/webdav_data \
+  --user 82 \
+  alpine \
+  ash -c 'touch -d@$(( $(date +%s) - 1209600 )) /webdav_data/data/my/new/path/test-hostnametoken-old.tar.gz'
+
+info "Create second backup and prune"
+docker compose exec backup backup
+
+docker run --rm \
+  -v webdav_backup_data:/webdav_data \
+  alpine \
+  ash -c 'test ! -f /webdav_data/data/my/new/path/test-hostnametoken-old.tar.gz && test -f /webdav_data/data/my/new/path/test-hostnametoken.tar.gz'
+
+pass "Old remote backup has been pruned, new one is still present."
--- a/test/zstd/run.sh
+++ b/test/zstd/run.sh
@@ -0,0 +1,41 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
+
+docker network create test_network
+docker volume create app_data
+
+LOCAL_DIR=$(mktemp -d)
+
+docker run -d -q \
+  --name offen \
+  --network test_network \
+  -v app_data:/var/opt/offen/ \
+  offen/offen:latest
+
+sleep 10
+
+docker run --rm -q \
+  --network test_network \
+  -v app_data:/backup/app_data \
+  -v $LOCAL_DIR:/archive \
+  -v /var/run/docker.sock:/var/run/docker.sock \
+  --env BACKUP_COMPRESSION=zst \
+  --env BACKUP_FILENAME='test.{{ .Extension }}' \
+  --entrypoint backup \
+  offen/docker-volume-backup:${TEST_VERSION:-canary}
+
+tmp_dir=$(mktemp -d)
+tar -xvf "$LOCAL_DIR/test.tar.zst" --zstd -C $tmp_dir
+if [ ! -f "$tmp_dir/backup/app_data/offen.db" ]; then
+  fail "Could not find expected file in untared archive."
+fi
+pass "Found relevant files in untared local backup."
+
+# This test does not stop containers during backup. This is happening on
+# purpose in order to cover this setup as well.
+expect_running_containers "1"
Author	SHA1	Message	Date
MaxJa4	336c5bed71	Replace Gzip with PGzip (#266 ) * Replace Gzip with optimized PGzip. Add concurrency option. * Add shortened timeout for 'dc down' too. * Add NaturalNumberZero to allow zero. * Add test for concurrency=0 * Rename to GZIP_PARALLELISM * Fix block size. Fix compression level. Fix CI. * Refactor compression writer fetching. Renamed WholeNumber	2023-09-03 16:49:52 +02:00
Frederik Ring	1e39ac41f4	Run tests Docker in Docker (#261 ) * Try running tests in Docker * Spawn new container for each test * Store test artifacts outside of mount * When requested, build up to date image in test script * sudo is unneccessary in containerized test env * Skip azure test * Backdate fixture file in JSON database * Pin versions for azure tools * Mount temp volume for /var/lib/docker to prevent dangling ones created by VOLUME instruction * Fail backdating tests with message * Add some documentation on test setup * Cache images * Run compose stacks with shortened default timeout	2023-09-02 15:17:46 +02:00
MaxJa4	43c4961116	Support _FILE based configuration values (#264 ) * Replace envconfig with env * Adjust config options and processing * Added _FILE variant for all password vars. * Try pathenvconfig * Revert everything so far * Use our fork of envconfig with custom lookup * Use our fork of envconfig with custom lookup * Test compose timeout option * Remove secret resolving and specific _FILE config * Fix timing issue in swarm tests * Revert "Test compose timeout option" This reverts commit `ab50b21748`, reversing changes made to `0282514b2b`. Revert "Test compose timeout option" This reverts commit `0282514b2b`. * Use offen/envconfig v1.5.0 * Add info about _FILE in README * Value > File. Panic on file error. Panic on duplicate presence. * Test panic on duplicate vars and panic on file error.	2023-08-30 20:14:24 +02:00
Frederik Ring	24a6ec9480	Dropbox was missing from notification docs	2023-08-28 20:42:45 +02:00
MaxJa4	ad4e2af83f	Exclude specific backends from pruning (#262 ) * Skip backends while pruning * Add pruning test step and silence download log for better readability * Add test cases for pruning in all backends Also add -q or --quiet-pull to all tests. * Add test case for skipping backends while pruning * Adjusted test logging, generate new test spec file * Gitignore for temp test file	2023-08-27 19:19:11 +02:00
MaxJa4	5fcc96edf9	Cleanup: Lint warnings and deprecated packages (#263 ) * Fix lint warnings and std lib deprecations * Replace deprecated std lib with maintained drop-in replacement fork Backwartds compatible with original package and suggested by std lib due to security and stability issues. * OAuth2 is now a direct dependency due to Dropbox * Undo change * Revert "Replace deprecated std lib with maintained drop-in replacement fork" This reverts commit `2887bd409f`. * Update channel handling * Add linter for PRs * Rename CI, fetch all issues, add govet	2023-08-27 18:14:55 +02:00
Frederik Ring	3d7677f02a	Print context in log field instead of prepending to message (#260 ) * Print context in log field instead of prepending to message * Log messages on pruning do not need a description anymore * Remove redundant information from logs and errors	2023-08-25 12:44:43 +02:00
Frederik Ring	88a4794083	Zstd test does not need to spin up MinIO server (#258 )	2023-08-24 22:14:04 +02:00
Frederik Ring	7011261dc5	Pin version of mock openapi server used in Dropbox test	2023-08-24 22:01:07 +02:00
Frederik Ring	9ba8143be2	Add license headers to vendored Dropbox swagger spec	2023-08-24 19:52:33 +02:00
dependabot[bot]	b90fc9ea4d	Bump github.com/minio/minio-go/v7 from 7.0.61 to 7.0.62 (#255 ) Bumps [github.com/minio/minio-go/v7](https://github.com/minio/minio-go) from 7.0.61 to 7.0.62. - [Release notes](https://github.com/minio/minio-go/releases) - [Commits](https://github.com/minio/minio-go/compare/v7.0.61...v7.0.62) --- updated-dependencies: - dependency-name: github.com/minio/minio-go/v7 dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>	2023-08-24 19:37:50 +02:00
MaxJa4	e08a3303bf	Add new storage backend: Dropbox (#103 ) (#251 ) * Add new storage backend: Dropbox (#103) * Remove duplicate check * Add concurrency level for parallel upload to dropbox. * Fixed some instabilites. Changed default concurrency to 6. * Added some env config vars to readme. WIP * Wrap errors for storage backend creation. * Fixed token issue, added OAuth2 including recipe and docs. * Readme typo fix * Test for dropbox integration * Update info and TOC * Missed a file * Docker-compose fix * Fix endpoint connection * Fix container names * Fix log fetching * Fix log fetching (again) * Print command output to logs * Addressing comments part 1 * Address comments part 2 * OpenAPI Mock spec path adjusted * Dropbox FileMetadata reflection refactored * NaturalNumber type added * Add OAuth2 mock server for CI testing * Fix env name of oauth2 endpoint * Remove hostname * Add forgotten change to commit... * Fix oauth2 endpoint "Worked on my machine" * Try again * Try suggested hostname again * Fix docker internal DNS resolving issues (as suggested by oauth2 mock docs) * Add docker network, remove hostname * Network not external * Last hostname try * Add more delay, add oauth2 endpoint log * Temp CI log output of command even when failing * Try different config and method * Add custom server-hostname. Rename test folder to accellerate debugging * Try that fix again * Adding quotes * Port fix attempt * Try localhost * Try extra hosts * Change network mode * Undo some changes * Use static IP * Remove specific IP binding * Change to default net driver * Fix static IP * Squash for revert * Revert "Squash for revert" This reverts commit `e9b617be9a`. * Actual fix for CI testing from #257	2023-08-24 19:33:47 +02:00
MaxJa4	47326c7c59	Fix storage backends not outputting any info logs (#250 )	2023-08-20 20:35:25 +02:00
Michal Middleton	67e7288855	Add support for zstd compression (#249 ) Co-authored-by: Michal Middleton <jafa81@gmail.com>	2023-08-19 19:20:13 +02:00
dependabot[bot]	1765b06835	Bump github.com/pkg/sftp from 1.13.5 to 1.13.6 (#248 )	2023-08-15 04:38:55 +00:00
Frederik Ring	67d978f515	Drop logrus dependency, log using slog package from stdlib (#247 )	2023-08-10 19:41:03 +02:00
Frederik Ring	a93ff6fe09	Build in Go 1.21 (#246 )	2023-08-10 16:03:59 +02:00
Frederik Ring	1c6f64e254	Current Docker client breaks in newer Go versions (#241 ) * Current Docker client breaks in newer Go versions * Cater for breaking API changes in Docker client * Update Docker client * Unpin Go version used for build * Tidy sum file	2023-07-25 19:46:57 +02:00
dependabot[bot]	085d2c5dfd	Bump github.com/minio/minio-go/v7 from 7.0.59 to 7.0.61 (#240 )	2023-07-24 19:16:02 +00:00
dependabot[bot]	b1382dee00	Bump github.com/Azure/azure-sdk-for-go/sdk/storage/azblob (#239 )	2023-07-24 19:15:56 +00:00
Frederik Ring	c3732107b1	Current Docker client breaks in Go 1.20.6 (#242 )	2023-07-24 21:01:28 +02:00
dependabot[bot]	d288c87c54	Bump github.com/minio/minio-go/v7 from 7.0.58 to 7.0.59 (#238 )	2023-07-04 07:53:19 +00:00
dependabot[bot]	47491439a1	Bump github.com/studio-b12/gowebdav (#235 )	2023-06-27 07:46:34 +00:00
dependabot[bot]	94f71ac765	Bump github.com/minio/minio-go/v7 from 7.0.57 to 7.0.58 (#236 )	2023-06-27 05:25:42 +00:00
dependabot[bot]	2addf1dd6c	Bump golang.org/x/sync from 0.2.0 to 0.3.0 (#234 )	2023-06-20 12:29:11 +00:00
dependabot[bot]	c07990eaf6	Bump github.com/minio/minio-go/v7 from 7.0.56 to 7.0.57 (#233 )	2023-06-20 12:28:06 +00:00
jsloane	a27743bd32	Update README.md (#230 )	2023-06-17 08:30:48 +02:00
dependabot[bot]	9d5b897ab4	Bump golang.org/x/sync from 0.1.0 to 0.2.0 (#229 )	2023-06-13 07:17:58 +00:00
dependabot[bot]	30bf31cd90	Bump github.com/Azure/azure-sdk-for-go/sdk/storage/azblob (#228 )	2023-06-13 07:04:03 +00:00
dependabot[bot]	32e9a05b40	Bump github.com/minio/minio-go/v7 from 7.0.44 to 7.0.56 (#227 )	2023-06-13 07:03:38 +00:00
dependabot[bot]	b302884447	Bump golang.org/x/crypto from 0.3.0 to 0.9.0 (#223 )	2023-06-10 13:15:41 +00:00
dependabot[bot]	b3e1ce27be	Bump github.com/Azure/azure-sdk-for-go/sdk/azidentity (#225 )	2023-06-10 12:57:44 +00:00
dependabot[bot]	66518ed0ff	Bump github.com/sirupsen/logrus from 1.9.0 to 1.9.3 (#226 )	2023-06-10 12:57:39 +00:00
dependabot[bot]	14d966d41a	Bump github.com/otiai10/copy from 1.10.0 to 1.11.0 (#224 )	2023-06-10 12:57:30 +00:00
Frederik Ring	336dece328	Set up automated updates for Docker base images and Go packages	2023-06-10 14:42:28 +02:00
Frederik Ring	dc8172b673	Use alpine-1.18 as the base image (#219 )	2023-06-03 13:08:35 +02:00
Erwan LE PRADO	5ea9a7ce15	feat: add better handler for part size (#214 ) * feat: add better handler for part size fix: use local file fix: try with another path fix: use bytes chore: go back go back readme goback goback goback * chore: better handling * fix: typo readme * chore: wrong comparaison * fix: typo	2023-06-02 16:30:02 +02:00
Frederik Ring	bcffe0bc25	Clarify docs section about user executing labeled commands	2023-05-26 16:15:09 +02:00
dependabot[bot]	144e65ce6f	Bump github.com/docker/distribution (#215 )	2023-05-11 21:07:45 +00:00
ba-tno	07afa53cd3	Update shoutrrr to 0.7 (#213 ) * Replace docker-compose reference with docker[space]compose * Update shoutrrr only to 0.7.1 * modules after go mod tidy * Refer to v0.7 docs of shoutrrr * Replace docker-compose reference with docker[space]compose * Update shoutrrr only to 0.7.1 * modules after go mod tidy * Refer to v0.7 docs of shoutrrr * Remove 'v' from shoutrrr doc link	2023-04-29 20:14:04 +02:00
Frederik Ring	9a07f5486b	Docs reference incorrect shoutrrr version	2023-04-29 14:44:39 +02:00
Frederik Ring	d4c5f65f31	Entrypoint permissions can be set on COPY (#211 )	2023-04-28 20:06:57 +02:00
Frederik Ring	5b8a484d80	Documentation around user label is lacking	2023-04-28 16:01:17 +02:00
Frederik Ring	37c01a578c	TaskTemplate.ForceUpdate is a counter (#209 )	2023-04-26 08:45:12 +02:00
Frederik Ring	46c6441d48	Add note about GHCR to README	2023-04-07 12:00:39 +02:00
Frederik Ring	5715d9ff9b	Update of package copy does not fail on deleted files (#206 )	2023-04-07 11:28:36 +02:00
dependabot[bot]	6ba173d916	Bump github.com/docker/docker (#205 )	2023-04-05 04:58:07 +00:00
Frederik Ring	301fe6628c	on: is expected to be an object	2023-04-02 19:45:46 +02:00
Frederik Ring	5ff2d53602	Items in on: are expected to be objects	2023-04-02 19:44:51 +02:00
Frederik Ring	cddd1fdcea	Prevent duplicate builds on pull request	2023-04-02 19:41:49 +02:00
Frederik Ring	808cf8f82d	Local directory can be used instead of volume for storing test artifact (#204 )	2023-04-02 19:41:00 +02:00
Frederik Ring	c177202ac1	Multi platform build requires explicit buildx setup	2023-04-02 11:51:35 +02:00
Frederik Ring	27c2201161	Branches filter is a glob pattern, not a regex	2023-04-02 11:46:06 +02:00
Diulgher Artiom	7f20036b15	Possibility to use -u (user) option in docker exec (#203 ) * Add user option for docker exec * Add test for user option * Return test version for image * remove gitea config file * refactor tests * remove comments & fix image name * add docs * cleanup * Update README.md with suggested correction Co-authored-by: Frederik Ring <frederik.ring@gmail.com> * fix backup command & bind folder instead of volume --------- Co-authored-by: tao <generaltao.md@gmail.com> Co-authored-by: Frederik Ring <frederik.ring@gmail.com>	2023-04-02 11:12:10 +02:00
Frederik Ring	2ac1f0cea4	Also trigger test runs on Pull Request	2023-03-29 07:57:09 +02:00
Frederik Ring	66ad124ddd	any can be used instead of interface{}	2023-03-16 19:48:12 +01:00
Frederik Ring	aee802cb09	Migrate CI setup to GitHub Actions, also publish to GHCR (#199 ) * Run tests in GitHub actions * Do not try to allocate a pseudo TTY when running compose commands * Try hard disabling TTY allocation * Use compose plugin * Test scripts shall not try to allocate a TTY * Pass correct base version * Check whether env var is even needed * Stop running tests in CircleCI * Run releases from GitHub actions as well * Manually construct tags to be pushed on release	2023-03-16 19:32:44 +01:00
dependabot[bot]	a06ad1957a	Bump github.com/docker/distribution (#195 )	2023-03-07 06:56:56 +00:00
dependabot[bot]	15786c5da3	Bump golang.org/x/net from 0.2.0 to 0.7.0 (#191 )	2023-02-18 06:34:40 +00:00
dependabot[bot]	641a3203c7	Bump github.com/containerd/containerd from 1.6.6 to 1.6.18 (#190 )	2023-02-16 19:32:46 +00:00
Frederik Ring	5adfe3989e	Document usage with rootless Docker installations As described in #189	2023-02-16 08:18:57 +01:00
dependabot[bot]	550833be33	Merge pull request #188 from offen/dependabot/go_modules/github.com/containrrr/shoutrrr-0.6.0	2023-02-14 19:09:43 +00:00
dependabot[bot]	201a983ea4	Bump github.com/containrrr/shoutrrr from 0.5.2 to 0.6.0 Bumps [github.com/containrrr/shoutrrr](https://github.com/containrrr/shoutrrr) from 0.5.2 to 0.6.0. - [Release notes](https://github.com/containrrr/shoutrrr/releases) - [Changelog](https://github.com/containrrr/shoutrrr/blob/main/goreleaser.yml) - [Commits](https://github.com/containrrr/shoutrrr/compare/v0.5.2...v0.6.0) --- updated-dependencies: - dependency-name: github.com/containrrr/shoutrrr dependency-type: direct:production ... Signed-off-by: dependabot[bot] <support@github.com>	2023-02-14 18:57:32 +00:00