Deprecate BACKUP_FROM_SNAPSHOT (#81 )

Tag releases with major version too (#82 )
Support identical cron schedule (#87 )
2025-12-05 17:18:02 +01:00 · 2022-03-25 18:28:58 +01:00 · 2022-03-25 18:27:00 +01:00 · 2022-03-25 18:26:34 +01:00 · 2022-03-17 11:22:41 +01:00 · 2022-03-17 11:13:07 +01:00
39 changed files with 2131 additions and 917 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -3,7 +3,7 @@ version: 2.1
 jobs:
  canary:
    machine:
-      image: ubuntu-1604:202007-01
+      image: ubuntu-2004:202201-02
    working_directory: ~/docker-volume-backup
    steps:
      - checkout
@@ -19,6 +19,7 @@ jobs:
          name: Run tests
          working_directory: ~/docker-volume-backup/test
          command: |
+            export GPG_TTY=$(tty)
            ./test.sh canary

  build:
@@ -47,6 +48,7 @@ jobs:
            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
--- a/13
+++ b/13
@@ -1,21 +1,22 @@
 # Copyright 2021 - Offen Authors <hioffen@posteo.de>
 # SPDX-License-Identifier: MPL-2.0

-FROM golang:1.17-alpine as builder
+FROM golang:1.18-alpine as builder

 WORKDIR /app
 COPY go.mod go.sum ./
 RUN go mod download
-COPY cmd/backup/main.go ./cmd/backup/main.go
-RUN go build -o backup cmd/backup/main.go
+COPY cmd/backup ./cmd/backup/
+WORKDIR /app/cmd/backup
+RUN go build -o backup .

-FROM alpine:3.14
+FROM alpine:3.15

 WORKDIR /root

-RUN apk add --update ca-certificates
+RUN apk add --no-cache ca-certificates

-COPY --from=builder /app/backup /usr/bin/backup
+COPY --from=builder /app/cmd/backup/backup /usr/bin/backup

 COPY ./entrypoint.sh /root/
 RUN chmod +x entrypoint.sh
--- a/README.md
+++ b/README.md
@@ -16,17 +16,23 @@ It handles __recurring or one-off backups of Docker volumes__ to a __local direc
  - [One-off backups using Docker CLI](#one-off-backups-using-docker-cli)
 - [Configuration reference](#configuration-reference)
 - [How to](#how-to)
-  - [Stopping containers during backup](#stopping-containers-during-backup)
+  - [Stop containers during backup](#stop-containers-during-backup)
  - [Automatically pruning old backups](#automatically-pruning-old-backups)
  - [Send email notifications on failed backup runs](#send-email-notifications-on-failed-backup-runs)
+  - [Customize notifications](#customize-notifications)
+  - [Run custom commands before / after backup](#run-custom-commands-before--after-backup)
  - [Encrypting your backup using GPG](#encrypting-your-backup-using-gpg)
  - [Restoring a volume from a backup](#restoring-a-volume-from-a-backup)
  - [Set the timezone the container runs in](#set-the-timezone-the-container-runs-in)
  - [Using with Docker Swarm](#using-with-docker-swarm)
  - [Manually triggering a backup](#manually-triggering-a-backup)
  - [Update deprecated email configuration](#update-deprecated-email-configuration)
+  - [Replace deprecated `BACKUP_FROM_SNAPSHOT` usage](#replace-deprecated-backup_from_snapshot-usage)
+  - [Using a custom Docker host](#using-a-custom-docker-host)
+  - [Run multiple backup schedules in the same container](#run-multiple-backup-schedules-in-the-same-container)
 - [Recipes](#recipes)
  - [Backing up to AWS S3](#backing-up-to-aws-s3)
+  - [Backing up to Filebase](#backing-up-to-filebase)
  - [Backing up to MinIO](#backing-up-to-minio)
  - [Backing up to WebDAV](#backing-up-to-webdav)
  - [Backing up locally](#backing-up-locally)
@@ -34,6 +40,7 @@ It handles __recurring or one-off backups of Docker volumes__ to a __local direc
  - [Running on a custom cron schedule](#running-on-a-custom-cron-schedule)
  - [Rotating away backups that are older than 7 days](#rotating-away-backups-that-are-older-than-7-days)
  - [Encrypting your backups using GPG](#encrypting-your-backups-using-gpg)
+  - [Using mysqldump to prepare the backup](#using-mysqldump-to-prepare-the-backup)
  - [Running multiple instances in the same setup](#running-multiple-instances-in-the-same-setup)
 - [Differences to `futurice/docker-volume-backup`](#differences-to-futuricedocker-volume-backup)

@@ -78,7 +85,8 @@ services:
      - data:/backup/my-app-backup:ro
      # Mounting the Docker socket allows the script to stop and restart
      # the container during backup. You can omit this if you don't want
-      # to stop the container
+      # to stop the container. In case you need to proxy the socket, you can
+      # also provide a location by setting `DOCKER_HOST` in the container
      - /var/run/docker.sock:/var/run/docker.sock:ro
      # If you mount a local directory or volume to `/archive` a local
      # copy of the backup will be stored there. You can override the
@@ -100,7 +108,7 @@ docker run --rm \
  --env AWS_SECRET_ACCESS_KEY="<xxx>" \
  --env AWS_S3_BUCKET_NAME="<xxx>" \
  --entrypoint backup \
-  offen/docker-volume-backup:latest
+  offen/docker-volume-backup:v2
 ```

 Alternatively, pass a `--env-file` in order to use a full config as described below.
@@ -135,13 +143,18 @@ You can populate below template according to your requirements and use it as you
 # Please note that you will need to escape the `$` when providing the value
 # in a docker-compose.yml file, i.e. using $$VAR instead of $VAR.

-# BACKUP_FILENAME_TEMPLATE="true"
+# BACKUP_FILENAME_EXPAND="true"

 # When storing local backups, a symlink to the latest backup can be created
 # in case a value is given for this key. This has no effect on remote backups.

 # BACKUP_LATEST_SYMLINK="backup.latest.tar.gz"

+# ************************************************************************
+# The BACKUP_FROM_SNAPSHOT option has been deprecated and will be removed
+# in the next major version. Please use exec-pre and exec-post
+# as documented below instead.
+# ************************************************************************
 # Whether to copy the content of backup folder before creating the tar archive.
 # In the rare scenario where the content of the source backup volume is continously
 # updating, but we do not wish to stop the container while performing the backup,
@@ -149,6 +162,11 @@ You can populate below template according to your requirements and use it as you

 # BACKUP_FROM_SNAPSHOT="false"

+# By default, the `/backup` directory inside the container will be backed up.
+# In case you need to use a custom location, set `BACKUP_SOURCES`.
+
+# BACKUP_SOURCES="/other/location"
+
 ########### BACKUP STORAGE

 # The name of the remote bucket that should be used for storing backups. If
@@ -156,6 +174,11 @@ You can populate below template according to your requirements and use it as you

 # AWS_S3_BUCKET_NAME="backup-bucket"

+# If you want to store the backup in a non-root location on your bucket
+# you can provide a path. The path must not contain a leading slash.
+
+# AWS_S3_PATH="my/backup/location"
+
 # Define credentials for authenticating against the backup storage and a bucket
 # name. Although all of these keys are `AWS`-prefixed, the setup can be used
 # with any S3 compatible storage.
@@ -171,7 +194,7 @@ You can populate below template according to your requirements and use it as you
 # AWS_IAM_ROLE_ENDPOINT="http://169.254.169.254"

 # This is the FQDN of your storage server, e.g. `storage.example.com`.
-# Do not set this when working against AWS S3 (the default value is 
+# Do not set this when working against AWS S3 (the default value is
 # `s3.amazonaws.com`). If you need to set a specific (non-https) protocol, you
 # will need to use the option below.

@@ -270,13 +293,35 @@ You can populate below template according to your requirements and use it as you

 # BACKUP_STOP_CONTAINER_LABEL="service1"

+########### EXECUTING COMMANDS IN CONTAINERS PRE/POST BACKUP
+
+# It is possible to define commands to be run in any container before and after
+# a backup is conducted. The commands themselves are defined in labels like
+# `docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump [options] > dump.sql'.
+# Several options exist for controlling this feature:
+
+# By default, any output of such a command is suppressed. If this value
+# is configured to be "true", command execution output will be forwarded to
+# the backup container's stdout and stderr.
+
+# EXEC_FORWARD_OUTPUT="true"
+
+# Without any further configuration, all commands defined in labels will be
+# run before and after a backup. If you need more fine grained control, you
+# can use this option to set a label that will be used for narrowing down
+# the set of eligible containers. When set, an eligible container will also need
+# to be labeled as `docker-volume-backup.exec-label=database`.
+
+# EXEC_LABEL="database"
+
 ########### NOTIFICATIONS

 # Notifications (email, Slack, etc.) can be sent out when a backup run finishes.
 # Configuration is provided as a comma-separated list of URLs as consumed
 # by `shoutrrr`: https://containrrr.dev/shoutrrr/v0.5/services/overview/
-# When providing multiple URLs or an URL that contains a comma, the values
-# can be URL encoded to avoid ambiguities.
+# The content of such notifications can be customized. Dedicated documentation
+# on how to do this can be found in the README. When providing multiple URLs or
+# an URL that contains a comma, the values can be URL encoded to avoid ambiguities.

 # The below URL demonstrates how to send an email using the provided SMTP
 # configuration and credentials.
@@ -289,6 +334,23 @@ You can populate below template according to your requirements and use it as you

 # NOTIFICATION_LEVEL="error"

+########### DOCKER HOST
+
+# If you are interfacing with Docker via TCP you can set the Docker host here
+# instead of mounting the Docker socket as a volume. This is unset by default.
+
+# DOCKER_HOST="tcp://docker_socket_proxy:2375"
+
+########### LOCK_TIMEOUT
+
+# In the case of overlapping cron schedules run by the same container,
+# subsequent invocations will wait for previous runs to finish before starting.
+# By default, this will time out and fail in case the lock could not be acquired
+# after 60 minutes. In case you need to adjust this timeout, supply a duration
+# value as per https://pkg.go.dev/time#ParseDuration to `LOCK_TIMEOUT`
+
+# LOCK_TIMEOUT="60m"
+
 ########### EMAIL NOTIFICATIONS

 # ************************************************************************
@@ -327,7 +389,7 @@ You can work around this by either updating `docker-compose` or unquoting your c

 ## How to

-### Stopping containers during backup
+### Stop containers during backup

 In many cases, it will be desirable to stop the services that are consuming the volume you want to backup in order to ensure data integrity.
 This image can automatically stop and restart containers and services (in case you are running Docker in Swarm mode).
@@ -345,7 +407,7 @@ services:
      - docker-volume-backup.stop-during-backup=service1

  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      BACKUP_STOP_CONTAINER_LABEL: service1
    volumes:
@@ -368,7 +430,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
      BACKUP_PRUNING_PREFIX: backup-
@@ -391,7 +453,7 @@ version: '3'

 services:
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      # ... other configuration values go here
      NOTIFICATION_URLS=smtp://me:secret@smtp.example.com:587/?fromAddress=no-reply@example.com&toAddresses=you@example.com
@@ -402,6 +464,87 @@ Refer to the documentation of [shoutrrr][shoutrrr-docs] to find out about option

 [shoutrrr-docs]: https://containrrr.dev/shoutrrr/v0.5/services/overview/

+### Customize notifications
+
+The title and body of the notifications can be easily tailored to your needs using [go templates](https://pkg.go.dev/text/template).
+Templates must be mounted inside the container in `/etc/dockervolumebackup/notifications.d/`: any file inside this directory will be parsed.
+
+The files have to define [nested templates](https://pkg.go.dev/text/template#hdr-Nested_template_definitions) in order to override the original values. An example:
+```
+{{ define "title_success" -}}
+✅ Successfully ran backup {{ .Config.BackupStopContainerLabel }}
+{{- end }}
+
+{{ define "body_success" -}}
+▶️ Start time: {{ .Stats.StartTime | formatTime }}
+⏹️ End time: {{ .Stats.EndTime | formatTime }}
+⌛ Took time: {{ .Stats.TookTime }}
+🛑 Stopped containers: {{ .Stats.Containers.Stopped }}/{{ .Stats.Containers.All }} ({{ .Stats.Containers.StopErrors }} errors)
+⚖️ Backup size: {{ .Stats.BackupFile.Size | formatBytesBin }} / {{ .Stats.BackupFile.Size | formatBytesDec }}
+🗑️ Pruned backups: {{ .Stats.Storages.Local.Pruned }}/{{ .Stats.Storages.Local.Total }} ({{ .Stats.Storages.Local.PruneErrors }} errors)
+{{- end }}
+```
+
+Overridable template names are: `title_success`, `body_success`, `title_failure`, `body_failure`.
+
+For a full list of available variables and functions, see [this page](https://github.com/offen/docker-volume-backup/blob/master/docs/NOTIFICATION-TEMPLATES.md).
+
+### Run custom commands before / after backup
+
+In certain scenarios it can be required to run specific commands before and after a backup is taken (e.g. dumping a database).
+When mounting the Docker socket into the `docker-volume-backup` container, you can define pre- and post-commands that will be run in the context of the target container.
+Such commands are defined by specifying the command in a `docker-volume-backup.exec-[pre|post]` label.
+
+Taking a database dump using `mysqldump` would look like this:
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  database:
+    image: mariadb
+    volumes:
+      - backup_data:/tmp/backups
+    labels:
+      - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump --all-databases > /backups/dump.sql'
+
+volumes:
+  backup_data:
+```
+
+Due to Docker limitations, you currently cannot use any kind of redirection in these commands unless you pass the command to `/bin/sh -c` or similar.
+I.e. instead of using `echo "ok" > ok.txt` you will need to use `/bin/sh -c 'echo "ok" > ok.txt'`.
+
+If you need fine grained control about which container's commands are run, you can use the `EXEC_LABEL` configuration on your `docker-volume-backup` container:
+
+```yml
+version: '3'
+
+services:
+  database:
+    image: mariadb
+    volumes:
+      - backup_data:/tmp/backups
+    labels:
+      - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump --all-databases > /tmp/volume/dump.sql'
+      - docker-volume-backup.exec-label=database
+
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      EXEC_LABEL: database
+    volumes:
+      - data:/backup/dump:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  backup_data:
+```
+
+
+The backup procedure is guaranteed to wait for all `pre` commands to finish.
+However there are no guarantees about the order in which they are run, which could also happen concurrently.

 ### Encrypting your backup using GPG

@@ -423,17 +566,37 @@ In case you need to restore a volume from a backup, the most straight forward pr
  ```console
  tar -C /tmp -xvf  backup.tar.gz
  ```
- Using a temporary one-off container, mount the volume (the example assumes it's named `data`) and copy over the backup. Make sure you copy the correct path level (this depends on how you mount your volume into the backup container), you might need to strip some leading elements
+- Using a temporary once-off container, mount the volume (the example assumes it's named `data`) and copy over the backup. Make sure you copy the correct path level (this depends on how you mount your volume into the backup container), you might need to strip some leading elements
  ```console
-  docker run -d --name backup_restore -v data:/backup_restore alpine
-  docker cp /tmp/backup/data-backup backup_restore:/backup_restore
-  docker stop backup_restore
-  docker rm backup_restore
+  docker run -d --name temp_restore_container -v data:/backup_restore alpine
+  docker cp /tmp/backup/data-backup temp_restore_container:/backup_restore
+  docker stop temp_restore_container
+  docker rm temp_restore_container
  ```
- Restart the container(s) that are using the volume 
+- Restart the container(s) that are using the volume

 Depending on your setup and the application(s) you are running, this might involve other steps to be taken still.

+---
+
+If you want to rollback an entire volume to an earlier backup snapshot (recommended for database volumes):
+
+- Trigger a manual backup if necessary (see `Manually triggering a backup`).
+- Stop the container(s) that are using the volume.
+- If volume was initially created using docker-compose, find out exact volume name using:
+  ```console
+  docker volume ls
+  ```
+- Remove existing volume (the example assumes it's named `data`):
+  ```console
+  docker volume rm data
+  ```
+- Create new volume with the same name and restore a snapshot:
+  ```console
+  docker run --rm -it -v data:/backup/my-app-backup -v /path/to/local_backups:/archive:ro alpine tar -xvzf /archive/full_backup_filename.tar.gz
+  ```
+- Restart the container(s) that are using the volume.
+
 ### Set the timezone the container runs in

 By default a container based on this image will run in the UTC timezone.
@@ -445,7 +608,7 @@ version: '3'

 services:
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    volumes:
      - data:/backup/my-app-backup:ro
      - /etc/timezone:/etc/timezone:ro
@@ -468,7 +631,7 @@ When running in Swarm mode, it's also advised to set a hard memory limit on your
 ```yml
 services:
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    deployment:
      resources:
        limits:
@@ -503,6 +666,73 @@ After:
 NOTIFICATION_URLS=smtp://me:secret@posteo.de:587/?fromAddress=no-reply@example.com&toAddresses=you@example.com
 ```

+### Replace deprecated `BACKUP_FROM_SNAPSHOT` usage
+
+Starting with version 2.15.0, the `BACKUP_FROM_SNAPSHOT` feature has been deprecated.
+If you need to prepare your sources before the backup is taken, use `exec-pre`, `exec-post` and an intermediate volume:
+
+```yml
+version: '3'
+
+services:
+  my_app:
+    build: .
+    volumes:
+      - data:/var/my_app
+      - backup:/tmp/backup
+    labels:
+      - docker-volume-backup.exec-pre=cp -r /var/my_app /tmp/backup/my-app
+      - docker-volume-backup.exec-post=rm -rf /tmp/backup/my-app
+
+  backup:
+    image: offen/docker-volume-backup:latest
+    environment:
+      BACKUP_SOURCES: /tmp/backup
+    volumes:
+      - backup:/backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+  backup:
+```
+
+### Using a custom Docker host
+
+If you are interfacing with Docker via TCP, set `DOCKER_HOST` to the correct URL.
+```ini
+DOCKER_HOST=tcp://docker_socket_proxy:2375
+```
+
+In case you are using a socket proxy, it must support `GET` and `POST` requests to the `/containers` endpoint. If you are using Docker Swarm, it must also support the `/services` endpoint. If you are using pre/post backup commands, it must also support the `/exec` endpoint.
+
+### Run multiple backup schedules in the same container
+
+Multiple backup schedules with different configuration can be configured by mounting an arbitrary number of configuration files (using the `.env` format) into `/etc/dockervolumebackup/conf.d`:
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ./configuration:/etc/dockervolumebackup/conf.d
+
+volumes:
+  data:
+```
+
+A separate cronjob will be created for each config file.
+If a configuration value is set both in the global environment as well as in the config file, the config file will take precedence.
+The `backup` command expects to run on an exclusive lock, so in case you provide the same or overlapping schedules in your cron expressions, the runs will still be executed serially, one after the other.
+The exact order of schedules that use the same cron expression is not specified.
+In case you need your schedules to overlap, you need to create a dedicated container for each schedule instead.
+When changing the configuration, you currently need to manually restart the container for the changes to take effect.
+
 ## Recipes

 This section lists configuration for some real-world use cases that you can mix and match according to your needs.
@@ -515,7 +745,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      AWS_BUCKET_NAME: backup-bucket
      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
@@ -528,6 +758,28 @@ volumes:
  data:
 ```

+### Backing up to Filebase
+
+```yml
+version: '3'
+
+services:
+  # ... define other services using the `data` volume here
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      AWS_ENDPOINT: s3.filebase.com
+      AWS_BUCKET_NAME: filebase-bucket
+      AWS_ACCESS_KEY_ID: FILEBASE-ACCESS-KEY
+      AWS_SECRET_ACCESS_KEY: FILEBASE-SECRET-KEY
+    volumes:
+      - data:/backup/my-app-backup:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  data:
+```
+
 ### Backing up to MinIO

 ```yml
@@ -536,7 +788,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      AWS_ENDPOINT: minio.example.com
      AWS_BUCKET_NAME: backup-bucket
@@ -558,7 +810,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      WEBDAV_URL: https://webdav.mydomain.me
      WEBDAV_PATH: /my/directory/
@@ -580,7 +832,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz
      BACKUP_LATEST_SYMLINK: backup-latest.tar.gz
@@ -601,7 +853,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      AWS_BUCKET_NAME: backup-bucket
      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
@@ -623,7 +875,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      # take a backup on every hour
      BACKUP_CRON_EXPRESSION: "0 * * * *"
@@ -646,7 +898,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      AWS_BUCKET_NAME: backup-bucket
      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
@@ -670,7 +922,7 @@ version: '3'
 services:
  # ... define other services using the `data` volume here
  backup:
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment:
      AWS_BUCKET_NAME: backup-bucket
      AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE
@@ -684,6 +936,32 @@ volumes:
  data:
 ```

+### Using mysqldump to prepare the backup
+
+```yml
+version: '3'
+
+services:
+  database:
+    image: mariadb:latest
+    labels:
+      - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump -psecret --all-databases > /tmp/dumps/dump.sql'
+    volumes:
+      - app_data:/tmp/dumps
+  backup:
+    image: offen/docker-volume-backup:v2
+    environment:
+      BACKUP_FILENAME: db.tar.gz
+      BACKUP_CRON_EXPRESSION: "0 2 * * *"
+    volumes:
+      - ./local:/archive
+      - data:/backup/data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+
+volumes:
+  data:
+```
+
 ### Running multiple instances in the same setup

 ```yml
@@ -692,7 +970,7 @@ version: '3'
 services:
  # ... define other services using the `data_1` and `data_2` volumes here
  backup_1: &backup_service
-    image: offen/docker-volume-backup:latest
+    image: offen/docker-volume-backup:v2
    environment: &backup_environment
      BACKUP_CRON_EXPRESSION: "0 2 * * *"
      AWS_BUCKET_NAME: backup-bucket
@@ -725,12 +1003,12 @@ This image is heavily inspired by `futurice/docker-volume-backup`. We decided to

 - The original image is based on `ubuntu` and requires additional tools, making it heavy.
 This version is roughly 1/25 in compressed size (it's ~12MB).
- The original image uses a shell script, when this version is written in Go, which makes it easier to extend and maintain (more verbose too).
+- The original image uses a shell script, when this version is written in Go.
 - The original image proposed to handle backup rotation through AWS S3 lifecycle policies.
 This image adds the option to rotate away old backups through the same command so this functionality can also be offered for non-AWS storage backends like MinIO.
 Local copies of backups can also be pruned once they reach a certain age.
 - InfluxDB specific functionality from the original image was removed.
 - `arm64` and `arm/v7` architectures are supported.
 - Docker in Swarm mode is supported.
- Notifications on failed backups are supported
- IAM authentication through instance profiles is supported
+- Notifications on finished backups are supported.
+- IAM authentication through instance profiles is supported.
--- a/cmd/backup/archive.go
+++ b/cmd/backup/archive.go
@@ -0,0 +1,142 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+// Portions of this file are taken from package `targz`, Copyright (c) 2014 Fredrik Wallgren
+// Licensed under the MIT License: https://github.com/walle/targz/blob/57fe4206da5abf7dd3901b4af3891ec2f08c7b08/LICENSE
+
+package main
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+)
+
+func createArchive(inputFilePath, outputFilePath string) error {
+	inputFilePath = stripTrailingSlashes(inputFilePath)
+	inputFilePath, outputFilePath, err := makeAbsolute(inputFilePath, outputFilePath)
+	if err != nil {
+		return fmt.Errorf("createArchive: error transposing given file paths: %w", err)
+	}
+	if err := os.MkdirAll(filepath.Dir(outputFilePath), 0755); err != nil {
+		return fmt.Errorf("createArchive: error creating output file path: %w", err)
+	}
+
+	if err := compress(inputFilePath, outputFilePath, filepath.Dir(inputFilePath)); err != nil {
+		return fmt.Errorf("createArchive: error creating archive: %w", err)
+	}
+
+	return nil
+}
+
+func stripTrailingSlashes(path string) string {
+	if len(path) > 0 && path[len(path)-1] == '/' {
+		path = path[0 : len(path)-1]
+	}
+
+	return path
+}
+
+func makeAbsolute(inputFilePath, outputFilePath string) (string, string, error) {
+	inputFilePath, err := filepath.Abs(inputFilePath)
+	if err == nil {
+		outputFilePath, err = filepath.Abs(outputFilePath)
+	}
+
+	return inputFilePath, outputFilePath, err
+}
+
+func compress(inPath, outFilePath, subPath string) error {
+	file, err := os.Create(outFilePath)
+	if err != nil {
+		return fmt.Errorf("compress: error creating out file: %w", err)
+	}
+
+	prefix := path.Dir(outFilePath)
+	gzipWriter := gzip.NewWriter(file)
+	tarWriter := tar.NewWriter(gzipWriter)
+
+	var paths []string
+	if err := filepath.WalkDir(inPath, func(path string, di fs.DirEntry, err error) error {
+		paths = append(paths, path)
+		return err
+	}); err != nil {
+		return fmt.Errorf("compress: error walking filesystem tree: %w", err)
+	}
+
+	for _, p := range paths {
+		if err := writeTarGz(p, tarWriter, prefix); err != nil {
+			return fmt.Errorf("compress error writing %s to archive: %w", p, err)
+		}
+	}
+
+	err = tarWriter.Close()
+	if err != nil {
+		return fmt.Errorf("compress: error closing tar writer: %w", err)
+	}
+
+	err = gzipWriter.Close()
+	if err != nil {
+		return fmt.Errorf("compress: error closing gzip writer: %w", err)
+	}
+
+	err = file.Close()
+	if err != nil {
+		return fmt.Errorf("compress: error closing file: %w", err)
+	}
+
+	return nil
+}
+
+func writeTarGz(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)
+	}
+
+	if fileInfo.Mode()&os.ModeSocket == os.ModeSocket {
+		return nil
+	}
+
+	var link string
+	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)
+		}
+	}
+
+	header, err := tar.FileInfoHeader(fileInfo, link)
+	if err != nil {
+		return fmt.Errorf("writeTarGz: 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)
+	}
+
+	if !fileInfo.Mode().IsRegular() {
+		return nil
+	}
+
+	file, err := os.Open(path)
+	if err != nil {
+		return fmt.Errorf("writeTarGz: 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 nil
+}
--- a/cmd/backup/config.go
+++ b/cmd/backup/config.go
@@ -0,0 +1,45 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import "time"
+
+// Config holds all configuration values that are expected to be set
+// by users.
+type Config struct {
+	BackupSources              string        `split_words:"true" default:"/backup"`
+	BackupFilename             string        `split_words:"true" default:"backup-%Y-%m-%dT%H-%M-%S.tar.gz"`
+	BackupFilenameExpand       bool          `split_words:"true"`
+	BackupLatestSymlink        string        `split_words:"true"`
+	BackupArchive              string        `split_words:"true" default:"/archive"`
+	BackupRetentionDays        int32         `split_words:"true" default:"-1"`
+	BackupPruningLeeway        time.Duration `split_words:"true" default:"1m"`
+	BackupPruningPrefix        string        `split_words:"true"`
+	BackupStopContainerLabel   string        `split_words:"true" default:"true"`
+	BackupFromSnapshot         bool          `split_words:"true"`
+	AwsS3BucketName            string        `split_words:"true"`
+	AwsS3Path                  string        `split_words:"true"`
+	AwsEndpoint                string        `split_words:"true" default:"s3.amazonaws.com"`
+	AwsEndpointProto           string        `split_words:"true" default:"https"`
+	AwsEndpointInsecure        bool          `split_words:"true"`
+	AwsAccessKeyID             string        `envconfig:"AWS_ACCESS_KEY_ID"`
+	AwsSecretAccessKey         string        `split_words:"true"`
+	AwsIamRoleEndpoint         string        `split_words:"true"`
+	GpgPassphrase              string        `split_words:"true"`
+	NotificationURLs           []string      `envconfig:"NOTIFICATION_URLS"`
+	NotificationLevel          string        `split_words:"true" default:"error"`
+	EmailNotificationRecipient string        `split_words:"true"`
+	EmailNotificationSender    string        `split_words:"true" default:"noreply@nohost"`
+	EmailSMTPHost              string        `envconfig:"EMAIL_SMTP_HOST"`
+	EmailSMTPPort              int           `envconfig:"EMAIL_SMTP_PORT" default:"587"`
+	EmailSMTPUsername          string        `envconfig:"EMAIL_SMTP_USERNAME"`
+	EmailSMTPPassword          string        `envconfig:"EMAIL_SMTP_PASSWORD"`
+	WebdavUrl                  string        `split_words:"true"`
+	WebdavPath                 string        `split_words:"true" default:"/"`
+	WebdavUsername             string        `split_words:"true"`
+	WebdavPassword             string        `split_words:"true"`
+	ExecLabel                  string        `split_words:"true"`
+	ExecForwardOutput          bool          `split_words:"true"`
+	LockTimeout                time.Duration `split_words:"true" default:"60m"`
+}
--- a/cmd/backup/exec.go
+++ b/cmd/backup/exec.go
@@ -0,0 +1,123 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+// Portions of this file are taken and adapted from `moby`, Copyright 2012-2017 Docker, Inc.
+// Licensed under the Apache 2.0 License: https://github.com/moby/moby/blob/8e610b2b55bfd1bfa9436ab110d311f5e8a74dcb/LICENSE
+
+package main
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/cosiner/argv"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/pkg/stdcopy"
+	"golang.org/x/sync/errgroup"
+)
+
+func (s *script) exec(containerRef string, command string) ([]byte, []byte, error) {
+	args, _ := argv.Argv(command, nil, nil)
+	execID, err := s.cli.ContainerExecCreate(context.Background(), containerRef, types.ExecConfig{
+		Cmd:          args[0],
+		AttachStdin:  true,
+		AttachStderr: true,
+	})
+	if err != nil {
+		return nil, nil, fmt.Errorf("exec: error creating container exec: %w", err)
+	}
+
+	resp, err := s.cli.ContainerExecAttach(context.Background(), execID.ID, types.ExecStartCheck{})
+	if err != nil {
+		return nil, nil, fmt.Errorf("exec: error attaching container exec: %w", err)
+	}
+	defer resp.Close()
+
+	var outBuf, errBuf bytes.Buffer
+	outputDone := make(chan error)
+
+	go func() {
+		_, err := stdcopy.StdCopy(&outBuf, &errBuf, resp.Reader)
+		outputDone <- err
+	}()
+
+	select {
+	case err := <-outputDone:
+		if err != nil {
+			return nil, nil, fmt.Errorf("exec: error demultiplexing output: %w", err)
+		}
+		break
+	}
+
+	stdout, err := ioutil.ReadAll(&outBuf)
+	if err != nil {
+		return nil, nil, fmt.Errorf("exec: error reading stdout: %w", err)
+	}
+	stderr, err := ioutil.ReadAll(&errBuf)
+	if err != nil {
+		return nil, nil, fmt.Errorf("exec: error reading stderr: %w", err)
+	}
+
+	res, err := s.cli.ContainerExecInspect(context.Background(), execID.ID)
+	if err != nil {
+		return nil, nil, fmt.Errorf("exec: error inspecting container exec: %w", err)
+	}
+
+	if res.ExitCode > 0 {
+		return stdout, stderr, fmt.Errorf("exec: running command exited %d", res.ExitCode)
+	}
+
+	return stdout, stderr, nil
+}
+
+func (s *script) runLabeledCommands(label string) error {
+	f := []filters.KeyValuePair{
+		{Key: "label", Value: label},
+	}
+	if s.c.ExecLabel != "" {
+		f = append(f, filters.KeyValuePair{
+			Key:   "label",
+			Value: fmt.Sprintf("docker-volume-backup.exec-label=%s", s.c.ExecLabel),
+		})
+	}
+	containersWithCommand, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
+		Quiet:   true,
+		Filters: filters.NewArgs(f...),
+	})
+	if err != nil {
+		return fmt.Errorf("runLabeledCommands: error querying for containers: %w", err)
+	}
+
+	if len(containersWithCommand) == 0 {
+		return nil
+	}
+
+	g := new(errgroup.Group)
+
+	for _, container := range containersWithCommand {
+		c := container
+		g.Go(func() error {
+			cmd, _ := c.Labels[label]
+			s.logger.Infof("Running %s command %s for container %s", label, cmd, strings.TrimPrefix(c.Names[0], "/"))
+			stdout, stderr, err := s.exec(c.ID, cmd)
+			if s.c.ExecForwardOutput {
+				os.Stderr.Write(stderr)
+				os.Stdout.Write(stdout)
+			}
+			if err != nil {
+				return fmt.Errorf("runLabeledCommands: error executing command: %w", err)
+			}
+			return nil
+		})
+	}
+
+	if err := g.Wait(); err != nil {
+		return fmt.Errorf("runLabeledCommands: error from errgroup: %w", err)
+	}
+	return nil
+}
--- a/cmd/backup/hooks.go
+++ b/cmd/backup/hooks.go
@@ -0,0 +1,56 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"fmt"
+	"sort"
+)
+
+// hook contains a queued action that can be trigger them when the script
+// reaches a certain point (e.g. unsuccessful backup)
+type hook struct {
+	level  hookLevel
+	action func(err error) error
+}
+
+type hookLevel int
+
+const (
+	hookLevelPlumbing hookLevel = iota
+	hookLevelError
+	hookLevelInfo
+)
+
+var hookLevels = map[string]hookLevel{
+	"info":  hookLevelInfo,
+	"error": hookLevelError,
+}
+
+// registerHook adds the given action at the given level.
+func (s *script) registerHook(level hookLevel, action func(err error) error) {
+	s.hooks = append(s.hooks, hook{level, action})
+}
+
+// runHooks runs all hooks that have been registered using the
+// given levels in the defined ordering. In case executing a hook returns an
+// error, the following hooks will still be run before the function returns.
+func (s *script) runHooks(err error) error {
+	sort.SliceStable(s.hooks, func(i, j int) bool {
+		return s.hooks[i].level < s.hooks[j].level
+	})
+	var actionErrors []error
+	for _, hook := range s.hooks {
+		if hook.level > s.hookLevel {
+			continue
+		}
+		if actionErr := hook.action(err); actionErr != nil {
+			actionErrors = append(actionErrors, fmt.Errorf("runHooks: error running hook: %w", actionErr))
+		}
+	}
+	if len(actionErrors) != 0 {
+		return join(actionErrors...)
+	}
+	return nil
+}
--- a/cmd/backup/lock.go
+++ b/cmd/backup/lock.go
@@ -0,0 +1,58 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/gofrs/flock"
+)
+
+// lock opens a lockfile at the given location, keeping it locked until the
+// caller invokes the returned release func. In case the lock is currently blocked
+// by another execution, it will repeatedly retry until the lock is available
+// or the given timeout is exceeded.
+func (s *script) lock(lockfile string) (func() error, error) {
+	start := time.Now()
+	defer func() {
+		s.stats.LockedTime = time.Now().Sub(start)
+	}()
+
+	retry := time.NewTicker(5 * time.Second)
+	defer retry.Stop()
+	deadline := time.NewTimer(s.c.LockTimeout)
+	defer deadline.Stop()
+
+	fileLock := flock.New(lockfile)
+
+	for {
+		acquired, err := fileLock.TryLock()
+		if err != nil {
+			return noop, fmt.Errorf("lock: error trying lock: %w", err)
+		}
+		if acquired {
+			if s.encounteredLock {
+				s.logger.Info("Acquired exclusive lock on subsequent attempt, ready to continue.")
+			}
+			return fileLock.Unlock, nil
+		}
+
+		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.encounteredLock = true
+		}
+
+		select {
+		case <-retry.C:
+			continue
+		case <-deadline.C:
+			return noop, errors.New("lock: timed out waiting for lockfile to become available")
+		}
+	}
+}
--- a/cmd/backup/main.go
+++ b/cmd/backup/main.go
@@ -1,50 +1,22 @@
-// Copyright 2021 - Offen Authors <hioffen@posteo.de>
+// Copyright 2021-2022 - Offen Authors <hioffen@posteo.de>
 // SPDX-License-Identifier: MPL-2.0

 package main

 import (
-	"bytes"
-	"context"
-	"errors"
-	"fmt"
-	"io"
-	"io/fs"
 	"os"
-	"path"
-	"path/filepath"
-	"sort"
-	"strings"
-	"time"
-
-	"github.com/containrrr/shoutrrr"
-	"github.com/containrrr/shoutrrr/pkg/router"
-	sTypes "github.com/containrrr/shoutrrr/pkg/types"
-	"github.com/docker/docker/api/types"
-	"github.com/docker/docker/api/types/filters"
-	"github.com/docker/docker/api/types/swarm"
-	"github.com/docker/docker/client"
-	"github.com/gofrs/flock"
-	"github.com/kelseyhightower/envconfig"
-	"github.com/leekchan/timeutil"
-	"github.com/m90/targz"
-	"github.com/minio/minio-go/v7"
-	"github.com/minio/minio-go/v7/pkg/credentials"
-	"github.com/otiai10/copy"
-	"github.com/sirupsen/logrus"
-	"github.com/studio-b12/gowebdav"
-	"golang.org/x/crypto/openpgp"
 )

 func main() {
-	unlock := lock("/var/lock/dockervolumebackup.lock")
-	defer unlock()
-
 	s, err := newScript()
 	if err != nil {
 		panic(err)
 	}

+	unlock, err := s.lock("/var/lock/dockervolumebackup.lock")
+	defer unlock()
+	s.must(err)
+
 	defer func() {
 		if pArg := recover(); pArg != nil {
 			if err, ok := pArg.(error); ok {
@@ -67,6 +39,13 @@ func main() {
 	}()

 	s.must(func() error {
+		runPostCommands, err := s.runCommands()
+		defer func() {
+			s.must(runPostCommands())
+		}()
+		if err != nil {
+			return err
+		}
 		restartContainers, err := s.stopContainers()
 		// The mechanism for restarting containers is not using hooks as it
 		// should happen as soon as possible (i.e. before uploading backups or
@@ -82,814 +61,5 @@ func main() {

 	s.must(s.encryptBackup())
 	s.must(s.copyBackup())
-	s.must(s.pruneOldBackups())
-}
-
-// script holds all the stateful information required to orchestrate a
-// single backup run.
-type script struct {
-	cli          *client.Client
-	minioClient  *minio.Client
-	webdavClient *gowebdav.Client
-	logger       *logrus.Logger
-	sender       *router.ServiceRouter
-	hooks        []hook
-	hookLevel    hookLevel
-
-	start  time.Time
-	file   string
-	output *bytes.Buffer
-
-	c *config
-}
-
-type config struct {
-	BackupSources              string        `split_words:"true" default:"/backup"`
-	BackupFilename             string        `split_words:"true" default:"backup-%Y-%m-%dT%H-%M-%S.tar.gz"`
-	BackupFilenameExpand       bool          `split_words:"true"`
-	BackupLatestSymlink        string        `split_words:"true"`
-	BackupArchive              string        `split_words:"true" default:"/archive"`
-	BackupRetentionDays        int32         `split_words:"true" default:"-1"`
-	BackupPruningLeeway        time.Duration `split_words:"true" default:"1m"`
-	BackupPruningPrefix        string        `split_words:"true"`
-	BackupStopContainerLabel   string        `split_words:"true" default:"true"`
-	BackupFromSnapshot         bool          `split_words:"true"`
-	AwsS3BucketName            string        `split_words:"true"`
-	AwsEndpoint                string        `split_words:"true" default:"s3.amazonaws.com"`
-	AwsEndpointProto           string        `split_words:"true" default:"https"`
-	AwsEndpointInsecure        bool          `split_words:"true"`
-	AwsAccessKeyID             string        `envconfig:"AWS_ACCESS_KEY_ID"`
-	AwsSecretAccessKey         string        `split_words:"true"`
-	AwsIamRoleEndpoint         string        `split_words:"true"`
-	GpgPassphrase              string        `split_words:"true"`
-	NotificationURLs           []string      `envconfig:"NOTIFICATION_URLS"`
-	NotificationLevel          string        `split_words:"true" default:"error"`
-	EmailNotificationRecipient string        `split_words:"true"`
-	EmailNotificationSender    string        `split_words:"true" default:"noreply@nohost"`
-	EmailSMTPHost              string        `envconfig:"EMAIL_SMTP_HOST"`
-	EmailSMTPPort              int           `envconfig:"EMAIL_SMTP_PORT" default:"587"`
-	EmailSMTPUsername          string        `envconfig:"EMAIL_SMTP_USERNAME"`
-	EmailSMTPPassword          string        `envconfig:"EMAIL_SMTP_PASSWORD"`
-	WebdavUrl                  string        `split_words:"true"`
-	WebdavPath                 string        `split_words:"true" default:"/"`
-	WebdavUsername             string        `split_words:"true"`
-	WebdavPassword             string        `split_words:"true"`
-}
-
-var msgBackupFailed = "backup run failed"
-
-// newScript creates all resources needed for the script to perform actions against
-// remote resources like the Docker engine or remote storage locations. All
-// reading from env vars or other configuration sources is expected to happen
-// in this method.
-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,
-		},
-		start:  time.Now(),
-		output: logBuffer,
-	}
-
-	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)
-	if s.c.BackupFilenameExpand {
-		s.file = os.ExpandEnv(s.file)
-		s.c.BackupLatestSymlink = os.ExpandEnv(s.c.BackupLatestSymlink)
-		s.c.BackupPruningPrefix = os.ExpandEnv(s.c.BackupPruningPrefix)
-	}
-	s.file = timeutil.Strftime(&s.start, s.file)
-
-	_, err := os.Stat("/var/run/docker.sock")
-	if !os.IsNotExist(err) {
-		cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
-		if err != nil {
-			return nil, fmt.Errorf("newScript: failed to create docker client")
-		}
-		s.cli = cli
-	}
-
-	if s.c.AwsS3BucketName != "" {
-		var creds *credentials.Credentials
-		if s.c.AwsAccessKeyID != "" && s.c.AwsSecretAccessKey != "" {
-			creds = credentials.NewStaticV4(
-				s.c.AwsAccessKeyID,
-				s.c.AwsSecretAccessKey,
-				"",
-			)
-		} else if s.c.AwsIamRoleEndpoint != "" {
-			creds = credentials.NewIAM(s.c.AwsIamRoleEndpoint)
-		} else {
-			return nil, errors.New("newScript: AWS_S3_BUCKET_NAME is defined, but no credentials were provided")
-		}
-
-		options := minio.Options{
-			Creds:  creds,
-			Secure: s.c.AwsEndpointProto == "https",
-		}
-
-		if s.c.AwsEndpointInsecure {
-			if !options.Secure {
-				return nil, errors.New("newScript: AWS_ENDPOINT_INSECURE = true is only meaningful for https")
-			}
-
-			transport, err := minio.DefaultTransport(true)
-			if err != nil {
-				return nil, fmt.Errorf("newScript: failed to create default minio transport")
-			}
-			transport.TLSClientConfig.InsecureSkipVerify = true
-			options.Transport = transport
-		}
-
-		mc, err := minio.New(s.c.AwsEndpoint, &options)
-		if err != nil {
-			return nil, fmt.Errorf("newScript: error setting up minio client: %w", err)
-		}
-		s.minioClient = mc
-	}
-
-	if s.c.WebdavUrl != "" {
-		if s.c.WebdavUsername == "" || s.c.WebdavPassword == "" {
-			return nil, errors.New("newScript: WEBDAV_URL is defined, but no credentials were provided")
-		} else {
-			webdavClient := gowebdav.NewClient(s.c.WebdavUrl, s.c.WebdavUsername, s.c.WebdavPassword)
-			s.webdavClient = webdavClient
-		}
-	}
-
-	if s.c.EmailNotificationRecipient != "" {
-		emailURL := fmt.Sprintf(
-			"smtp://%s:%s@%s:%d/?from=%s&to=%s",
-			s.c.EmailSMTPUsername,
-			s.c.EmailSMTPPassword,
-			s.c.EmailSMTPHost,
-			s.c.EmailSMTPPort,
-			s.c.EmailNotificationSender,
-			s.c.EmailNotificationRecipient,
-		)
-		s.c.NotificationURLs = append(s.c.NotificationURLs, emailURL)
-		s.logger.Warn(
-			"Using EMAIL_* keys for providing notification configuration has been deprecated and will be removed in the next major version.",
-		)
-		s.logger.Warn(
-			"Please use NOTIFICATION_URLS instead. Refer to the README for an upgrade guide.",
-		)
-	}
-
-	hookLevel, ok := hookLevels[s.c.NotificationLevel]
-	if !ok {
-		return nil, fmt.Errorf("newScript: unknown NOTIFICATION_LEVEL %s", s.c.NotificationLevel)
-	}
-	s.hookLevel = hookLevel
-
-	if len(s.c.NotificationURLs) > 0 {
-		sender, senderErr := shoutrrr.CreateSender(s.c.NotificationURLs...)
-		if senderErr != nil {
-			return nil, fmt.Errorf("newScript: error creating sender: %w", senderErr)
-		}
-		s.sender = sender
-		// To prevent duplicate notifications, ensure the regsistered callbacks
-		// run mutually exclusive.
-		s.registerHook(hookLevelError, func(err error) error {
-			if err == nil {
-				return nil
-			}
-			return s.notifyFailure(err)
-		})
-		s.registerHook(hookLevelInfo, func(err error) error {
-			if err != nil {
-				return nil
-			}
-			return s.notifySuccess()
-		})
-	}
-
-	return s, nil
-}
-
-var noop = func() error { return nil }
-
-// registerHook adds the given action at the given level.
-func (s *script) registerHook(level hookLevel, action func(err error) error) {
-	s.hooks = append(s.hooks, hook{level, action})
-}
-
-// notifyFailure sends a notification about a failed backup run
-func (s *script) notifyFailure(err error) error {
-	body := fmt.Sprintf(
-		"Running docker-volume-backup failed with error: %s\n\nLog output of the failed run was:\n\n%s\n", err, s.output.String(),
-	)
-	title := fmt.Sprintf("Failure running docker-volume-backup at %s", s.start.Format(time.RFC3339))
-	if err := s.sendNotification(title, body); err != nil {
-		return fmt.Errorf("notifyFailure: error notifying: %w", err)
-	}
-	return nil
-}
-
-// notifyFailure sends a notification about a successful backup run
-func (s *script) notifySuccess() error {
-	title := fmt.Sprintf("Success running docker-volume-backup at %s", s.start.Format(time.RFC3339))
-	body := fmt.Sprintf(
-		"Running docker-volume-backup succeeded.\n\nLog output was:\n\n%s\n", s.output.String(),
-	)
-	if err := s.sendNotification(title, body); err != nil {
-		return fmt.Errorf("notifySuccess: error notifying: %w", err)
-	}
-	return nil
-}
-
-// sendNotification sends a notification to all configured third party services
-func (s *script) sendNotification(title, body string) error {
-	var errs []error
-	for _, result := range s.sender.Send(body, &sTypes.Params{"title": title}) {
-		if result != nil {
-			errs = append(errs, result)
-		}
-	}
-	if len(errs) != 0 {
-		return fmt.Errorf("sendNotification: error sending message: %w", join(errs...))
-	}
-	return nil
-}
-
-// stopContainers stops all Docker containers that are marked as to being
-// stopped during the backup and returns a function that can be called to
-// restart everything that has been stopped.
-func (s *script) stopContainers() (func() error, error) {
-	if s.cli == nil {
-		return noop, nil
-	}
-
-	allContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
-		Quiet: true,
-	})
-	if err != nil {
-		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers: %w", err)
-	}
-
-	containerLabel := fmt.Sprintf(
-		"docker-volume-backup.stop-during-backup=%s",
-		s.c.BackupStopContainerLabel,
-	)
-	containersToStop, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
-		Quiet: true,
-		Filters: filters.NewArgs(filters.KeyValuePair{
-			Key:   "label",
-			Value: containerLabel,
-		}),
-	})
-
-	if err != nil {
-		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers to stop: %w", err)
-	}
-
-	if len(containersToStop) == 0 {
-		return noop, nil
-	}
-
-	s.logger.Infof(
-		"Stopping %d container(s) labeled `%s` out of %d running container(s).",
-		len(containersToStop),
-		containerLabel,
-		len(allContainers),
-	)
-
-	var stoppedContainers []types.Container
-	var stopErrors []error
-	for _, container := range containersToStop {
-		if err := s.cli.ContainerStop(context.Background(), container.ID, nil); err != nil {
-			stopErrors = append(stopErrors, err)
-		} else {
-			stoppedContainers = append(stoppedContainers, container)
-		}
-	}
-
-	var stopError error
-	if len(stopErrors) != 0 {
-		stopError = fmt.Errorf(
-			"stopContainersAndRun: %d error(s) stopping containers: %w",
-			len(stopErrors),
-			join(stopErrors...),
-		)
-	}
-
-	return func() error {
-		servicesRequiringUpdate := map[string]struct{}{}
-
-		var restartErrors []error
-		for _, container := range stoppedContainers {
-			if swarmServiceName, ok := container.Labels["com.docker.swarm.service.name"]; ok {
-				servicesRequiringUpdate[swarmServiceName] = struct{}{}
-				continue
-			}
-			if err := s.cli.ContainerStart(context.Background(), container.ID, types.ContainerStartOptions{}); err != nil {
-				restartErrors = append(restartErrors, err)
-			}
-		}
-
-		if len(servicesRequiringUpdate) != 0 {
-			services, _ := s.cli.ServiceList(context.Background(), types.ServiceListOptions{})
-			for serviceName := range servicesRequiringUpdate {
-				var serviceMatch swarm.Service
-				for _, service := range services {
-					if service.Spec.Name == serviceName {
-						serviceMatch = service
-						break
-					}
-				}
-				if serviceMatch.ID == "" {
-					return fmt.Errorf("stopContainersAndRun: couldn't find service with name %s", serviceName)
-				}
-				serviceMatch.Spec.TaskTemplate.ForceUpdate = 1
-				if _, err := s.cli.ServiceUpdate(
-					context.Background(), serviceMatch.ID,
-					serviceMatch.Version, serviceMatch.Spec, types.ServiceUpdateOptions{},
-				); err != nil {
-					restartErrors = append(restartErrors, err)
-				}
-			}
-		}
-
-		if len(restartErrors) != 0 {
-			return fmt.Errorf(
-				"stopContainersAndRun: %d error(s) restarting containers and services: %w",
-				len(restartErrors),
-				join(restartErrors...),
-			)
-		}
-		s.logger.Infof(
-			"Restarted %d container(s) and the matching service(s).",
-			len(stoppedContainers),
-		)
-		return nil
-	}, stopError
-}
-
-// takeBackup creates a tar archive of the configured backup location and
-// saves it to disk.
-func (s *script) takeBackup() error {
-	backupSources := s.c.BackupSources
-
-	if s.c.BackupFromSnapshot {
-		backupSources = filepath.Join("/tmp", s.c.BackupSources)
-		// copy before compressing guard against a situation where backup folder's content are still growing.
-		s.registerHook(hookLevelPlumbing, func(error) error {
-			if err := remove(backupSources); err != nil {
-				return fmt.Errorf("takeBackup: error removing snapshot: %w", err)
-			}
-			s.logger.Infof("Removed snapshot `%s`.", backupSources)
-			return nil
-		})
-		if err := copy.Copy(s.c.BackupSources, backupSources, copy.Options{
-			PreserveTimes: true,
-			PreserveOwner: true,
-		}); err != nil {
-			return fmt.Errorf("takeBackup: error creating snapshot: %w", err)
-		}
-		s.logger.Infof("Created snapshot of `%s` at `%s`.", s.c.BackupSources, backupSources)
-	}
-
-	tarFile := s.file
-	s.registerHook(hookLevelPlumbing, func(error) error {
-		if err := remove(tarFile); err != nil {
-			return fmt.Errorf("takeBackup: error removing tar file: %w", err)
-		}
-		s.logger.Infof("Removed tar file `%s`.", tarFile)
-		return nil
-	})
-	if err := targz.Compress(backupSources, tarFile); err != nil {
-		return fmt.Errorf("takeBackup: error compressing backup folder: %w", err)
-	}
-
-	s.logger.Infof("Created backup of `%s` at `%s`.", backupSources, tarFile)
-	return nil
-}
-
-// encryptBackup encrypts the backup file using PGP and the configured passphrase.
-// In case no passphrase is given it returns early, leaving the backup file
-// untouched.
-func (s *script) encryptBackup() error {
-	if s.c.GpgPassphrase == "" {
-		return nil
-	}
-
-	gpgFile := fmt.Sprintf("%s.gpg", s.file)
-	s.registerHook(hookLevelPlumbing, func(error) error {
-		if err := remove(gpgFile); err != nil {
-			return fmt.Errorf("encryptBackup: error removing gpg file: %w", err)
-		}
-		s.logger.Infof("Removed GPG file `%s`.", gpgFile)
-		return nil
-	})
-
-	outFile, err := os.Create(gpgFile)
-	defer outFile.Close()
-	if err != nil {
-		return fmt.Errorf("encryptBackup: error opening out file: %w", err)
-	}
-
-	_, name := path.Split(s.file)
-	dst, err := openpgp.SymmetricallyEncrypt(outFile, []byte(s.c.GpgPassphrase), &openpgp.FileHints{
-		IsBinary: true,
-		FileName: name,
-	}, nil)
-	defer dst.Close()
-	if err != nil {
-		return fmt.Errorf("encryptBackup: error encrypting backup file: %w", err)
-	}
-
-	src, err := os.Open(s.file)
-	if err != nil {
-		return fmt.Errorf("encryptBackup: error opening backup file `%s`: %w", s.file, err)
-	}
-
-	if _, err := io.Copy(dst, src); err != nil {
-		return fmt.Errorf("encryptBackup: error writing ciphertext to file: %w", err)
-	}
-
-	s.file = gpgFile
-	s.logger.Infof("Encrypted backup using given passphrase, saving as `%s`.", s.file)
-	return nil
-}
-
-// copyBackup makes sure the backup file is copied to both local and remote locations
-// as per the given configuration.
-func (s *script) copyBackup() error {
-	_, name := path.Split(s.file)
-	if s.minioClient != nil {
-		if _, err := s.minioClient.FPutObject(context.Background(), s.c.AwsS3BucketName, name, s.file, minio.PutObjectOptions{
-			ContentType: "application/tar+gzip",
-		}); err != nil {
-			return fmt.Errorf("copyBackup: error uploading backup to remote storage: %w", err)
-		}
-		s.logger.Infof("Uploaded a copy of backup `%s` to bucket `%s`.", s.file, s.c.AwsS3BucketName)
-	}
-
-	if s.webdavClient != nil {
-		bytes, err := os.ReadFile(s.file)
-		if err != nil {
-			return fmt.Errorf("copyBackup: error reading the file to be uploaded: %w", err)
-		}
-		if err := s.webdavClient.MkdirAll(s.c.WebdavPath, 0644); err != nil {
-			return fmt.Errorf("copyBackup: error creating directory '%s' on WebDAV server: %w", s.c.WebdavPath, err)
-		}
-		if err := s.webdavClient.Write(filepath.Join(s.c.WebdavPath, name), bytes, 0644); err != nil {
-			return fmt.Errorf("copyBackup: error uploading the file to WebDAV server: %w", err)
-		}
-		s.logger.Infof("Uploaded a copy of backup `%s` to WebDAV-URL '%s' at path '%s'.", s.file, s.c.WebdavUrl, s.c.WebdavPath)
-	}
-
-	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
-		if err := copyFile(s.file, path.Join(s.c.BackupArchive, name)); err != nil {
-			return fmt.Errorf("copyBackup: error copying file to local archive: %w", err)
-		}
-		s.logger.Infof("Stored copy of backup `%s` in local archive `%s`.", s.file, s.c.BackupArchive)
-		if s.c.BackupLatestSymlink != "" {
-			symlink := path.Join(s.c.BackupArchive, s.c.BackupLatestSymlink)
-			if _, err := os.Lstat(symlink); err == nil {
-				os.Remove(symlink)
-			}
-			if err := os.Symlink(name, symlink); err != nil {
-				return fmt.Errorf("copyBackup: error creating latest symlink: %w", err)
-			}
-			s.logger.Infof("Created/Updated symlink `%s` for latest backup.", s.c.BackupLatestSymlink)
-		}
-	}
-	return nil
-}
-
-// pruneOldBackups rotates away backups from local and remote storages using
-// the given configuration. In case the given configuration would delete all
-// backups, it does nothing instead.
-func (s *script) pruneOldBackups() error {
-	if s.c.BackupRetentionDays < 0 {
-		return nil
-	}
-
-	if s.c.BackupPruningLeeway != 0 {
-		s.logger.Infof("Sleeping for %s before pruning backups.", s.c.BackupPruningLeeway)
-		time.Sleep(s.c.BackupPruningLeeway)
-	}
-
-	deadline := time.Now().AddDate(0, 0, -int(s.c.BackupRetentionDays))
-
-	// Prune minio/S3 backups
-	if s.minioClient != nil {
-		candidates := s.minioClient.ListObjects(context.Background(), s.c.AwsS3BucketName, minio.ListObjectsOptions{
-			WithMetadata: true,
-			Prefix:       s.c.BackupPruningPrefix,
-		})
-
-		var matches []minio.ObjectInfo
-		var lenCandidates int
-		for candidate := range candidates {
-			lenCandidates++
-			if candidate.Err != nil {
-				return fmt.Errorf(
-					"pruneOldBackups: error looking up candidates from remote storage: %w",
-					candidate.Err,
-				)
-			}
-			if candidate.LastModified.Before(deadline) {
-				matches = append(matches, candidate)
-			}
-		}
-
-		if len(matches) != 0 && len(matches) != lenCandidates {
-			objectsCh := make(chan minio.ObjectInfo)
-			go func() {
-				for _, match := range matches {
-					objectsCh <- match
-				}
-				close(objectsCh)
-			}()
-			errChan := s.minioClient.RemoveObjects(context.Background(), s.c.AwsS3BucketName, objectsCh, minio.RemoveObjectsOptions{})
-			var removeErrors []error
-			for result := range errChan {
-				if result.Err != nil {
-					removeErrors = append(removeErrors, result.Err)
-				}
-			}
-
-			if len(removeErrors) != 0 {
-				return fmt.Errorf(
-					"pruneOldBackups: %d error(s) removing files from remote storage: %w",
-					len(removeErrors),
-					join(removeErrors...),
-				)
-			}
-			s.logger.Infof(
-				"Pruned %d out of %d remote backup(s) as their age exceeded the configured retention period of %d days.",
-				len(matches),
-				lenCandidates,
-				s.c.BackupRetentionDays,
-			)
-		} else if len(matches) != 0 && len(matches) == lenCandidates {
-			s.logger.Warnf(
-				"The current configuration would delete all %d remote backup copies.",
-				len(matches),
-			)
-			s.logger.Warn("Refusing to do so, please check your configuration.")
-		} else {
-			s.logger.Infof("None of %d remote backup(s) were pruned.", lenCandidates)
-		}
-	}
-
-	// Prune WebDAV backups
-	if s.webdavClient != nil {
-		candidates, err := s.webdavClient.ReadDir(s.c.WebdavPath)
-		if err != nil {
-			return fmt.Errorf("pruneOldBackups: error looking up candidates from remote storage: %w", err)
-		}
-		var matches []fs.FileInfo
-		var lenCandidates int
-		for _, candidate := range candidates {
-			lenCandidates++
-			if candidate.ModTime().Before(deadline) {
-				matches = append(matches, candidate)
-			}
-		}
-
-		if len(matches) != 0 && len(matches) != lenCandidates {
-			for _, match := range matches {
-				if err := s.webdavClient.Remove(filepath.Join(s.c.WebdavPath, match.Name())); err != nil {
-					return fmt.Errorf("pruneOldBackups: error removing a file from remote storage: %w", err)
-				}
-				s.logger.Infof("Pruned %s from WebDAV: %s", match.Name(), filepath.Join(s.c.WebdavUrl, s.c.WebdavPath))
-			}
-			s.logger.Infof("Pruned %d out of %d remote backup(s) as their age exceeded the configured retention period of %d days.", len(matches), lenCandidates, s.c.BackupRetentionDays)
-		} else if len(matches) != 0 && len(matches) == lenCandidates {
-			s.logger.Warnf("The current configuration would delete all %d remote backup copies.", len(matches))
-			s.logger.Warn("Refusing to do so, please check your configuration.")
-		} else {
-			s.logger.Infof("None of %d remote backup(s) were pruned.", lenCandidates)
-		}
-	}
-
-	// Prune local backups
-	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
-		globPattern := path.Join(
-			s.c.BackupArchive,
-			fmt.Sprintf("%s*", s.c.BackupPruningPrefix),
-		)
-		globMatches, err := filepath.Glob(globPattern)
-		if err != nil {
-			return fmt.Errorf(
-				"pruneOldBackups: error looking up matching files using pattern %s: %w",
-				globPattern,
-				err,
-			)
-		}
-
-		var candidates []string
-		for _, candidate := range globMatches {
-			fi, err := os.Lstat(candidate)
-			if err != nil {
-				return fmt.Errorf(
-					"pruneOldBackups: error calling Lstat on file %s: %w",
-					candidate,
-					err,
-				)
-			}
-
-			if fi.Mode()&os.ModeSymlink != os.ModeSymlink {
-				candidates = append(candidates, candidate)
-			}
-		}
-
-		var matches []string
-		for _, candidate := range candidates {
-			fi, err := os.Stat(candidate)
-			if err != nil {
-				return fmt.Errorf(
-					"pruneOldBackups: error calling stat on file %s: %w",
-					candidate,
-					err,
-				)
-			}
-			if fi.ModTime().Before(deadline) {
-				matches = append(matches, candidate)
-			}
-		}
-
-		if len(matches) != 0 && len(matches) != len(candidates) {
-			var removeErrors []error
-			for _, match := range matches {
-				if err := os.Remove(match); err != nil {
-					removeErrors = append(removeErrors, err)
-				}
-			}
-			if len(removeErrors) != 0 {
-				return fmt.Errorf(
-					"pruneOldBackups: %d error(s) deleting local files, starting with: %w",
-					len(removeErrors),
-					join(removeErrors...),
-				)
-			}
-			s.logger.Infof(
-				"Pruned %d out of %d local backup(s) as their age exceeded the configured retention period of %d days.",
-				len(matches),
-				len(candidates),
-				s.c.BackupRetentionDays,
-			)
-		} else if len(matches) != 0 && len(matches) == len(candidates) {
-			s.logger.Warnf(
-				"The current configuration would delete all %d local backup copies.",
-				len(matches),
-			)
-			s.logger.Warn("Refusing to do so, please check your configuration.")
-		} else {
-			s.logger.Infof("None of %d local backup(s) were pruned.", len(candidates))
-		}
-	}
-	return nil
-}
-
-// runHooks runs all hooks that have been registered using the
-// given levels in the defined ordering. In case executing a hook returns an
-// error, the following hooks will still be run before the function returns.
-func (s *script) runHooks(err error) error {
-	sort.SliceStable(s.hooks, func(i, j int) bool {
-		return s.hooks[i].level < s.hooks[j].level
-	})
-	var actionErrors []error
-	for _, hook := range s.hooks {
-		if hook.level > s.hookLevel {
-			continue
-		}
-		if actionErr := hook.action(err); actionErr != nil {
-			actionErrors = append(actionErrors, fmt.Errorf("runHooks: error running hook: %w", actionErr))
-		}
-	}
-	if len(actionErrors) != 0 {
-		return join(actionErrors...)
-	}
-	return nil
-}
-
-// must exits the script run prematurely in case the given error
-// is non-nil.
-func (s *script) must(err error) {
-	if err != nil {
-		s.logger.Errorf("Fatal error running backup: %s", err)
-		panic(err)
-	}
-}
-
-// remove removes the given file or directory from disk.
-func remove(location string) error {
-	fi, err := os.Lstat(location)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return nil
-		}
-		return fmt.Errorf("remove: error checking for existence of `%s`: %w", location, err)
-	}
-	if fi.IsDir() {
-		err = os.RemoveAll(location)
-	} else {
-		err = os.Remove(location)
-	}
-	if err != nil {
-		return fmt.Errorf("remove: error removing `%s`: %w", location, err)
-	}
-	return nil
-}
-
-// lock opens a lockfile at the given location, keeping it locked until the
-// caller invokes the returned release func. When invoked while the file is
-// still locked the function panics.
-func lock(lockfile string) func() error {
-	fileLock := flock.New(lockfile)
-	acquired, err := fileLock.TryLock()
-	if err != nil {
-		panic(err)
-	}
-	if !acquired {
-		panic("unable to acquire file lock")
-	}
-	return fileLock.Unlock
-}
-
-// copy creates a copy of the file located at `dst` at `src`.
-func copyFile(src, dst string) error {
-	in, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-	defer in.Close()
-
-	out, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-
-	_, err = io.Copy(out, in)
-	if err != nil {
-		out.Close()
-		return err
-	}
-	return out.Close()
-}
-
-// join takes a list of errors and joins them into a single error
-func join(errs ...error) error {
-	if len(errs) == 1 {
-		return errs[0]
-	}
-	var msgs []string
-	for _, err := range errs {
-		if err == nil {
-			continue
-		}
-		msgs = append(msgs, err.Error())
-	}
-	return errors.New("[" + strings.Join(msgs, ", ") + "]")
-}
-
-// buffer takes an io.Writer and returns a wrapped version of the
-// writer that writes to both the original target as well as the returned buffer
-func buffer(w io.Writer) (io.Writer, *bytes.Buffer) {
-	buffering := &bufferingWriter{buf: bytes.Buffer{}, writer: w}
-	return buffering, &buffering.buf
-}
-
-type bufferingWriter struct {
-	buf    bytes.Buffer
-	writer io.Writer
-}
-
-func (b *bufferingWriter) Write(p []byte) (n int, err error) {
-	if n, err := b.buf.Write(p); err != nil {
-		return n, fmt.Errorf("bufferingWriter: error writing to buffer: %w", err)
-	}
-	return b.writer.Write(p)
-}
-
-// hook contains a queued action that can be trigger them when the script
-// reaches a certain point (e.g. unsuccessful backup)
-type hook struct {
-	level  hookLevel
-	action func(err error) error
-}
-
-type hookLevel int
-
-const (
-	hookLevelPlumbing hookLevel = iota
-	hookLevelError
-	hookLevelInfo
-)
-
-var hookLevels = map[string]hookLevel{
-	"info":  hookLevelInfo,
-	"error": hookLevelError,
+	s.must(s.pruneBackups())
 }
--- a/cmd/backup/notifications.go
+++ b/cmd/backup/notifications.go
@@ -0,0 +1,105 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"bytes"
+	_ "embed"
+	"fmt"
+	"text/template"
+	"time"
+
+	sTypes "github.com/containrrr/shoutrrr/pkg/types"
+)
+
+//go:embed notifications.tmpl
+var defaultNotifications string
+
+// NotificationData data to be passed to the notification templates
+type NotificationData struct {
+	Error  error
+	Config *Config
+	Stats  *Stats
+}
+
+// notify sends a notification using the given title and body templates.
+// Automatically creates notification data, adding the given error
+func (s *script) notify(titleTemplate string, bodyTemplate string, err error) error {
+	params := NotificationData{
+		Error:  err,
+		Stats:  s.stats,
+		Config: s.c,
+	}
+
+	titleBuf := &bytes.Buffer{}
+	if err := s.template.ExecuteTemplate(titleBuf, titleTemplate, params); err != nil {
+		return fmt.Errorf("notifyFailure: error executing %s template: %w", titleTemplate, err)
+	}
+
+	bodyBuf := &bytes.Buffer{}
+	if err := s.template.ExecuteTemplate(bodyBuf, bodyTemplate, params); err != nil {
+		return fmt.Errorf("notifyFailure: error executing %s template: %w", bodyTemplate, err)
+	}
+
+	if err := s.sendNotification(titleBuf.String(), bodyBuf.String()); err != nil {
+		return fmt.Errorf("notifyFailure: error notifying: %w", err)
+	}
+	return nil
+}
+
+// notifyFailure sends a notification about a failed backup run
+func (s *script) notifyFailure(err error) error {
+	return s.notify("title_failure", "body_failure", err)
+}
+
+// notifyFailure sends a notification about a successful backup run
+func (s *script) notifySuccess() error {
+	return s.notify("title_success", "body_success", nil)
+}
+
+// sendNotification sends a notification to all configured third party services
+func (s *script) sendNotification(title, body string) error {
+	var errs []error
+	for _, result := range s.sender.Send(body, &sTypes.Params{"title": title}) {
+		if result != nil {
+			errs = append(errs, result)
+		}
+	}
+	if len(errs) != 0 {
+		return fmt.Errorf("sendNotification: error sending message: %w", join(errs...))
+	}
+	return nil
+}
+
+var templateHelpers = template.FuncMap{
+	"formatTime": func(t time.Time) string {
+		return t.Format(time.RFC3339)
+	},
+	"formatBytesDec": func(bytes uint64) string {
+		return formatBytes(bytes, true)
+	},
+	"formatBytesBin": func(bytes uint64) string {
+		return formatBytes(bytes, false)
+	},
+}
+
+// formatBytes converts an amount of bytes in a human-readable representation
+// the decimal parameter specifies if using powers of 1000 (decimal) or powers of 1024 (binary)
+func formatBytes(b uint64, decimal bool) string {
+	unit := uint64(1024)
+	format := "%.1f %ciB"
+	if decimal {
+		unit = uint64(1000)
+		format = "%.1f %cB"
+	}
+	if b < unit {
+		return fmt.Sprintf("%d B", b)
+	}
+	div, exp := unit, 0
+	for n := b / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+	return fmt.Sprintf(format, float64(b)/float64(div), "kMGTPE"[exp])
+}
--- a/cmd/backup/notifications.tmpl
+++ b/cmd/backup/notifications.tmpl
@@ -0,0 +1,26 @@
+{{ define "title_failure" -}}
+Failure running docker-volume-backup at {{ .Stats.StartTime | formatTime }}
+{{- end }}
+
+
+{{ define "body_failure" -}}
+Running docker-volume-backup failed with error: {{ .Error }}
+
+Log output of the failed run was:
+
+{{ .Stats.LogOutput }}
+{{- end }}
+
+
+{{ define "title_success" -}}
+Success running docker-volume-backup at {{ .Stats.StartTime | formatTime }}
+{{- end }}
+
+
+{{ define "body_success" -}}
+Running docker-volume-backup succeeded.
+
+Log output was:
+
+{{ .Stats.LogOutput }}
+{{- end }}
--- a/cmd/backup/script.go
+++ b/cmd/backup/script.go
@@ -0,0 +1,693 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"text/template"
+	"time"
+
+	"github.com/containrrr/shoutrrr"
+	"github.com/containrrr/shoutrrr/pkg/router"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/api/types/swarm"
+	"github.com/docker/docker/client"
+	"github.com/kelseyhightower/envconfig"
+	"github.com/leekchan/timeutil"
+	"github.com/minio/minio-go/v7"
+	"github.com/minio/minio-go/v7/pkg/credentials"
+	"github.com/otiai10/copy"
+	"github.com/sirupsen/logrus"
+	"github.com/studio-b12/gowebdav"
+	"golang.org/x/crypto/openpgp"
+)
+
+// script holds all the stateful information required to orchestrate a
+// single backup run.
+type script struct {
+	cli          *client.Client
+	minioClient  *minio.Client
+	webdavClient *gowebdav.Client
+	logger       *logrus.Logger
+	sender       *router.ServiceRouter
+	template     *template.Template
+	hooks        []hook
+	hookLevel    hookLevel
+
+	file  string
+	stats *Stats
+
+	encounteredLock bool
+
+	c *Config
+}
+
+// newScript creates all resources needed for the script to perform actions against
+// remote resources like the Docker engine or remote storage locations. All
+// reading from env vars or other configuration sources is expected to happen
+// in this method.
+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,
+		},
+		stats: &Stats{
+			StartTime: time.Now(),
+			LogOutput: logBuffer,
+			Storages:  StoragesStats{},
+		},
+	}
+
+	s.registerHook(hookLevelPlumbing, func(error) error {
+		s.stats.EndTime = time.Now()
+		s.stats.TookTime = s.stats.EndTime.Sub(s.stats.StartTime)
+		return nil
+	})
+
+	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)
+	if s.c.BackupFilenameExpand {
+		s.file = os.ExpandEnv(s.file)
+		s.c.BackupLatestSymlink = os.ExpandEnv(s.c.BackupLatestSymlink)
+		s.c.BackupPruningPrefix = os.ExpandEnv(s.c.BackupPruningPrefix)
+	}
+	s.file = timeutil.Strftime(&s.stats.StartTime, s.file)
+
+	_, err := os.Stat("/var/run/docker.sock")
+	_, dockerHostSet := os.LookupEnv("DOCKER_HOST")
+	if !os.IsNotExist(err) || dockerHostSet {
+		cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
+		if err != nil {
+			return nil, fmt.Errorf("newScript: failed to create docker client")
+		}
+		s.cli = cli
+	}
+
+	if s.c.AwsS3BucketName != "" {
+		var creds *credentials.Credentials
+		if s.c.AwsAccessKeyID != "" && s.c.AwsSecretAccessKey != "" {
+			creds = credentials.NewStaticV4(
+				s.c.AwsAccessKeyID,
+				s.c.AwsSecretAccessKey,
+				"",
+			)
+		} else if s.c.AwsIamRoleEndpoint != "" {
+			creds = credentials.NewIAM(s.c.AwsIamRoleEndpoint)
+		} else {
+			return nil, errors.New("newScript: AWS_S3_BUCKET_NAME is defined, but no credentials were provided")
+		}
+
+		options := minio.Options{
+			Creds:  creds,
+			Secure: s.c.AwsEndpointProto == "https",
+		}
+
+		if s.c.AwsEndpointInsecure {
+			if !options.Secure {
+				return nil, errors.New("newScript: AWS_ENDPOINT_INSECURE = true is only meaningful for https")
+			}
+
+			transport, err := minio.DefaultTransport(true)
+			if err != nil {
+				return nil, fmt.Errorf("newScript: failed to create default minio transport")
+			}
+			transport.TLSClientConfig.InsecureSkipVerify = true
+			options.Transport = transport
+		}
+
+		mc, err := minio.New(s.c.AwsEndpoint, &options)
+		if err != nil {
+			return nil, fmt.Errorf("newScript: error setting up minio client: %w", err)
+		}
+		s.minioClient = mc
+	}
+
+	if s.c.WebdavUrl != "" {
+		if s.c.WebdavUsername == "" || s.c.WebdavPassword == "" {
+			return nil, errors.New("newScript: WEBDAV_URL is defined, but no credentials were provided")
+		} else {
+			webdavClient := gowebdav.NewClient(s.c.WebdavUrl, s.c.WebdavUsername, s.c.WebdavPassword)
+			s.webdavClient = webdavClient
+		}
+	}
+
+	if s.c.EmailNotificationRecipient != "" {
+		emailURL := fmt.Sprintf(
+			"smtp://%s:%s@%s:%d/?from=%s&to=%s",
+			s.c.EmailSMTPUsername,
+			s.c.EmailSMTPPassword,
+			s.c.EmailSMTPHost,
+			s.c.EmailSMTPPort,
+			s.c.EmailNotificationSender,
+			s.c.EmailNotificationRecipient,
+		)
+		s.c.NotificationURLs = append(s.c.NotificationURLs, emailURL)
+		s.logger.Warn(
+			"Using EMAIL_* keys for providing notification configuration has been deprecated and will be removed in the next major version.",
+		)
+		s.logger.Warn(
+			"Please use NOTIFICATION_URLS instead. Refer to the README for an upgrade guide.",
+		)
+	}
+
+	hookLevel, ok := hookLevels[s.c.NotificationLevel]
+	if !ok {
+		return nil, fmt.Errorf("newScript: unknown NOTIFICATION_LEVEL %s", s.c.NotificationLevel)
+	}
+	s.hookLevel = hookLevel
+
+	if len(s.c.NotificationURLs) > 0 {
+		sender, senderErr := shoutrrr.CreateSender(s.c.NotificationURLs...)
+		if senderErr != nil {
+			return nil, fmt.Errorf("newScript: error creating sender: %w", senderErr)
+		}
+		s.sender = sender
+
+		tmpl := template.New("")
+		tmpl.Funcs(templateHelpers)
+		tmpl, err = tmpl.Parse(defaultNotifications)
+		if err != nil {
+			return nil, fmt.Errorf("newScript: unable to parse default notifications templates: %w", err)
+		}
+
+		if fi, err := os.Stat("/etc/dockervolumebackup/notifications.d"); err == nil && fi.IsDir() {
+			tmpl, err = tmpl.ParseGlob("/etc/dockervolumebackup/notifications.d/*.*")
+			if err != nil {
+				return nil, fmt.Errorf("newScript: unable to parse user defined notifications templates: %w", err)
+			}
+		}
+		s.template = tmpl
+
+		// To prevent duplicate notifications, ensure the regsistered callbacks
+		// run mutually exclusive.
+		s.registerHook(hookLevelError, func(err error) error {
+			if err == nil {
+				return nil
+			}
+			return s.notifyFailure(err)
+		})
+		s.registerHook(hookLevelInfo, func(err error) error {
+			if err != nil {
+				return nil
+			}
+			return s.notifySuccess()
+		})
+	}
+
+	return s, nil
+}
+
+func (s *script) runCommands() (func() error, error) {
+	if s.cli == nil {
+		return noop, nil
+	}
+
+	if err := s.runLabeledCommands("docker-volume-backup.exec-pre"); err != nil {
+		return noop, fmt.Errorf("runCommands: error running pre commands: %w", err)
+	}
+	return func() error {
+		if err := s.runLabeledCommands("docker-volume-backup.exec-post"); err != nil {
+			return fmt.Errorf("runCommands: error running post commands: %w", err)
+		}
+		return nil
+	}, nil
+}
+
+// stopContainers stops all Docker containers that are marked as to being
+// stopped during the backup and returns a function that can be called to
+// restart everything that has been stopped.
+func (s *script) stopContainers() (func() error, error) {
+	if s.cli == nil {
+		return noop, nil
+	}
+
+	allContainers, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
+		Quiet: true,
+	})
+	if err != nil {
+		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers: %w", err)
+	}
+
+	containerLabel := fmt.Sprintf(
+		"docker-volume-backup.stop-during-backup=%s",
+		s.c.BackupStopContainerLabel,
+	)
+	containersToStop, err := s.cli.ContainerList(context.Background(), types.ContainerListOptions{
+		Quiet: true,
+		Filters: filters.NewArgs(filters.KeyValuePair{
+			Key:   "label",
+			Value: containerLabel,
+		}),
+	})
+
+	if err != nil {
+		return noop, fmt.Errorf("stopContainersAndRun: error querying for containers to stop: %w", err)
+	}
+
+	if len(containersToStop) == 0 {
+		return noop, nil
+	}
+
+	s.logger.Infof(
+		"Stopping %d container(s) labeled `%s` out of %d running container(s).",
+		len(containersToStop),
+		containerLabel,
+		len(allContainers),
+	)
+
+	var stoppedContainers []types.Container
+	var stopErrors []error
+	for _, container := range containersToStop {
+		if err := s.cli.ContainerStop(context.Background(), container.ID, nil); err != nil {
+			stopErrors = append(stopErrors, err)
+		} else {
+			stoppedContainers = append(stoppedContainers, container)
+		}
+	}
+
+	var stopError error
+	if len(stopErrors) != 0 {
+		stopError = fmt.Errorf(
+			"stopContainersAndRun: %d error(s) stopping containers: %w",
+			len(stopErrors),
+			join(stopErrors...),
+		)
+	}
+
+	s.stats.Containers = ContainersStats{
+		All:     uint(len(allContainers)),
+		ToStop:  uint(len(containersToStop)),
+		Stopped: uint(len(stoppedContainers)),
+	}
+
+	return func() error {
+		servicesRequiringUpdate := map[string]struct{}{}
+
+		var restartErrors []error
+		for _, container := range stoppedContainers {
+			if swarmServiceName, ok := container.Labels["com.docker.swarm.service.name"]; ok {
+				servicesRequiringUpdate[swarmServiceName] = struct{}{}
+				continue
+			}
+			if err := s.cli.ContainerStart(context.Background(), container.ID, types.ContainerStartOptions{}); err != nil {
+				restartErrors = append(restartErrors, err)
+			}
+		}
+
+		if len(servicesRequiringUpdate) != 0 {
+			services, _ := s.cli.ServiceList(context.Background(), types.ServiceListOptions{})
+			for serviceName := range servicesRequiringUpdate {
+				var serviceMatch swarm.Service
+				for _, service := range services {
+					if service.Spec.Name == serviceName {
+						serviceMatch = service
+						break
+					}
+				}
+				if serviceMatch.ID == "" {
+					return fmt.Errorf("stopContainersAndRun: couldn't find service with name %s", serviceName)
+				}
+				serviceMatch.Spec.TaskTemplate.ForceUpdate = 1
+				if _, err := s.cli.ServiceUpdate(
+					context.Background(), serviceMatch.ID,
+					serviceMatch.Version, serviceMatch.Spec, types.ServiceUpdateOptions{},
+				); err != nil {
+					restartErrors = append(restartErrors, err)
+				}
+			}
+		}
+
+		if len(restartErrors) != 0 {
+			return fmt.Errorf(
+				"stopContainersAndRun: %d error(s) restarting containers and services: %w",
+				len(restartErrors),
+				join(restartErrors...),
+			)
+		}
+		s.logger.Infof(
+			"Restarted %d container(s) and the matching service(s).",
+			len(stoppedContainers),
+		)
+		return nil
+	}, stopError
+}
+
+// takeBackup creates a tar archive of the configured backup location and
+// saves it to disk.
+func (s *script) takeBackup() error {
+	backupSources := s.c.BackupSources
+
+	if s.c.BackupFromSnapshot {
+		s.logger.Warn(
+			"Using BACKUP_FROM_SNAPSHOT has been deprecated and will be removed in the next major version.",
+		)
+		s.logger.Warn(
+			"Please use `exec-pre` and `exec-post` commands to prepare your backup sources. Refer to the README for an upgrade guide.",
+		)
+		backupSources = filepath.Join("/tmp", s.c.BackupSources)
+		// copy before compressing guard against a situation where backup folder's content are still growing.
+		s.registerHook(hookLevelPlumbing, func(error) error {
+			if err := remove(backupSources); err != nil {
+				return fmt.Errorf("takeBackup: error removing snapshot: %w", err)
+			}
+			s.logger.Infof("Removed snapshot `%s`.", backupSources)
+			return nil
+		})
+		if err := copy.Copy(s.c.BackupSources, backupSources, copy.Options{
+			PreserveTimes: true,
+			PreserveOwner: true,
+		}); err != nil {
+			return fmt.Errorf("takeBackup: error creating snapshot: %w", err)
+		}
+		s.logger.Infof("Created snapshot of `%s` at `%s`.", s.c.BackupSources, backupSources)
+	}
+
+	tarFile := s.file
+	s.registerHook(hookLevelPlumbing, func(error) error {
+		if err := remove(tarFile); err != nil {
+			return fmt.Errorf("takeBackup: error removing tar file: %w", err)
+		}
+		s.logger.Infof("Removed tar file `%s`.", tarFile)
+		return nil
+	})
+	if err := createArchive(backupSources, tarFile); err != nil {
+		return fmt.Errorf("takeBackup: error compressing backup folder: %w", err)
+	}
+
+	s.logger.Infof("Created backup of `%s` at `%s`.", backupSources, tarFile)
+	return nil
+}
+
+// encryptBackup encrypts the backup file using PGP and the configured passphrase.
+// In case no passphrase is given it returns early, leaving the backup file
+// untouched.
+func (s *script) encryptBackup() error {
+	if s.c.GpgPassphrase == "" {
+		return nil
+	}
+
+	gpgFile := fmt.Sprintf("%s.gpg", s.file)
+	s.registerHook(hookLevelPlumbing, func(error) error {
+		if err := remove(gpgFile); err != nil {
+			return fmt.Errorf("encryptBackup: error removing gpg file: %w", err)
+		}
+		s.logger.Infof("Removed GPG file `%s`.", gpgFile)
+		return nil
+	})
+
+	outFile, err := os.Create(gpgFile)
+	defer outFile.Close()
+	if err != nil {
+		return fmt.Errorf("encryptBackup: error opening out file: %w", err)
+	}
+
+	_, name := path.Split(s.file)
+	dst, err := openpgp.SymmetricallyEncrypt(outFile, []byte(s.c.GpgPassphrase), &openpgp.FileHints{
+		IsBinary: true,
+		FileName: name,
+	}, nil)
+	defer dst.Close()
+	if err != nil {
+		return fmt.Errorf("encryptBackup: error encrypting backup file: %w", err)
+	}
+
+	src, err := os.Open(s.file)
+	if err != nil {
+		return fmt.Errorf("encryptBackup: error opening backup file `%s`: %w", s.file, err)
+	}
+
+	if _, err := io.Copy(dst, src); err != nil {
+		return fmt.Errorf("encryptBackup: error writing ciphertext to file: %w", err)
+	}
+
+	s.file = gpgFile
+	s.logger.Infof("Encrypted backup using given passphrase, saving as `%s`.", s.file)
+	return nil
+}
+
+// copyBackup makes sure the backup file is copied to both local and remote locations
+// as per the given configuration.
+func (s *script) copyBackup() error {
+	_, name := path.Split(s.file)
+	if stat, err := os.Stat(s.file); err != nil {
+		return fmt.Errorf("copyBackup: unable to stat backup file: %w", err)
+	} else {
+		size := stat.Size()
+		s.stats.BackupFile = BackupFileStats{
+			Size:     uint64(size),
+			Name:     name,
+			FullPath: s.file,
+		}
+	}
+
+	if s.minioClient != nil {
+		if _, err := s.minioClient.FPutObject(context.Background(), s.c.AwsS3BucketName, filepath.Join(s.c.AwsS3Path, name), s.file, minio.PutObjectOptions{
+			ContentType: "application/tar+gzip",
+		}); err != nil {
+			return fmt.Errorf("copyBackup: error uploading backup to remote storage: %w", err)
+		}
+		s.logger.Infof("Uploaded a copy of backup `%s` to bucket `%s`.", s.file, s.c.AwsS3BucketName)
+	}
+
+	if s.webdavClient != nil {
+		bytes, err := os.ReadFile(s.file)
+		if err != nil {
+			return fmt.Errorf("copyBackup: error reading the file to be uploaded: %w", err)
+		}
+		if err := s.webdavClient.MkdirAll(s.c.WebdavPath, 0644); err != nil {
+			return fmt.Errorf("copyBackup: error creating directory '%s' on WebDAV server: %w", s.c.WebdavPath, err)
+		}
+		if err := s.webdavClient.Write(filepath.Join(s.c.WebdavPath, name), bytes, 0644); err != nil {
+			return fmt.Errorf("copyBackup: error uploading the file to WebDAV server: %w", err)
+		}
+		s.logger.Infof("Uploaded a copy of backup `%s` to WebDAV-URL '%s' at path '%s'.", s.file, s.c.WebdavUrl, s.c.WebdavPath)
+	}
+
+	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
+		if err := copyFile(s.file, path.Join(s.c.BackupArchive, name)); err != nil {
+			return fmt.Errorf("copyBackup: error copying file to local archive: %w", err)
+		}
+		s.logger.Infof("Stored copy of backup `%s` in local archive `%s`.", s.file, s.c.BackupArchive)
+		if s.c.BackupLatestSymlink != "" {
+			symlink := path.Join(s.c.BackupArchive, s.c.BackupLatestSymlink)
+			if _, err := os.Lstat(symlink); err == nil {
+				os.Remove(symlink)
+			}
+			if err := os.Symlink(name, symlink); err != nil {
+				return fmt.Errorf("copyBackup: error creating latest symlink: %w", err)
+			}
+			s.logger.Infof("Created/Updated symlink `%s` for latest backup.", s.c.BackupLatestSymlink)
+		}
+	}
+	return nil
+}
+
+// pruneBackups rotates away backups from local and remote storages using
+// the given configuration. In case the given configuration would delete all
+// backups, it does nothing instead and logs a warning.
+func (s *script) pruneBackups() error {
+	if s.c.BackupRetentionDays < 0 {
+		return nil
+	}
+
+	deadline := time.Now().AddDate(0, 0, -int(s.c.BackupRetentionDays)).Add(s.c.BackupPruningLeeway)
+
+	// doPrune holds general control flow that applies to any kind of storage.
+	// Callers can pass in a thunk that performs the actual deletion of files.
+	var doPrune = func(lenMatches, lenCandidates int, description string, doRemoveFiles func() error) error {
+		if lenMatches != 0 && lenMatches != lenCandidates {
+			if err := doRemoveFiles(); err != nil {
+				return err
+			}
+			s.logger.Infof(
+				"Pruned %d out of %d %s as their age exceeded the configured retention period of %d days.",
+				lenMatches,
+				lenCandidates,
+				description,
+				s.c.BackupRetentionDays,
+			)
+		} else if lenMatches != 0 && lenMatches == lenCandidates {
+			s.logger.Warnf("The current configuration would delete all %d existing %s.", lenMatches, description)
+			s.logger.Warn("Refusing to do so, please check your configuration.")
+		} else {
+			s.logger.Infof("None of %d existing %s were pruned.", lenCandidates, description)
+		}
+		return nil
+	}
+
+	if s.minioClient != nil {
+		candidates := s.minioClient.ListObjects(context.Background(), s.c.AwsS3BucketName, minio.ListObjectsOptions{
+			WithMetadata: true,
+			Prefix:       s.c.BackupPruningPrefix,
+		})
+
+		var matches []minio.ObjectInfo
+		var lenCandidates int
+		for candidate := range candidates {
+			lenCandidates++
+			if candidate.Err != nil {
+				return fmt.Errorf(
+					"pruneBackups: error looking up candidates from remote storage: %w",
+					candidate.Err,
+				)
+			}
+			if candidate.LastModified.Before(deadline) {
+				matches = append(matches, candidate)
+			}
+		}
+
+		s.stats.Storages.S3 = StorageStats{
+			Total:  uint(lenCandidates),
+			Pruned: uint(len(matches)),
+		}
+
+		doPrune(len(matches), lenCandidates, "remote backup(s)", func() error {
+			objectsCh := make(chan minio.ObjectInfo)
+			go func() {
+				for _, match := range matches {
+					objectsCh <- match
+				}
+				close(objectsCh)
+			}()
+			errChan := s.minioClient.RemoveObjects(context.Background(), s.c.AwsS3BucketName, objectsCh, minio.RemoveObjectsOptions{})
+			var removeErrors []error
+			for result := range errChan {
+				if result.Err != nil {
+					removeErrors = append(removeErrors, result.Err)
+				}
+			}
+			if len(removeErrors) != 0 {
+				return join(removeErrors...)
+			}
+			return nil
+		})
+	}
+
+	if s.webdavClient != nil {
+		candidates, err := s.webdavClient.ReadDir(s.c.WebdavPath)
+		if err != nil {
+			return fmt.Errorf("pruneBackups: error looking up candidates from remote storage: %w", err)
+		}
+		var matches []fs.FileInfo
+		var lenCandidates int
+		for _, candidate := range candidates {
+			if !strings.HasPrefix(candidate.Name(), s.c.BackupPruningPrefix) {
+				continue
+			}
+			lenCandidates++
+			if candidate.ModTime().Before(deadline) {
+				matches = append(matches, candidate)
+			}
+		}
+
+		s.stats.Storages.WebDAV = StorageStats{
+			Total:  uint(lenCandidates),
+			Pruned: uint(len(matches)),
+		}
+
+		doPrune(len(matches), lenCandidates, "WebDAV backup(s)", func() error {
+			for _, match := range matches {
+				if err := s.webdavClient.Remove(filepath.Join(s.c.WebdavPath, match.Name())); err != nil {
+					return fmt.Errorf("pruneBackups: error removing file from WebDAV storage: %w", err)
+				}
+			}
+			return nil
+		})
+	}
+
+	if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) {
+		globPattern := path.Join(
+			s.c.BackupArchive,
+			fmt.Sprintf("%s*", s.c.BackupPruningPrefix),
+		)
+		globMatches, err := filepath.Glob(globPattern)
+		if err != nil {
+			return fmt.Errorf(
+				"pruneBackups: error looking up matching files using pattern %s: %w",
+				globPattern,
+				err,
+			)
+		}
+
+		var candidates []string
+		for _, candidate := range globMatches {
+			fi, err := os.Lstat(candidate)
+			if err != nil {
+				return fmt.Errorf(
+					"pruneBackups: error calling Lstat on file %s: %w",
+					candidate,
+					err,
+				)
+			}
+
+			if fi.Mode()&os.ModeSymlink != os.ModeSymlink {
+				candidates = append(candidates, candidate)
+			}
+		}
+
+		var matches []string
+		for _, candidate := range candidates {
+			fi, err := os.Stat(candidate)
+			if err != nil {
+				return fmt.Errorf(
+					"pruneBackups: error calling stat on file %s: %w",
+					candidate,
+					err,
+				)
+			}
+			if fi.ModTime().Before(deadline) {
+				matches = append(matches, candidate)
+			}
+		}
+
+		s.stats.Storages.Local = StorageStats{
+			Total:  uint(len(candidates)),
+			Pruned: uint(len(matches)),
+		}
+
+		doPrune(len(matches), len(candidates), "local backup(s)", func() error {
+			var removeErrors []error
+			for _, match := range matches {
+				if err := os.Remove(match); err != nil {
+					removeErrors = append(removeErrors, err)
+				}
+			}
+			if len(removeErrors) != 0 {
+				return fmt.Errorf(
+					"pruneBackups: %d error(s) deleting local files, starting with: %w",
+					len(removeErrors),
+					join(removeErrors...),
+				)
+			}
+			return nil
+		})
+	}
+	return nil
+}
+
+// must exits the script run prematurely in case the given error
+// is non-nil.
+func (s *script) must(err error) {
+	if err != nil {
+		s.logger.Errorf("Fatal error running backup: %s", err)
+		panic(err)
+	}
+}
--- a/cmd/backup/stats.go
+++ b/cmd/backup/stats.go
@@ -0,0 +1,50 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"bytes"
+	"time"
+)
+
+// ContainersStats stats about the docker containers
+type ContainersStats struct {
+	All        uint
+	ToStop     uint
+	Stopped    uint
+	StopErrors uint
+}
+
+// BackupFileStats stats about the created backup file
+type BackupFileStats struct {
+	Name     string
+	FullPath string
+	Size     uint64
+}
+
+// StorageStats stats about the status of an archival directory
+type StorageStats struct {
+	Total       uint
+	Pruned      uint
+	PruneErrors uint
+}
+
+// StoragesStats stats about each possible archival location (Local, WebDAV, S3)
+type StoragesStats struct {
+	Local  StorageStats
+	WebDAV StorageStats
+	S3     StorageStats
+}
+
+// Stats global stats regarding script execution
+type Stats struct {
+	StartTime  time.Time
+	EndTime    time.Time
+	TookTime   time.Duration
+	LockedTime time.Duration
+	LogOutput  *bytes.Buffer
+	Containers ContainersStats
+	BackupFile BackupFileStats
+	Storages   StoragesStats
+}
--- a/cmd/backup/util.go
+++ b/cmd/backup/util.go
@@ -0,0 +1,90 @@
+// Copyright 2022 - Offen Authors <hioffen@posteo.de>
+// SPDX-License-Identifier: MPL-2.0
+
+package main
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+var noop = func() error { return nil }
+
+// copy creates a copy of the file located at `dst` at `src`.
+func copyFile(src, dst string) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+
+	out, err := os.Create(dst)
+	if err != nil {
+		return err
+	}
+
+	_, err = io.Copy(out, in)
+	if err != nil {
+		out.Close()
+		return err
+	}
+	return out.Close()
+}
+
+// join takes a list of errors and joins them into a single error
+func join(errs ...error) error {
+	if len(errs) == 1 {
+		return errs[0]
+	}
+	var msgs []string
+	for _, err := range errs {
+		if err == nil {
+			continue
+		}
+		msgs = append(msgs, err.Error())
+	}
+	return errors.New("[" + strings.Join(msgs, ", ") + "]")
+}
+
+// remove removes the given file or directory from disk.
+func remove(location string) error {
+	fi, err := os.Lstat(location)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return fmt.Errorf("remove: error checking for existence of `%s`: %w", location, err)
+	}
+	if fi.IsDir() {
+		err = os.RemoveAll(location)
+	} else {
+		err = os.Remove(location)
+	}
+	if err != nil {
+		return fmt.Errorf("remove: error removing `%s`: %w", location, err)
+	}
+	return nil
+}
+
+// buffer takes an io.Writer and returns a wrapped version of the
+// writer that writes to both the original target as well as the returned buffer
+func buffer(w io.Writer) (io.Writer, *bytes.Buffer) {
+	buffering := &bufferingWriter{buf: bytes.Buffer{}, writer: w}
+	return buffering, &buffering.buf
+}
+
+type bufferingWriter struct {
+	buf    bytes.Buffer
+	writer io.Writer
+}
+
+func (b *bufferingWriter) Write(p []byte) (n int, err error) {
+	if n, err := b.buf.Write(p); err != nil {
+		return n, fmt.Errorf("bufferingWriter: error writing to buffer: %w", err)
+	}
+	return b.writer.Write(p)
+}
--- a/docs/NOTIFICATION-TEMPLATES.md
+++ b/docs/NOTIFICATION-TEMPLATES.md
@@ -0,0 +1,39 @@
+# Notification templates reference
+
+In order to customize title and body of notifications you'll have to write a [go template](https://pkg.go.dev/text/template) and mount it inside the `/etc/dockervolumebackup/notifications.d/` directory.
+
+Configuration, data about the backup run and helper functions will be passed to this template, this page documents them fully.
+
+## Data
+Here is a list of all data passed to the template:
+
+* `Config`: this object holds the configuration that has been passed to the script. The field names are the name of the recognized environment variables converted in PascalCase. (e.g. `BACKUP_STOP_CONTAINER_LABEL` becomes `BackupStopContainerLabel`)
+* `Error`: the error that made the backup fail. Only available in the `title_failure` and `body_failure` templates
+* `Stats`: objects that holds stats regarding script execution. In case of an unsuccessful run, some information may not be available.
+  * `StartTime`: time when the script started execution
+  * `EndTime`: time when the backup has completed successfully (after pruning)
+  * `TookTime`: amount of time it took for the backup to run. (equal to `EndTime - StartTime`)
+  * `LockedTime`: amount of time it took for the backup to acquire the exclusive lock
+  * `LogOutput`: full log of the application
+  * `Containers`: object containing stats about the docker containers
+    * `All`: total number of containers
+    * `ToStop`: number of containers matched by the stop rule
+    * `Stopped`: number of containers successfully stopped
+    * `StopErrors`: number of containers that were unable to be stopped (equal to `ToStop - Stopped`)
+  * `BackupFile`: object containing information about the backup file
+    * `Name`: name of the backup file (e.g. `backup-2022-02-11T01-00-00.tar.gz`)
+    * `FullPath`: full path of the backup file (e.g. `/archive/backup-2022-02-11T01-00-00.tar.gz`)
+    * `Size`: size in bytes of the backup file
+  * `Storages`: object that holds stats about each storage
+    * `Local`, `S3` or `WebDAV`:
+      * `Total`: total number of backup files
+      * `Pruned`: number of backup files that were deleted due to pruning rule
+      * `PruneErrors`: number of backup files that were unable to be pruned
+
+## Functions
+
+Some formatting functions are also available:
+
+* `formatTime`: formats a time object using [RFC3339](https://datatracker.ietf.org/doc/html/rfc3339) format (e.g. `2022-02-11T01:00:00Z`)
+* `formatBytesBin`: formats an amount of bytes using powers of 1024 (e.g. `7055258` bytes will be `6.7 MiB`) 
+* `formatBytesDec`: formats an amount of bytes using powers of 1000 (e.g. `7055258` bytes will be `7.1 MB`)
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -5,10 +5,21 @@

 set -e

-BACKUP_CRON_EXPRESSION="${BACKUP_CRON_EXPRESSION:-@daily}"
+if [ ! -d "/etc/dockervolumebackup/conf.d" ]; then
+  BACKUP_CRON_EXPRESSION="${BACKUP_CRON_EXPRESSION:-@daily}"

-echo "Installing cron.d entry with expression $BACKUP_CRON_EXPRESSION."
-echo "$BACKUP_CRON_EXPRESSION backup 2>&1" | crontab -
+  echo "Installing cron.d entry with expression $BACKUP_CRON_EXPRESSION."
+  echo "$BACKUP_CRON_EXPRESSION backup 2>&1" | crontab -
+else
+  echo "/etc/dockervolumebackup/conf.d was found, using configuration files from this directory."
+
+  for file in /etc/dockervolumebackup/conf.d/*; do
+    source $file
+    BACKUP_CRON_EXPRESSION="${BACKUP_CRON_EXPRESSION:-@daily}"
+    echo "Appending cron.d entry with expression $BACKUP_CRON_EXPRESSION and configuration file $file"
+    (crontab -l; echo "$BACKUP_CRON_EXPRESSION /bin/sh -c 'set -a; source $file; set +a && backup' 2>&1") | crontab -
+  done
+fi

 echo "Starting cron in foreground."
 crond -f -l 8
--- a/go.mod
+++ b/go.mod
@@ -1,19 +1,20 @@
 module github.com/offen/docker-volume-backup

-go 1.17
+go 1.18

 require (
 	github.com/containrrr/shoutrrr v0.5.2
+	github.com/cosiner/argv v0.1.0
 	github.com/docker/docker v20.10.11+incompatible
 	github.com/gofrs/flock v0.8.1
 	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d
-	github.com/m90/targz v0.0.0-20211229090208-2f22c2d9278e
 	github.com/minio/minio-go/v7 v7.0.16
 	github.com/otiai10/copy v1.7.0
 	github.com/sirupsen/logrus v1.8.1
 	github.com/studio-b12/gowebdav v0.0.0-20211109083228-3f8721cd4b6f
 	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5
+	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 )

 require (
--- a/go.sum
+++ b/go.sum
@@ -208,6 +208,8 @@ github.com/coreos/go-systemd/v22 v22.1.0/go.mod h1:xO0FLkIi5MaZafQlIrOotqXZ90ih+
 github.com/coreos/go-systemd/v22 v22.3.2/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/coreos/pkg v0.0.0-20160727233714-3ac0863d7acf/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
+github.com/cosiner/argv v0.1.0 h1:BVDiEL32lwHukgJKP87btEPenzrrHUjajs/8yzaqcXg=
+github.com/cosiner/argv v0.1.0/go.mod h1:EusR6TucWKX+zFgtdUsKT2Cvg45K5rtpCcWz4hK06d8=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
@@ -428,7 +430,6 @@ github.com/klauspost/compress v1.13.5/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47e
 github.com/klauspost/compress v1.13.6 h1:P76CopJELS0TiO2mebmnzgWaajssP/EszplttgQxcgc=
 github.com/klauspost/compress v1.13.6/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
 github.com/klauspost/cpuid v1.2.3/go.mod h1:Pj4uuM528wm8OyEC2QMXAi2YiTZ96dNQPGgoMS4s3ek=
-github.com/klauspost/cpuid v1.3.1 h1:5JNjFYYQrZeKRJ0734q51WCEEn2huer72Dc7K+R/b6s=
 github.com/klauspost/cpuid v1.3.1/go.mod h1:bYW4mA6ZgKPob1/Dlai2LviZJO7KGI3uoWLd42rAQw4=
 github.com/klauspost/cpuid/v2 v2.0.1/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
 github.com/klauspost/cpuid/v2 v2.0.4/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
@@ -450,8 +451,6 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d h1:2puqoOQwi3Ai1oznMOsFIbifm6kIfJaLLyYzWD4IzTs=
 github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d/go.mod h1:hO90vCP2x3exaSH58BIAowSKvV+0OsY21TtzuFGHON4=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
-github.com/m90/targz v0.0.0-20211229090208-2f22c2d9278e h1:Kzm2zfxS40RUGD5UVtVtOo9RT5TtGoNJnmWORtCEaxM=
-github.com/m90/targz v0.0.0-20211229090208-2f22c2d9278e/go.mod h1:YZK3bSO/oVlk9G+v00BxgzxW2Us4p/R4ysHOBjk0fJI=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/magiconair/properties v1.8.1/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/mailru/easyjson v0.0.0-20190403194419-1ea4449da983/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
@@ -806,6 +805,8 @@ golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
--- a/test/cli/run.sh
+++ b/test/cli/run.sh
@@ -7,6 +7,8 @@ cd $(dirname $0)
 docker network create test_network
 docker volume create backup_data
 docker volume create app_data
+# This volume is created to test whether empty directories are handled
+# correctly. It is not supposed to hold any data.
 docker volume create empty_data

 docker run -d \
@@ -42,14 +44,16 @@ docker run --rm \
  --env BACKUP_FILENAME=test.tar.gz \
  --env "BACKUP_FROM_SNAPSHOT=true" \
  --entrypoint backup \
-  offen/docker-volume-backup:$TEST_VERSION
+  offen/docker-volume-backup:${TEST_VERSION:-canary}

 docker run --rm -it \
  -v backup_data:/data alpine \
  ash -c 'tar -xvf /data/backup/test.tar.gz && test -f /backup/app_data/offen.db && test -d /backup/empty_data'

-echo "[TEST:PASS] Found relevant files in untared backup."
+echo "[TEST:PASS] Found relevant files in untared remote backup."

+# This test does not stop containers during backup. This is happening on
+# purpose in order to cover this setup as well.
 if [ "$(docker ps -q | wc -l)" != "2" ]; then
  echo "[TEST:FAIL] Expected all containers to be running post backup, instead seen:"
  docker ps
--- a/test/commands/.gitignore
+++ b/test/commands/.gitignore
@@ -0,0 +1 @@
+local
--- a/test/commands/docker-compose.yml
+++ b/test/commands/docker-compose.yml
@@ -0,0 +1,36 @@
+version: '3.8'
+
+services:
+  database:
+    image: mariadb:10.7
+    deploy:
+      restart_policy:
+        condition: on-failure
+    environment:
+      MARIADB_ROOT_PASSWORD: test
+      MARIADB_DATABASE: backup
+    labels:
+      - docker-volume-backup.exec-pre=/bin/sh -c 'mysqldump -ptest --all-databases > /tmp/volume/dump.sql'
+      - docker-volume-backup.exec-post=/bin/sh -c 'echo "post" > /tmp/volume/post.txt'
+      - docker-volume-backup.exec-label=test
+    volumes:
+      - app_data:/tmp/volume
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    deploy:
+      restart_policy:
+        condition: on-failure
+    environment:
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      EXEC_LABEL: test
+      EXEC_FORWARD_OUTPUT: "true"
+    volumes:
+      - archive:/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
@@ -0,0 +1,62 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+
+
+docker-compose up -d
+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
+  echo "[TEST:FAIL] Could not find file written by pre command."
+  exit 1
+fi
+echo "[TEST:PASS] Found expected file."
+
+if [ -f ./backup/data/post.txt ]; then
+  echo "[TEST:FAIL] File created in post command was present in backup."
+  exit 1
+fi
+echo "[TEST:PASS] Did not find unexpected file."
+
+docker-compose down --volumes
+sudo rm -rf ./local
+
+
+echo "[TEST:INFO] Running commands test in swarm mode next."
+
+docker swarm init
+
+docker stack deploy --compose-file=docker-compose.yml test_stack
+
+while [ -z $(docker ps -q -f name=backup) ]; do
+  echo "[TEST:INFO] Backup container not ready yet. Retrying."
+  sleep 1
+done
+
+sleep 20
+
+docker exec $(docker ps -q -f name=backup) backup
+
+sudo cp -r $(docker volume inspect --format='{{ .Mountpoint }}' test_stack_archive) ./local
+
+tar -xvf ./local/test.tar.gz
+if [ ! -f ./backup/data/dump.sql ]; then
+  echo "[TEST:FAIL] Could not find file written by pre command."
+  exit 1
+fi
+echo "[TEST:PASS] Found expected file."
+
+if [ -f ./backup/data/post.txt ]; then
+  echo "[TEST:FAIL] File created in post command was present in backup."
+  exit 1
+fi
+echo "[TEST:PASS] Did not find unexpected file."
+
+docker stack rm test_stack
+docker swarm leave --force
--- a/test/compose/docker-compose.yml
+++ b/test/compose/docker-compose.yml
@@ -21,8 +21,8 @@ services:
    volumes:
      - webdav_backup_data:/var/lib/dav

-  backup: &default_backup_service
-    image: offen/docker-volume-backup:${TEST_VERSION}
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
    hostname: hostnametoken
    depends_on:
      - minio
--- a/test/compose/run.sh
+++ b/test/compose/run.sh
@@ -9,34 +9,39 @@ mkdir -p local
 docker-compose up -d
 sleep 5

+# A symlink for a known file in the volume is created so the test can check
+# whether symlinks are preserved on backup.
 docker-compose exec offen ln -s /var/opt/offen/offen.db /var/opt/offen/db.link
 docker-compose exec backup backup

-docker run --rm -it \
-  -v compose_minio_backup_data:/minio_data \
-  -v compose_webdav_backup_data:/webdav_data alpine \
-  ash -c 'apk add gnupg && \
-          echo 1234secret | gpg -d --pinentry-mode loopback --passphrase-fd 0 --yes /minio_data/backup/test-hostnametoken.tar.gz.gpg > /tmp/test-hostnametoken.tar.gz && tar -xf /tmp/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db && \
-          echo 1234secret | gpg -d --pinentry-mode loopback --passphrase-fd 0 --yes /webdav_data/data/my/new/path/test-hostnametoken.tar.gz.gpg > /tmp/test-hostnametoken.tar.gz && tar -xf /tmp/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db'
-
-echo "[TEST:PASS] Found relevant files in untared remote backups."
-
-test -L ./local/test-hostnametoken.latest.tar.gz.gpg
-echo 1234secret | gpg -d --yes --passphrase-fd 0 ./local/test-hostnametoken.tar.gz.gpg > ./local/decrypted.tar.gz
-tar -xf ./local/decrypted.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db
-rm ./local/decrypted.tar.gz
-test -L /tmp/backup/app_data/db.link
-
-echo "[TEST:PASS] Found relevant files in untared local backup."
-
+sleep 5
 if [ "$(docker-compose ps -q | wc -l)" != "4" ]; then
  echo "[TEST:FAIL] Expected all containers to be running post backup, instead seen:"
  docker-compose ps
  exit 1
 fi
-
 echo "[TEST:PASS] All containers running post backup."

+
+docker run --rm -it \
+  -v compose_minio_backup_data:/minio_data \
+  -v compose_webdav_backup_data:/webdav_data alpine \
+  ash -c 'apk add gnupg && \
+          echo 1234secret | gpg -d --pinentry-mode loopback --passphrase-fd 0 --yes /minio_data/backup/test-hostnametoken.tar.gz.gpg > /tmp/test-hostnametoken.tar.gz && tar -xvf /tmp/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db && \
+          echo 1234secret | gpg -d --pinentry-mode loopback --passphrase-fd 0 --yes /webdav_data/data/my/new/path/test-hostnametoken.tar.gz.gpg > /tmp/test-hostnametoken.tar.gz && tar -xvf /tmp/test-hostnametoken.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db'
+
+echo "[TEST:PASS] Found relevant files in decrypted and untared remote backups."
+
+echo 1234secret | gpg -d --pinentry-mode loopback --yes --passphrase-fd 0 ./local/test-hostnametoken.tar.gz.gpg > ./local/decrypted.tar.gz
+tar -xf ./local/decrypted.tar.gz -C /tmp && test -f /tmp/backup/app_data/offen.db
+rm ./local/decrypted.tar.gz
+test -L /tmp/backup/app_data/db.link
+
+echo "[TEST:PASS] Found relevant files in decrypted and untared local backup."
+
+test -L ./local/test-hostnametoken.latest.tar.gz.gpg
+echo "[TEST:PASS] Found symlink to latest version in local backup."
+
 # The second part of this test checks if backups get deleted when the retention
 # is set to 0 days (which it should not as it would mean all backups get deleted)
 # TODO: find out if we can test actual deletion without having to wait for a day
@@ -56,8 +61,8 @@ echo "[TEST:PASS] Remote backups have not been deleted."
 if [ "$(find ./local -type f | wc -l)" != "1" ]; then
  echo "[TEST:FAIL] Backups should not have been deleted, instead seen:"
  find ./local -type f
+  exit 1
 fi
-
 echo "[TEST:PASS] Local backups have not been deleted."

 docker-compose down --volumes
--- a/test/confd/.gitignore
+++ b/test/confd/.gitignore
@@ -0,0 +1 @@
+local
--- a/test/confd/01backup.env
+++ b/test/confd/01backup.env
@@ -0,0 +1,2 @@
+BACKUP_FILENAME="conf.tar.gz"
+BACKUP_CRON_EXPRESSION="*/1 * * * *"
--- a/test/confd/02backup.env
+++ b/test/confd/02backup.env
@@ -0,0 +1,2 @@
+BACKUP_FILENAME="other.tar.gz"
+BACKUP_CRON_EXPRESSION="*/1 * * * *"
--- a/test/confd/03never.env
+++ b/test/confd/03never.env
@@ -0,0 +1,2 @@
+BACKUP_FILENAME="never.tar.gz"
+BACKUP_CRON_EXPRESSION="0 0 5 31 2 ?"
--- a/test/confd/docker-compose.yml
+++ b/test/confd/docker-compose.yml
@@ -0,0 +1,23 @@
+version: '3'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    restart: always
+    volumes:
+      - ./local:/archive
+      - app_data:/backup/app_data:ro
+      - ./01backup.env:/etc/dockervolumebackup/conf.d/01backup.env
+      - ./02backup.env:/etc/dockervolumebackup/conf.d/02backup.env
+      - ./03never.env:/etc/dockervolumebackup/conf.d/03never.env
+      - /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/confd/run.sh
+++ b/test/confd/run.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+
+mkdir -p local
+
+docker-compose up -d
+
+# sleep until a backup is guaranteed to have happened on the 1 minute schedule
+sleep 100
+
+docker-compose down --volumes
+
+if [ ! -f ./local/conf.tar.gz ]; then
+  echo "[TEST:FAIL] Config from file was not used."
+  exit 1
+fi
+echo "[TEST:PASS] Config from file was used."
+
+if [ ! -f ./local/other.tar.gz ]; then
+  echo "[TEST:FAIL] Run on same schedule did not succeed."
+  exit 1
+fi
+echo "[TEST:PASS] Run on same schedule succeeded."
+
+if [ -f ./local/never.tar.gz ]; then
+  echo "[TEST:FAIL] Unexpected file was found."
+  exit 1
+fi
+echo "[TEST:PASS] Unexpected cron did not run."
--- a/test/notifications/.gitignore
+++ b/test/notifications/.gitignore
@@ -0,0 +1 @@
+local
--- a/test/notifications/docker-compose.yml
+++ b/test/notifications/docker-compose.yml
@@ -0,0 +1,36 @@
+version: '3'
+
+services:
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    restart: always
+    environment:
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_PRUNING_PREFIX: test
+      NOTIFICATION_LEVEL: info
+      NOTIFICATION_URLS: ${NOTIFICATION_URLS}
+    volumes:
+      - ./local:/archive
+      - app_data:/backup/app_data:ro
+      - ./notifications.tmpl:/etc/dockervolumebackup/notifications.d/notifications.tmpl
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/var/opt/offen
+
+  gotify:
+    image: gotify/server
+    ports:
+      - 8080:80
+    environment:
+      - GOTIFY_DEFAULTUSER_PASS=custom
+    volumes:
+      - gotify_data:/app/data
+
+volumes:
+  app_data:
+  gotify_data:
--- a/test/notifications/notifications.tmpl
+++ b/test/notifications/notifications.tmpl
@@ -0,0 +1,7 @@
+{{ define "title_success" -}}
+Successful test run, yay!
+{{- end }}
+
+{{ define "body_success" -}}
+Backing up {{ .Stats.BackupFile.FullPath }} succeeded.
+{{- end }}
--- a/test/notifications/run.sh
+++ b/test/notifications/run.sh
@@ -0,0 +1,52 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+
+mkdir -p local
+
+docker-compose up -d
+sleep 5
+
+GOTIFY_TOKEN=$(curl -sSLX POST -H 'Content-Type: application/json' -d '{"name":"test"}' http://admin:custom@localhost:8080/application | jq -r '.token')
+echo "[TEST:INFO] Set up Gotify application using token $GOTIFY_TOKEN"
+
+docker-compose exec backup backup
+
+NUM_MESSAGES=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages | length')
+if [ "$NUM_MESSAGES" != 0 ]; then
+  echo "[TEST:FAIL] Expected no notifications to be sent when not configured"
+  exit 1
+fi
+echo "[TEST:PASS] No notifications were sent when not configured."
+
+docker-compose down
+
+NOTIFICATION_URLS="gotify://gotify/${GOTIFY_TOKEN}?disableTLS=true" docker-compose up -d
+
+docker-compose exec backup backup
+
+NUM_MESSAGES=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages | length')
+if [ "$NUM_MESSAGES" != 1 ]; then
+  echo "[TEST:FAIL] Expected one notifications to be sent when configured"
+  exit 1
+fi
+echo "[TEST:PASS] Correct number of notifications were sent when configured."
+
+MESSAGE_TITLE=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages[0].title')
+MESSAGE_BODY=$(curl -sSL http://admin:custom@localhost:8080/message | jq -r '.messages[0].message')
+
+if [ "$MESSAGE_TITLE" != "Successful test run, yay!" ]; then
+  echo "[TEST:FAIL] Unexpected notification title $MESSAGE_TITLE"
+  exit 1
+fi
+echo "[TEST:PASS] Custom notification title was used."
+
+if [ "$MESSAGE_BODY" != "Backing up /tmp/test.tar.gz succeeded." ]; then
+  echo "[TEST:FAIL] Unexpected notification body $MESSAGE_BODY"
+  exit 1
+fi
+echo "[TEST:PASS] Custom notification body was used."
+
+docker-compose down --volumes
--- a/test/ownership/.gitignore
+++ b/test/ownership/.gitignore
@@ -0,0 +1 @@
+local
--- a/test/ownership/docker-compose.yml
+++ b/test/ownership/docker-compose.yml
@@ -0,0 +1,27 @@
+version: '3'
+
+services:
+  db:
+    image: postgres:14-alpine
+    restart: unless-stopped
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    environment:
+      - POSTGRES_PASSWORD=1FHJMSwt0yhIN1zS7I4DilGUhThBKq0x
+      - POSTGRES_USER=test
+      - POSTGRES_DB=test
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION}
+    restart: always
+    environment:
+      BACKUP_FILENAME: backup.tar.gz
+    volumes:
+      - postgres_data:/backup/postgres:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - ./local:/archive
+
+volumes:
+  postgres_data:
--- a/test/ownership/run.sh
+++ b/test/ownership/run.sh
@@ -0,0 +1,28 @@
+#!/bin/sh
+# This test refers to https://github.com/offen/docker-volume-backup/issues/71
+
+set -e
+
+cd $(dirname $0)
+
+mkdir -p local
+
+docker-compose up -d
+sleep 5
+
+docker-compose exec backup backup
+
+sudo tar --same-owner -xvf ./local/backup.tar.gz -C /tmp
+
+sudo find /tmp/backup/postgres > /dev/null
+echo "[TEST:PASS] Backup contains files at expected location"
+
+for file in $(sudo find /tmp/backup/postgres); do
+  if [ "$(sudo stat -c '%u:%g' $file)" != "70:70" ]; then
+    echo "[TEST:FAIL] Unexpected file ownership for $file: $(sudo stat -c '%u:%g' $file)"
+    exit 1
+  fi
+done
+echo "[TEST:PASS] All files and directories in backup preserved their ownership."
+
+docker-compose down --volumes
--- a/test/swarm/docker-compose.yml
+++ b/test/swarm/docker-compose.yml
@@ -18,8 +18,8 @@ services:
    volumes:
      - backup_data:/data

-  backup: &default_backup_service
-    image: offen/docker-volume-backup:${TEST_VERSION}
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
    depends_on:
      - minio
    deploy:
@@ -43,13 +43,15 @@ services:
    image: offen/offen:latest
    labels:
      - docker-volume-backup.stop-during-backup=true
+    healthcheck:
+      disable: true
    deploy:
      replicas: 2
      restart_policy:
        condition: on-failure

  pg:
-    image: postgres:12.2-alpine
+    image: postgres:14-alpine
    environment:
      POSTGRES_PASSWORD: example
    labels:
--- a/test/swarm/run.sh
+++ b/test/swarm/run.sh
@@ -23,14 +23,13 @@ docker run --rm -it \

 echo "[TEST:PASS] Found relevant files in untared backup."

+sleep 5
 if [ "$(docker ps -q | wc -l)" != "5" ]; then
  echo "[TEST:FAIL] Expected all containers to be running post backup, instead seen:"
  docker ps -a
  exit 1
 fi
-
 echo "[TEST:PASS] All containers running post backup."

 docker stack rm test_stack
-
 docker swarm leave --force
Author	SHA1	Message	Date
Frederik Ring	51af8c3c77	Deprecate BACKUP_FROM_SNAPSHOT (#81 )	2022-03-25 18:28:58 +01:00
Frederik Ring	1ea0b51b23	Tag releases with major version too (#82 )	2022-03-25 18:27:00 +01:00
Frederik Ring	da8c63f755	Support identical cron schedule (#87 ) * Retry on lock being unavailable * Refactor locking to return plain error * Collect LockedTime in stats * Add test case * Add documentation for LOCK_TIMEOUT * Log in case lock needs to be awaited * Release resources created for awaiting lock	2022-03-25 18:26:34 +01:00
Frederik Ring	9bc8db0f7c	Build using Go 1.18 (#86 )	2022-03-17 11:22:41 +01:00
Frederik Ring	508bc07b4f	Disable healthcheck in swarm test (#85 )	2022-03-17 11:13:07 +01:00
Frederik Ring	b8f71b04a1	Use errgroup for running commands in parallel (#83 )	2022-03-10 11:09:39 +01:00
Frederik Ring	5f3832d621	Consider prefix rules when pruning WebDAV storages (#79 )	2022-03-05 13:33:15 +01:00
Frederik Ring	4b1127b8c4	Document BACKUP_SOURCES	2022-03-04 19:57:32 +01:00
Frederik Ring	ae50a3ac4f	Add attribution to code taken from moby repository	2022-03-04 16:40:34 +01:00
Frederik Ring	bad22eee93	Fix syntax highlighting in container	2022-03-04 14:08:31 +01:00
Frederik Ring	c9ebb9e14e	Allow multiple schedules in the same container (#78 ) * Allow mounting of config directory for multiple schedules * Add docs for conf.d feature * Fix behavior on multiple files * Define default case first in entrypoint script	2022-03-04 13:51:26 +01:00
Frederik Ring	6e1b8553e6	Remove superfluous --update flag from cert install	2022-02-26 16:45:29 +01:00
Frederik Ring	5ec2b2c3ff	Install ca-certs with --no-cache to reduce image size	2022-02-25 08:54:07 +01:00
Rajan Patel	3bbeba5b83	update custom docker host documentation for pre/post commands (#77 )	2022-02-24 05:31:36 +01:00
Frederik Ring	9155b4d130	Add missing print directive, fix go.mod	2022-02-23 10:12:57 +01:00
Kazi	2a17e84ab6	snapshot-style restore example (#76 ) * snapshot-style restore example * manual backup recommendation	2022-02-23 07:58:09 +01:00
Rajan Patel	00f2359461	Add DOCKER_HOST documentation (#74 ) * add DOCKER_HOST documentation * add which endpoints are required for DOCKER_HOST * Update README.md Co-authored-by: Frederik Ring <frederik.ring@gmail.com>	2022-02-22 08:00:26 +01:00
Frederik Ring	0504a92a1f	Add option to run pre/post commands for any container (#73 ) * Add option to run pre commands on arbitrary container * Correctly handle quoted args in commands * Provide defaults for test version arg * Allow filtering of target containers * Add documentation on exec commands * Use mysqldump in exec test * Add mysqldump section to recipes * Also run commands test in swarm mode * Use name instead of id * Add syntax highlighting * Add missing license headers	2022-02-22 07:53:33 +01:00
Frederik Ring	3ded77448c	Do not skip directories when creating tar archive (#72 ) * Update targz library to include potential ownership fix * Move archive logic to main repo * Remove assertions for debugging * Use relative path in assertion * Strip local part from archive location * Log when extracting in tests * Fix trimming of prfix * Add license info to archive.go file * Undo change in test assertion * Add test checking for preserved file ownership * use same postgres version in tests * Wrap errors when archiving, handle deletion at script layer	2022-02-22 07:49:24 +01:00
Frederik Ring	58b42b9036	Supporting proxied Docker APIs through DOCKER_HOST (#70 )	2022-02-18 09:08:21 +01:00
Frederik Ring	180438f1fc	Update ubuntu image used for running integration tests (#67 )	2022-02-15 21:05:03 +01:00
Mauro Molin	30265c14ba	Fixed TookTime (#66 )	2022-02-14 17:32:05 +01:00
Frederik Ring	a57e93d01e	Split source into multiple files, deduplicate pruning logic, do not parse templates when notifications are not used (#63 ) * Split code into multiple files * Deduplicate logic for pruning backups against different storages * Only parse templates when notifications are enabled * Use better description	2022-02-13 10:52:19 +01:00
Frederik Ring	3e17d1b123	Ensure end time is recorded for unsuccessful runs too (#62 ) * Ensure end time is also recorded for unsuccessful runs * Clean up integration tests	2022-02-13 09:41:36 +01:00
Frederik Ring	0e248010a8	Add note about how notifications can be customized to config reference	2022-02-12 20:34:51 +01:00
Frederik Ring	e6af6efd8a	Add test setup for notification feature (#61 ) * Add test case for notification feature * Fix template data * bash is needed to interpret test * Do not use bashisms in test * Only print FullPath * Fix assertion	2022-02-12 20:28:38 +01:00
Frederik Ring	34d04211eb	Update README TOC	2022-02-11 20:06:23 +01:00
Mauro Molin	8dfdd14527	Added custom notification messages using text/template (#60 ) * Added custom notification messages using text/template * Change notification template path and removed automatic newline trim * Added stats and changed structure of template params * Stat file hotfix * Embedded and fixed default notification templates Fix * Changed Output to LogOutput * Changed stats integer to unsigned * Bytes formatting in template func fix * Changed Archives to Storages * Removed unecessary sleep for pruning leeway * Set EndTime after pruning is completed * Added custom notifications documentation * Added 5s sleep in swarm test * Fixed documentation * Dockerfile copies all files in cmd/backup	2022-02-11 20:05:16 +01:00
Frederik Ring	3bb99a7117	Update package targz	2022-02-08 15:12:46 +01:00
Fridgemagnet	ddc34be55d	Updated README.md "Restoring..." section example (#56 ) Edited the "Restoring a volume from a backup" section example to be able to better differentiate between the names of the temporary restore container and the name of the mounted restore volume. New example container name: temp_restore_container The restore volume name remains the same: backup_restore Also changed "one-off container" to "once-off container".	2022-02-04 11:52:59 +01:00
Joshua Noble	cb9b4bfcff	Add support for Filebase (#54 )	2022-02-02 17:22:42 +01:00
Frederik Ring	62bd2f4a5a	Update base docker image to alpine 3.15 (#53 )	2022-01-27 14:40:56 +01:00
Frederik Ring	6fe629ce87	Allow path to be set for bucket storage (#52 )	2022-01-25 21:16:16 +01:00