Merge pull request #36 from djmaze/add-prune

Add prune support using a separate service and cron schedule

Dockerfile

@@ -48,7 +48,7 @@ RUN apk add --no-cache --repository=http://dl-cdn.alpinelinux.org/alpine/edge/co
 ENV RESTIC_REPOSITORY /mnt/restic
 
 COPY --from=builder /usr/local/bin/* /usr/local/bin/
-COPY backup /usr/local/bin/
+COPY backup prune /usr/local/bin/
 COPY entrypoint /
 
 ENTRYPOINT ["/entrypoint"]

README.md

@@ -11,13 +11,16 @@ Run automatic [restic](https://restic.github.io/) backups via a Docker container
 * backup to any (local or remote) target supported by restic
 * add custom tags to backups
 * automatic forgetting of old backups
+* prune backups on a schedule
 * can be used as a (global) Docker swarm service in order to backup every cluster node
 * multi-arch: the image `mazzolino/restic` runs on `amd64` as well as `armv7` (for now)
 
 ## Usage
 
 Use the supplied example configs to set up a backup schedule.
 
+The Compose files contain a *backup* and a *prune* service which can be scheduled independently of each other. Feel free to remove the *prune* service if you want to run the prune jobs manually.
+
 ### With Docker Compose
 
 Adjust the supplied [docker-compose.yml](docker-compose.example.yml) as needed. Then run:
@@ -57,7 +60,10 @@ E.g.
 
 ## Configuration options
 
-* `BACKUP_CRON` - A cron expression for when to run the backup. E.g. `0 30 3 * * *` in order to run every night at 3:30 am. See [the go-cron documentation](https://godoc.org/github.com/robfig/cron) for details on the expression format
+*Note: `BACKUP_CRON` and `PRUNE_CRON` are mutually exclusive.*
+
+* `BACKUP_CRON`- A cron expression for when to run the backup. E.g. `0 30 3 * * *` in order to run every night at 3:30 am. See [the go-cron documentation](https://godoc.org/github.com/robfig/cron) for details on the expression format
+* `PRUNE_CRON` - A cron expression for when to run the prune job. E.g. `0 0 4 * * *` in order to run every night at 4:00 am. See [the go-cron documentation](https://godoc.org/github.com/robfig/cron) for details on the expression format
 * `RESTIC_REPOSITORY` - location of the restic repository. You can use [any target supported by restic](https://restic.readthedocs.io/en/stable/030_preparing_a_new_repo.html). Default `/mnt/restic`
 * `RESTIC_BACKUP_SOURCES` - source directory to backup. Make sure to mount this into the container as a volume (see the example configs). Default `/data`
 * `RESTIC_PASSWORD` - password for the restic repository. Will also be used to initialize the repository if it is not yet initialized

docker-compose.example.yml

@@ -1,7 +1,7 @@
 version: "3.3"
 
 services:
- app:
+ backup:
  image: mazzolino/restic
  hostname: docker
  environment:
@@ -16,3 +16,14 @@ services:
  TZ: Europe/Berlin
  volumes:
  - /var/lib/docker/volumes:/mnt/volumes:ro
+
+ prune:
+ image: mazzolino/restic
+ hostname: docker
+ environment:
+ PRUNE_CRON: "0 0 4 * * *"
+ RESTIC_REPOSITORY: b2:my-repo:/restic
+ RESTIC_PASSWORD: supersecret
+ B2_ACCOUNT_ID: xxxxxxx
+ B2_ACCOUNT_KEY: yyyyyyyy
+ TZ: Europe/Berlin

docker-swarm.example.yml

@@ -1,7 +1,7 @@
 version: "3.3"
 
 services:
- app:
+ backup:
  image: mazzolino/restic
  environment:
  BACKUP_CRON: "0 30 3 * * *"
@@ -18,3 +18,14 @@ services:
  - /var/lib/docker/volumes:/mnt/volumes:ro
  deploy:
  mode: global
+
+ prune:
+ image: mazzolino/restic
+ hostname: docker
+ environment:
+ PRUNE_CRON: "0 0 4 * * *"
+ RESTIC_REPOSITORY: b2:my-repo:/restic
+ RESTIC_PASSWORD: supersecret
+ B2_ACCOUNT_ID: xxxxxxx
+ B2_ACCOUNT_KEY: yyyyyyyy
+ TZ: Europe/Berlin

entrypoint

@@ -1,8 +1,9 @@
-#!/bin/sh
+#!/bin/bash
+set -euo pipefail
 
 if [ -z "${RESTIC_REPOSITORY##*:*}" ]; then
  echo "Trying to initialize remote repository '${RESTIC_REPOSITORY}' (in case it has not been initialized yet)"
- restic init
+ restic init || true
 elif [ ! -f "$RESTIC_REPOSITORY/config" ]; then
  echo "Restic repository '${RESTIC_REPOSITORY}' does not exist. Running restic init"
  restic init
@@ -11,6 +12,12 @@ fi
 if [[ $# -gt 0 ]]; then
  exec restic "$@"
 else
- exec go-cron "$BACKUP_CRON" /usr/local/bin/backup
+ if [[ -n "${BACKUP_CRON:-}" ]]; then
+ exec go-cron "$BACKUP_CRON" /usr/local/bin/backup
+ fi
+ if [[ -n "${PRUNE_CRON:-}" ]]; then
+ exec go-cron "$PRUNE_CRON" /usr/local/bin/prune
+ fi
+ >&2 echo "No valid operating mode configured! Exiting."
 fi
 

prune

@@ -0,0 +1,39 @@
+#!/bin/bash
+set -euo pipefail
+
+function run_commands {
+ COMMANDS=$1
+ while IFS= read -r cmd; do echo $cmd && eval $cmd ; done < <(printf '%s\n' "$COMMANDS")
+}
+
+function run_exit_commands {
+ set +e
+ set +o pipefail
+ run_commands "${POST_COMMANDS_EXIT:-}"
+}
+
+main() {
+ run_commands "${PRE_COMMANDS:-}"
+
+ start=$(date +%s)
+ echo Starting prune at "$(date +"%Y-%m-%d %H:%M:%S")"
+
+ set +e
+ if ! restic prune "${RESTIC_REPOSITORY}"; then
+ set -e
+ run_commands "${POST_COMMANDS_FAILURE:-}"
+ exit
+ else
+ set -e
+ fi
+
+ echo Prune successful
+
+ end="$(date +%s)"
+ echo Finished prune at "$(date +"%Y-%m-%d %H:%M:%S")" after $((end-start)) seconds
+
+ run_commands "${POST_COMMANDS_SUCCESS:-}"
+}
+
+trap run_exit_commands EXIT
+main "$@"