Support Cron in docker image

.dockerignore

@@ -4,3 +4,4 @@
 !cmd
 !internal
 !go.*
+!/*.sh

Dockerfile

@@ -9,4 +9,12 @@ RUN go build
 FROM alpine
 RUN apk add --no-cache restic rclone bash openssh
 COPY --from=builder /app/autorestic /usr/bin/autorestic
-CMD [ "autorestic" ]
+COPY entrypoint.sh /entrypoint.sh
+COPY crond.sh /crond.sh
+RUN chmod +x /entrypoint.sh /crond.sh
+# show autorestic cron logs in docker
+RUN ln -sf /proc/1/fd/1 /var/log/autorestic-cron.log
+# run autorestic-cron every minute
+RUN echo -e "*/1 * * * * bash /crond.sh" >> /etc/crontabs/root
+
+CMD [ "/entrypoint.sh" ]

crond.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+echo "autorestic cron process has started"
+autorestic -c $CRON_CONFIG_DIR --ci cron > /var/log/autorestic-cron.log 2>&1
+echo "autorestic cron process has finished"

docs/markdown/docker.md

@@ -13,6 +13,38 @@ docker run --rm \\
   autorestic backup -va -c /data/.autorestic.yaml
 ```
 
+## Cron
+
+To use cron with the docker image,
+you have 2 environment variables.
+`AUTORESTIC_INITIAL_ARGS` and `CRON_CONFIG_DIR`
+
+- `AUTORESTIC_INITIAL_ARGS` is arguments used for the initial autorestic command on container start up, if you don't set it, autorestic would show available commands.
+
+For example:
+```
+AUTORESTIC_INITIAL_ARGS=backup -va -c /.autorestic.yaml
+```
+Would mean `autorestic backup -va -c /.autorestic.yaml` on container startup.
+
+- `CRON_CONFIG_DIR` to enable Cron, you need to set this to the in-contaier directory of the config file you want to use with Cron.
+
+### Example
+
+```
+version: '3.3'
+
+services:
+  autorestic:
+    image: cupcakearmy/autorestic:latest
+    environment:
+      - AUTORESTIC_INITIAL_ARGS=backup -va -c /.autorestic.yaml
+      - CRON_CONFIG_DIR=/.autorestic.yaml
+    volumes:
+      - ./autorestic.yaml:/.autorestic.yaml
+```
+This would run `autorestic backup -va -c /.autorestic.yaml` on container startup, and check for any backups due in /.autorestic.yaml.
+
 ## Rclone
 
 For rclone you will have to also mount the rclone config file to `/root/.config/rclone/rclone.conf`.
@@ -25,4 +57,4 @@ To check where it is located you can run the following command: `rclone config f
 docker run \\
   -v /home/user/.config/rclone/rclone.conf:/root/.config/rclone/rclone.conf:ro \\
   ...
-```
+```

entrypoint.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+autorestic $AUTORESTIC_INITIAL_ARGS
+if [ -n "$CRON_CONFIG_DIR" ]
+then
+    echo "CRON_CONFIG_DIR is set, cron enabled"
+    crond -f -L /var/log/cron.log
+fi