Cronjob image with configurable cron expression

cronjob/Dockerfile

@@ -1,9 +1,11 @@
 ARG COMMAND_VERSION=latest
-FROM ghcr.io/daniele-athome/immich-carddav-sync:${COMMAND_VERSION}
+FROM ghcr.io/daniele-athome/immich-carddav-sync:${COMMAND_VERSION} as runtime
 
-RUN apt-get update && apt-get install --no-install-recommends -y cron
+RUN apt-get update && apt-get install --no-install-recommends -y gettext-base cron
 
-COPY cronjob.sh /etc/cron.daily/immich-carddav-sync
-RUN chmod 0755 /etc/cron.daily/immich-carddav-sync
+COPY crontab.tmpl /app/crontab.tmpl
 
-ENTRYPOINT ["cron", "-f"]
+COPY entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]

cronjob/crontab.tmpl

@@ -0,0 +1,9 @@
+# Example of job definition:
+# .---------------- minute (0 - 59)
+# |  .------------- hour (0 - 23)
+# |  |  .---------- day of month (1 - 31)
+# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
+# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
+# |  |  |  |  |
+# *  *  *  *  * user-name command to be executed
+${CRON_EXPRESSION}   root    cd / && PATH=/app/.venv/bin python -m immich_carddav_sync.main >/proc/1/fd/1 2>/proc/1/fd/2

cronjob/entrypoint.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+env >> /etc/environment
+
+envsubst < /app/crontab.tmpl >/etc/cron.d/immich-carddav-sync
+
+exec cron -f