feat: run in cron or one-shot mode depending if KOPIA_CRON_SCHEDULE is set

Dockerfile

@@ -3,7 +3,7 @@ FROM kopia/kopia
 ENV DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y cron && rm -rf /var/lib/apt/lists/*
 
-ARG KOPIA_CRON_SCHEDULE="*/30 * * * *"
+ARG KOPIA_CRON_SCHEDULE
 ENV KOPIA_CRON_SCHEDULE ${KOPIA_CRON_SCHEDULE}
 
 ARG KOPIA_USERNAME

entrypoint.sh

@@ -1,14 +1,21 @@
-#!/bin/sh
+#!/bin/bash
 
-CRONTAB=/etc/cron.d/kopia-backup
+if [[ -z ${KOPIA_CRON_SCHEDULE} ]]; 
+then
+    echo "Running in one-shot mode"
 
-printenv > /etc/environment 
+    /run-backup.sh
+else 
+    CRONTAB=/etc/cron.d/kopia-backup
 
-echo "Running cron with schedule ${KOPIA_CRON_SCHEDULE}"
+    printenv > /etc/environment 
 
-echo "${KOPIA_CRON_SCHEDULE} /run-backup.sh > /var/log/kopia-backup.log 2>&1" > ${CRONTAB}
-chmod 0644 ${CRONTAB}
-crontab ${CRONTAB}
+    echo "Running cron with schedule ${KOPIA_CRON_SCHEDULE}"
 
-touch /var/log/kopia-backup.log
-cron && tail -f /var/log/kopia-backup.log
+    echo "${KOPIA_CRON_SCHEDULE} /run-backup.sh > /var/log/kopia-backup.log 2>&1" > ${CRONTAB}
+    chmod 0644 ${CRONTAB}
+    crontab ${CRONTAB}
+
+    touch /var/log/kopia-backup.log
+    cron && tail -f /var/log/kopia-backup.log
+fi