Add environment variable for CRON_SCHEDULE

Dockerfile

@@ -11,10 +11,6 @@ RUN apk add --no-cache git rsync openssh-client dcron tzdata
 COPY backup-script.sh /backup-script.sh
 RUN chmod +x /backup-script.sh
 
-# Schedule the backup script to run daily at midnight using crontab
-# Output is redirected to /var/log/cron.log for logging
-RUN echo "0 0 * * * /backup-script.sh >> /var/log/cron.log 2>&1" > /etc/crontabs/root
-
 # Create the log file to enable log output via 'docker logs'
 RUN touch /var/log/cron.log
 
@@ -35,6 +31,13 @@ ENV GIT_REMOTE_URL=""
 # This environment variable must be set externally.
 ENV SSH_PRIVATE_KEY=""
 
+# CRON_SCHEDULE defines when the backup script runs, defaulting to midnight every day.
+# Use standard cron format (e.g., "0 0 * * *" for midnight).
+ENV CRON_SCHEDULE="0 0 * * *"
+
+# Configure crontab based on CRON_SCHEDULE environment variable
+RUN echo "${CRON_SCHEDULE} /backup-script.sh >> /var/log/cron.log 2>&1" > /etc/crontabs/root
+
 # ----------
 # Entrypoint
 # ----------

README.md

@@ -8,7 +8,7 @@ This solution provides an automated way to back up a Git repository hosted on an
 
 ## Features
 
-- **Scheduled Backups**: Leverages `dcron` to schedule daily backups at midnight (located in Dockerfile).
+- **Scheduled Backups**: Leverages `dcron` to schedule daily backups at midnight by default (ENV variable `CRON_SCHEDULE`).
 - **Environment Customization**: Allows configuration of source directory, commit message template, Git remote URL, and SSH private key through environment variables.
 - **SSH Key Management**: Incorporates SSH setup for Git operations to securely connect to the remote repository.
 - **Timezone Management**: Timezone configuration within the container.
@@ -42,6 +42,7 @@ services:
       - git-volume:/git-repo/
     environment:
       TZ: Europe/Zurich
+      CRON_SCHEDULE: "0 0 * * *"
       SOURCE_FOLDER_PATH: "/obsidian/"
       COMMIT_MESSAGE_TEMPLATE: "Backup on CURRENT_DATE" # CURRENT_DATE is a placeholder
       GIT_REMOTE_URL: "<Your_remote_ssh_git_repo>"