Daily Sync

Daily Sync is a lightweight solution for syncing files to various targets. It currently supports syncing to a WebDAV server, an FTP server, or another directory on the host. It was originally developed for use on NAS systems that lack built-in WebDAV sync capabilities or encryption options. It supports optional encryption using password-protected zip files (AES-256) and is designed to run as a Docker container with a configurable cron schedule.

Features

• Sync files to a WebDAV server, FTP server, or a local directory.
• Optional encryption using password-protected zip files.
• Configurable cron schedule for automated syncing.
• Debug mode for manual testing.

Docker Hub

This Docker image is available on Docker Hub under the tag ghcr.io/tsafs/daily-sync:latest. You can pull it directly using:

docker pull ghcr.io/tsafs/daily-sync:latest

Prerequisites

• Docker installed on your system.
• A WebDAV server with valid credentials.

Build the Docker Image

To build the Docker image locally, run:

docker build -t daily-sync .

Run the Container Directly

Production Mode - WebDAV Sync

Run the container in production mode to sync to WebDAV:

docker run -d \
    --name daily-sync-webdav \
    -v /path/to/your/data:/data:ro \
    -e SYNC_MODE="webdav" \
    -e WEBDAV_URL="https://<webdav-host>/remote.php/dav/files/<username>/<folder>" \
    -e WEBDAV_USERNAME="<username>" \
    -e WEBDAV_PASSWORD="<password>" \
    -e WEBDAV_TARGET_DIR="<target-directory>" \
    -e USE_ENCRYPTION=true \
    -e ENCRYPTION_PASSWORD="<password-for-encryption>" \
    -e CRON_TIME="<time>" \
    -e CRON_DAYS="<days>" \
    -e TIMEZONE="Europe/Berlin" \
    ghcr.io/tsafs/daily-sync:latest

Production Mode - FTP Sync

Run the container in production mode to sync to FTP:

docker run -d \
    --name daily-sync-ftp \
    -v /path/to/your/data:/data:ro \
    -e SYNC_MODE="ftp" \
    -e FTP_HOST="<ftp-host>" \
    -e FTP_USER="<username>" \
    -e FTP_PASSWORD="<password>" \
    -e FTP_TARGET_DIR="<target-directory>" \
    -e USE_ENCRYPTION=true \
    -e ENCRYPTION_PASSWORD="<password-for-encryption>" \
    -e CRON_TIME="<time>" \
    -e CRON_DAYS="<days>" \
    -e TIMEZONE="Europe/Berlin" \
    ghcr.io/tsafs/daily-sync:latest

Production Mode - Directory Sync

Run the container in production mode to sync to another directory on the host:

docker run -d \
    --name daily-sync-dir \
    -v /path/to/your/data:/data:ro \
    -v /path/to/target/directory:/target \
    -e SYNC_MODE="directory" \
    -e USE_ENCRYPTION=true \
    -e ENCRYPTION_PASSWORD="<password-for-encryption>" \
    -e CRON_TIME="<time>" \
    -e CRON_DAYS="<days>" \
    -e TIMEZONE="Europe/Berlin" \
    ghcr.io/tsafs/daily-sync:latest

Note: Ensure the target directory (/path/to/target/directory on the host) exists. The ownership of the synced file will automatically match the ownership of the /path/to/target/directory on the host.

Debug Mode

Run the container in debug mode to test the sync process manually. This will essentially skip using cron entirely.

docker run --rm \
    -v ./test_data:/data:ro \
    -e SYNC_MODE="webdav" \
    ... \
    -e DEBUG=true \
    ghcr.io/tsafs/daily-sync:latests

Run the Container with Docker Compose

WebDAV Sync Example

version: '3.8'
services:
  daily-sync-webdav:
    image: ghcr.io/tsafs/daily-sync:latest
    container_name: daily-sync-webdav
    volumes:
      - /path/to/your/data:/data:ro
      - /etc/localtime:/etc/localtime:ro
      - /etc/timezone:/etc/timezone:ro
    environment:
      SYNC_MODE: "webdav"
      WEBDAV_URL: "https://<webdav-host>/remote.php/dav/files/<username>"
      WEBDAV_USERNAME: "<username>"
      WEBDAV_PASSWORD: "<password>"
      WEBDAV_TARGET_DIR: "<target-directory>"
      USE_ENCRYPTION: "true"
      ENCRYPTION_PASSWORD: "<password-for-encryption>"
      CRON_TIME: "<time>"
      CRON_DAYS: "<days>"

FTP Sync Example

version: '3.8'
services:
  daily-sync-ftp:
    image: ghcr.io/tsafs/daily-sync:latest
    container_name: daily-sync-ftp
    volumes:
      - /path/to/your/data:/data:ro
      - /etc/localtime:/etc/localtime:ro
      - /etc/timezone:/etc/timezone:ro
    environment:
      SYNC_MODE: "ftp"
      FTP_HOST: "<ftp-host>"
      FTP_USER: "<username>"
      FTP_PASSWORD: "<password>"
      FTP_TARGET_DIR: "<target-directory>"
      USE_ENCRYPTION: "true"
      ENCRYPTION_PASSWORD: "<password-for-encryption>"
      CRON_TIME: "<time>"
      CRON_DAYS: "<days>"

Directory Sync Example

version: '3.8'
services:
  daily-sync-dir:
    image: ghcr.io/tsafs/daily-sync:latest
    container_name: daily-sync-dir
    volumes:
      - /path/to/your/data:/data:ro
      - /path/to/target/directory:/target
      - /etc/localtime:/etc/localtime:ro
      - /etc/timezone:/etc/timezone:ro
    environment:
      SYNC_MODE: "directory"
      USE_ENCRYPTION: "true"
      ENCRYPTION_PASSWORD: "<password-for-encryption>"
      CRON_TIME: "<time>"
      CRON_DAYS: "<days>"

Start the container with:

docker-compose up -d

Environment Variables

Variable	Description	Default Value	Required For
SYNC_MODE	Sync target mode (webdav, directory, or ftp).	webdav	Always
WEBDAV_URL	URL of the WebDAV server.	None	webdav
WEBDAV_USERNAME	Username for the WebDAV server.	None	webdav
WEBDAV_PASSWORD	Password for the WebDAV server.	None	webdav
WEBDAV_TARGET_DIR	Target directory on the WebDAV server.	/data	webdav (Optional)
FTP_HOST	Hostname or IP address of the FTP server.	None	ftp
FTP_USER	Username for the FTP server.	None	ftp
FTP_PASSWORD	Password for the FTP server.	None	ftp
FTP_TARGET_DIR	Target directory on the FTP server.	/	ftp (Optional)
USE_ENCRYPTION	Whether to encrypt the files before syncing (true or false).	true	Always
ENCRYPTION_PASSWORD	Password for encrypting the zip file. Required if USE_ENCRYPTION is true.	None	If USE_ENCRYPTION=true
RETAIN_BACKUPS	Number of recent backups to keep in the target location. Older backups are deleted.	1	Always (Optional)
CHUNK_SIZE_MB	Maximum size (in MB) for each part of the multi-volume zip archive for WebDAV or FTP uploads. Must be > 10 MB. Internally, 10 MB is subtracted from this value as a safety margin before creating zip volumes to avoid potential size limit issues. If set to 0 or less than 11, a single archive file will be created.	0	webdav, ftp (Optional)
CRON_TIME	Cron schedule time (e.g., 0 2 for 2:00 AM, 30 22 for 22:30).	0 2	Always (Optional)
CRON_DAYS	Days for the cron job (e.g., * for every day, 0 for Sunday, 1,3,5 for Monday, Wednesday, and Friday).	*	Always (Optional)
DEBUG	Enable debug mode to skip cron and run the sync script directly.	false	Always (Optional)
TIMEZONE	Timezone for cron jobs (e.g., Europe/Berlin, UTC). See IANA Time Zone Database for valid values.	None	Always (Optional)

Note: For directory sync mode, the ownership of the created zip file in the target directory will automatically match the ownership of the mounted target directory itself.

Timezone Configuration

The container supports timezone configuration to ensure cron jobs run at the correct local time, including adjustments for daylight saving time (DST).

Default Behavior

If the TIMEZONE variable is unset and the /etc/localtime and /etc/timezone files are not mounted, the container will use the default timezone of the base image. This could lead to unexpected behavior. To avoid this, you should either use the host's timezone or set the TIMEZONE variable explicitly.

Using the Host's Timezone

To use the host's timezone, you can mount the /etc/localtime and /etc/timezone files into the container. This is supported on Linux systems where these files are available. For example:

docker run -d \
    --name webdav-sync \
    -v /path/to/your/data:/data:ro \
    -v /etc/localtime:/etc/localtime:ro \
    -v /etc/timezone:/etc/timezone:ro \
    ...
    ghcr.io/tsafs/daily-sync:latest

This approach works on most Linux distributions that use /etc/localtime and /etc/timezone for timezone configuration. Note that this method is not supported on systems like macOS or Windows, as they do not use these files for timezone management.

Using the TIMEZONE Variable

If you explicitly set the TIMEZONE variable, this ensures that the container uses the specified timezone, regardless of whether the timezone files are mounted. For example:

docker run -d \
    --name webdav-sync \
    -v /path/to/your/data:/data:ro \
    ...
    -e TIMEZONE="Europe/Berlin" \
    ghcr.io/tsafs/daily-sync:latest

Setting the TIMEZONE variable to a UTC-based value (e.g., UTC) ensures that the container operates without being affected by daylight saving time (DST) changes, providing consistent scheduling behavior.

Contribution Guidelines

I welcome contributions to the Daily Sync project! To contribute, please follow these steps:

1. Fork the Repository: Create a fork of this repository on GitHub.
2. Create a Branch: Create a new branch for your feature or bug fix. Use a descriptive name for the branch (e.g., feature/add-logging or bugfix/fix-sync-issue).
3. Make Changes: Implement your changes in the new branch. Ensure your code adheres to the project's coding standards and is well-documented.
4. Test Your Changes: Thoroughly test your changes to ensure they work as expected and do not introduce regressions.
5. Submit a Pull Request (PR): Open a pull request to the main branch of this repository. Provide a clear description of your changes and the problem they solve.

Reporting Issues

If you encounter a bug or have a feature request, please open an issue on GitHub. Provide as much detail as possible to help me understand and address the issue.

Versioning

This project uses a custom versioning format stored in the version.txt file. The version format is:

YYYY-MM-DD-Index

• YYYY-MM-DD: The release date in the format year-month-day.
• Index: A numeric index starting at 0 for the first release of the day. If multiple releases occur on the same day, increment the index (e.g., 2025-04-13-0, 2025-04-13-1).

Example

If the first release of the day is on April 13, 2025, the version would be:

2025-04-13-0

If a second release is made on the same day, the version would be:

2025-04-13-1

The version.txt file is located in the root directory of the project and should be updated with each release.

License

Copyright (c) 2025, Sebastian Fast All rights reserved.

This source code is licensed under the GPL-style license found in the LICENSE file in the root directory of this source tree.