FlareSync

FlareSync is a lightweight Rust application that automatically updates your Cloudflare DNS records with your current public IP address. It's designed to run as a background service, periodically checking for IP changes and updating the specified DNS records accordingly.

What's New in v2.2.0

• Runtime Status File: FlareSync now writes a JSON status file with startup time, last public IP check, per-domain state, recent errors, and shutdown state. The path defaults to status/flaresync-status.json and can be changed with STATUS_FILE_PATH.
• Graceful Shutdown: The app now handles SIGINT and SIGTERM, including during IP discovery, Cloudflare updates, and interval waits, then writes a final status update before exiting.
• Safer Status Writes: Status updates are written through a temporary file and atomic rename so health readers do not observe partial JSON.
• Docker Status Persistence: Docker examples now mount ./status:/app/status and document host directory ownership requirements for rootless containers.
• Version Bump: The package version is now 2.2.0.

What's New in v2.1.0

• Multiple Domain Support: You can now specify multiple domain names to be updated. In your .env file, list them as a comma-separated string for the DOMAIN_NAME variable (e.g., DOMAIN_NAME=example.com,sub.example.com).
• Major Refactoring: The codebase has been significantly refactored for better readability, maintainability, and performance.
• Docker-Compatible Logs: Logging is now directed to stdout, making it easy to monitor using docker logs.
• Modern Toolchain: The project now uses Rust 1.92 and has all dependencies updated to their latest versions for improved performance and security.

Disclaimer

This application was developed using AI. Please note that while AI tools help accelerate development, it is important to review and test the code thoroughly for your specific use cases.

Features

• Periodically checks your current public IP address (using multiple public IP sources for reliability).
• Updates your Cloudflare DNS records only when necessary.
• Asynchronous operation powered by tokio for efficiency.
• Detailed and structured logging with log4rs.
• Dockerised for easy deployment.
• For improved security, the official Docker image is distroless and runs rootless (non-root).
• Backup of DNS records before updates.
• Runtime status file for health monitoring.
• Graceful shutdown on SIGINT and SIGTERM.
• Retry mechanism with exponential backoff for improved reliability.

Getting Started

Prerequisites

• Rust (if building from source)
• Docker (for containerized deployment)
• A Cloudflare account with an API token.

Installation

The recommended way to run FlareSync is using Docker or Docker Compose.

1. Clone the repository: bash git clone https://github.com/BattermanZ/FlareSync.git cd FlareSync

2. Set up your environment: Create a .env file by copying the example file: bash cp .env.example .env Edit the .env file and fill in your details. See the Configuration section for more details on the environment variables.

Using Docker

Create the mounted directories before starting the container and make them writable by the container user:

mkdir -p backups status
chown -R 1000:1000 backups status

docker run -d \
  --name flaresync \
  --env-file .env \
  -v $(pwd)/logs:/app/logs \
  -v $(pwd)/backups:/app/backups \
  -v $(pwd)/status:/app/status \
  --restart unless-stopped \
  battermanz/flaresync:latest

Using Docker Compose

This is the recommended method for deployment.

docker-compose up -d

The docker-compose.yml file is already included in the repository. For reference, it contains:

services:
  flaresync:
    image: battermanz/flaresync:latest
    container_name: flaresync
    env_file:
      - .env
    volumes:
      - ./backups:/app/backups
      - ./status:/app/status
    restart: unless-stopped

Building from Source

If you prefer to build from source: 1. Make sure you have Rust installed (min. version 1.70). 2. Set up your .env file as described above. The application will load it automatically. 3. Build and run the application: bash cargo run --release

Configuration

Environment Variables

This project uses environment variables for configuration. Create a .env file in the project root by copying the .env.example file.

Variable	Description	Default
CLOUDFLARE_API_TOKEN	Your Cloudflare API token.	(required)
CLOUDFLARE_ZONE_ID	The Zone ID of your domain.	(required)
DOMAIN_NAME	A single domain or multiple domains separated by commas (e.g., domain1.com,domain2.com).	(required)
UPDATE_INTERVAL	The update interval in minutes.	5
STATUS_FILE_PATH	Path to the runtime status JSON file.	status/flaresync-status.json
TZ	The timezone for the container.	Etc/UTC
PUID	The user ID for file permissions.	1000
PGID	The group ID for file permissions.	1000

Usage

Make sure your .env file is in the same directory as the docker-compose.yml file.

Backups

DNS record backups are stored in the backups directory. A new backup is created each time a DNS record is updated.

Runtime Status

FlareSync writes a JSON status file to status/flaresync-status.json by default. The file includes startup time, last successful public IP check, per-domain status, recent errors, and shutdown state. In Docker deployments, mount /app/status to persist this file on the host and ensure the mounted directory is writable by UID/GID 1000:1000.

Shutdown

FlareSync handles SIGINT and SIGTERM and exits cleanly after writing a final status update. This allows Docker and systemd to stop the service without waiting for the full update interval sleep to finish.

Security Notice

Keep your .env file secure and avoid sharing it publicly. It contains sensitive information like your Cloudflare API token.

System Architecture

The following diagram shows the overall system architecture of FlareSync:

+-------------------+       +------------------+       +-------------------+
|  Public IP API    | <---> |    FlareSync     | <---> |   Cloudflare API  |
+-------------------+       +------------------+       +-------------------+
         |                           |                           |
         |                           |                           |
    [Check IP]              [Update DNS Record]          [Update Confirmed]

This diagram helps illustrate how FlareSync interacts with public IP services and Cloudflare to maintain updated DNS records.

License

This project is licensed under the GNU General Public License v3.0 (GPL-3.0). See the LICENSE file for details.

Contributing

Contributions are welcome! Please open an issue or submit a pull request.

Acknowledgements

• Built with Rust 🦀
• Powered by tokio, reqwest, and log4rs.
• Thanks to Cloudflare for their powerful API.

Contact

For any questions or issues, feel free to open an issue on this repository.