# DDNS Updater

A lightweight dynamic DNS updater for Cloudflare written in Go. Automatically detects your public IP changes and updates specified DNS A records.

## Features

- Automatic public IP detection with fallback services
- Multiple subdomain support
- Cloudflare API v4 integration
- Configurable check intervals
- Retry logic with exponential backoff
- Structured JSON logging
- Graceful shutdown handling
- Cross-platform (Linux, macOS)

## Building and running

### 1. Generate config

```bash
go run main.go -init-config > config.yaml
# edit config.yaml with your Cloudflare token, zone_id, zone_name, and subdomains
```

Key fields:

```yaml
cloudflare:
  api_token: "your-token"
  zone_id: "your-zone-id"
  zone_name: "example.com"
  subdomains:
    - name: "lc"
      proxied: false
logging:
  file: "/config/logs/ddns-updater.log"
```

### 2. Local binary (Linux/macOS)

```bash
make build
./bin/ddns-updater -config config.yaml
```

***

## Production: Linux (systemd)

1. Install:

```bash
sudo make install
sudo mkdir -p /etc/ddns-updater
sudo cp config.yaml /etc/ddns-updater/config.yaml
sudo chmod 600 /etc/ddns-updater/config.yaml
```

2. Create `/etc/systemd/system/ddns-updater.service`:

```ini
[Unit]
Description=DDNS Updater
After=network-online.target

[Service]
ExecStart=/usr/local/bin/ddns-updater -config /etc/ddns-updater/config.yaml
Restart=always
RestartSec=10
User=root

[Install]
WantedBy=multi-user.target
```

3. Enable:

```bash
sudo systemctl daemon-reload
sudo systemctl enable --now ddns-updater
sudo systemctl status ddns-updater
```

***

## Production: macOS (launchd)

1. Install:

```bash
sudo make install
sudo mkdir -p /usr/local/etc /usr/local/var/log
sudo cp config.yaml /usr/local/etc/ddns-updater.yaml
sudo chmod 600 /usr/local/etc/ddns-updater.yaml
```

2. Create `~/Library/LaunchAgents/com.ddns-updater.plist` pointing at:

```xml
<array>
  <string>/usr/local/bin/ddns-updater</string>
  <string>-config</string>
  <string>/usr/local/etc/ddns-updater.yaml</string>
</array>
```

3. Load:

```bash
launchctl load ~/Library/LaunchAgents/com.ddns-updater.plist
launchctl start com.ddns-updater
```

***

## Docker usage

### 1. Prepare appdata on host (e.g. Unraid)

```bash
mkdir -p /mnt/user/appdata/ddns-updater/logs
cp config.yaml /mnt/user/appdata/ddns-updater/config.yaml
chmod -R 775 /mnt/user/appdata/ddns-updater
```

Ensure `logging.file` in `/mnt/user/appdata/ddns-updater/config.yaml` is:

```yaml
logging:
  file: "/config/logs/ddns-updater.log"
```

### 2. Dockerfile (multi-stage)

Already in repo, using `/config/config.yaml` inside the container and writing logs to `/config/logs`.

### 3. Run with docker

```bash
docker run -d \
  --name ddns-updater \
  --restart unless-stopped \
  -v /mnt/user/appdata/ddns-updater:/config \
  kccleoc/ddns-updater:latest
```

### 4. Docker Compose (Unraid 7 friendly)

```yaml
services:
  ddns-updater:
    image: kccleoc/ddns-updater:latest
    container_name: ddns-updater
    restart: unless-stopped
    user: "0:0"
    volumes:
      - /mnt/user/appdata/ddns-updater:/config
```

Bring it up from the Compose UI (or CLI):

```bash
docker compose up -d
```

## Makefile (Docker image build)

Usage examples:

```bash
make build-dockerimg IMAGE=kccleoc/ddns-updater:latest
make push-dockerimg IMAGE=kccleoc/ddns-updater:latest
```