# Container Watchdog

The Container Watchdog is a systemd service that monitors Docker containers and automatically restarts unhealthy or stopped ones. This is useful for ensuring reliability, especially on resource-constrained systems.

## Features

- **Health monitoring** - Checks container status every 30 seconds
- **Automatic restart** - Restarts containers that become unhealthy
- **Auto-start stopped containers** - Starts containers that have stopped (configurable)
- **Diagnostic logging** - Captures container logs before restart for troubleshooting
- **HTTP status endpoint** - Query container status via HTTP API
- **Restart history** - Tracks all automatic restarts with timestamps

## Installation

```bash
cd ~/mc-webui
sudo ./scripts/watchdog/install.sh
```

The installer will:
- Create a systemd service `mc-webui-watchdog`
- Start monitoring containers immediately
- Enable automatic startup on boot
- Create log file at `/var/log/mc-webui-watchdog.log`

## Usage

### Check service status

```bash
systemctl status mc-webui-watchdog
```

### View watchdog logs

```bash
# Real-time logs
tail -f /var/log/mc-webui-watchdog.log

# Or via journalctl
journalctl -u mc-webui-watchdog -f
```

### HTTP Status Endpoints

The watchdog provides HTTP endpoints on port 5051:

```bash
# Service health
curl http://localhost:5051/health

# Container status
curl http://localhost:5051/status

# Restart history
curl http://localhost:5051/history
```

### Diagnostic Files

When a container is restarted, diagnostic information is saved to:
```
/tmp/mc-webui-watchdog-{container}-{timestamp}.log
```

These files contain:
- Container status at the time of failure
- Recent container logs (last 200 lines)
- Timestamp and restart result

## Configuration (Optional)

**No configuration required** - the installer automatically detects paths and sets sensible defaults.

If you need to customize the behavior, the service supports these environment variables:

| Variable | Default | Description |
|----------|---------|-------------|
| `MCWEBUI_DIR` | *(auto-detected)* | Path to mc-webui directory |
| `CHECK_INTERVAL` | `30` | Seconds between health checks |
| `LOG_FILE` | `/var/log/mc-webui-watchdog.log` | Path to log file |
| `HTTP_PORT` | `5051` | HTTP status port (0 to disable) |
| `AUTO_START` | `true` | Start stopped containers (set to `false` to disable) |

To modify defaults, create an override file:
```bash
sudo systemctl edit mc-webui-watchdog
```

Then add your overrides, for example:
```ini
[Service]
Environment=CHECK_INTERVAL=60
Environment=AUTO_START=false
```

## Uninstall

```bash
sudo ~/mc-webui/scripts/watchdog/install.sh --uninstall
```

Note: The log file is preserved after uninstall. Remove manually if needed:
```bash
sudo rm /var/log/mc-webui-watchdog.log
```

## Troubleshooting

### Service won't start

Check the logs:
```bash
journalctl -u mc-webui-watchdog -n 50
```

Common issues:
- Docker not running
- Python 3 not installed
- Permission issues

### Containers keep restarting

Check the diagnostic files in `/tmp/mc-webui-watchdog-*.log` to see what's causing the containers to become unhealthy.

### HTTP endpoint not responding

Verify the service is running and check if port 5051 is available:
```bash
systemctl status mc-webui-watchdog
ss -tlnp | grep 5051
```