# Slack to ntfy Middleware

A lightweight Go service that acts as a middleware between Slack webhooks and ntfy servers, with Bearer token authentication and basic authentication support.

## Features

- ✅ Parses Slack webhook format
- ✅ Forwards alerts to self-hosted ntfy servers
- ✅ Bearer token authentication support
- ✅ Health check endpoint
- ✅ Lightweight Docker container (~8.4MB)
- ✅ High performance and low resource usage

## Quick Start

1. **Configure the service**:
   ```bash
   # Edit docker-compose.yml and set:
   # - NTFY_BASE_URL=https://your-ntfy-server.com
   # - NTFY_TOKEN=tk_your_bearer_token
   # OR
   # - NTFY_USERNAME=your_username
   # - NTFY_PASSWORD=your_password
   ```

2. **Run the service**:
   ```bash
   docker compose up -d
   ```

3. **Configure Slack**:
   - Go to Slack Integrations → Incoming Webhooks
   - Add new webhook
   - Webhook URL: `https://your-server-ip:8080/your-topic-name`

4. **Test the service**:
   ```bash
   # Test webhook with HTTP (if TLS is disabled)
   curl -X POST https://localhost:8080/test-topic \
        -H 'Content-Type: application/json' \
        -d '{"text": "Test alert from Slack to ntfy"}'

   # Test webhook with HTTPS (if TLS is enabled, and if using self-signed certs, add -k or --insecure)
   curl -k -X POST https://localhost:8080/test-topic -k \
        -H 'Content-Type: application/json' \
        -d '{"text": "Test alert from Slack to ntfy (TLS)"}'

   # Check health with HTTP (if TLS is disabled)
   curl http://localhost:8080/health

   # Check health with HTTPS (if TLS is enabled, and if using self-signed certs, add -k or --insecure)
   curl https://localhost:8080/health -k
   ```

## Configuration

| Environment Variable | Default | Description |
|---------------------|---------|-------------|
| `NTFY_BASE_URL` | `https://ntfy.sh` | Your ntfy server URL (without topic) |
| `NTFY_TOKEN` | `""` | Bearer token for ntfy authentication |
| `NTFY_USERNAME` | `""` | Username for ntfy basic authentication |
| `NTFY_PASSWORD` | `""` | Password for ntfy basic authentication |
| `BIND_ADDRESS` | `0.0.0.0` | Interface to bind to |
| `BIND_PORT` | `8080` | Port to listen on |
| `TLS_CERT_FILE` | `""` | Path to TLS certificate file (e.g., `/app/certs/server.crt`) |
| `TLS_KEY_FILE` | `""` | Path to TLS private key file (e.g., `/app/certs/server.key`) |

### Enabling TLS

TLS is enabled by default. If `TLS_CERT_FILE` and `TLS_KEY_FILE` environment variables are not set, a self-signed certificate and key will be automatically generated on startup.

**To provide your own certificate and key files (optional)**:

1.  **Create a `certs` directory** in the root of your project:
    ```bash
    mkdir certs
    # Copy your server.crt and server.key into the certs/ directory
    ```
2.  **Uncomment and set `TLS_CERT_FILE` and `TLS_KEY_FILE`** in your `docker-compose.yml` (e.g., pointing to `/app/certs/server.crt` and `/app/certs/server.key`):
    ```yaml
    environment:
      # ... existing environment variables ...
      - TLS_CERT_FILE=/app/certs/server.crt
      - TLS_KEY_FILE=/app/certs/server.key
    ```
3.  Ensure the `volumes` section is uncommented and correctly mounts the `certs` directory:
    ```yaml
    volumes:
      - ./certs:/app/certs
    ```

**Important:** Regardless of whether you use generated or custom certificates:

*   **Update your Slack webhook URL** to use `https`.
*   **Restart your Docker service**:
    ```bash
    docker compose down
    docker compose up -d
    ```
*   When testing with `curl` against a self-signed certificate, you may need to add the `-k` or `--insecure` flag to bypass certificate validation.
*   **Exposing on standard HTTPS port (443) in production**: While the service runs on port 8080 internally, it's common to map it to port 443 externally (e.g., `- "443:8080"` in `docker-compose.yml`) or use a reverse proxy to handle TLS termination on port 443 and forward traffic to the container's port 8080.

## Development

### Build locally
```bash
make build
make run
```

### Build Docker image
```bash
make docker-build
```

### Run tests
```bash
make test
```

## License

MIT License