# Internal Notifier API

A FastAPI-based internal service that receives notification requests and forwards them to RabbitMQ for asynchronous processing and delivery to end users.

## Features

- **RabbitMQ Integration**: Asynchronous message queuing for reliable notification delivery
- **Internal API Key Authentication**: Secure service-to-service communication
- **MySQL Connection Pooling**: Database connection management with automatic health checks
- **Prometheus Metrics**: Built-in request monitoring and tracking

## Architecture

This service acts as a gateway between internal services and the notification delivery system:

```
Internal Services → Internal Notifier API → RabbitMQ → Notification Workers → End Users
```

## Prerequisites

- Python 3.8+
- MySQL database
- RabbitMQ server
- Required Python packages (see Installation)

## Installation

```bash
pip install -r requirements.txt
```

## Running the Application

```bash
python main.py
```

This starts two servers:
- **Main API**: `http://0.0.0.0:8101`
- **Metrics Server**: `http://0.0.0.0:9000`

## API Endpoints

### Receive Notifications
```
POST /internal/receive-notifications
```

Receives notification data from internal services and queues it to RabbitMQ for delivery.

**Headers:**
- `X-API-Key-Internal`: Your internal API key

**Request Body:**
```json
{
    "receipent_user_id": 12345,
    "message": {
        "title": "New Message",
        "body": "You have a new notification",
        "data": {
            "category": "utility",
            "link": "https://example.com",
            "timestamp": "1760734800"
        }
    }
}
```

- `category` - Optional.
- `link` - Optional.
- `timestamp` - Optional.

**Response:**
```json
{
    "status": "queued"
}
```

**Success:** Returns 200 status code when message is successfully queued to RabbitMQ

## Error Responses

- `403 Forbidden`: Invalid, missing, or inactive API key
- `500 Internal Server Error`: Database, RabbitMQ, or server error

## Monitoring

### Prometheus Metrics

Prometheus metrics are exposed on port 9000 and include:
- HTTP request counters by method, path, and status code
- Custom metrics from the metrics server

Access metrics at: `http://0.0.0.0:9000/metrics`