github.com/Nicolas-ggd/go-notification

Notification Microservice

This microservice is designed to handle system notifications using Go, NATS, and WebSocket. Clients can connect via WebSocket and receive notifications either for all users or for specific clients.

Features

• WebSocket Connectivity: It lets clients access the service over WebSocket.
• Broadcast Notifications: Messages are sent to all connected clients.
• Targeted Notifications: Messages are sent to specific clients.
• Priority Notifications: Notifications have different types and priorities (error, warning, info).
• Easy Configuration: Command-line arguments can be used to configure the application.

Installation

1. Clone repository:

     git clone https://github.com/Nicolas-ggd/go-notification.git
   

2. Navigate to the project directory:

     cd go-notifications
   

3. Install dependencies:

     go mod download
   

Configuration

You can configure the application using command-line arguments. The following parameters are available:

• --nats-url: The URL of the NATS server (default: nats://nats:4222).
• --http-server-port: The port for the HTTP server (default: 8741).

Example:

  go run ./cmd/gonotification http-server-port=5432 nats-url=nats://127.0.0.1:4222

Usage

Start the service with the following command:

  go run ./cmd/gonotification http-server-port=5432 nats-url=nats://127.0.0.1:4222

Environment Variables

To use environment variables for configuration, follow these steps:

1. Copy the .env.example file to .env and fill in your environment variables:

   cp .env.example .env
   nano .env
   

2. After creating environment file, load the environment variables:

   ./load_env.sh
   

Sending Notifications

1. Broadcast Notification: Send a message to all connected clients.

   {
     "type": "broadcast",
     "message": "This is a broadcast go-notification.",
     "time": "2024-04-17T09:00:00Z",
     "is_view": false
   }
   

2. Targeted Notification: Send a message to specific clients.

   {
     "type": "targeted",
     "clients": ["1", "2"],
     "message": "This is a targeted go-notification.",
     "time": "2024-04-17T09:00:00Z",
     "is_view": false
   }
   

3. Command line notification request using NATS: Send a message to all connected clients

   nats req NOTIFICATION.send-to-all '{"type": "warning", "message": "example", "time": "2024-04-17T09:00:00Z", "is_view": true}'
   

   Send a message to specific clients

   nats req NOTIFICATION.send-to-clients '{"type": "warning", "message": "example", "time": "2024-04-17T09:00:00Z", "clients": ["1", "2"], "is_view": false}'
   

   Notification is viewed, so send event to update record

   nats req NOTIFICATION.viewed '{"id": 1, "is_view": true}'
   

Notification Types and Priorities

There are three types of system notifications, each with a different priority level:

• Error: Highest priority. These notifications are sent first.
• Warning: Medium priority. These notifications are sent after error notifications.
• Info: Lowest priority. These notifications are sent last.

If there is a list of notification that are received simultaneously, the client will receive this list in the following order as described

Example Client

Here's a simple example of a client connecting to the WebSocket server and handling messages:

const socket = new WebSocket('ws://localhost:8080/ws');

socket.onopen = function(event) {
  console.log('Connected to WebSocket server.');
};

socket.onmessage = function(event) {
  const message = JSON.parse(event.data);
  console.log('Received:', message);
};

socket.onclose = function(event) {
  console.log('Disconnected from WebSocket server.');
};

socket.onerror = function(error) {
  console.error('WebSocket Error:', error);
};

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.

License

This project is licensed under the MIT License.