notifier/README.md

Notifier Module

The Notifier module provides a flexible notification system that supports multiple notification modes (e.g., SMTP, SMS, Slack, Ntfy, and Stdout). It can operate as a standalone gRPC or REST microservice, or be used as an imported module in other projects.

Features

• Multi-Mode Notification: Supports different notification methods including SMTP email, SMS, Slack, Ntfy, and standard output.
• Extensible Design: Add new notification modes by implementing the Notifier interface.
• gRPC and REST APIs: Accessible through both gRPC and RESTful APIs, allowing easy integration into various systems.
• Configuration Management: Easily configurable for different environments and API keys.

Project Structure

notifier/
├── api/
│   ├── grpc/               # gRPC service definitions and generated code
│   └── rest/               # REST API handlers and router
├── cmd/
│   ├── grpcserver/         # Entrypoint for running the gRPC server
│   └── restserver/         # Entrypoint for running the REST server
├── internal/
│   ├── config/             # Configuration loading
│   └── notifier/           # Core notification logic with multiple implementations
├── pkg/
│   ├── grpcclient/         # gRPC client for interacting with the notifier service
│   └── restclient/         # REST client for interacting with the notifier service
├── Dockerfile              # Docker configuration for deploying as a microservice
├── LICENSE                 # License file
├── README.md               # Documentation
└── go.mod                  # Defines the module's dependencies, module path, and Go version

Getting Started

Prerequisites

• Go: Install Go 1.18 or higher.
• Protocol Buffers: Required if you want to regenerate gRPC code.
• Docker (optional): For containerized deployment.

Installation

To install the notifier module as a dependency in another Go project, run:

go get github.com/igodwin/notifier

Running the Service

gRPC Server

To start the gRPC server:

cd cmd/grpcserver
go run main.go

REST Server

To start the REST server:

cd cmd/restserver
go run main.go

Configuration

Configure notification modes via environment variables or a configuration file (e.g., config.yaml). Configuration settings may include:

• SMTP: SMTP server details, port, credentials.
• SMS: SMS provider API keys.
• Slack: Slack webhook URLs.
• Ntfy: Ntfy service URL and options.

For example, using a config.yaml:

smtp:
  server: "smtp.example.com"
  port: 587
  username: "user@example.com"
  password: "password"

slack:
  webhook_url: "https://hooks.slack.com/services/..."

Usage

Using gRPC API

1. Define a gRPC client using the pkg/grpcclient package.
2. Call SendNotification to send a message through a chosen notification method.

Example:

client, err := grpcclient.NewClient("localhost:50051")
if err != nil {
    log.Fatalf("Failed to create gRPC client: %v", err)
}

resp, err := client.SendNotification("recipient@example.com", "Hello via gRPC!")
if err != nil {
    log.Fatalf("Failed to send notification: %v", err)
}

Using REST API

1. Define a REST client using the pkg/restclient package.
2. Call SendNotification via REST.

Example:

client := restclient.NewClient("http://localhost:8080")
err := client.SendNotification("recipient@example.com", "Hello via REST!")
if err != nil {
    log.Fatalf("Failed to send notification: %v", err)
}

Implementing New Notification Modes

To add a new notification method, implement the Notifier interface in internal/notifier/:

type Notifier interface {
    Send(notification Notification) error
}

Add the new mode (e.g., sms.go) with the Send method to implement custom logic.

Contributing

Contributions are welcome! To contribute, fork the repository, make your changes, and submit a pull request.

1. Fork the repository.
2. Create a feature branch (git checkout -b feature/NewMode).
3. Commit your changes (git commit -am 'Add new notification mode').
4. Push to the branch (git push origin feature/NewMode).
5. Create a new Pull Request.

License

This project is licensed under the MIT License. See the LICENSE file for details.