Email Validator

This application provides a gRPC-based email validation service using Golang. It checks the validity of email addresses by verifying their format and checking the associated domain's MX records. Additionally, it includes a Gateway for handling HTTP requests and forwarding them to the gRPC server.

Features

• Validates email format.
• Checks MX records of the email domain.
• Caches results using Redis.
• Supports both gRPC and HTTP interfaces.
• Implements a gRPC Gateway for RESTful API access.

Prerequisites

Before you begin, ensure you have the following installed:

• Go (version 1.22 or later)
• Docker
• Docker Compose (optional, as it can be included in Docker installation)

Setup

Generate Protocol Buffers

The application uses Protocol Buffers to define the service and message types. Run the following command to generate the Go code from the .proto files:

make generate

Build the Docker Images

You can build the Docker images for both the email validator and the gateway using:

make build

Running the Application

To run the application with Docker Compose, use the following command:

make docker-run

This will start the email validator, gateway, and Redis in separate containers.

Stopping the Application

To stop and remove the containers, run:

make docker-stop

Testing

To run the tests for the application, use:

make test

API Endpoints

gRPC Endpoint

The gRPC server listens for requests on the configured port. You can use a gRPC client to send requests to validate emails.

HTTP Gateway

The application also exposes an HTTP Gateway. You can send requests to the Gateway, which will forward them to the gRPC server.

• POST /v1/validate

Request Body:

{
  "email": "[email protected]"
}

Response:

• 200 OK: If the email is valid.
• 503 Service Unavailable: If the email server cannot be reached.
• 400 Bad Request: If the email format is invalid.

Environment Variables

You can set the following environment variables to configure the application:

• GRPC_SERVER_ENDPOINT: The endpoint for the gRPC server (default: email-validator:50051).
• HTTP_PORT: The port for the HTTP server (default: 8080).
• REDIS_HOST: The hostname for the Redis server (default: redis).
• REDIS_PORT: The port for the Redis server (default: 6379).
• REDIS_DB: The Redis database number (default: 0).
• REDIS_MAXMEMORY: The maximum memory limit for Redis (default: 100mb).
• DNS_HOSTS: The DNS servers to use for MX record lookups (default: 1.1.1.1,1.0.0.1).

Contributing

Contributions are welcome! Please feel free to submit a pull request or open an issue for suggestions and improvements.

License

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