Golang Serverless Application

This project is a serverless REST API built using AWS Lambda, DynamoDB, and the Go programming language. It provides functionality for managing user records in a DynamoDB table and is structured to facilitate scalability and maintainability.

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Project Structure

The project follows a modular file structure:

cmd
│   main.go
pkg
├── handlers
│   ├── handlers.go
│   ├── api_response.go
├── user
│   ├── user.go
├── validators
│   ├── is_email_valid.go

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File Descriptions

cmd/main.go

• Entry point of the application.
• Initializes AWS session and DynamoDB client.
• Routes HTTP methods (GET, POST, PUT, DELETE) to their respective handlers.

pkg/handlers/handlers.go

• Implements HTTP handlers for user-related operations:
  • GetUser: Fetches user(s) based on query parameters.
  • CreateUser: Adds a new user to the DynamoDB table.
  • UpdateUser: Updates an existing user's data.
  • DeleteUser: Removes a user from the DynamoDB table.
  • UnhandledMethod: Handles unsupported HTTP methods.

pkg/handlers/api_response.go

• Provides the apiResponse function to format API responses with status codes, headers, and JSON bodies.

pkg/user/user.go

• Contains the core logic for interacting with DynamoDB:
  • FetchUser: Fetches a single user by email.
  • FetchUsers: Retrieves all users.
  • CreateUser: Validates and adds a new user.
  • UpdateUser: Validates and updates user details.
  • DeleteUser: Deletes a user from the table.

pkg/validators/is_email_valid.go

• Provides the IsEmailValid function to validate email addresses using regex.

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Setup and Configuration

Prerequisites

1. Install Go (version 1.16 or later).
2. Configure AWS CLI with valid credentials.
3. Create a DynamoDB table with a primary key named email.
4. Set environment variables:
   • AWS_REGION: The AWS region for your DynamoDB table.
   • TABLE_NAME: The name of your DynamoDB table.

Installation

1. Clone the repository:

   git clone <repository-url>
   cd <project-directory>

2. Install dependencies:

   go mod tidy

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Running Locally

1. Use the AWS SAM CLI to run the application locally:

   sam local start-api

2. Test the endpoints with curl or tools like Postman.

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API Endpoints and Example Commands

1. Create a New User

• Endpoint: POST /users
• Command:

  curl --header "Content-Type: application/json" \
       --request POST \
       --data '{"email":"chdvanshsingh@gmail.com", "firstname":"Vansh", "lastname":"Singh"}' \
       https://<api-gateway-url>/users

2. Get All Users

• Endpoint: GET /users
• Command:

  curl --request GET https://<api-gateway-url>/users

3. Get a User by Email

• Endpoint: GET /users?email=<email>
• Command:

  curl --request GET https://<api-gateway-url>/users?email=chdvanshsingh@gmail.com

4. Update a User

• Endpoint: PUT /users
• Command:

  curl --header "Content-Type: application/json" \
       --request PUT \
       --data '{"email":"chdvanshsingh@gmail.com", "firstname":"VanshUpdated", "lastname":"SinghUpdated"}' \
       https://<api-gateway-url>/users

5. Delete a User

• Endpoint: DELETE /users?email=<email>
• Command:

  curl --request DELETE https://<api-gateway-url>/users?email=chdvanshsingh@gmail.com

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Testing

• Use curl, Postman, or other tools to test the API.
• Write unit tests for individual functions in the pkg/ directory.

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Contributing

1. Fork the repository.
2. Create a feature branch.
3. Commit your changes and create a pull request.

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License

This project is licensed under the MIT License.