MDSDigital-Microservice

Description

MDSDigital-Microservice is a NestJS project designed to run serverless on AWS Lambda with API Gateway and DynamoDB. This project includes five microservices: Retrieve, Add, Update and Remove items, auth in the database. The application follows SOLID principles, includes validation, and unit tests to ensure quality and maintainability.

Table of Contents

1. Project Structure
2. Setup Instructions
3. Running the Application
4. Deployment
5. AWS Lambda Configure
6. Best Practices
7. Testing

Project Structure

mds-digital-microservice/ 
|-- .github/
| |-- workflows/
|   |-- deploy.yml 
|-- src/ 
| |-- add/ 
| │ ├── add.controller.spec.ts 
| │ ├── add.controller.ts 
| │ ├── add.module.ts 
| │ ├── add.service.spec.ts 
| │ └── add.sercive.ts 
| |-- auth/ 
| │ ├── auth.controller.spec.ts 
| │ ├── auth.controller.ts 
| │ ├── auth.module.ts 
| │ ├── auth.service.spec.ts 
| │ ├── auth.service.ts 
| │ ├── jwt-auth.guard.spec.ts 
| │ ├── jwt-auth.guard.ts 
| │ ├── jwt.strategy.spec.ts 
| │ └── jwt.strategy.ts
| |-- remove/ 
| │ ├── remove.controller.spec.ts 
| │ ├── remove.controller.ts 
| │ ├── remove.module.ts 
| │ ├── remove.service.spec.ts 
| │ └── remove.sercive.ts
| |-- retrieve/ 
| │ ├── retrieve.controller.spec.ts 
| │ ├── retrieve.controller.ts 
| │ ├── retrieve.module.ts 
| │ ├── retrieve.service.spec.ts 
| │ └── retrieve.service.ts 
| |-- shared/ 
| │ |-- dto/ 
| | │ ├── item.dto.ts
| │ │ └── login.dto.ts 
| │ |-- exceptions/ 
| | │ ├── custom-exception.spec.ts
| │ │ └── custom-exception.ts 
| │ |-- repositories/ 
| | | ├── item.repository.spec.ts
| │ | └── item.repository.ts 
| | |-- utils/ 
| | | ├── dynamoDB.utils.spec.ts
| │ | └── dynamoDB.utils.ts 
| | |-- shared.module.ts
| |-- update/ 
| │ ├── update.controller.spec.ts 
| │ ├── update.controller.ts 
| │ ├── update.module.ts 
| │ ├── update.service.spec.ts 
| │ └── update.service.ts 
| ├── app.module.ts 
| ├── lambda.ts 
| └── main.ts 
|-- test/ 
|-- .env.example
|-- .eslintrc.js 
|-- .gitignore
|-- .prettierrc
|-- jest.config.js 
|-- nest-cli.json 
|-- package-lock.json
|-- package.json
|-- README.md
|-- serverless.yml 
|-- tsconfig.build.json
|-- tsconfig.json

Setup Instructions

Prerequisites

• Node.js v14.x or newer
• npm or yarn
• AWS CLI configured with appropriate permissions
• Serverless Framework installed globally

npm install -g serverless

Installation

1. Clone the repository:

git clone https://github.com/your-repo/MDSDigital-Microservice.git
cd MDSDigital-Microservice

2. Install dependencies:

npm install

Environment Configuration

Create a .env file in the root of the project and add the following variables:

# AWS Configuration
AWS_ACCESS_KEY_ID=your_access_key_id
AWS_SECRET_ACCESS_KEY=your_secret_access_key
AWS_REGION=your_region
AWS_ACCOUNT_ID=your_acound_ID

# DynamoDB Configuration
DYNAMODB_TABLE=your_dynamodb_table_name

# Other settings
NODE_ENV=development
PORT=3000

# JWT Secret
JWT_SECRET=TacosAlPastor
EXPIRE_IN=1d

CI/CD Pipeline

This project leverages Continuous Integration (CI) and Continuous Deployment (CD) using GitHub Actions and the Serverless Framework to ensure efficient and reliable deployment processes.

Continuous Integration (CI)

Every code change pushed to the main branch or submitted via a pull request triggers automated workflows in GitHub Actions. These workflows perform:

• Linting and formatting checks.
• Unit and integration tests using Jest.
• Build verification.

Continuous Deployment (CD)

Upon successful completion of the CI processes, the project is automatically deployed to AWS Lambda using Serverless Framework. The deployment process includes:

• Packaging the project and dependencies.
• Updating API Gateway and DynamoDB configurations as required.
• Leveraging environment variables for secure and dynamic configuration.

This setup ensures fast feedback on code changes, consistent deployments, and scalable infrastructure management.

Running the Application

Development

1. Start the application in development mode:

npm run start:dev

2. The application will be available at http://localhost:3000 or http://127.0.0.1:3000

Production

1. Build the application:

npm run build

2. Start the application:

npm run start:prod

Deployment

Deploy to AWS

1. Ensure you have configured AWS CLI with appropriate permissions.
2. Deploy the application using Serverless Framework:

serverless deploy --verbose

3. Monitor the deployment logs and ensure there are no errors.

AWS Lambda Configuration

• Retrieve Service:

  • Method: GET /items/{id}
  • Description: This service receives an ID and returns the details of an item stored in the database.
  • Response: HTTP 200 if the item exists, HTTP 404 if not found.

• Add Service:

  • Method: POST /items
  • Description: This service allows adding a new item to the database.
  • Input: JSON body with the new item’s data.
  • Response: HTTP 201 if the operation is successful.

• Update Service:

  • Method: PUT /items/{id}
  • Description: This service allows updating an existing item.
  • Input: ID in URL and a JSON body with the fields to be updated.
  • Response: HTTP 200 if the update is successful, HTTP 404 i the item does not exist.

• remove Service:

  • Method: DELETE /items/{id}
  • Description: This service allows remove an existing item.
  • Input: ID in URL and a JSON body with the fields to be updated.
  • Response: HTTP 200 if the update is successful, HTTP 404 i the item does not exist.

• Add Service:

  • Method: POST /auth/login
  • Description: This service authentic a new user to the database.
  • Input: JSON body with the new item’s data.
  • Response: HTTP 201 with a JSON access_token message body that has a token.

Best Practices

1. SOLID Principles: Ensure code follows SOLID principles for maintainability and scalability.
2. Validation: Use class-validator to validate DTOs.
3. Logging: Utilize NestJS Logger for debugging and monitoring.
4. Exception Handling: Implement custom exceptions to handle errors gracefully.
5. Repository Pattern: Use repositories to interact with the database, ensuring a clean separation of concerns.

Testing

Unit Tests

1. Run unit tests:

npm run test

2. Watch mode:

npm run test:watch

3. Coverage:

npm run test:cov

Example Test for AddController

import { Test, TestingModule } from '@nestjs/testing';
import { AddController } from './add.controller';
import { AddService } from './add.service';
import { CreateItemDto } from '../shared/dto/item.dto';
import { ValidationPipe } from '@nestjs/common';
import { CustomException } from '../shared/exceptions/custom-exception';

describe('AddController', () => {
  let addController: AddController;
  let addService: AddService;

  beforeEach(async () => {
    const module: TestingModule = await Test.createTestingModule({
      controllers: [AddController],
      providers: [
        {
          provide: AddService,
          useValue: {
            addItem: jest.fn(),
          },
        },
      ],
    }).compile();

    addController = module.get<AddController>(AddController);
    addService = module.get<AddService>(AddService);
  });

  it('should be defined', () => {
    expect(addController).toBeDefined();
  });

  describe('addItem', () => {
    it('should add a new item and return the result', async () => {
      const createItemDto: CreateItemDto = {
        name: 'Test Item',
        description: 'Test Description',
        price: 100,
      };

      const result = { id: '1', ...createItemDto };
      jest.spyOn(addService, 'addItem').mockResolvedValue(result);

      const response = await addController.addItem(createItemDto);

      expect(response).toEqual(result);
      expect(addService.addItem).toHaveBeenCalledWith(createItemDto);
    });

    it('should throw an error if the service throws an error', async () => {
      const createItemDto: CreateItemDto = {
        name: 'Test Item',
        description: 'Test Description',
        price: 100,
      };

      jest.spyOn(addService, 'addItem').mockRejectedValue(new CustomException('Failed to add item', 500));

      await expect(addController.addItem(createItemDto)).rejects.toThrow(CustomException);
    });
  });
});