Be A Hero

NestJS, Docker, Circle, CI/CD, Testing

  • NestJS

  • Docker

  • Circle

  • CI/CD

  • Testing

Agenda

Presentation

Need to install

https://www.pgadmin.org/

https://www.docker.com/products/docker-desktop/

http://www.postman.com/downloads/

NestJS Links

https://github.com/nestjs/nest-cli#readme

 

https://docs.nestjs.com/cli/overview

APP

https://github.com/OlegRovenskyi/be-a-hero/tree/master

NestJS: APP

User Management

Endpoint Method Description
users/ GET Get all users
users/:id GET Get one user
users/ POST Create user
users/:id DELETE Delete user
users/:id PUT/PATCH Update user

Endpoints which we will implement

NestJS: APP

User Management

  • In the first part, we will implement endpoints without integration with DataBase.
  • In the second part, we will integrate with DataBase.

NestJS: How To Start

$ npm install -g @nestjs/cli

$ nest new my-nest-project

$ cd my-nest-project
$ npm run start:dev

NestJS: Objectives

  • Modules
  • Controllers
  • Services
  • DTO
  • Validation
  • Pipes
  • Meegration/Seeds

NestJS: NestJS CLI

$ nest g --help
$ nest g module users

NestJS: Modules

  • providers
  • controllers
  • exports
  • imports

NestJS: Controllers

  • Responsible for handling requests
  • Specific path
  • Contains handlers (GET, POST, PUT, DELETE)
  • DI

NestJS: Controllers

$ nest g controller users

NestJS: Controllers

@Controller('/user-management')
export class UsersController {
  ...
}

Define path

NestJS: Controllers

@Controller('/user-management')
export class UsersController {
  @Get()
  getAllUsers() {
    return ...
  }
}

Define Handlers

NestJS: Providers

  • DI Services
  • exports

NestJS: Providers

@Module({
  controllers: [UsersController],
  providers: [],
})
export class UsersModule {}

NestJS: Services

  • Services is Singleton
  • Need to provide service inside the module and add as an attribute in the controller
  • We can use it for:
    • communication with BD
    • formatting data
    • logging data

NestJS: Services

$ nest g service users

NestJS: Services

Time to implement base mock GET request

NestJS: base module link

https://github.com/OlegRovenskyi/be-a-hero/tree/base-module

NestJS: Postman

https://www.postman.com/downloads/

and

Postman collection

NestJS: Model

  • Provide a model for User
  • Provide Handlers for create User

NestJS:  DTO

DTO - Data Transfer Object

  • Need to control transferred data
    • Contracts
    • Validations
  • Can be Classes or Interfaces
    • Classes provide more options

NestJS:  CRUD

https://github.com/OlegRovenskyi/be-a-hero/tree/base-crud

NestJS:  Pipes

  • Routes handlers
  • Perform data transformation and data validation
  • Can throw exceptions
  • Can be async

NestJS:  Custom Pipes

  • @Injectable()
  • Must implement Pipetransform
  • transform() method accepts two params:
    • value
    • metadata (optional)

NestJS:  Custom Pipes

  • We can use it in a different way:
    • As Decorator
    • As Argument
    • useGlobalPipes

NestJS:  Validation Pipes

npm install class-validator --save

npm i class-transformer --save

NestJS:  Validation Pipes

  • Go to add
    • Validation Pipe
    • Not Found Exeption

NestJS:  Validations

Small Task

NestJS:  Validations

https://github.com/OlegRovenskyi/be-a-hero/tree/validations

PostgreSQL

Install:

PgAdmin https://www.pgadmin.org/

Docker https://www.docker.com/products/docker-desktop/

Docker

$ docker container ls

$ docker run --name postgres-nest -p 5432:5432 -e POSTGRES_PASSWORD=postgres -d postgres

$ docker container ls

$ docker stop $(docker ps -a -q)
$ docker rm $(docker ps -a -q)

To avoid local installation of Postgresql we will use Docker container.

PgAdmin

Go to PgAdmin: 

  • Create server
  • Create Database
  • Try to connect

TypeORM

https://www.npmjs.com/package/@nestjs/typeorm

$ npm i --save @nestjs/typeorm typeorm pg

TypeORM

Object Relation Mapping

  • Writing Data model in one place
  • Data types, data handling, relations 
  • No need to write SQL syntax
  • Database abstraction

https://github.com/typeorm/typeorm/blob/master/docs/active-record-data-mapper.md

TypeORM

Depricated

@EntityRepository(User)
export class UsersRepository extends Repository<User> {
}

https://docs.nestjs.com/techniques/database#repository-pattern

TypeORM

https://github.com/OlegRovenskyi/be-a-hero/tree/postgresql

Configuration

  • env variables
  • docker

ENV Variables

$ npm install -g cross-env
"start:dev": "STAGE=dev nest start --watch",

"start:dev": "cross-env STAGE=dev nest start --watch",

$ npm install @nestjs/config --save

ENV Variables

$ npm i @nestjs/config --save

ENV Variables

https://github.com/OlegRovenskyi/be-a-hero/tree/configuration

Docker

  • Docker
  • docker-compose

Deploy

  • Create Heroku app
  • Configure Circleci

Nee to add links to 'How to' docs

Deploy

  1. Create app
  2. Go to your account and copy API key
  3. Create Procfile

Heroku Configuration

Deploy

  1. Copy config

Circleci Configuration

version: 2.1
orbs:
  heroku: circleci/heroku@1.0.1
workflows:
  heroku_deploy:
    jobs:
      - heroku/deploy-via-git

2. Go to Circleci

3. Add env variables:

HEROKU_APP_NAME and HEROKU_API_KEY

Deploy

  1. Copy config
  2. Create addon
  3. Update DB config

Heroku additional configuration

Testing

https://github.com/OlegRovenskyi/be-a-hero/tree/tests

Testing

JS Doc

https://jsdoc.app/

https://dev.to/paulasantamaria/document-your-javascript-code-with-jsdoc-2fbf

TDD

Jest

  • Suites - describe
  • Specs - it or test
  • Expectation - expect

Jest

describe('A suite', () => {
    test('contains spec with n expectation', () => {
        expect(Math.max(1, 5, 10)).toBe(10);
    });
})

Jest

function sum(a, b) {
    return a + b;
}

describe('sum', () => {
    test('should be 3 when called sum with args 1 and 2', () => {
        expect(sum(1,2)).toBe(3);
    });
})

describe('A suite', () => {
    test('contains spec with n expectation', () => {
        expect(Math.max(1, 5, 10)).toBe(10);
    });
})

Jest

const mockRepository = () => ({
  getById: jest.fn(),
});

beforeEach(async () => {
  const module: TestingModule = await Test.createTestingModule({
    providers: [
      UsersService,
      {
        provide: UsersRepository,
        useFactory: mockRepository,
      },
    ],
  }).compile();

  service = module.get<UsersService>(UsersService);
  repository = module.get<UsersRepository>(UsersRepository);
});

Mocking

Jest

Coverage

Jest

e2e - check endpoints, factories etc

Thank You!

Questions?

Be A Hero

By Oleg Rovenskyi

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Be A Hero

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