Sequelizeとは

Sequelize：http://docs.sequelizejs.com/

Nest.jsにSequelizeを組み込む

公式に手順が載っているため、それに従います

なお、今回使用するDBはPostgresです。

sequelize-typescriptのインストール

sequelize、sequelize-typescript、pg（postgres）、sequelizeの型定義パッケージをインストールします

$ npm install --save sequelize sequelize-typescript pg
$ npm install --save-dev @types/sequelize

DB接続準備

公式だと接続情報はコードにべた書きですが、環境ごとにDBを切り替えられるように設定ファイルで外だしします。

src/database/database.config.ts

export const config = {
    development: {
        host: process.env.POSTGRES_HOST,
        port: process.env.POSTGRES_PORT,
        database: process.env.POSTGRES_DB_NAME,
        username: process.env.POSTGRES_USER,
        password: process.env.POSTGRES_PASSWORD,
        dialect: 'postgres',
    },
    production: {
        // TODO 本番用
    }
}

src/database/database.providers.ts

import { Sequelize } from 'sequelize-typescript';
import { Cat } from '../cats/cat.entity';
import { config } from 'src/config/database.config';

export const databaseProviders = [
    {
        provide: 'SEQUELIZE',
        useFactory: async () => {
            const sequelize = new Sequelize(
                config[process.env.NODE_ENV || 'development']
            );
            sequelize.addModels([Cat]);
            await sequelize.sync();
            return sequelize;
        },
    },
];

database.module.ts

import { Module } from '@nestjs/common';
import { databaseProviders } from './database.providers';

@Module({
  providers: [...databaseProviders],
  exports: [...databaseProviders],
})
export class DatabaseModule {}

Catsテーブルアクセス用ファイル作成

公式の手順に従って、Catsテーブルにアクセスするためのファイルを準備します。

src/cats/cats.entity.ts

import { Table, Column, Model } from 'sequelize-typescript';

@Table
export class Cat extends Model<Cat> {
  @Column
  name: string;

  @Column
  age: number;

  @Column
  breed: string;
}

src/cats/cats.providers.ts

import { Cat } from './cat.entity';

export const catsProviders = [
  {
    provide: 'CATS_REPOSITORY',
    useValue: Cat,
  },
];

src/cats/cats.module.ts

import { Module } from '@nestjs/common';
import { CatsController } from './cats.controller';
import { CatsService } from './cats.service';
import { catsProviders } from './cats.providers';
import { DatabaseModule } from '../database/database.module';

@Module({
  imports: [DatabaseModule],
  controllers: [CatsController],
  providers: [
    CatsService,
    ...catsProviders,
  ],
})
export class CatsModule {}

src/cats/cats.service.ts

import { Injectable, Inject } from '@nestjs/common';
import { Cat } from './cat.entity';

@Injectable()
export class CatsService {
  constructor(
    @Inject('CATS_REPOSITORY') private readonly CATS_REPOSITORY: typeof Cat) {}

  async findAll(): Promise<Cat[]> {
    return await this.CATS_REPOSITORY.findAll<Cat>();
  }
}

src/cats/cats.controller.ts

import { Controller, Get } from '@nestjs/common';
import { CatsService } from './cats.service';
import { Cat } from './cat.entity';

@Controller({
  path: 'cats'
})
export class CatsController {
  constructor(private readonly catsService: CatsService) {}

  @Get()
  getCats(): Promise<Cat[]> {
    return this.catsService.findAll();
  }
}

起動してみる

以下のようなdocker-compose.ymlを用意し、docker-compose upで起動してみます。

docker-compose.yml

version: '2'
services:
  nestjs-web:
    image: node:latest
    container_name: nestjs-web
    ports:
      - "3000:3000"
    links:
      - nestjs-db
    working_dir: /develop
    command: [sh, -c, 'npm install --unsafe-perm && npm run start:dev']
    volumes:
      - "./:/develop:z"
    environment:
      - "POSTGRES_HOST=192.168.33.20"
      - "POSTGRES_PORT=15432"
      - "POSTGRES_DB_NAME=postgres"
      - "POSTGRES_USER=postgres"
      - "POSTGRES_PASSWORD=postgres"

  nestjs-db:
    image: postgres:latest
    container_name: nestjs-db
    ports:
      - "15432:5432"
    environment:
      - "POSTGRES_USER=postgres"
      - "POSTGRES_PASSWORD=postgres"
    volumes:
      - "/data/db:/var/lib/postgresql/data:z"