I’m building a full-stack application for a college assignment. I’m using a PostgreSQL database and NestJS with TypeORM. Throughout development, the database was dockerized and I used it without any problems. During that time, my API was running locally. Now I’m trying to dockerize the API as well, but I cannot get it to connect to the database. And worst of all, I can’t get it to log anything except for:

[Nest] 237  - 09/14/2024, 8:36:42 PM   ERROR [ExceptionHandler]
api-1     | AggregateError:
api-1     |     at internalConnectMultiple (node:net:1117:18)
api-1     |     at afterConnectMultiple (node:net:1684:7)

I’ve tried different things to make it log more verbosely, but i couldn’t get it to. Just those 4 lines.

This is my docker compose file

services:
  client:
    ...
  api:
    build:
      context: .
      dockerfile: ./apps/api/api.Dockerfile
    environment:
      JWT_SECRET: ...
      GOOGLE_KEY: ...
      DATABASE_NAME: rwa
      DATABASE_USERNAME: postgres
      DATABASE_PASSWORD: password
      DATABASE_HOST: db
    depends_on:
      db:
        condition: service_healthy
    ports:
      - '3000:3000'
  db:
    image: postgres
    environment:
      POSTGRES_PASSWORD: password
      POSTGRES_DB: rwa
    shm_size: 128mb
    healthcheck:
      test: ['CMD', 'pg_isready', '-U', 'postgres', '-d', 'rwa']
      interval: 10s
      timeout: 5s
      retries: 5
    ports:
      - '5432:5432'

This is api.Dockerfile

FROM node:lts-alpine3.19

WORKDIR /usr/src/api

COPY package*.json ./
RUN npm install

COPY . .
EXPOSE 3000

CMD [ "npx", "nx", "serve", "api", "--host", "0.0.0.0"]

This is the part of the code where i connect to the db

@Module({
  imports: [
    ...
    TypeOrmModule.forRoot({
      type: 'postgres',
      host: process.env.DATABASE_HOST ?? 'localhost',
      port: 5432,
      username: process.env.DATABASE_USERNAME,
      password: process.env.DATABASE_PASSWORD,
      database: process.env.DATABASE_NAME,
      entities: [
        ...
      ],
      synchronize: true,
    }),
    ...
  ]
  ...
})
export class AppModule {}

I’ve tried setting up a Docker network, checked if process.env.DATABASE_HOST has no value, and tried using 'localhost' instead of process.env.DATABASE_HOST ?? 'localhost'. Nothing helped. I’ve used the docker exec command to ping the database from the API container, and it was successful, which is why I think this is a problem with TypeORM. After the API failed to connect from the container to the database, I tried connecting locally, and it was successful.