无法将主机名“postgres”转换为地址：名称或服务未知

Question

I'm trying to run a service that depends on a postgresql database but I can't figure out how to link the two together / connect.

I'm 'depending on' the database which seems to mean I should be able to use the service name as the database host name (ie due_database ) but whenever I do I just get the error:

could not translate host name "due_database" to address: Name or service not known

What's wrong here?

version: '3'
services:
  due:
    restart: always
    build:
      context: ./
      dockerfile: ./docker/bot/Dockerfile
    command: ./due
    depends_on:
      - due_database
  due_database:
    build:
      context: ./
      dockerfile: ./docker/database/Dockerfile
    ports:
        - "5432:5432"
    environment:
      - POSTGRES_PASSWORD="docker"
    entrypoint: /entry.sh
    volumes:
      - ./.dueutil_db:/dueutil_data

Update :

version: '2.1'
services:
  due:
    restart: always
    build:
      context: ./
      dockerfile: ./docker/bot/Dockerfile
    entrypoint: /entry.sh
    command: ./due
    depends_on:
      due_database:
        condition: service_healthy
    environment:
      - PGPASSWORD="docker"
  due_database:
    image: postgres:11
    ports:
        - "5432:5432"
    environment:
      - POSTGRES_PASSWORD="docker"
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 10s
      timeout: 5s
      retries: 5
    volumes:
      - ./.dueutil_db:/var/lib/postgresql/data

I fixed the first issue by moving my create database scripts outside the postgres image, since that conflicts with the postgres entrypoint. However I still can't figure out how to connect to the database from my app's container.

I'm currently trying psql -U postgres -h due_database postgres -f <sql script> but I'm just getting:

psql: could not connect to server: Connection refused
    Is the server running on host "due_database" (172.18.0.2) and accepting
    TCP/IP connections on port 5432?

Note I did see: psql: could not translate host name "somePostgres" to address: Name or service not known but the question seems outdated & did not get any good answers.

Answer 1

Try to use network , I'm not sure but maybe it can help you :

version: '3'
# ----------------
# CREATE NEW NETWORK
networks:
  app:
    driver: bridge
# ----------------
services:
  due:
    restart: always
    build:
      context: ./
      dockerfile: ./docker/bot/Dockerfile
    command: ./due
    depends_on:
      - due_database
    # ---------------
    # SPECIFY NETWORK
    networks:
      - app
    # ---------------

  due_database:
    build:
      context: ./
      dockerfile: ./docker/database/Dockerfile
    ports:
        - "5432:5432"
    environment:
      - POSTGRES_PASSWORD="docker"
    entrypoint: /entry.sh
    volumes:
      - ./.dueutil_db:/dueutil_data
    # ---------------
    # SPECIFY NETWORK
    networks:
      - app
    # ---------------

Answer 2

So my first issue was trying to make changes to the PostgreSQL image, copy some scripts in and add a custom entry point. That overrides the postgres startup script & means the database fails to load.

The second issue was using the non-alpine postgres image. Switching to postgres:12.1-apline 'just worked'. I'm not sure what's wrong with the other image though.