I have Spring Boot 3 and Docker.

docker-compose.yml

version: '1.0'
services:
  app:
    image: 'docker-spring-boot-postgres:latest'
    build:
      context: .
      dockerfile: Dockerfile
    container_name: app
    ports:
      - "8081:8080"
    #network_mode: host
    depends_on:
      - db
    environment:
      - SPRING_PROFILES_ACTIVE=dev
      - SPRING_DATASOURCE_URL=jdbc:postgresql://db:5432/expiry_service_db
      - SPRING_DATASOURCE_USERNAME=postgres
      - SPRING_DATASOURCE_PASSWORD=postgres
      - SPRING_JPA_HIBERNATE_DDL_AUTO=update
  db:
    image: postgres:latest
    container_name: db
    restart: always
      - POSTGRES_DB=expiry_service_db
      - POSTGRES_PASSWORD=postgres
      - POSTGRES_USER=postgres
    ports:
      - "5432:5432"
    #network_mode: host
    volumes:
      - postgres_data:/var/lib/postgresql

volumes:
  postgres_data:

My application can successfully connect to my database (within the container).

Question

How do I configure it to allow a SQL client (e.g. DBeaver) to also connect to the postgres database (outside the container)?

The url is defined above as:

jdbc:postgresql://db:5432/expiry_service_db

So I guess I need to somehow map db in the url to localhost, and then connect the SQL Client via:

jdbc:postgresql://localhost:5432/expiry_service_db