PostgreSQL + metabase connection refused

Question

I am trying to configure postgres to run with springboot and metabase. Each service is running separately alone but when I try to put the 3 together in a docker-compose file, I am getting the following error :

 Caused by: org.postgresql.util.PSQLException: Connection to 0.0.0.0:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
metabase-container |    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:303)

However, I have mapped the port 5432 of db to the port 5432 of the metabase container.

And yet, It doesn't seem to work. Any help on this issue? (please find my docker-compose file below)

version: '2'

services:
  spring:
    image: 'realtime:latest'
    container_name: spring
    depends_on:
      - db
    environment:
      - SPRING_DATASOURCE_URL=jdbc:postgresql://db:5432/compose-postgres
      - SPRING_DATASOURCE_USERNAME=compose-postgres
      - SPRING_DATASOURCE_PASSWORD=same
      - SPRING_JPA_HIBERNATE_DDL_AUTO=update
    volumes:
      - /home/vagrant/valorisation-2.0:/app
    command: ["java", "-jar", "rtv-1.jar"] 
    mem_limit: 10g
    mem_reservation: 10g
    ports:
      - "8079:8080"
  db:
    image: 'postgres:13.1-alpine'
    container_name: db
    environment:
      - POSTGRES_USER=compose-postgres
      - POSTGRES_PASSWORD=********
      - METABASE_PASSWORD=same
    ports:
      - "8078:5432"
      - "54320:5432"
  metabase:
    container_name: metabase-container
    restart: "always"
    image: metabase/metabase
    ports:
      - "3000:3000"
      - "5432:5432"
    environment:
      - MB_DB_TYPE=postgres
      - MB_DB_DBNAME=db
      - MB_DB_PORT=5432
      - MB_DB_USER=compose-postgres
      - MB_DB_PASS=same
      - MB_DB_HOST=0.0.0.0
      - MB_ENCRYPTION_SECRET_KEY=********

Answer 1

Try changing MB_DB_HOST in the metabase environmental variables from 0.0.0.0 to db.