Connection refused (Connection refused) while trying to connect between docker containers

Question

Trying to establish connection from app container to mysql container in localhost, getting connection refused exception

We are taking a docker approach to call rest api services to adopt microservice approach. We are establishing connection between app container and mysql container While doing so we have written a docker-compose file created mysql container and application container, exposed ports for both containers. Following is command for running docker-compose file docker-compose up.

docker-compose.yml file

version: '3'

services: docker-mysql: image: mysql:latest container_name: mysql-server environment: - MYSQL_ROOT_PASSWORD=abc123 - MYSQL_DATABASE=fitapp - MYSQL_PASSWORD=root ports: - 3307:3306

spring-webap:
    build:
        dockerfile: Dockerfile
        context: .
    image: fitapp:1.0
    depends_on:
      - docker-mysql
    ports:
      - 8092:8080


spring-webap_1  | Caused by: java.net.ConnectException: Connection refused

Answer 1

From what I could see below will be your docker-compose.yml (have changed the password for better understanding)

version: '3'
services:
  docker-mysql:
    image: mysql
    ports:
        - "3301:3306"
    environment:
        - MYSQL_USER=root
        - MYSQL_DATABASE=fitapp
        - MYSQL_ROOT_PASSWORD=pass
        - MYSQL_PASSWORD=pass
  spring-webap:
    build:
      dockerfile: Dockerfile
      context: .
    image: fitapp:1.0
    depends_on:
      - docker-mysql
    ports:
      - 8092:8080

The spring application.properties / application.yml should be like below

    driverClassName: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://docker-mysql:3301/fitapp
    username: root
    password: pass

Check that, if you have given localhost in url it will not work as the MySql and Spring service are running in different container.It should be linked or in a same network