Docker compose with dependent mysql gives connection refused

Question

I have a simple Java application using a mysql.

This is my docker-compose.yaml :

version: '2.1'

services:
  docker-mysql:
    image: mysql:latest
    environment:
      - MYSQL_ROOT_PASSWORD=root
      - MYSQL_DATABASE=test2
      - MYSQL_PASSWORD=root
    ports:
      - 3306:3306
  my-app:
    image: 0935a6b56fe5
    depends_on:
      - docker-mysql
    ports:
      - 8080:8080
    environment:
      - DATABASE_HOST=docker-mysql
      - DATABASE_USER=root
      - DATABASE_PASSWORD=root
      - DATABASE_NAME=test2
      - DATABASE_PORT=3306

Image with id 0935a6b56fe5 is a mysql image.

And this is my application.properties :

## Server config
server.port=8080
server.tomcat.uri-encoding=utf-8
## MYSQL JPA
spring.jpa.database=MYSQL
spring.jpa.show-sql=true
spring.datasource.url=jdbc:mysql://localhost:3306/test2?characterEncoding=utf8
spring.datasource.username=root
spring.datasource.password=
spring.datasource.test-while-idle=true
spring.datasource.test-on-borrow=true
spring.datasource.validationQuery=SELECT 1
#Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto=none
spring.datasource.driverClassName=com.mysql.jdbc.Driver

When i try docker-compose up application tries to run but it gives me a Connection Refused error.

What is wrong with this?

Answer 1

Your spring.datasource.url=jdbc:mysql://localhost:3306/test2?characterEncoding=utf8 refers to localhost. Can you try spring.datasource.url=jdbc:mysql://docker-mysql:3306/test2?characterEncoding=utf8

Also the spring.datasource.password= is blank. How do you provide the password?

Answer 2

Most likely this line

spring.datasource.url=jdbc:mysql://localhost:3306/test2?characterEncoding=utf8

should read

spring.datasource.url=jdbc:mysql://docker-mysql:3306/test2?characterEncoding=utf8

because your my-app is running inside of the docker container and localhost is not what you think it is. You can access other docker containers inside of docker-compose with the name of the service you have chosen inside your docker-compose.yml .