Unable to connect mysql from docker container?

Question

I have created a docker-compose file it has two services with Go and Mysql. It creates container for go and mysql. Now i am running code which try

Answer 1

First, if you are using latest version of docker compose you don't need the link argument in you app service. I quote the docker compose documentation Warning: The --link flag is a legacy feature of Docker. It may eventually be removed. Unless you absolutely need to continue using it, https://docs.docker.com/compose/compose-file/#links

I think the solution is to use the networks argument. This create a docker network and add each service to it.

Try this

version: "2"
services:
  app:
    container_name: golang
    restart: always
    build: .
    ports:
      - "49160:8800"
    networks:
     - my_network
    depends_on:
      - "mysql" 

  mysql:
    image: mysql
    container_name: mysql
    volumes:
      - dbdata:/var/lib/mysql
    restart: always
    networks:
     - my_network
    environment:
      - MYSQL_ROOT_PASSWORD=root
      - MYSQL_DATABASE=testDB
      - MYSQL_USER=root
      - MYSQL_PASSWORD=root
    ports:
      - "3307:3306"
volumes:
  dbdata:
networks:
  my_network:
    driver: bridge

By the way, if you only connect to Mysql from your app service you don't need to expose the mysql port. If the containers runs in the same network they can reach all ports inside this network.

If my example doesn't works try this run the docker compose and next go into the app container using docker container exec -it CONTAINER_NAME bash Install ping in order to test connection and then run ping mysql.