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mysql host not resolving with docker container for Nodejs and express – Phpmyadmin

I’m trying to use NodeJS+Express, MySQL, phpmyadmin altogether. phpmyadmin itself resolving the address by port 8183 in my situation. But whenever I’m going to connect it through with mysql js package of NodeJS. it is not working and throwing error

Error: connect ECONNREFUSED 127.0.0.1:3306

Note: I tried with few variations as host anyone didn’t work for me!

example: mysql, my_machine_ip, localhost, 0.0.0.0

nothing worked for me.

Here’s my yml file.

version : '3'

services:
  phpmyadmin:
    image: phpmyadmin/phpmyadmin
    container_name: node_pa
    links:
      - mysql
    depends_on:
      - mysql
    environment:
      PMA_HOST: mysql
      PMA_PORT: 3306
      PMA_ARBITRARY: 1
    restart: always
    ports:
      - 8183:80
  node_backend:
    container_name: node_with_pa_msql
    build: ./backend_app
    # volumes: 
    #   - ./backend_app:/usr/src/app
    links:
      - mysql
    depends_on:
      - mysql
    restart: on-failure
    ports:
      - 3004:4006
  mysql:
    image: mysql:latest
    container_name: node_mysql
    # volumes:
    #   - backend_app/db_sample:/docker-entrypoint-initdb.d
    environment:
      MYSQL_USER: user
      MYSQL_PASSWORD: user
      MYSQL_ROOT_PASSWORD: root
      MYSQL_DATABASE: default_schema

And mysqlJS connection details

// environment variables
const PORT = process.env.PORT || 4006;
const HOST = process.env.HOST || 'localhost';

// // mysql credentials
const connection = mysql.createConnection({
    host: HOST,
    user: process.env.MYSQL_USER || 'root',
    password: process.env.MYSQL_PASSWORD || 'root',
    connectTimeout: 20000
});

So, phpmyadmin is working and i can access databases/create/delete/edit by that so this assure that mysql itself also working, But right now I’m unable to connect it with mysqlJS of my nodejs app.

here’s the sample project with the problem if you would like to try on your machine project GitHub link with YAML file

Note: Check answer added a complete solution of this issue.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    Finally after a big mess, solved this issue!

    With stated above YAML file. everything is almost OK, But the main problem is order of image.

    That means I have total 3 image from them node is dependent to mysql. So first mysql must has to start so then you can get the connection of mysql and use it with your application (nodeJS). This is the reason why any host were not resolving with my implementation.

    I followd this article: https://docs.docker.com/compose/startup-order/

    and for implementation example this: https://dev.to/hugodias/wait-for-mongodb-to-start-on-docker-3h8b

    You are done! now use your desired driver

    Now

    this is node (mysqlJS) package specific. the package by itself doesn't support latest mysql and if you use latest tagged mysql mysql:latest then you may face this issue.

    Error: ER_NOT_SUPPORTED_AUTH_MODE: Client does not support authentication protocol requested by server; consider upgrading MySQL client docker mysql node

    quick solution downgrade it to lower until it works. I'm not sure about minimum version but mysql:5.6 works!

    If you want a quick starter with everything phpmyadmin,mysql,nodejs app then you can use this repo: Here


  2. 0

    I’m assuming the phpMyAdmin instance is working since you are actually passing the env var PMA_HOST and PMA_PORT correctly to the container.

    You will need to do the same for the JS application, so your docker-compose config will look like the following:

      node_backend:
    container_name: node_with_pa_msql
    build: ./backend_app
    # volumes: 
    #   - ./backend_app:/usr/src/app
    environment:
      MYSQL_HOST: mysql
      MYSQL_PORT: 3306
    links:
      - mysql
    depends_on:
      - mysql
    restart: on-failure
    ports:
      - 3004:4006

    Then in your JS code you need to get the connection information from your env variables:

    // environment variables
const PORT = process.env.MYSQL_PORT || 4006;
const HOST = process.env.MYSQL_HOST || 'localhost';

// // mysql credentials
const connection = mysql.createConnection({
    host: HOST,
    port: PORT,
    user: process.env.MYSQL_USER || 'root',
    password: process.env.MYSQL_PASSWORD || 'root',
    connectTimeout: 20000
});

    This works because when you link the mysql container, a hosts entry is added to your js container which makes the hostname mysql point to the (docker internal) ip address of the mysql container.

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