Trying to connect database to backend using Docker and I get the following error: Error: getaddrinfo-CodePudding

I'm trying to make a Docker project containing Backend (express.js), GUI(Angular), and Database(MySQL)containers. Each container runs correctly individually, but when I try to make the connection between database and backend I get the following error.

The file composition of the project is the following.

My docker-compose file is the following.


version: '3.8'

services:


  gui:
    container_name: gui-container
    restart: always
    build: ./gui
    ports:
      - '4200:4200'

    environment:
      NODE_ENV: dev
      DEBUG: 'true'
    volumes:
      - ./gui:/usr/src/app/gui
      - /usr/src/app/gui/node_modules
    links:
      - backend
    command: npm run start

  backend:
    container_name: backend-container
    restart: always
    # command: sh -c "npm cache clean --force && npm start"
    build: ./backend
    ports:
      - 3000:3000
    volumes:
      - ./backend:/usr/src/app/backend
      - /usr/src/app/backend/node_modules
    environment:
      NODE_ENV: dev
      DATABASE_HOST: database
    depends_on:
      - database
    # command: npm run debug

  database: 
    build: ./database
    container_name: database-container
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    ports: 
      - 3318:3306

My config file is the following.

var mysql = require("mysql");

function DataBaseHandler() {
    this.connection = null;
}

DataBaseHandler.prototype.createConnection = function () {

    console.log("Trying to connect to database.");
    this.connection = mysql.createConnection({
        host: 'database',
        user: 'root',
        password: 'testingpassword',
        database: 'KuoteSuite',
        port: 3318
    });
    this.connection.connect(function (err) {
        if (err) {
            console.error("error connecting "   err.stack);
            return null;
        }
        console.log("connected as id "   this.threadId);
    });
    return this.connection;
};

module.exports = DataBaseHandler;

I'm trying to establish the connection inside the lead.repository.js file inside backend/repositories.

const Lead = require('../models/lead');
const mysql = require('mysql');

var DataBaseHandler = require("../config/DataBaseHandler");
var dataBaseHandler = new DataBaseHandler();

var connection = dataBaseHandler.createConnection();


const table = 'Lead';
// Repository uses Object Models to interact with Tables from Databases
class LeadRepository{

    async getAllLeads(){
        const result = await connection.query(`SELECT * FROM ${table}`);
        console.log("Leads in repository= " result);
        await connection.commit();
        return result;
    }

    

}


module.exports = LeadRepository;

CodePudding user response：

Connections between containers ignore Compose ports: (if they're present at all). In your configuration, you always need to connect to the default port: 3306; since it's the default port you can probably omit that configuration.

Also consider making these parameters configurable via environment variables, since they'll be different in different environments. For instance, the connection parameters will be different running the same code against the same containerized database if the application is running in a container or in a non-container development environment, and they'll be different again if you're running in a production environment with a cloud-hosted non-container database.

this.connection = mysql.createConnection({
    host: process.env.DATABASE_HOST || 'localhost',
    user: process.env.DATABASE_USER || 'root',
    password: process.env.DATABASE_PASSWORD || 'testingpassword',
    database: process.env.DATABASE_DATABASE || 'KuoteSuite',
    port: process.env.DATABASE_PORT || 3306              // not 3318
});

# Local development:
export MYSQL_HOST=localhost MYSQL_PORT=3318
npm run dev

# Compose setup:
version: '3.8'
services:
  database:
    build: ./database
    ports:                     # ignored for inter-container connections
      - '3318:3306'
  backend:
    build: ./backend
    depends_on:
      - database
    ports:
      - '3000:3000'
    environment:
      NODE_ENV: dev
      DATABASE_HOST: database
      DATABASE_PORT: '3306'    # default MySQL port, not remapped ports:

CodePudding user response：

Keep in mind docker-compose by default uses the service name as hostname. So if you want to connect with database from another container in the same docker-compose.yml file, you have to use the service name as hostname. In your case you should change your database host to: http://database instead of 127.0.0.1 in your DatabaseHandler line 11.

And port to 3318 on line 15, as you declared in your docker-compose.yml to port the database port to 3318 instead of 3306. Keep in mind that for porting the syntax is: HOST_PORT:CONTAINER_PORT.