Docker Assignments #13: Node.js, MySQL, Express, Nodemon and Docker Compose

Docker Compose is a tool in the form of YAML configuration to run multi-container docker applications. With a single command, we can start or stop all the services specified in YAML configuration.

Docker Compose is a 3 step process

1. Define app configuration using Dockerfile
2. Define the services that app requires in docker-compose.yml so they can be run together in an isolated environment
3. Run docker-compose up to starts and runs entire app

In the previous article (http://millionvisit.blogspot.com/2020/05/docker-assignments-12-nodejs-mysql.html) we had written docker run command to spin up "mysql" instance. But, In this article we are going to spin up "mysql" instance by using docker-compose.yml file

Create a folder structure as per below image in the host machine

1. Add "mysql" and "express" npm packages as a dependency in the package.json file
2. Add "nodemon" npm package as a dev dependency in the package.json file
3. configure npm start command as "nodemon -L index.js" in package.json
4. Write required code into index.js file to connect "mysql" container and expose endpoint using      express.js
5. Configure Dockerfile with below instructions

• set base image as "mhart/alpine-node"
• set working directory  as "/usr/app"
• copy all files from host machine and do npm install
• set CMD command to execute npm run start

     6. Write following instructions in docker-compose yml file 

• Configure "testmysql-service" service by pulling "mysql:5.7" image, set "MY_SQL_ROOT_PASSWORD" as "mysql123" and port mapping - 3306
• Configure "testnodeexpress-service" service by specifying build context as Dockerfile, create bindmount to /usr/app container path, volume mount to /usr/app/node_modules, dependent on "testmysql-service" and link to "testmysql-service"

     7. Spin up containers using docker-compose up command

     8. check http://localhost:9030

Step 1: 

     > npm install mysql

     > npm install express

Step 2: 

     > npm install -D nodemon

Step 3: 

  "scripts": {

    "start": "nodemon -L index.js"

  }

Step 4: 

var express = require('express');

var mysql=require('mysql');

var app = express();

app.get('/mysql', function (req, res) {

    var con = mysql.createConnection({

        host: "testmysql",

        user: "root",

        password: "mysql123",

        port:"3306",

      });

      con.connect(function(err) {

        if (err) throw err;

        res.send("mysql connected successfully");      

      });

});

app.listen(9030, function () {

    console.log('App listening on port 9030!');

});

Step 5:

FROM mhart/alpine-node

WORKDIR /usr/app

COPY package*.json ./

RUN npm install

COPY . .

EXPOSE 9030

CMD ["npm", "run", "start"]

Step 6:

version: '3'

services:

    testnodeexpress-service:

      build: .

      volumes:

        - .:/usr/app 

        - /usr/app/node_modules       

      environment:

        NODE_ENV: development  

      ports:

        - 9030:9030

      command: npm run start

      depends_on: 

        - testmysql-service

      links: 

        - "testmysql-service:testmysql"  

    testmysql-service:

      image: mysql:5.7      

      environment: 

        MYSQL_ROOT_PASSWORD: mysql123  

      ports: 

        - 3306:3306  

Step 7:

> docker-compose up

Source Code available under https://github.com/ramasubbareddy1224/dockercompose-node-mysql-express-nodemon

Happy Coding :)