I get port in use error when I try to run the docker container for the nodejs and mysql application using the docker-compose

Question

How can I use the docker-compose to create container and pass the parameter to my Node.js application during the start?

I am trying to write a program where I can connect MYSQL using the NODEJS and using the DOCKER-COMPOSE. I need to run the application in the terminal so that I can pass some parameters to my Node.js application during the start hence I need to run the DOCKER-COMPOSE UP to bring up the application and MYSQL then I want to run the application using the CLI in another window.

Here is my index.js file present within web folder which will take the input from the user when I run with following command nodemon start New .

     //Make NodeJS to Listen to a particular Port in Localhost
const   port        =   9010; 
     app.listen(port, function(){
        // Start the server and read the parameter passed by User
        console.log("Node js is Running on : "+port);
        // Get process.stdin as the standard input object.
        var standard_input = process.stdin;

        // Set input character encoding.
        standard_input.setEncoding('utf-8');

        // Prompt user to input data in console.
        console.log("Please input text in command line.");

        // When user input data and click enter key.
        standard_input.on('data', function (data) {
            console.log(" DATA ENTERED BY USER IS :"+data);
        });
    });

I want to achieve this using the docker-compose hence I have the following code for docker-compose.yml file.

version: '3'

services:
  db:
    build: ./db
    environment:
      MYSQL_DATABASE: mydb
      MYSQL_ROOT_PASSWORD: mypass
      MYSQL_USER: mysql
      MYSQL_PASSWORD: mypass
      DATABASE_HOST: myhost
  web:
    build: ./web
    depends_on:
      - db
    restart: on-failure
    ports:
      - "9010:9010"

  adminer:
    image: adminer
    restart: always
    ports:
      - "7778:8080"

My Dockerfile for the web or Node.js within web folder is:

FROM node:8

WORKDIR /usr/src/app

COPY package*.json ./

RUN npm install

COPY . .

EXPOSE 9010

CMD ["npm","start"]

My Dockerfile for the database MYSQL within db folder is:

FROM mysql:5.7

EXPOSE 3306

COPY ./scripts /docker-entrypoint-initdb.d/

Now when I run the command docker-compose up --build for the docker-compose.yml file then everything works fine; the container and Node.js application gets started.

When I open another terminal window and try to navigate to web container using docker-compose exec web sh and start the node application to pass the parameters nodemon start New then I get the following error.

events.js:183
      throw er; // Unhandled 'error' event
      ^

Error: listen EADDRINUSE :::9010
    at Server.setupListenHandle [as _listen2] (net.js:1360:14)

Since the Nodejs application is already running when I ran the command docker-compose up --build the port is already asssigned so I am getting this error how can I start the Indey.js application and pass parameters to it?

I am using Ubuntu Os for the application.

Answer 1

The reason is that there is already running nodejs application that run from CMD and occupied the port, so when run command inside docker you get the EDDRINUSE error.

You will multiple options,

• Do not start the node application from CMD of docker but you will not notice when the nodejs process down inside container. But this can be the option to deal with, so change CMD in node Dockerfile

CMD ["npm","start"]
#change the above cmd to
CMD tail -f /dev/null

This will just keep your nodejs container running and then run the command inside the container.

docker-compose exec web sh
nodemon start New

• Change the port for the script that you run manually so there will be no conflict as the script will start on a different port,

Update the nodejs code a bit

//Make NodeJS to Listen to a particular Port in Localhost
const   port        =   process.env.PORT; 

Now start the process with different port

PORT=9011 nodemon start New