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Dockerize a Node.js app with VS Code

Vladislav Guleaev on June 23, 2019

Hello dear coder, welcome to my tech articles series dedicated to Node.js and Docker. Hope you enjoy! Problem: You have never used Dock...

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Bassem • Jun 24 '19

Great article 👏, I remember wanting to dockerize a NodeJS server before. I managed to do it, but I struggled with the mysql database.

Ummm, Interesting topic for a future article maybe? Just saying 🖐️😂

Vladislav Guleaev • Jun 24 '19

I plan to do the same but with MongoDb :) thank you for the feedback

Henry Quinn • Jun 24 '19

What exactly are you having problems with, @Bassem?

Bassem • Jun 24 '19

I read about it online for a while first. Everyone was saying that it is better to have the database as a standalone image. So I got myself an Ubuntu MySQL dockerfile off the internet to create that DB image.

Now I have 2 images, one for the NodeJS server and another for MySql DB.

But, I can't connect them both. I even tried accessing the database using phpmyadmin from outside the docker container and failed.

In my docker-compose, I created a network, set both images on the same network. and added the links: - db:db to make the backend server depend on the database.

I know that the network is fine. because I have a third frontend server image and it can communicate with the backend successfully.

Henry Quinn • Jun 24 '19

For the PHPMyAdmin bit, are you exposing a port on the DB image? If you put two images on a Docker network like that, they just talk to everything on that network. You have to explicitly expose a port to have that container talk to anything "local" not on that network.

Henry Quinn • Jun 24 '19

For the Node -> DB bit, do you mind sharing your docker-compose.yaml and the connection string you're using in your Node container?

Bassem • Jun 24 '19

Yeah sure, No problem!

version: "2"

networks:
  app-tier:
    driver: bridge

services:
  # Mysql database
  frostdb:
    image: frost/db
    hostname: frostdb

    networks:
      - app-tier
    ports:
      - "3306:3306"

  # NodeJS backend server
  frostback:
    image: frost/back
    hostname: frostback

    networks:
      - app-tier
    links:
      - frostdb:frostdb
    depends_on:
      - frostdb
    ports:
      - "49160:8080"

  # Frontend server
  frostgui:
    image: frost/gui
    hostname: frostgui

    links:
      - frostback:frostback
    ports:
      - "49170:3000"

I think that I am exposing ports using the "3306:3306". and for the backend config, I have a .env file

NODE_ENV=development

DB_TYPE=mysql
DB_NAME=frost
DB_HOST=localhost
DB_USER=USER
DB_PASSWORD=PASS
DB_PORT=3306

Actually, I have no idea what the username/password for the DB should be. But that's not the issue anyway according to the logs.

Henry Quinn • Jun 24 '19

You're correct that you're exposing port 3306.

Your ENV file looks good, but what about the line of code that's using those ENV variables?

Comment deleted

Bassem • Jun 25 '19

I am using a package called Sequelize for connecting to the DB and here is how :

const url = `${process.env.DB_TYPE}://${process.env.DB_USER}:${
      process.env.DB_PASSWORD
    }@${process.env.DB_HOST}:${process.env.DB_PORT}/${process.env.DB_NAME}`;
    this.db = new Sequelize(url, {
      define: {
        charset: "utf8mb4",
        collate: "utf8mb4_general_ci",
        timestamps: true
      }
    });

Running docker-compose up produces this error :

Unhandled rejection SequelizeConnectionRefusedError: connect ECONNREFUSED 127.0.0.1:3306

Could it be that the DB is not yet up and running?

Henry Quinn • Jun 25 '19 • Edited

I mean, could be. Have you tried using Kitematic or docker exec -it <container name> /bin/bash?

Also, what is your output for docker ps -a when you have your compose file spun up?

Edit: I see a couple things that could be at fault here, but I want to see the answer to those two questions before I take a stab at it. ^{^}

Henry Quinn • Jun 26 '19

I'd consider updating your docker-compose.yaml to version 3.x and use the container_name item to force a name on your container.

Then, in your ENV file, use whatever you set that container_name to DB_HOST. I understand why you're trying to use localhost, but if all of these containers are on one Docker network, they'll want to refer to each other by their container names.

Bassem • Jun 26 '19

I feel like i need to have a better understanding of docker.

Definitely will try doing that and will update you.

Henry Quinn • Jun 26 '19

We all start somewhere, my dude. :)

Vladislav Guleaev • Jun 28 '19

Hello man, I created next part of series, you should see it 🖐️

Bassem • Jun 28 '19

Will do, definitely 👍

pclewisnz • Dec 18 '20

I failed at the second hurdle. Some pre-requisite knowledge that you have not explained. For a topic that appeared to be aimed at new docker user and using Windows system with VS Code as I have, I did not expect to be stumped so soon. I have reviewed a lot of tutorials and I have found ever one of them to be missing vital information (some are outright wrong). The effort you have gone to here looked promising so I have signed up to this site just to see if you still monitor this old topic and might have a response.
Here is the issue:
In the opening paragraph you write:
"Next command creates a new folder with name test-node-app, then creates npm package file and opens folder in VS Code.
mkdir test-node-app && cd test-node-app && npm init -y && code ."

Where do you type that? the syntax is wrong for powershell or command prompt and WSL doesn't know about npm so there must be some other pre-requsite knowledge or something missing in the Setup section.

Using powershell and appropriate commands to achieve the same as the linux style command line intends I have been able to continue. Perhaps though I am misisng something really important. Do you assume for example that the reader has already installed a unix VM and that they are running from that shell?

Henry Quinn • Jun 24 '19

Was there anything specific to VSCode in here?

Vladislav Guleaev • Jun 24 '19

Only Docker Extension and command line

Henry Quinn • Jun 24 '19

Word, I was gonna say I love VSCode but nothing about the editor really does any Docker stuff for me besides the Quake terminal. I have the Docker extension but it doesn't really add anything for me.

Miguel Viñas • Dec 30 '20 • Edited

Thank you so much for the article!