Docker Compose : NodeJS + MongoDB

Question

I can't make my docker compose work.

Here's my dockerfile:

FROM node:0.12
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev
RUN mkdir /myapp
WORKDIR /myapp
ADD . /myapp
RUN npm install

My docker-compose.yml

db:
  image: mongo
  ports:
    - 27017
web:
  build: .
  command: npm start
  volumes:
    - .:/myapp
  ports:
    - 3000:3000
  links:
    - db
  environment:
    PORT: 3000

And in server.js:

  var MONGO_DB;
  var DOCKER_DB = process.env.DB_1_PORT;
  if ( DOCKER_DB ) {
    MONGO_DB = DOCKER_DB.replace( "tcp", "mongodb" ) + "/dev_db";
  } else {
    MONGO_DB = process.env.MONGODB;
  }

  mongoose.connect(MONGO_DB);

as from duplicated from this repo: https://github.com/projectweekend/Node-Backend-Seed but process.env.DB_1_PORT is empty. How can I add it?

Thanks

Augustin Riedinger · Accepted Answer · 2017-09-11 15:48:32Z

25

Sorry @gettho.child, I accepted your answer too quickly. I thought it was working but it wasn't. I'll report here my final solution since I have been struggling quite some to achieve it.

Dockerfile:

FROM node:0.12
RUN apt-get update -qq && apt-get install -y build-essential libpq-dev libkrb5-dev
RUN mkdir /myapp
WORKDIR /myapp
ADD package.json /myapp/package.json
RUN npm install
ADD . /myapp

docker-compose.yml:

db:
  image: mongo
  ports:
    - "27017:27017"
  command: "--smallfiles --logpath=/dev/null"
web:
  build: .
  command: node app.js
  volumes:
    - .:/myapp
  ports:
    - "3000:3000"
  links:
    - db
  environment:
    PORT: 3000 # this is optional, allows express to use process.env.PORT instead of a raw 3000

And the interesting app.js extracts:

var MONGO_DB;
var DOCKER_DB = process.env.DB_PORT;
if ( DOCKER_DB ) {
  MONGO_DB = DOCKER_DB.replace( 'tcp', 'mongodb' ) + '/myapp';
} else {
  MONGO_DB = process.env.MONGODB;
}
var retry = 0;
mongoose.connect(MONGO_DB);

app.listen(process.env.PORT || 3000);

Regarding the process.env.DB_PORT I've tried many things around. If it doesn't work out-of-the-box, I suggest to console.log(process.env); and look for mongo's IP.

The final URL should look like: mongodb://172.17.0.76:27017/myapp

Good luck, it is worth it, Docker's awesome!

EDIT:

If the above works, I now found a techno-agnostic workflow by running:

docker-compose run web /bin/bash
and in there running printenv

I hope this is not too much self promotion but I wrote a double article on the topic which may help some of the readers: https://augustin-riedinger.fr/en/resources/using-docker-as-a-development-environment-part-1/

Cheers

edited Sep 11, 2017 at 15:48

answered Oct 7, 2015 at 15:34

Augustin Riedinger

22.4k33 gold badges150 silver badges220 bronze badges

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8 Comments

GHETTO.CHiLD Over a year ago

the port under environment should be declared like PORT=3000, that turns it into an environment variable on build. you can test by going echo $PORT which should produce 3000.

Augustin Riedinger Over a year ago

Yep, that's what I commented in the docker-compose.yml: # this is optional, allows express to use process.env.PORT instead of a raw 3000

Leon Over a year ago

I think what @GHETTO.CHiLD is saying is that PORT: 3000 should be - PORT=3000. My apologies I dont know how to format this answer.

rndstr Over a year ago

@GHETTO.CHiLD both ways work docs.docker.com/v1.8/compose/yml/#environment

StanislavL Over a year ago

About the final URL. It could be mongodb://<db image name>:27017/myapp in your case mongodb://db:27017/myapp should work. +1 for the great question and answer.

|

Asher A · Accepted Answer · 2017-02-19 10:49:10Z

1

Make sure that mongoDB IP (and port) in your 'Server.js' file is set to 'PORT_27017_TCP_ADDR' (check port too) - can be found when running 'docker exec {web app container id} env'.

answered Feb 19, 2017 at 10:49

Asher A

3492 silver badges5 bronze badges

1 Comment

Augustin Riedinger Over a year ago

Indeed. Now I don't bother anymore. I run docker-compose run web /bin/bash and make printenv of whatever in the container!

Roman · Accepted Answer · 2022-02-05 21:02:52Z

0

Since we use docker-compose.yml and for reliable connection web service with db (mondoDB in this case) the final MONGO_DB connection string should look like (without authorization and additional args) as the following:

mongodb://db:27017/myapp

where:

db - name of the docker-composer MongoDB service
myapp - name of the mongoDB database

More see here

answered Feb 5, 2022 at 21:02

Roman

22.3k18 gold badges103 silver badges105 bronze badges

1 Comment

Augustin Riedinger Over a year ago

Correct. this was visible in the comments but indeed it is better to have a proper answer for this. Cheers

GHETTO.CHiLD · Accepted Answer · 2015-10-07 16:04:58Z

0

Your docker-compose should be

environment:
   - MONGODB=3000

See this link for more information on mapping environment variables. You are declaring the environment variable as PORT instead of MONGODB.

edited Oct 7, 2015 at 16:04

answered Sep 2, 2015 at 18:46

GHETTO.CHiLD

3,4161 gold badge26 silver badges36 bronze badges

2 Comments

Augustin Riedinger Over a year ago

Not sure of why it should work, but it actually does.

Augustin Riedinger Over a year ago

In fact it didn't, sorry. I reported my answer.

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