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

Answer 1

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

Answer 2

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'.