docker-compose NodeJS + Mongodb with mongoose, dynamically get the mongo container ip
docker, docker-compose, express, mongodb, node.js
Solution
Check out Networking section in Docker Compose Manual. Especially this interesting paragraph:
Each container can now look up the hostname web or db and get back the appropriate container’s IP address. For example, web’s application code could connect to the URL postgres://db:5432 and start using the Postgres database.
So given your example, you can freely change line
mongoose.connect('mongodb://172.19.0.2/test');
to line
mongoose.connect('mongodb://mongo/test');
Problem
I have a dockerized nodejs app linked with a mongo container. Here is the dockerfile and docker-compose.yml : ``` FROM node:boron # Create app directory RUN mkdir -p /usr/src/app WORKDIR /usr/src/app # Install app dependencies COPY package.json /usr/src/app/ RUN npm install # Bundle app source COPY . /usr/src/app EXPOSE 3000 CMD [ "npm", "start" ] ``` ``` version: "2" services: web: build: . volumes: - .:/usr/src/app ports: - "3000:3000" links: - mongo mongo: image: mongo ports: - "27017:27017" ``` and here is my app.js handling the mongo connection via the mongoose tool : ``` var express = require('express'); var path = require('path'); var favicon = require('serve-favicon'); var logger = require('morgan'); var cookieParser = require('cookie-parser'); var bodyParser = require('body-parser'); var mongoose = require('mongoose'); var index = require('./routes/index'); var users = require('./routes/users'); var app = express(); // view engine setup app.set('views', path.join(__dirname, 'views')); app.set('view engine', 'ejs'); //DB setup mongoose.connect('mongodb://172.19.0.2/test'); // uncomment after placing your favicon in /public //app.use(favicon(path.join(__dirname, 'public', 'favicon.ico'))); app.use(logger('dev')); app.use(bodyParser.json()); app.use(bodyParser.urlencoded({ extended: false })); app.use(cookieParser()); app.use(express.static(path.join(__dirname, 'public'))); app.use('/', index); app.use('/users', users); // catch 404 and forward to error handler app.use(function(req, res, next) { var err = new Error('Not Found'); err.status = 404; next(err); }); // error handler app.use(function(err, req, res, next) { // set locals, only providing error in development res.locals.message = err.message; res.locals.error = req.app.get('env') === 'development' ? err : {}; // render the error page res.status(err.status || 500); res.render('error'); }); module.exports = app; ``` My app launches, if I go on http://localhost:3000 on my computer my view displays and in my terminal I see that mongo accepted a connection. Problem is : In my app.js I added manually the mongo container ip. I believe if I push this app on github and someone gets it. His mongo container ip won't be the same as the one i added manually. Is there some way to dynamise all of this so that my app gets automatically the mongo container ip?