Connecting to mongo docker container from host - node.js

Question

I'm running Docker on OS X with:
docker run --name mongo -p 27017:27017 -v ./data/db:/data/db -d mongo mongod
and using the ip I get from:
docker inspect --format '{{ .NetworkSettings.IPAddress }}' <cid>
in:
var MongoClient = require('mongodb').MongoClient;
var assert = require('assert');
var url = 'mongodb://<ip>:27017';
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
db.close();
});
and I'm getting a timed out error.
I'm using the official mongo repository from Docker Hub. Is there any additional setup that I need to do in order to connect from the host?

Answer 1

Is the node.js code being run from a container or from the host?
If it's on the host, just use the localhost address i.e:
var url = 'mongodb://localhost:27017';
This will work because you published the port with -p 27017:27017.
If the code is running inside a container, it would be best to rewrite it to use links and referring to the mongo container by name e.g:
var url = 'mongodb://mongo:27017';
Then when you launch the container with the Node.js code, you can just do something like:
docker run -d --link mongo:mongo my_container
Docker will then add an entry to /etc/hosts inside the container so that the name mongo resolves to the IP of the mongo container.

Answer 2

If you use a user defined network you should be able to pick it up without linking or specifying 27017
const MONGO_NAME_STR = "mongodb://" + "your_docker_container_name";
var db = {};
mongo_client.connect(MONGO_NAME_STR, function(err, _db){
//some err handling
db = _db;
});

Answer 3

Another option for anyone who use docker-compose
version: '3.1'
services:
mongo:
image: mongo
container_name: "mongo"
restart: always
environment:
MONGO_INITDB_ROOT_USERNAME: root
MONGO_INITDB_ROOT_PASSWORD: example
volumes:
- './dockervolume/mongodb:/data/db'
ports:
- 27017:27017
And u can connect using the url string
MongoClient.connect("mongodb://root:example#localhost:27017")
.then(()=>{
console.log("db connect success");
})
.catch((err)=>{
throw err
});

Answer 4

Using docker-compose, same can be achieved as below
version: '3.1'
services:
mongo:
image: mongo
restart: always
ports:
- 27017:27017
environment:
MONGO_INITDB_ROOT_USERNAME: root
MONGO_INITDB_ROOT_PASSWORD: example
mongo-express:
image: mongo-express
restart: always
ports:
- 8081:8081
environment:
ME_CONFIG_MONGODB_ADMINUSERNAME: root
ME_CONFIG_MONGODB_ADMINPASSWORD: example
ME_CONFIG_MONGODB_URL: mongodb://root:example#mongo:27017/
The connection string is as below,
On Host -
const uri = "mongodb://root:example#localhost:27017/
On Container -
const url = 'mongodb://root:example#mongo:27017'
Port mapping can be configured to use a custom host port [8000] like - 8000:27017