docker-compose: Connect to mongodb using node - node.js

Question

I'm looking for some help on how I can connect to a mongodb using node in two different containers.
I have three services set up in my docker compose:
webserver (irrelevant to question)
nodeJs
mongo database
The nodejs container is essentially an api which I can use to communicate with mongodb:
require('dotenv').config();
const express = require('express');
const cors = require('cors')
const app = express();
var MongoClient = require('mongodb').MongoClient;
var mongodb = require('mongodb');
app.use(express.json())
app.use(cors())
app.post('/api/fetch-items', (req, res) => {
if (req.headers.apikey !== process.env.API_KEY) return res.sendStatus(401)
// URL is in the format: mongodb://user:pwd#database:27017
MongoClient.connect(process.env.MONGODB_URL, function(err, db) {
if (err) return res.status(500).send(err);
var dbo = db.db("db");
dbo.collection("col").find({}).toArray(function(err, result) {
if (err) return res.status(500).send(err);
db.close();
return res.status(200).send(result);
});
});
})
app.listen(4000)
This all works perfectly fine if I run node as a standalone container (not using docker-compose) and use localhost in the URL.
However, when I use the image in docker-compose I receive the response:
{
"name": "MongoNetworkError"
}
when sending a request to the API.
I am currently using the hostname 'database' in the URL and this does not work. I have also tried using localhost.
There are also no errors as a result of the command node server.
If needed my Dockerfile for the node server is:
FROM node:10-alpine
RUN mkdir -p /home/node/app/node_modules && chown -R node:node /home/node/app
WORKDIR /home/node/app
COPY package*.json ./
RUN chown node:node ./package*.json
USER node
RUN npm install
COPY --chown=node:node . .
EXPOSE 4000
CMD [ "node", "server" ]
My docker-compose.yml file:
version: "3.1"
services:
mongodb:
image: mongo
restart: always
container_name: database
ports:
- 27017:27017
environment:
MONGO_INITDB_ROOT_USERNAME: root
MONGO_INITDB_ROOT_PASSWORD: xxxxxxxx
# Web server stuff
node:
image: created-node-server
container_name: node
ports:
- 4000:4000
Finally, the output of docker network inspect:
[
{
"Name": "network_default",
"Id": "3e51a90a23f2785cfc405243ad4c73991852f52826fd1cd0b14da5d4eaa180e4",
"Created": "2021-01-12T01:07:42.656013002Z",
"Scope": "local",
"Driver": "bridge",
"EnableIPv6": false,
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "172.23.0.0/16",
"Gateway": "172.23.0.1"
}
]
},
"Internal": false,
"Attachable": true,
"Ingress": false,
"ConfigFrom": {
"Network": ""
},
"ConfigOnly": false,
"Containers": {
"418876a06c3f8fa430804ae77c66cca986a49dbc88374266346463f7f448baa7": {
"Name": "database",
"EndpointID": "ac08c5a439edd43e612723d269714e9dfbae29dbdb50790b61c66207287d70c8",
"MacAddress": "02:42:ac:17:00:04",
"IPv4Address": "172.23.0.4/16",
"IPv6Address": ""
},
"7b6dcbb8f76618575c988a026ac0308075a116f79a2e58d8a146e33fb5d7674c": {
"Name": "node",
"EndpointID": "e6beb412a2fe97ae7d04d2484a7ca3634bfa37c82680becc412d1f44502da72f",
"MacAddress": "02:42:ac:17:00:03",
"IPv4Address": "172.23.0.3/16",
"IPv6Address": ""
},
"f2ea250bccdb2c6a0c4d7818912ddbf29196eff072dad699e8dbcef466cd38a3": {
"Name": "webserver",
"EndpointID": "f6617aab4001032069e68300c5303fa730f3458e2fe0092ace45a9f67e16d7c5",
"MacAddress": "02:42:ac:17:00:02",
"IPv4Address": "172.23.0.2/16",
"IPv6Address": ""
}
},
"Options": {},
"Labels": {
"com.docker.compose.network": "default",
"com.docker.compose.project": "proj",
"com.docker.compose.version": "1.27.4"
}
}
]
Essentially, I am retrieving the MongoNetworkError when trying to communicate with mongodb through node, both of which are docker containers created using docker-compose.
I hope all the above makes sense, sorry if it is a bit wordy, I have tried to include as much info as possible. Comment if you need any more info
Thanks :)

Answer 1

You just need to include an environmental variable under the node service MONGODB_URL=mongodb://database:27017