MongoNetworkError when connecting from different container - mongodb

Question

PHP dev new to NodeJS and I am struggling to get my NodeJS container to connect to my MongoDB container. As far I can see I have all the correct NPMs installed in my Docker file and the docker-compose is correct. Please note that I have not added the containers to the same network or but in the link to the db service into the nodejs container, although I did try this and got pretty much the same result.
Unsure why I am getting the error below when I bash into the nodejs container and run node app.js
Error
[nodemon] clean exit - waiting for changes before restart
[nodemon] restarting due to changes...
[nodemon] starting `node app.js`
(node:92) DeprecationWarning: current Server Discovery and Monitoring engine is deprecated, and will be removed in a future version. To use the new Server Discover and Monitoring engine, pass option { useUnifiedTopology: true } to the MongoClient constructor.
Server is listening on port 3000
Could not connect to the database. Exiting now... { MongoNetworkError: failed to connect to server [localhost:27017] on first connect [MongoNetworkError: connect ECONNREFUSED localhost:27017]
at Pool.<anonymous> (/usr/src/app/node_modules/mongodb/lib/core/topologies/server.js:431:11)
at Pool.emit (events.js:193:13)
at createConnection (/usr/src/app/node_modules/mongodb/lib/core/connection/pool.js:559:14)
at connect (/usr/src/app/node_modules/mongodb/lib/core/connection/pool.js:973:11)
at makeConnection (/usr/src/app/node_modules/mongodb/lib/core/connection/connect.js:39:11)
at callback (/usr/src/app/node_modules/mongodb/lib/core/connection/connect.js:261:5)
at Socket.err (/usr/src/app/node_modules/mongodb/lib/core/connection/connect.js:286:7)
at Object.onceWrapper (events.js:281:20)
at Socket.emit (events.js:193:13)
at emitErrorNT (internal/streams/destroy.js:91:8)
at emitErrorAndCloseNT (internal/streams/destroy.js:59:3)
at processTicksAndRejections (internal/process/task_queues.js:81:17)
name: 'MongoNetworkError',
errorLabels: [ 'TransientTransactionError' ],
[Symbol(mongoErrorContextSymbol)]: {} }
docker-compose.yml
version: '3.5' # We use version 3.5 syntax
services: # Here we define our service(s)
frontend:
container_name: angular
build: ./angular_app
volumes:
- ./angular_app:/usr/src/app
ports:
- 4200:4200
command: >
bash -c "npm install && ng serve --host 0.0.0.0 --port 4200"
depends_on:
- api
# NodeJS/Express service for API
api:
image: nodeexpress
build:
context: ./node_server
dockerfile: Dockerfile
volumes:
- ./node_server:/usr/src/app
- /usr/src/app/node_modules
ports:
- 3000:3000
links:
- mongoservice
depends_on:
- mongoservice
# Mongo database service
mongoservice:
image: mongo
container_name: mongocontainer
restart: always
environment:
MONGO_INITDB_ROOT_USERNAME: ${DB_MONGO_ROOTUSER}
MONGO_INITDB_ROOT_PASSWORD: ${DB_MONGO_ROOTPWD}
ports:
- ${DB_MONGO_EXTERNAL_PORT}:${DB_MONGO_INTERNAL_PORT}
volumes:
- ${DB_MONGO_VOLUME1}
volumes:
data:
external: true
networks:
default:
driver: bridge
Dockerfile (for api service - nodejs express)
FROM node:11-alpine
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app
COPY . .
RUN npm install
#RUN npm install mysql
RUN npm install mongodb --save
#RUN npm install --save body-parser express mysql2 sequelize helmet cors
RUN npm install --save body-parser express mongoose helmet cors
RUN npm install --save nocache
RUN npm install nodemon --save
EXPOSE 4300
#CMD ["npm", "run", "start"]
CMD [ "npm", "run", "start.dev" ]
app.js
const express = require('express');
const bodyParser = require('body-parser');
// create express app
const app = express();
// parse requests of content-type - application/x-www-form-urlencoded
app.use(bodyParser.urlencoded({ extended: true }))
// parse requests of content-type - application/json
app.use(bodyParser.json());
// Configuring the database
const dbConfig = require('./config/database.config');
const mongoose = require('mongoose');
mongoose.Promise = global.Promise;
// Connecting to the database
// Connection string variants attempted
// mongodb://root:secret#0.0.0.0:27017/angapp2
// mongodb://root:secret#127.0.0.1:27017/angapp2
// mongodb://root:secret#mongoservice:27017/angapp2
mongoose.connect('mongodb://root:secret#localhost:27017/angapp2', {
useNewUrlParser: true
}).then(() => {
console.log("Successfully connected to the database");
}).catch(err => {
console.log('Could not connect to the database. Exiting now...', err);
process.exit();
});
// define a simple route
app.get('/', (req, res) => {
res.json({"message": "Welcome to EasyNotes application. Take notes quickly. Organize and keep track of all your notes."});
});
// Require Notes routes
require('./routes/note.routes.js')(app);
// listen for requests
app.listen(3000, () => {
console.log("Server is listening on port 3000");
});
What I've tried:
Attempted the various connection string variants in terms of the host name, i.e. localhost, 127.0.0.1, 0.0.0.0, mongoservice
Also ran docker inspect <container-id> on the mongo service and got the internal IP address of the container and tried that in the connection string
Added RUN npm install mongodb --save to node servers Dockerfile
Managed to connect Robo 3D GUI to the Mongo container without issue
Bashed into Mongo service and managed to log into the DB and run some statements as a test that the service was working fine.

Answer 1

Maybe its just me being blind but, it seems that you are trying to connect to your Database on Port 27017 but in your Docker-Compose File you set the Port of the Database to 8081. Try Matching the ports.