Error while connecting node to mongodb using docker - docker

Question

i'm getting this error while connecting node to mongodb:
techworld-js-docker-demo-app-mongo-express-1 | Could not connect to database using connectionString: mongodb://admin:password#mongodb:27017/"
techworld-js-docker-demo-app-mongo-express-1 | (node:7) UnhandledPromiseRejectionWarning: MongoNetworkError: failed to connect to server [mongodb:27017] on first connect [Error: connect ECONNREFUSED 172.19.0.3:27017
techworld-js-docker-demo-app-mongo-express-1 | at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1144:16) {
techworld-js-docker-demo-app-mongo-express-1 | name: 'MongoNetworkError'
techworld-js-docker-demo-app-mongo-express-1 | }]
techworld-js-docker-demo-app-mongo-express-1 | at Pool.<anonymous> (/node_modules/mongodb/lib/core/topologies/server.js:441:11)
techworld-js-docker-demo-app-mongo-express-1 | at Pool.emit (events.js:314:20)
techworld-js-docker-demo-app-mongo-express-1 | at /node_modules/mongodb/lib/core/connection/pool.js:564:14
techworld-js-docker-demo-app-mongo-express-1 | at /node_modules/mongodb/lib/core/connection/pool.js:1000:11
techworld-js-docker-demo-app-mongo-express-1 | at /node_modules/mongodb/lib/core/connection/connect.js:32:7
techworld-js-docker-demo-app-mongo-express-1 | at callback (/node_modules/mongodb/lib/core/connection/connect.js:300:5)
techworld-js-docker-demo-app-mongo-express-1 | at Socket.<anonymous> (/node_modules/mongodb/lib/core/connection/connect.js:330:7)
techworld-js-docker-demo-app-mongo-express-1 | at Object.onceWrapper (events.js:421:26)
techworld-js-docker-demo-app-mongo-express-1 | at Socket.emit (events.js:314:20)
techworld-js-docker-demo-app-mongo-express-1 | at emitErrorNT (internal/streams/destroy.js:92:8)
techworld-js-docker-demo-app-mongo-express-1 | at emitErrorAndCloseNT (internal/streams/destroy.js:60:3)
techworld-js-docker-demo-app-mongo-express-1 | at processTicksAndRejections (internal/process/task_queues.js:84:21)
techworld-js-docker-demo-app-mongo-express-1 | (node:7) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
Docker-compose.yaml file :
version: '3'
services:
my-app:
image: nihalchandra/myapp:4.0
ports:
- 3000:3000
mongodb:
image: mongo
restart: always
ports:
- 27017:27017
environment:
- MONGO_INITDB_ROOT_USERNAME=admin
- MONGO_INITDB_ROOT_PASSWORD=password
volumes:
- mongo-data:/data/db
mongo-express:
image: mongo-express
restart: always # fixes MongoNetworkError when mongodb is not ready when mongo-express starts
ports:
- 8081:8081
environment:
- ME_CONFIG_MONGODB_ADMINUSERNAME=admin
- ME_CONFIG_MONGODB_ADMINPASSWORD=password
- ME_CONFIG_MONGODB_SERVER=mongodb
volumes:
mongo-data:
driver: local
done this in server.js file:
let mongoUrlLocal = "mongodb://admin:password#localhost:27017";
let mongoUrlDocker = "mongodb://admin:password#mongodb";
i tried changing the server but it still didnt work

Answer 1

You should add into your my-app definition a link to database:
my-app:
image: nihalchandra/myapp:4.0
ports:
- 3000:3000
links:
- mongodb:mongodb
Then your application will be able to connect to MongoDB using mongodb as a hostname.
More details about this you can find in documentation: https://docs.docker.com/compose/networking/