Unable to use POSTGRESQL in docker container, getting ECONNREFUSED - node.js

Question

Docker file for my node app
FROM node:latest
COPY . .
RUN npm install
EXPOSE 5000
CMD ["npm", "start"]
docker compose file -
version: '3'
services:
pern-todo-backend:
image: pern-todo-backend
ports:
- 5000:5000
command: bash -c 'while !</dev/tcp/db/5432; do sleep 1; done; npm start'
depends_on:
- db
environment:
- DATABASE_URL=postgres://postgres:*****#db:5432/pern
- PORT=5000
db:
image: postgres
ports:
- 5432:5432
environment:
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=****
- POSTGRES_DB=pern
when i try to hit the endpoint from postman -
{
"errno": -111,
"code": "ECONNREFUSED",
"syscall": "connect",
"address": "172.26.0.3",
"port": 5432
}
I tried updating my pg pool hostname as the name of my container also
const pool = new Pool({
user : 'postgres',
password : 'subh1994',
host : 'localhost',
port : 5432,
database : 'pern'
})
I'm new with Docker , please help . thanks

Answer 1

Can you check your container name of db service by docker ps
It can be different than service name (db), you can try replacing it in DATABASE_URL connection string.
But one weird thing is db is getting resolved to 172.26.0.3 if the db is correct container name then you can try checking logs by docker logs db to get details on what might be wrong.
On side note if you don't want datbase exposed to host you can skip the ports mapping in db service.
By default Compose sets up a single network for your app. Each container for a service joins the default network and is both reachable by other containers on that network, and discoverable by them at a hostname identical to the container name.
https://docs.docker.com/compose/networking/