Cannot send requests to my express API w/ redis after docker-compose - node.js

Question

I've been working on a small project with Node.js/Express + redis, with basic frontend w/o any frameworks (full code can be seen here). I've been testing my API with Postman (because my frontend is currently not working), and it worked like a charm.
So, after implementing redis to the project, I've tried adding it to my docker-compose.yml file, here it is and some other files:
docker-compose.yml
version: '3.8'
services:
redis:
container_name: redis-db
image: redis
networks:
- webnet
backend:
container_name: api
build: ./backend
restart: always
ports:
- '8080:8080'
networks:
- webnet
depends_on:
- redis
frontend:
container_name: frontend
build: ./frontend
restart: always
ports:
- '5000:5000'
networks:
- webnet
depends_on:
- backend
networks:
webnet:
config.yml
server:
host: localhost
port: 8080
app:
# '-1' for turning expiry off; otherwise, should be at least '1' (minute)
timeToLive: -1
db:
type: redis # ['in-memory', 'redis']
redis:
# select 'redis' if using docker-compose
host: redis # ['localhost', 'redis']
port: 6379
redis.js
import Redis from 'redis';
import config from 'config';
import AppError from '../utils/appError.js';
import { StatusCodes } from 'http-status-codes';
import { promisify } from 'util';
export const redisClient = Redis.createClient({
host: config.get('db.redis.host'),
port: config.get('db.redis.port'),
});
redisClient.on('error', function (err) {
throw new AppError(err, StatusCodes.INTERNAL_SERVER_ERROR);
});
redisClient.on('connect', () => {
console.log('💃 connected redis successfully 💃');
});
But, unfortunately, after docker-compose up I'm not able to make Postman requests anymore. Redis connected without any problems, in the console everything seems to be fine, and I even can access my frontend pages, but I cannot make requests to my backend anymore.
My frontend is running on localhost:5000, backend supposed to be running on localhost:8080, and redis seems to be running on redis:6379.
I've tried my best searching for the answer, but there are hundreds of questions on how to connect redis to your express project with docker-compose, but no questions about troubles accessing backend after connecting redis.
EDIT_1: here is what postman says:
POST http://127.0.0.1:8080/api/v1/queue
Error: socket hang up
Request Headers
Content-Type: application/json
User-Agent: PostmanRuntime/7.28.3
Accept: */*
Postman-Token: a61d8b9c-a2f5-4fe4-92e1-921a5680bb85
Host: 127.0.0.1:8080
Accept-Encoding: gzip, deflate, br
Here is docker ps output:
f7f6fbe12863 project1_frontend "docker-entrypoint.s…" 3 minutes ago Up 2 minutes 0.0.0.0:5000->5000/tcp, :::5000->5000/tcp frontend
9802680a1a3d project1_backend "docker-entrypoint.s…" 3 minutes ago Up 3 minutes 0.0.0.0:8080->8080/tcp, :::8080->8080/tcp api
66fde12be888 redis "docker-entrypoint.s…" 3 minutes ago Up 3 minutes 0.0.0.0:6379->6379/tcp, :::6379->6379/tcp redis-db
And here are my console logs after docker-compose up:
api |
api | > queue-resolution-api#0.1.0 start /app
api | > nodemon server.js
api |
api | [nodemon] 2.0.12
api | [nodemon] to restart at any time, enter `rs`
api | [nodemon] watching path(s): *.*
api | [nodemon] watching extensions: js
api | [nodemon] starting `node server.js`
api | NODE_ENV: development
api | Listening on port 8080...
api | 💃 connected redis successfully 💃
redis-db | 1:C 16 Aug 2021 14:35:18.728 # oO0OoO0OoO0Oo Redis is starting oO0OoO0OoO0Oo
redis-db | 1:C 16 Aug 2021 14:35:18.728 # Redis version=6.2.5, bits=64, commit=00000000, modified=0, pid=1, just started
redis-db | 1:C 16 Aug 2021 14:35:18.728 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
redis-db | 1:M 16 Aug 2021 14:35:18.728 * monotonic clock: POSIX clock_gettime
redis-db | 1:M 16 Aug 2021 14:35:18.729 * Running mode=standalone, port=6379.
redis-db | 1:M 16 Aug 2021 14:35:18.729 # Server initialized
redis-db | 1:M 16 Aug 2021 14:35:18.729 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
redis-db | 1:M 16 Aug 2021 14:35:18.729 * Ready to accept connections
redis-db | 1:M 16 Aug 2021 14:35:20.587 * DB saved on disk
frontend |
frontend | > frontend#1.0.0 start /app
frontend | > nodemon server.js
frontend |
frontend | [nodemon] 2.0.12
frontend | [nodemon] to restart at any time, enter `rs`
frontend | [nodemon] watching path(s): *.*
frontend | [nodemon] watching extensions: js,mjs,json
frontend | [nodemon] starting `node server.js`
frontend | Listening on port 5000...

Answer 1

I've figured out the answer. In my server.js file I've been forcing the app to listen on host = localhost, and after deleting the host part everything started working.
app.listen(port, host, () => {
console.log('NODE_ENV: ' + config.util.getEnv('NODE_ENV'));
console.log(`Listening on port ${port}...`);
});