Can't reach database server which run in Docker

I currently try run Postgresql in Docker, and use that database in prisma2 in my docker list, my Postgresql running on localhost:5555 and I connecting it on DBeaver, it was successfully , after i run prisma2 app with Postgresql in docker-compose it does’t work,

my docker-compose.yml like this

version: "3"
services:
  app:
    env_file:
      - .env
    build:
      context: .
      dockerfile: Dockerfile
    links:
      - postgres
    ports:
      - "8100:8100"
  postgres:
    container_name: postgres
    image: postgres:10-alpine
    ports:
      - "5555:5432"
    environment:
      POSTGRES_USER: username
      POSTGRES_PASSWORD: mypassword
      POSTGRES_DB: prod

in my .env DB_URI = postgres://username:s@localhost:5555/prod for my schema.prisma

and after I run my docker-compose I got error like this :

Error: P1001: Can't reach database server at `localhost`:`5555`

Please make sure your database server is running at `localhost`:`5555`.

thought my Postgresql already running on that localhost:5555 is there any way to resolve this ?

[umlx5h]

I think this issue should be closed because lacking docker basic network knowledge is the cause of the problem in the first place. If you want to ask a question about Docker networking, you can do it on stackoverflow or to learn.

[pantharshit00]

Localhost inside docker is bound to the container, not the machine. So you can’t access your postgres container via localhost on inside you application docker container. So please use postgres(the container name) instead of localhost as a host in order to connect to your database instance.

If you still want to access your machines loopback interface inside docker for some reason, you can use host.docker.internal(It doesn’t work on linux though). But I would highly recommend you to use your container name as the database host.