I have one problem with docker

func ConnectToDB() {
    var err error
    dsn := "host=localhost user=postgres password=postgres dbname=yandex port=5432 sslmode=disable"
    DB, err = gorm.Open(postgres.Open(dsn), &gorm.Config{})
    if err != nil {
        log.Fatal("failed to connect with database")
    }
}

that’s my function that connect’s to db

and that’s my docker-compose file

version: "3.8"
services:
  server:
    container_name: server
    build:
      context: .
    restart: unless-stopped
    depends_on:
      postgres:
        condition: service_healthy
    ports:
      - "8080:8080"
    volumes:
      - type: bind
        source: ./static
        target: /app/static
    environment:
      POSTGRES_PASSWORD: "postgres"
  postgres:
    container_name: storage
    image: postgres:16.2
    restart: unless-stopped
    environment:
      POSTGRES_PASSWORD: postgres
      POSTGRES_USER: postgres
      POSTGRES_DB: yandex
    healthcheck:
      test: [ "CMD-SHELL", "pg_isready -U postgres" ]
      interval: 10s
      timeout: 5s
      retries: 5
    ports:
      - "5432:5432"
    volumes:
      - type: bind
        source: ./init.sql
        target: /docker-entrypoint-initdb.d/init.sql

So after commands
docker-compose build
docker-compose up
that gives me an error

server | [error] failed to initialize database, got error failed to connect to host=localhost user=postgres database=yandex: dial error (dial tcp [::1]:5432: connect: cannot assign requested address)
server | 2024/05/02 20:17:58 failed to connect with database

can you tell what am I doing wrong?

I tried to change localhost in function
like thist

func ConnectToDB() {
    var err error
    dsn := "host=postgres user=postgres password=postgres dbname=yandex port=5432 sslmode=disable"
    DB, err = gorm.Open(postgres.Open(dsn), &gorm.Config{})
    if err != nil {
        log.Fatal("failed to connect with database")
    }
}

and that worked

but why?