[FIXED] Docker with postgresql in flask web application

Issue

I am building a Flask application in Python. I'm using SQLAlchemy to connect to PostgreSQL.

In the flask application, I'm using this to connect SQLAlchemy to PostgreSQL

engine = create_engine('postgresql://postgres:[mypassword]@db:5432/employee-manager-db')

And this is my docker-compose.yml

version: '3.8'
services:
  backend:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - 8000:8000
    volumes:
      - .:/app

    depends_on:
      - db

  db:
    image: postgres:14.5
    restart: always
    expose:
      - '5432'
    volumes:
      - .dbdata:/var/lib/postgresql
    ports:
      - '5432:5432'
    environment:
      POSTGRES_PASSWORD: [mypassword]

However, I get an error saying "Is the server running on host "db" (172.21.0.2) and accepting TCP/IP connections on port 5432?"

These are my docker containers:

Inside the employee-manager_db_1, it says "PostgreSQL init process complete; ready for start up". Inside the employee-manager_backend_1, it says "psycopg2.OperationalError: could not connect to server: Connection refused. Is the server running on host "db" (172.21.0.2) and accepting TCP/IP connections on port 5432?"

Thank you so much for help.

Solution

I solved it adding pgadmin service.

  pgadmin:
    image: 'dpage/pgadmin4'
    restart: always
    ....

Answered By - NendoRiki