docker_entrypoint.py

import os
import socket
import subprocess
import sys
import time


def wait_for_service(name, host, port, timeout=60):
    if not host or not port:
        return

    print(f"Waiting for {name} at {host}:{port}...", flush=True)
    deadline = time.time() + timeout
    while time.time() < deadline:
        try:
            with socket.create_connection((host, int(port)), timeout=2):
                return
        except OSError:
            time.sleep(1)

    raise TimeoutError(f"Timed out waiting for {name} at {host}:{port}")


def run_manage_command(*args):
    subprocess.check_call([sys.executable, "manage.py", *args])


def wait_for_django_migration(app_label, migration_name, timeout=120):
    if not app_label or not migration_name:
        return

    print(f"Waiting for Django migration {app_label}.{migration_name}...", flush=True)
    deadline = time.time() + timeout
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "Car_Rental_System.settings")

    while time.time() < deadline:
        try:
            import django
            from django.db import connection

            django.setup()
            with connection.cursor() as cursor:
                cursor.execute(
                    """
                    SELECT 1
                    FROM django_migrations
                    WHERE app = %s AND name = %s
                    LIMIT 1
                    """,
                    [app_label, migration_name],
                )
                if cursor.fetchone():
                    return
        except Exception:
            time.sleep(2)
            continue

        time.sleep(2)

    raise TimeoutError(f"Timed out waiting for Django migration {app_label}.{migration_name}")


def main():
    wait_for_service("PostgreSQL", os.environ.get("DB_HOST"), os.environ.get("DB_PORT", "5432"))
    wait_for_service("Redis", os.environ.get("REDIS_HOST"), os.environ.get("REDIS_PORT", "6379"))

    if os.environ.get("RUN_MIGRATIONS") == "1":
        run_manage_command("migrate", "--noinput")

    wait_for_django_migration(
        os.environ.get("WAIT_FOR_MIGRATION_APP"),
        os.environ.get("WAIT_FOR_MIGRATION_NAME"),
    )

    if os.environ.get("RUN_COLLECTSTATIC") == "1":
        run_manage_command("collectstatic", "--noinput")

    os.execvp(sys.argv[1], sys.argv[1:])


if __name__ == "__main__":
    main()