native python tcp socket checker similar to the bash wait-for-it project. https://github.com/vishnubob/wait-for-it

wait-for-it.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""Wait for a tcp network port to become open."""
import argparse
import socket
import sys
import time
from argparse import Namespace

SLEEP_SECONDS = 1


def wait_for_it(args: Namespace):
    """Waits for a host:port to become available."""
    has_timeout = args.timeout != 0
    if not has_timeout:
        print(f"Running forever, no timeout configured: '{args.host}:{args.port}'")

    start_time = time.time()
    while True:
        try:
            if args.verbose:
                print(f"Trying connection to {args.host}:{args.port}")
            with socket.create_connection((args.host, args.port), timeout=1):
                if args.verbose:
                    print(f"Success! {args.host}:{args.port}")
                break  # Connection successful
        except OSError as e:
            is_timedout = time.time() - start_time > args.timeout
            if has_timeout and is_timedout:
                raise TimeoutError(
                    f"Timeout waiting for {args.host}:{args.port}"
                ) from e
            if args.verbose:
                print(
                    f"Connect timed out: {args.host}:{args.port}, sleeping {SLEEP_SECONDS}"
                )
            time.sleep(SLEEP_SECONDS)


def main():
    """Run main function."""
    parser = argparse.ArgumentParser(
        formatter_class=argparse.RawDescriptionHelpFormatter,
        description=__doc__,
    )
    parser.add_argument(
        "--verbose",
        "-v",
        help="enable verbose logging",
        action="store_true",
        default=False,
    )
    parser.add_argument(
        "host",
        help="host / ip address",
        type=str,
    )
    parser.add_argument(
        "port",
        help="tcp port number",
        type=int,
    )
    parser.add_argument(
        "--timeout",
        "-t",
        help="timeout",
        type=int,
        default=0,
    )
    args = parser.parse_args()

    try:
        wait_for_it(args)
        print(f"{args.host}:{args.port} is available!")
    except TimeoutError as e:
        print(e)
        sys.exit(1)
    except KeyboardInterrupt:
        print("Goodbye!")
        sys.exit(0)


if __name__ == "__main__":
    main()