import sys
import subprocess
import time


def wait_and_print():
    """Do nothing for 5 seconds except print something each second"""
    for i in range(5):
        print("waited ", i, flush=True)
        time.sleep(1)


def start_grandchild():
    """Start a subprocess to run wait_and_print"""
    subprocess.run([sys.executable, __file__, "wait_and_print"])


def run_with_timeout(function, timeout=None):
    """Run a function in this file with subprocess.run and a timeout of 1 second.
    Print the stdout of the process if it completed or timed out"""
    try:
        p = subprocess.run([sys.executable, __file__, function], stdout=subprocess.PIPE, timeout=timeout)
        print("Finished: ", repr(p.stdout))
    except subprocess.TimeoutExpired as e:
        print("Timeout:  ", repr(e.stdout))


if __name__ == "__main__":
    if(len(sys.argv) > 1):
        # If we have an argument interpret it as function name to execute
        func = sys.argv[1]
        globals()[func](*sys.argv[2:])
        sys.exit(0)

    # Ok, if we run wait_and_print() in a subprocess with timeout we will get a
    # Timeout:   b'waited  0\n'
    run_with_timeout("wait_and_print")
    # But if we run the start_grandchild() in a subprocess it will wait for the
    # grandchild to be completed and thus we get
    # Timeout:   b'waited  0\nwaited  1\nwaited  2\nwaited  3\nwaited  4\n
    run_with_timeout("start_grandchild")