forkexample.py

import os
import sys
import time
import traceback
rpipe, wpipe = os.pipe()

pid = os.fork()
if pid == -1:
    raise TestError("Failed to fork() in prepare_test_dir")

if pid == 0:
    # Child -- do the copy, print log to pipe and exit
    try:
        os.close(rpipe)
        os.dup2(wpipe, sys.stdout.fileno())
        os.dup2(wpipe, sys.stderr.fileno())
        os.close(wpipe)
        counter = 0
        while True:
            print(counter)
            counter += 1
            time.sleep(1)
            sys.stdout.flush()
            sys.stderr.flush()
            if counter == 10:
                break
    except:
        traceback.print_exc(20, sys.stderr)
    finally:
        sys.stdout.flush()
        sys.stderr.flush()
        os._exit(1)
else:

    os.close(wpipe)
    # _, status = os.waitpid(pid, 0)

    from IPython import embed
    print("DEBUG NOW 8888")
    embed()
    raise RuntimeError("stop debug here")

    outf = os.fdopen(rpipe)
    copy_log = outf.read()

    # return os.WEXITSTATUS(status)