import subprocess, sys, time
import os
import threading

code3 = '; '.join((
    'import os, time, sys',
    'print("process 3: pid", os.getpid(), file=sys.stderr)',
    'print("process 3: stdout", os.fstat(sys.stdout.fileno()), file=sys.stderr, flush=True)',
    'time.sleep(5)',
    'print("process 3: exit", file=sys.stderr, flush=True)',
))
args3 = [sys.executable, '-c', code3]

code2 = '; '.join((
    'import subprocess, os, sys',
    'print("process 2: pid", os.getpid(), file=sys.stderr)',
    'print("process 2: stdout", os.fstat(sys.stdout.fileno()), file=sys.stderr)',
    'args = %r' % args3,
    'popen=subprocess.Popen(args)',
    # this code never completes since process 1 kills process 2
    'popen.wait()',
))
args2 = [sys.executable, '-c', code2]

popen = subprocess.Popen(args2, stdout=subprocess.PIPE)
print("process 1: pid", os.getpid())
print("process 1: process 2 spawned (pid %s)" % popen.pid)
print("process 1: stdout pipe", os.fstat(popen.stdout.fileno()))

def kill(popen):
    # wait until communicate() is running
    time.sleep(1)
    print("process 1 (thread): kill process 2 (pid %s)" % popen.pid)
    popen.kill()
    print("process 1 (thread): close process 2 stdout pipe (fd %s)" % popen.stdout.fileno())
    popen.stdout.close()

t = threading.Thread(target=kill, args=(popen,))
t.start()

start_time = time.monotonic()
print("process 1: communicate with process 2 (pid %s) ..." % popen.pid)
popen.communicate()

dt = time.monotonic() - start_time
print("process 1: communicate with process 2 (pid %s) ... done in %.1f sec"
      % (popen.pid, dt))