xref: /aosp_15_r20/external/autotest/client/bin/autotestd_monitor (revision 9c5db1993ded3edbeafc8092d69fe5de2ee02df7) 
1#!/usr/bin/python3
2
3from __future__ import absolute_import
4from __future__ import division
5from __future__ import print_function
6import common
7import sys, os, signal, time, subprocess, fcntl
8
9
10def _print_to_file_and_flush(msg, file):
11    """Print to the provided file, and flush after printing."""
12    print(msg, file=file)
13    file.flush()
14
15logdir = sys.argv[1]
16stdout_start = int(sys.argv[2])  # number of bytes we can skip on stdout
17stderr_start = int(sys.argv[3])  # nubmer of bytes we can skip on stderr
18# TODO (crosbug.com/38224)- sbasi: Remove extra logging.
19stderr = open(os.path.join(logdir, 'stderr'), 'a', buffering=2)
20
21_print_to_file_and_flush('Entered autotestd_monitor.', file=stderr)
22
23# if any of our tail processes die, the monitor should die too
24def kill_self(signum, frame):
25    os.kill(os.getpid(), signal.SIGTERM)
26signal.signal(signal.SIGCHLD, kill_self)
27
28devnull = open(os.devnull, 'w')
29
30# launch some tail processes to pump the std* streams
31def launch_tail(filename, outstream, start):
32    path = os.path.join(logdir, filename)
33    argv = ['tail', '--retry', '--follow=name', '--bytes=+%d' % start, path]
34    # stdout=sys.stdout fails on pre-2.5 python (bug in subprocess module)
35    if outstream != subprocess.PIPE and outstream.fileno() == 1:
36        return subprocess.Popen(argv, stderr=devnull)
37    else:
38        return subprocess.Popen(argv, stdout=outstream, stderr=devnull)
39stdout_pump = launch_tail('stdout', sys.stdout, stdout_start)
40stderr_pump = launch_tail('stderr', sys.stderr, stderr_start)
41
42_print_to_file_and_flush('Finished launching tail subprocesses.', file=stderr)
43# wait for logdir/started to exist to be sure autotestd is started
44start_time = time.time()
45started_file_path = os.path.join(logdir, 'started')
46while not os.path.exists(started_file_path):
47    time.sleep(1)
48    if time.time() - start_time >= 30:
49        raise Exception("autotestd failed to start in %s" % logdir)
50
51_print_to_file_and_flush('Finished waiting on autotestd to start.',
52                         file=stderr)
53
54# watch the exit code file for an exit
55exit_code_file = open(os.path.join(logdir, 'exit_code'))
56fcntl.flock(exit_code_file, fcntl.LOCK_EX)
57_print_to_file_and_flush('Got lock of exit_code_file.', file=stderr)
58
59try:
60    exit_code = exit_code_file.read()
61    if len(exit_code) != 4:
62        exit_code = -signal.SIGKILL   # autotestd was nuked
63    else:
64        exit_code = int(exit_code)
65finally:
66    fcntl.flock(exit_code_file, fcntl.LOCK_UN)
67    exit_code_file.close()
68    _print_to_file_and_flush('Released lock of exit_code_file and closed it.',
69                              file=stderr)
70
71# Give tail a tiny bit of time to finish.
72time.sleep(0.01)
73
74_print_to_file_and_flush('Killing child processes.', file=stderr)
75
76# clear the SIGCHLD handler so that killing the tails doesn't kill us
77signal.signal(signal.SIGCHLD, signal.SIG_DFL)
78os.kill(stdout_pump.pid, signal.SIGTERM)
79os.kill(stderr_pump.pid, signal.SIGTERM)
80
81stderr.close()
82# exit (with the same code as autotestd)
83sys.exit(exit_code)
84