Wait cloudtail termination in goma module

scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py

 #!/usr/bin/env python
 # Copyright (c) 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import argparse
 import errno
 import os
 import signal
 import subprocess
 import sys
+import time
 
 from slave import goma_utils
 
 
 def start_cloudtail(args):
   """Write process id of started cloudtail to file object f"""
 
   proc = subprocess.Popen([args.cloudtail_path,
                            'tail',
                            '--log-id', 'goma_compiler_proxy',
                            '--path',
                            goma_utils.GetLatestGomaCompilerProxyInfo()])
   with open(args.pid_file, 'w') as f:
     f.write(str(proc.pid))
 
+def is_running_posix(pid):
+  try:
+    os.kill(pid, 0)
+  except OSError as e:
+    if e.errno == errno.ESRCH:

[ukai, 2016/10/03 02:52:52]

kill may get errno.EPERM and I think we should return false for it too?
0 may not cause EINVAL?

[Vadim Sh., 2016/10/03 19:07:06]

+1 for EPERM handling and returning false

[tikuta, 2016/10/04 03:45:26]

Done.

+      return False
+    raise e

[Yoshisato Yanagisawa, 2016/10/03 04:49:05]

So, in this case, we do not guarantee cloud tail died?

[tikuta, 2016/10/04 03:45:25]

I send SIGKILL

+  return True
+
 def main():
   parser = argparse.ArgumentParser(
       description='cloudtail utility for goma recipe module.')
 
   subparsers = parser.add_subparsers(help='commands for cloudtail')
 
   parser_start = subparsers.add_parser('start',
                                        help='subcommand to start cloudtail')
   parser_start.set_defaults(command='start')
   parser_start.add_argument('--cloudtail-path', required=True,
                             help='path of cloudtail binary')
   parser_start.add_argument('--pid-file', required=True,
                             help='file written pid')
 
   parser_stop = subparsers.add_parser('stop',
                                       help='subcommand to stop cloudtail')
   parser_stop.set_defaults(command='stop')
   parser_stop.add_argument('--killed-pid-file', required=True,
                            help='file written the pid to be killed.')
 
   args = parser.parse_args()
 
   if args.command == 'start':
     start_cloudtail(args)
   elif args.command == 'stop':
     with open(args.killed_pid_file) as f:
       # cloudtail flushes log and terminates
       # within 5 seconds when it recieves SIGINT.
-      os.kill(int(f.read()), signal.SIGINT)
+      pid = int(f.read())
+      os.kill(pid, signal.SIGINT)
+      if os.name == 'nt':

[ukai, 2016/10/03 02:52:52]

factor out a func to wait for pid?

[Vadim Sh., 2016/10/03 19:07:06]

+1

[tikuta, 2016/10/04 03:45:26]

Done.

+        os.waitpid(pid, 0)
+      else:
+        while True:

[ukai, 2016/10/03 02:52:52]

might be better to abandon if it tried >5 sec or so, and kill with SIGKILL?

[Vadim Sh., 2016/10/03 19:07:06]

+1

also nit

while is_running_posix(pid):
  time.sleep(1)

[tikuta, 2016/10/04 03:45:26]

Done.

+          if is_running_posix(pid):
+            time.sleep(1)
+          else:
+            break
 
 if '__main__' == __name__:
   sys.exit(main())