Add cloudtail start/stop in recipe_modules/goma

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 os
+import signal
+import subprocess
+import sys
+import time
+
+from slave import goma_utils
+
+
+def start_cloudtail(args, f):
+  """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()])
+
+  f.write(str(proc.pid))
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description='cloudtail utility for goma recipe module.')
+
+  parser.add_argument('--cloudtail-path',
+                      help='path of cloudtail binary')
+  parser.add_argument('--start-cloudtail', action='store_true',
+                      help='start cloudtail if this option is enabled')
+  parser.add_argument('--killed-pid',

[ukai, 2016/08/17 01:13:15]

type=int
?

[tikuta, 2016/08/17 02:29:56]

Done.

+                      help=('pid that is killed.'
+                            ' Do not set this option and'
+                            ' --start-cloudtail at the same time'))
+
+  args = parser.parse_args()
+
+  if args.start_cloudtail:
+    # Do not set killed_pid and start_cloudtail at the same time
+    assert args.killed_pid is None
+    start_cloudtail(args, sys.stdout)
+
+  if args.killed_pid is not None:
+    killed_pid = int(args.killed_pid)
+    os.kill(killed_pid, signal.SIGTERM)
+
+    for _ in range(3):
+      time.sleep(1)
+      pid, retcode = os.waitpid(killed_pid, os.WNOHANG)

[ukai, 2016/08/17 01:13:15]

check OSError?

[ukai, 2016/08/17 01:13:15]

os.waitpid won't work with the process id that is not child process of the
process?
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: [Errno 10] No child processes

[tikuta, 2016/08/17 02:29:56]

I decided to send kill signal only for killed_pid.

+      if pid == 0 and retcode == 0:

[ukai, 2016/08/17 01:13:15]

if pid == 0 and retcode ==0 is still running, so should check os.waitpid again?
otherwise, can break the loop.

+        break
+
+    if pid != 0 or retcode != 0:

[ukai, 2016/08/17 01:13:15]

if pid == 0 and retcode == 0?

+      os.kill(killed_pid, os.SIGKILL)
+
+
+if '__main__' == __name__:
+  sys.exit(main())