Add cloudtail start/stop in recipe_modules/goma

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

Index: scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py
diff --git a/scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py b/scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py
new file mode 100644
index 0000000000000000000000000000000000000000..9bb4a439680fce118074d97c20093d2b2c73bc89
--- /dev/null
+++ b/scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py
@@ -0,0 +1,55 @@
+#!/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', type=int,

[Paweł Hajdan Jr., 2016/08/17 06:27:01]

This can easily get messy.

Could you refactor this into a set of subcommands instead? See
https://docs.python.org/2.7/library/argparse.html#sub-commands .

[tikuta, 2016/08/17 07:51:32]

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 = args.killed_pid
+    # only send SIGKILL signal, let init process do wait for killed_pid
+    os.kill(killed_pid, os.SIGKILL)
+
+
+if '__main__' == __name__:
+  sys.exit(main())