Make os.waitpid timeout on Windows.

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
index af8e3e1d11757601ad6a5f8501c979cebddf8142..380df88e98c1b464e05fb3165f1e1b7b5af4d182 100644
--- a/scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py
+++ b/scripts/slave/recipe_modules/goma/resources/cloudtail_utils.py
@@ -5,6 +5,7 @@
 
 import argparse
 import errno
+import multiprocessing
 import os
 import signal
 import subprocess
@@ -49,6 +50,24 @@ def is_running_posix(pid):
   return True
 
 
+def waitpid_for_win(pid):
+  """Return exception if raised in os.waitpid, or None.
+
+  Args:
+    pid(int): pid of process which this function checks
+              whether it is running or not.
+
+  Returns:
+    Exception: if something raised in os.waitpid.

[tikuta, 2016/10/21 02:35:04]

nit: I prefer to use 'If' here or use 'otherwise' below.

[Yoshisato Yanagisawa, 2016/10/21 02:38:15]

good catch.

+    None: Otherwise.
+  """
+  try:
+    os.waitpid(pid, 0)
+  except Exception as e:
+    return e
+  return None
+
+
 class NotDiedError(Exception):
   def __str__(self):
     return "NotDiedError"
@@ -76,13 +95,19 @@ def wait_termination(pid):
   print('SIGINT has been sent to process %d. '
         'Going to wait for the process finishes.' % pid)
   if os.name == 'nt':
+    pool = multiprocessing.Pool(1)
+    res = pool.apply_async(waitpid_for_win)
     try:
-      os.waitpid(pid, 0)
-    except OSError as e:
-      if e.errno == errno.ECHILD:
+      e = res.get(10)
+    except multiprocessing.TimeoutError:
+      print('process %d running more than 10 seconds' % pid)
+      raise NotDiedError()
+    if e is None:
+      return
+    if isinstance(e, OSError) and e.errno == errno.ECHILD:
         print('process %d died before waitpitd' % pid)
         return
-      raise e
+    raise e
   else:
     for _ in xrange(10):
       time.sleep(1)