[android] Pass SIGTERM from logdog_wrapper to its wrapped test command.

build/android/test_wrapper/logdog_wrapper.py

 #!/usr/bin/env python
 # Copyright 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.
 
 """Wrapper for adding logdog streaming support to swarming tasks."""
 
 import argparse
 import logging
 import os
+import signal
 import subprocess
 import sys
 import urllib
 
 
 def CommandParser():
   # Parses the command line arguments being passed in
   parser = argparse.ArgumentParser()
   parser.add_argument('--logdog-bin-cmd', required=True,
                       help='Command for running logdog butler binary')
@@ skipping 11 matching lines @@
   parser.add_argument('--name', required=True,
                       help='Name to be used for logdog stream')
   return parser
 
 
 def CreateUrl(server, project, prefix, name):
   stream_name = '%s/%s/+/%s' % (project, prefix, name)
   return 'https://%s/v/?s=%s' % (server, urllib.quote_plus(stream_name))
 
 
+def CreateSignalForwarder(proc):
+  def handler(signum, _frame):
+    logging.error('Forwarding signal %s to test process', str(signum))
+    proc.send_signal(signum)
+
+  return handler
+
+
 def main():
   parser = CommandParser()
   args, test_cmd = parser.parse_known_args(sys.argv[1:])
   logging.basicConfig(level=logging.INFO)
   if not test_cmd:
     parser.error('Must specify command to run after the logdog flags')
-  result = subprocess.call(test_cmd)
+  test_proc = subprocess.Popen(test_cmd)
+  original_sigterm_handler = signal.signal(
+      signal.SIGTERM, CreateSignalForwarder(test_proc))
+  try:
+    result = test_proc.wait()
+  finally:
+    signal.signal(signal.SIGTERM, original_sigterm_handler)
   if '${SWARMING_TASK_ID}' in args.prefix:
     args.prefix = args.prefix.replace('${SWARMING_TASK_ID}',
                                       os.environ.get('SWARMING_TASK_ID'))
   url = CreateUrl('luci-logdog.appspot.com', args.project, args.prefix,
                   args.name)
   logdog_cmd = [args.logdog_bin_cmd, '-project', args.project,
                 '-output', 'logdog,host=%s' % args.logdog_server,
                 '-prefix', args.prefix,
                 '-service-account-json', args.service_account_json,
                 'stream', '-source', args.source,
                 '-stream', '-name=%s' % args.name]
   if os.path.exists(args.logdog_bin_cmd):
     subprocess.call(logdog_cmd)
     logging.info('Logcats are located at: %s', url)
   return result
 
 
 if __name__ == '__main__':
   sys.exit(main())