Adding a server side, non-blocking subprocess mechanism.

testing/legion/client_lib.py

 # Copyright 2015 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.
 
 """Defines the client library."""
 
 import argparse
 import datetime
 import logging
 import os
 import socket
 import subprocess
 import sys
 import tempfile
 import threading
 import xmlrpclib
 
 #pylint: disable=relative-import
 import common_lib
 
-THIS_DIR = os.path.dirname(os.path.abspath(__file__))
-SWARMING_DIR = os.path.join(THIS_DIR, '..', '..', 'tools/swarming_client')
-ISOLATE_PY = os.path.join(SWARMING_DIR, 'isolate.py')
-SWARMING_PY = os.path.join(SWARMING_DIR, 'swarming.py')
+ISOLATE_PY = os.path.join(common_lib.SWARMING_DIR, 'isolate.py')
+SWARMING_PY = os.path.join(common_lib.SWARMING_DIR, 'swarming.py')
 
 
 class Error(Exception):
   pass
 
 
 class ConnectionTimeoutError(Error):
   pass
 
 
@@ skipping 169 matching lines @@
     if p.returncode != 0:
       raise Error(stderr)
 
   def OnConnect(self, ip_address):
     """Receives client ip address on connection."""
     self._ip_address = ip_address
     self._connected = True
     self._rpc = common_lib.ConnectToServer(self._ip_address)
     logging.info('%s connected from %s', self._name, ip_address)
     self._connect_event.set()