Add logs for update_engine and image_to_live to test artifacts.

bin/au_test_harness/dev_server_wrapper.py

 # Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Module containing methods and classes to interact with a devserver instance.
 """
 
+import os
 import threading
 
 import cros_build_lib as cros_lib
 
 def GenerateUpdateId(target, src, key):
   """Returns a simple representation id of target and src paths."""
   update_id = target
   if src: update_id = '->'.join([update_id, src])
   if key: update_id = '+'.join([update_id, key])
   return update_id
 
 class DevServerWrapper(threading.Thread):
   """A Simple wrapper around a dev server instance."""
 
-  def __init__(self):
+  def __init__(self, test_root):
     self.proc = None
+    self.test_root = test_root
     threading.Thread.__init__(self)
 
   def run(self):
     # Kill previous running instance of devserver if it exists.
     cros_lib.RunCommand(['sudo', 'pkill', '-f', 'devserver.py'], error_ok=True,
                         print_cmd=False)
     cros_lib.RunCommand(['sudo',
                          'start_devserver',
                          '--archive_dir=./static',
                          '--client_prefix=ChromeOSUpdateEngine',
                          '--production',
-                        ], enter_chroot=True, print_cmd=False)
+                         ], enter_chroot=True, print_cmd=False,
+                         log_to_file=os.path.join(self.test_root,
+                                                  'dev_server.log'))
 
   def Stop(self):
     """Kills the devserver instance."""
     cros_lib.RunCommand(['sudo', 'pkill', '-f', 'devserver.py'], error_ok=True,
                         print_cmd=False)
 
   @classmethod
   def GetDevServerURL(cls, port, sub_dir):
     """Returns the dev server url for a given port and sub directory."""
     ip_addr = cros_lib.GetIPAddress()
     if not port: port = 8080
     url = 'http://%(ip)s:%(port)s/%(dir)s' % {'ip': ip_addr,
                                               'port': str(port),
                                               'dir': sub_dir}
     return url