[webpagereplay] Add command exit.

servermanager.py

 #!/usr/bin/env python
 # Copyright 2011 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
@@ skipping 16 matching lines @@
   server's initializer is called successfully, the __exit__() function
   is guaranteed to be called when ServerManager.Run() completes.
   """
 
   def __init__(self, is_record_mode):
     """Initialize a server manager."""
     self.initializers = []
     self.record_callbacks = []
     self.replay_callbacks = []
     self.is_record_mode = is_record_mode
+    self.should_exit = False
 
   def Append(self, initializer, *init_args, **init_kwargs):
     """Append a server to the end of the list to run.
 
     Servers start in the order they are appended and stop in the
     opposite order.
 
     Args:
       initializer: a function that returns a server instance.
           A server needs to implement the with-statement interface.
@@ skipping 45 matching lines @@
     server_exits = []
     exception_info = (None, None, None)
     try:
       for initializer, init_args, init_kwargs in self.initializers:
         server = initializer(*init_args, **init_kwargs)
         if server:
           server_exits.insert(0, server.__exit__)
           server.__enter__()
       while True:
         time.sleep(1)
+        if self.should_exit:

[chrisgao (Use stgao instead), 2013/08/27 16:34:18]

I think we don't need a lock for |should_exit|. It can only be set to True. And
if we miss the updated value, we should not miss it in the next round.

[tonyg, 2013/08/28 01:35:58]

Agreed. Python's GIL takes care of this.

+          break
     except:
       exception_info = sys.exc_info()
     finally:
       for server_exit in server_exits:
         try:
           if server_exit(*exception_info):
             exception_info = (None, None, None)
         except:
           exception_info = sys.exc_info()
       if exception_info != (None, None, None):
         raise exception_info[0], exception_info[1], exception_info[2]