Source Code for Module jazzparser.utils.multiproc

 1  """Multiprocessing utilities. 
 2  """ 
 3  """ 
 4  ============================== License ======================================== 
 5   Copyright (C) 2008, 2010-12 University of Edinburgh, Mark Granroth-Wilding 
 6    
 7   This file is part of The Jazz Parser. 
 8    
 9   The Jazz Parser is free software: you can redistribute it and/or modify 
10   it under the terms of the GNU General Public License as published by 
11   the Free Software Foundation, either version 3 of the License, or 
12   (at your option) any later version. 
13    
14   The Jazz Parser is distributed in the hope that it will be useful, 
15   but WITHOUT ANY WARRANTY; without even the implied warranty of 
16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
17   GNU General Public License for more details. 
18    
19   You should have received a copy of the GNU General Public License 
20   along with The Jazz Parser.  If not, see <http://www.gnu.org/licenses/>. 
21   
22  ============================ End license ====================================== 
23   
24  """ 
25  __author__ = "Mark Granroth-Wilding <mark.granroth-wilding@ed.ac.uk>"  
26   
27  from multiprocessing import TimeoutError 
28  from threading import Thread 
29   
30 -class Result(object): 
31 -    def __init__(self): 
32          self.result = None 
33   
34 -def timeout(fun, *args, **kwargs): 
35      """ 
36      Decorator that applies a function with the given args and kwargs,  
37      enforcing a timeout. Blocks until the function completes or the  
38      timeout expires. If the timeout expires, raises a TimeoutError. 
39       
40      The intended use of this is to submit a job to a multiprocessing  
41      pool with a timeout, after which the whole processing terminates. 
42      This only makes sense if you have just one task per process or  
43      set C{maxtasksperchild=1} on the pool. 
44       
45      @note: the function execution does not actually halt when the  
46      exception is raised, but continues in another thread. There is  
47      no way to terminate this thread from outside it. 
48       
49      """ 
50      result = Result() 
51      timeout_length = kwargs.pop('timeout', 60) 
52      def _get_target(): 
53          # Closure to capture result 
54          def _target(*args, **kwargs): 
55              result.result = fun(*args, **kwargs) 
56          return _target 
57       
58      # Run the function in a thread 
59      runner = Thread(target=_get_target(), args=args, kwargs=kwargs) 
60      # Wait until it finishes or the timeout expires 
61      runner.start() 
62      runner.join(timeout_length) 
63      if runner.is_alive(): 
64          # The function timed out 
65          raise TimeoutError, "call to %s timed out (%s secs)" % (fun,timeout_length) 
66      else: 
67          return result.result 
68