Source Code for Module Ganga.Core.InternalServices.ShutdownManager

  1  ################################################################################ 
  2  # Ganga - a computational task management tool for easy access to Grid resources 
  3  # http://cern.ch/ganga 
  4  # 
  5  # $Id: ShutdownManager.py,v 1.1 2008-07-17 16:40:50 moscicki Exp $ 
  6  # 
  7  # Copyright (C) 2003-2007 The Ganga Project 
  8  # 
  9  # This file is part of Ganga.  
 10  # 
 11  # Ganga is free software; you can redistribute it and/or modify 
 12  # it under the terms of the GNU General Public License as published by 
 13  # the Free Software Foundation; either version 2 of the License, or 
 14  # (at your option) any later version. 
 15  # 
 16  # Ganga is distributed in the hope that it will be useful, 
 17  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 18  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 19  # GNU General Public License for more details. 
 20   
 21  # You should have received a copy of the GNU General Public License 
 22  # along with this program; if not, write to the Free Software 
 23  # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA 
 24  ################################################################################ 
 25  """ 
 26  Extend the behaviour of the default *atexit* module to support: 
 27   
 28   1) automatically catching of the (possible) exceptions thrown by exit function 
 29    
 30   2) exit function prioritization (lower value means higher priority)  
 31    E.g: 
 32      import atexit 
 33      atexit.register((<PRIORITY>,myfunc),args)   
 34      
 35    The backward-compatibility is kept so the existing code using : 
 36      import atexit 
 37      atexit.register(myfunc,args) 
 38    registers the function with the lowest priority (sys.maxint) 
 39  """ 
 40   
 41  import atexit 
 42   
 43  from Ganga.Utility.logging import getLogger,log_user_exception 
 44  logger = getLogger() 
 45   
 46 -def _ganga_run_exitfuncs(): 
 47      """run any registered exit functions 
 48   
 49      atexit._exithandlers is traversed based on the priority. 
 50      If no priority was registered for a given function 
 51      than the lowest priority is assumed (LIFO policy) 
 52       
 53      We keep the same functionality as in *atexit* bare module but 
 54      we run each exit handler inside a try..catch block to be sure all 
 55      the registered handlers are executed 
 56      """ 
 57   
 58      def priority_cmp(f1,f2): 
 59          """ 
 60          Sort the exit functions based on priority in reversed order 
 61          """         
 62          #extract the priority number from the function element  
 63          p1 = f1[0][0] 
 64          p2 = f2[0][0]         
 65          #sort in reversed order 
 66          return cmp(p2,p1) 
 67       
 68      def add_priority(x): 
 69          """ 
 70          add a default priority to the functions not defining one (default priority=sys.maxint) 
 71          return a list containg ((priority,func),*targs,*kargs) elements 
 72          """         
 73          import sys 
 74          func = x[0] 
 75          if type(func)==type(()) and len(x[0])==2: 
 76              return x 
 77          else: 
 78              new = [(sys.maxint,func)] 
 79              new.extend(x[1:]) 
 80              return new 
 81   
 82      atexit._exithandlers = map(add_priority,atexit._exithandlers) 
 83      atexit._exithandlers.sort(priority_cmp) 
 84       
 85      while atexit._exithandlers: 
 86          (priority, func), targs, kargs = atexit._exithandlers.pop() 
 87          try: 
 88              func(*targs, **kargs) 
 89          except Exception,x: 
 90              s = 'Cannot run one of the exit handlers: %s ... Cause: %s' % (func.__name__,str(x)) 
 91              logger.warning(s) 
 92   
 93 -def install(): 
 94      """ 
 95      Install a new shutdown manager, by overriding metods from atexit module 
 96      """     
 97      #override the atexit exit function 
 98      atexit._run_exitfuncs = _ganga_run_exitfuncs 
 99      #del atexit 
100       
101      #override the default exit function 
102      import sys 
103      sys.exitfunc = atexit._run_exitfuncs  
104   
105  # 
106  #$Log: not supported by cvs2svn $ 
107  #Revision 1.2  2007/07/27 14:31:56  moscicki 
108  #credential and clean shutdown updates from Adrian (from Ganga-4-4-0-dev-branch) 
109  # 
110  #Revision 1.1.2.2  2007/07/27 13:03:17  amuraru 
111  #*** empty log message *** 
112  # 
113  # 
114