decorator and pickle and wraps

wraps.py

  1 from functools import wraps                                                                                                                                                                                                                                            
  2 import pickle                                                                                                                                                                                                                                                          
  3 import sys                                                                                                                                                                                                                                                             
  4                                                                                                                                                                                                                                                                        
  5                                                                                                                                                                                                                                                                        
  6 def logged(func):                                                                                                                                                                                                                                                      
  7     """                                                                                                                                                                                                                                                                
  8     if not wrapped, the decoreated function has the same name as the original                                                                                                                                                                                          
  9     cannot pickle                                                                                                                                                                                                                                                      
 10     """                                                                                                                                                                                                                                                                
 11     # @wraps(func)                                                                                                                                                                                                                                                     
 12     def with_logging(*args, **kwargs):                                                                                                                                                                                                                                 
 13         print func.__name__ + " was called"                                                                                                                                                                                                                            
 14         return func(*args, **kwargs)                                                                                                                                                                                                                                   
 15     return with_logging                                                                                                                                                                                                                                                
 16                                                                                                                                                                                                                                                                        
 17                                                                                                                                                                                                                                                                        
 18 def f(x):                                                                                                                                                                                                                                                              
 19     """does some math                                                                                                                                                                                                                                                  
 20     """                                                                                                                                                                                                                                                                
 21     return x**2                                                                                                                                                                                                                                                        
 22                                                                                                                                                                                                                                                                        
 23 if __name__ == '__main__':                                                                                                                                                                                                                                             
 24     try:                                                                                                                                                                                                                                                               
 25         c = int(raw_input("input 1,2,3: "))                                                                                                                                                                                                                            
 26     except ValueError:                                                                                                                                                                                                                                                 
 27         print 'not an int'                                                                                                                                                                                                                                             
 28                                                                                                                                                                                                                                                                        
 29     if c == 1:                                                                                                                                                                                                                                                         
 30         """                                                                                                                                                                                                                                                            
 31         this doesn't work because the name conflict                                                                                                                                                                                                                    
 32         """                                                                                                                                                                                                                                                            
 33         print 'test1'                                                                                                                                                                                                                                                  
 34         """                                                                                                                                                                                                                                                            
 35         note this is equivalent to decoration syntax:                                                                                                                                                                                                                  
 36             @logged                                                                                                                                                                                                                                                    
 37             def f(x) ....                                                                                                                                                                                                                                              
 38         """                                                                                                                                                                                                                                                            
 39         f = logged(f)                                                                                                                                                                                                                                                  
 40         print f(2)                                                                                                                                                                                                                                                     
 41         # name is with_logging, lose of function information                                                                                                                                                                                                           
 42         print f.__name__                                                                                                                                                                                                                                               
 43                                                                                                                                                                                                                                                                        
 44         with open('./delme', 'w') as ff:                                                                                                                                                                                                                               
 45             pickle.dump(f, ff)                                                                                                                                                                                                                                         
 46     elif c == 2:                                                                                                                                                                                                                                                       
 47         """                                                                                                                                                                                                                                                            
 48         this works, the returned fucntion name has to match __name__                                                                                                                                                                                                   
 49         which is 'with_logging' in our case, this is a huge limitation.                                                                                                                                                                                                
 50         for example, in debugging                                                                                                                                                                                                                                      
 51         """                                                                                                                                                                                                                                                            
 52         print 'test2'                                                                                                                                                                                                                                                  
 53         with_logging = logged(f)                                                                                                                                                                                                                                       
 54         print with_logging(2)                                                                                                                                                                                                                                          
 55         # name is with_logging, lose of function information                                                                                                                                                                                                           
 56         print with_logging.__name__                                                                                                                                                                                                                                    
 57                                                                                                                                                                                                                                                                        
 58         with open('./delme', 'w') as ff:                                                                                                                                                                                                                               
 59             pickle.dump(with_logging, ff)