Class-based Python decorators

class_decorator.py

import time

""" EXAMPLE LOGGING DECORATOR """
class log_function(object):
  
  def __init__(self, time_it=False):
    self.time_it = time_it
    
  def __call__(self, func, *args, **kwargs):
    
    def wrapper(*args, **kwargs):
      print('LOGGING :: Start function {}'.format(func.__name__))
      if self.time_it:
        start_time = time.time()
      res = func(*args, **kwargs)
      print('LOGGING :: End function {}'.format(func.__name__))
      if self.time_it:
        time_spent = time.time() - start_time
        print('LOGGING :: Exec time: {:.4f} s'.format(time_spent))
      print()
      return res
    
    return wrapper
  
""" DECORATED EXAMPLE FUNCTIONS """
@log_function()
def greet_default(name, surname):
  print('Good morning {} {}!'.format(name, surname)) 

# Another greet function, timing included
@log_function(time_it=True)
def greet_timing(name):
  print('Good morning {}!'.format(name))
  # Simulate execution time to observe the timing log
  time.sleep(1)

""" MAIN """  
if __name__ == '__main__':
  
  greet_default('John', 'Doe')
  # LOGGING :: Start function greet_default
  # Good morning John Doe!
  # LOGGING :: End function greet_default
  
  greet_default(surname='John', name='Doe')
  # LOGGING :: Start function greet_default
  # Good morning Doe John!
  # LOGGING :: End function greet_default

  greet_timing('James')
  # LOGGING :: Start function greet_timing
  # Good morning James!
  # LOGGING :: End function greet_timing
  # LOGGING :: Exec time: 1.0014 s
   
  greet_timing(name='James')
  # LOGGING :: Start function greet_timing
  # Good morning James!
  # LOGGING :: End function greet_timing
  # LOGGING :: Exec time: 1.0004 s