Wrapping functions in python

wrapping_functions_in_python

"""
This is a simple example on how to wrap functions in python:
- it uses inspect and wraps from functools

(this is built for python 3.6, you can copy this into a Jupyter notebook and execute!)
"""

# --------------------------------------------------------------------------
# Define the wrapper for logging the function
# --------------------------------------------------------------------------

# importing the libraries
import inspect
from functools import wraps

# this will be the wrapper decorator

def log(f):
    """wrapping a function in order ot log its features"""
   
    # this decorator is from functools, it makes sure that the wrapped function inherits
    # important attributes from the function
    @wraps(f)
    def wrapped_function(*args, **kwds):
    
        # you have to execute the function inside the wrappe   
        result = f(*args, **kwds)
        
        # now you can print out and collect information on the function:
        
        # collect with magic attributes
        print("Function name: {}\n".format(f.__qualname__))
        
        # or collect with the inspect module from python
        print("Docstring: {}\n".format(inspect.getdoc(f)))
        print("Source code:\n{}\n".format(inspect.getsource(f)))
        print("Signature: {}\n".format(inspect.signature(f)))
        
        # you still need to return the result in the wrapper
        return result
        
    # now return the wrapper function 
    return wrapped_function

# --------------------------------------------------------------------------
# Try this with an example:
# --------------------------------------------------------------------------
@log
def example(x, y=3):
    """multiplies the first argument with 2 and adds the second argument"""
    return(x*2 + y)

# call the function and see what is logged!
example(3, 4)