Implementing a Python decorator for function logging

Last update on April 21 2025 12:58:28 (UTC/GMT +8 hours)

8. Implement a Decorator to Add Logging Functionality

Write a Python program that implements a decorator to add logging functionality to a function.

Logging functionality refers to the capability of recording and storing information about program execution. It allows you to capture significant events, messages, and errors that occur during code execution.

Sample Solution:

Python Code:

def add_logging(func):
    def wrapper(*args, **kwargs):
        # Log the function name and arguments
        print(f"Calling {func.__name__} with args: {args}, kwargs: {kwargs}")
        
        # Call the original function
        result = func(*args, **kwargs)
        
        # Log the return value
        print(f"{func.__name__} returned: {result}")
        
        # Return the result
        return result
    return wrapper

# Example usage
@add_logging
def add_numbers(x, y):
    return x + y

# Call the decorated function
result = add_numbers(200, 300)
print("Result:", result)

Sample Output:

Calling add_numbers with args: (200, 300), kwargs: {}
add_numbers returned: 500
Result: 500

Explanation:

In the above exercise,

The code defines a decorator called add_logging that adds logging functionality to a function. When a function is decorated with @add_logging, it wraps the original function and performs the following actions:

Log the function name and arguments before calling the original function.
Call the original function.
Log the return value after the function execution.
Return the result.

In the example usage, the add_numbers function is decorated with @add_logging. When the decorated function is called, the decorator logs the function name, arguments, and return value.

Flowchart:

For more Practice: Solve these Related Problems:

Write a Python decorator that logs the start and end times of a function call along with its name using the logging module.
Write a Python decorator that writes log messages to a file every time the decorated function is invoked.
Write a Python decorator that logs both the input arguments and the return value of a function call in a structured format.
Write a Python decorator that integrates with the logging module to include the module and function name in each log entry.

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