Logging and Debugging in Python

Logging and debugging are essential aspects of software development to identify and fix issues in your code. Here’s an overview of logging and debugging in Python:

Logging in Python:

  1. Logging Basics:
  • The logging module provides a flexible and powerful framework for emitting log messages.
  • Import the module and configure it based on your needs.
   import logging

  1. Logging Levels:
  • Logging supports different levels: DEBUG, INFO, WARNING, ERROR, and CRITICAL.
   logging.debug("Debug message")
   logging.info("Information message")
   logging.warning("Warning message")
   logging.error("Error message")
   logging.critical("Critical message")
  1. Logging to a File:
  • You can configure logging to write messages to a file.
   logging.basicConfig(filename='example.log', level=logging.DEBUG)
  1. Logging Variables and Exceptions:
  • Include variable values and exception information in log messages.
       result = 10 / 0
   except Exception as e:
       logging.error(f"An error occurred: {e}", exc_info=True)
  1. Log Formatting:
  • Customize log message formatting using the format parameter.
   logging.basicConfig(format='%(asctime)s - %(levelname)s - %(message)s', level=logging.INFO)
  1. Log Handlers:
  • Use different log handlers for more advanced logging, such as sending logs to multiple destinations.
   file_handler = logging.FileHandler('example.log')
   console_handler = logging.StreamHandler()

   logging.basicConfig(handlers=[file_handler, console_handler], level=logging.DEBUG)

Debugging in Python:

  1. Print Statements:
  • Simplest form of debugging involves adding print statements to output variable values or messages at different points in your code.
   x = 10
   print(f"Value of x: {x}")
  1. Debugger:
  • Python comes with a built-in debugger called pdb.
   import pdb

   def my_function():
       result = 10 / 0
       return result
  • Use commands like n (next), c (continue), q (quit), and others to navigate through the code.
  1. Logging for Debugging:
  • Use logging for more structured debugging information.
   import logging


   def my_function():
       logging.debug("Starting my_function")
       result = 10 / 0
       logging.debug("Ending my_function")
       return result
  1. Debugging Tools:
  • Utilize Integrated Development Environments (IDEs) like PyCharm or Visual Studio Code, which provide interactive debugging tools.
  1. Assertions:
  • Use assert statements to enforce conditions during development.
   x = 10
   assert x > 0, "Value must be positive"
  1. Exception Tracebacks:
  • When an unhandled exception occurs, Python provides a traceback that helps identify the location of the error.
       result = 10 / 0
   except ZeroDivisionError as e:
       import traceback
  1. Profiling:
  • Use profilers like cProfile or profile to identify performance bottlenecks.
   import cProfile

   def my_function():
       # Function code


Both logging and debugging are crucial skills for any developer. Logging helps you gather information about the state of your application, while debugging tools and techniques aid in identifying and resolving issues during development and testing. Choose the approach that suits your specific needs and the nature of the problem you are trying to solve.

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