The Most Effective Debugging and Development Method in Django

Python generates a traceback when an exception is raised. You can use the Python traceback module to extract, format, and print stack traces. Tracebacks are typically read from the bottom to the top, and the exception or error that was encountered is always displayed on the last line of the traceback.

Traceback

To catch and print an exception you can use traceback

import sys, traceback

def run_user_code(envdir):
    source = input(">>> ")
    try:
        exec(source, envdir)
    except Exception:
        print("Exception in user code:")
        print("-"*60)
        traceback.print_exc(file=sys.stdout)
        print("-"*60)

envdir = {}
while True:
    run_user_code(envdir)

When writing code, it's essential to follow a structured approach to debugging and development. One highly effective method is the top-down approach, where you start with defining entry points and then build upon them with specific functions.

For example, consider the following Python code:

def entry_point():
    sandwich = toaster(bread)
    sandwich = add(cheese, sandwich)
    sandwich = add(spam, sandwich)

Each function should have a single, well-defined task, making it easier to identify and fix issues. Debugging in Python can be facilitated by using the Python Debugger (PDB) with commands like 'c' to continue execution, 'n' to step to the next line, 's' to step into functions, and 'q' to quit the debugger.

For logical errors, breakpoints can be set in Django views, allowing you to pause execution and inspect variables to diagnose problems.

While PDB is a valuable tool, remember that debugging is just one part of development. Performance issues often require collaboration and a combination of tools and techniques. Always consider seeking information from online sources and consider the limitations of AI tools like ChatGPT when using them for assistance.

https://docs.python.org/3/library/pdb.html

The typical usage to break into the debugger is to insert:

import pdb; pdb.set_trace()

Or:

breakpoint()

   

def double(x):
   breakpoint()
   return x * 2
val = 3
print(f"{val} * 2 is {double(val)}")

 > ...(3)double()

-> return x * 2
(Pdb) p x
3
(Pdb) continue
3 * 2 is 6