Debugging Adventure

Debugging is an essential skill for software developers. It is the process of identifying and resolving issues or bugs that are preventing a program from functioning correctly. Debugging can be a challenging and time-consuming task, but it's one that every developer must learn to do effectively. In this article, I'll share one of my debugging adventures and how I overcame it.

The bug I encountered was a strange issue where a user was unable to log in to our web application. Our web application used a third-party library for authentication, and the login process worked fine for most users. However, a few users were encountering an error message that read "Invalid username or password" even though their credentials were correct.

When I encountered the bug, the first step I took was to examine the code that handled the login process. I reviewed the code to ensure that there were no syntax or logic errors that could cause the issue. This involved analyzing the server-side code that handled the login process, including the validation of the user's credentials and generating an authentication token.

Here's an example of how I checked the user's credentials:

def login(request):
    username = request.POST.get('username')
    password = request.POST.get('password')

    user = authenticate(username=username, password=password)

    if user is not None:
        login(request, user)
        # generate authentication token
        return HttpResponse('Successful login')
    else:
        # return error message
        return HttpResponse('Invalid username or password')

In the code above, I retrieved the username and password from the login form's POST request. I then passed the username and password to theauthenticate() function, which returned a user object meaning the credentials were correct. We then called thelogin() function to log the user in and generate an authentication token.

I could not find anything that would cause the issue. I then decided to dig deeper and look at the logs generated by the third-party library.

import logging

logger = logging.getLogger(__name__)

def login(request):
    try:
        # third-party library login
        # ...
    except Exception as e:
        logger.error(f'Error logging in user: {e}')
        return HttpResponse('Unable to login')

I found that the library was returning an error code that indicated the user's account was locked due to too many failed login attempts. This was surprising because the user insisted that they had never attempted to log in before.

To further investigate the issue, I reached out to the user and asked them to send me their login credentials. Using those credentials, I attempted to log in and encountered the same error message. At this point, I was confident that the issue was not with our code but with the third-party library. I contacted their support team and provided them with the user's account information and the error code.

After some investigation, the third-party library support team found that their system had incorrectly flagged the user's account as being locked due to failed login attempts. They reset the account and confirmed that the user could now log in without any issues. We updated our code to handle this edge case, and the issue was resolved.

In conclusion, debugging is an essential skill that every developer must learn to do effectively. Sometimes the root cause of an issue may not be immediately apparent, and it requires a systematic approach to identify and resolve the issue. In this debugging adventure, I had to dig deeper and examine the logs generated by the third-party library to find the root cause of the issue. By collaborating with the user and the third-party library support team, we were able to resolve the issue and provide a better user experience.