Fast forward six months, and Client A needs a patch built for that same service to comply with some new requirements. It’s your job to maintain it, since you were the one who built it in the first place. You open up your text editor and
What did you even write?!
You spend hours parsing through your old code, but you’re completely lost in the mess. You were in such a rush at the time that you didn’t name your variables properly or even set your functions up in the proper control flow. Worst of all, you don’t have any comments in the script to tell you what’s what!

Developers forget what their own code does all the time, especially if it was written a long time ago or under a lot of pressure. When a deadline is fast approaching, and hours in front of the computer have led to bloodshot eyes and cramped hands, that pressure can be reflected in the form of code that is messier than usual.

But don’t freak out, bro! With the power of Python’s debugging tools at your fingertips, you too can become a master of code spelunking. In this article, we’ll cover how to use Visual Studio Code and its Python extension for debugging Flask applications. We’ll also provide some tips on how to write cleaner, more maintainable code in the first place.
First: what makes a good comment. A great comment is clear, concise, and adds value to your code without being redundant or unnecessary. Here are some best practices for writing comments that will help you avoid getting lost in your own spaghetti code:
1. Keep it short and sweet. Comments should be brief and to the point. Avoid long paragraphs of text that could easily be replaced with a well-written function name or variable label.
2. Use active voice. Write comments as if they’re instructions for someone else who is reading your code. Instead of saying “This calculates the total price,” say “Calculate the total price.”
3. Be specific. Don’t use vague language that could be interpreted in multiple ways. For example, instead of writing “This function does something with data,” write “This function converts Celsius to Fahrenheit using a formula.”
4. Use comments sparingly. Comments should only be used when necessary. If your code is clear and self-explanatory, you may not need any additional comments at all.
5. Update comments as needed. Make sure that your comments accurately reflect the current state of your code. Outdated or inaccurate comments can lead to confusion and errors down the line.
Now that we’ve covered some basic commenting best practices, how to use Visual Studio Code for debugging Flask applications using the Python extension. First, make sure you have both VS Code and the Python extension installed on your machine. You can download them from their respective websites or through your preferred package manager (such as Homebrew or Chocolatey).
Once you have everything set up, create a new project in VS Code by clicking File > New Window/File > Open Folder… and selecting the folder containing your Flask application. Alternatively, you can use the command palette to open a folder using Ctrl + Shift + P (Windows, Linux) or Command + Shift + P (Mac).

To start debugging, click on Run > Start Debugging or press F5. This will launch your Python interpreter and attach the debugger to it. If you’re running Flask in a separate terminal window, make sure that you have set up the environment variables correctly so that VS Code can find your application.
When the debugger is attached, navigate to the URL of your Flask app using your web browser or by clicking on Run > Start Debugging (in Chrome) or Ctrl + Shift + D (in Firefox). This will open a new tab in your default browser and start running your Flask application.
To set breakpoints in your code, click on the left margin of any line that you want to pause execution at. You can also use the command palette to add or remove breakpoints using Ctrl + Shift + P (Windows/Linux) or Command + Shift + P (Mac).
When a breakpoint is hit, VS Code will stop executing your code and highlight the line that was executed before the breakpoint. You can then use the debugger console to inspect variables, step through your code using F5 or Step Over (F8), or continue execution using Resume (Ctrl + Shift + I on Windows/Linux or Command + Option + R on Mac).
To make it easier to navigate between files and functions in your Flask application, you can use the debugger’s call stack window. This will show you a list of all the currently running functions and their respective line numbers. You can click on any function to jump directly to its source code or set a breakpoint within it using Ctrl + Shift + P (Windows/Linux) or Command + Shift + P (Mac).

To make your Flask application more maintainable, you should follow some basic coding principles such as:
– Use descriptive variable names that accurately reflect their purpose. For example, instead of writing “x”, write “total_price”.
– Write functions with clear and concise comments that explain what they do and how to use them. This will make it easier for other developers (or your future self) to understand the code and modify it as needed.
– Use control flow statements such as if/else, try/except, or while loops to handle different scenarios in your Flask application. This will help you avoid writing long chains of conditional statements that are difficult to read and maintain.
– Test your Flask application using unit tests or integration tests. This will help you catch any bugs or errors before they become a problem for your users.
By following these tips, you can write cleaner, more maintainable code in your Flask applications and make debugging easier by catching issues early on.