Breakpoints are not hitting in VS Code while debugging Python Flask app

[iamshivprasad]

I'm new to Python Flask development and VS Code. I've been trying to create an app by referring the below tutorials.

https://code.visualstudio.com/docs/python/tutorial-flask

https://github.com/Microsoft/python-sample-vscode-flask-tutorial\

https://code.visualstudio.com/docs/python/debugging

Repo for reference: https://github.com/iamshivprasad/analytics

Cloned folder structure is:

• Development
  • .vscode
    • launch.json
  • analyticspyengine
    • analytics_modules
    • controllers
    • datainterfaces
    • utils
    • init.py
    • analyticsservices.py
    • webapp.py
      .
      .
      .

I am able to launch the program successfully with below settings in launch.json.

 {
    "name": "Python: Flask",
    "type": "python",
    "request": "launch",
    "module": "flask",
    "env": {
        "FLASK_APP": "analyticspyengine.webapp",
        "FLASK_DEBUG": true,
        "FLASK_ENV": "development"
    },
    "args": [
        "run"
    ],
    "jinja": true
}

Content of webapp.py

#!/usr/bin/python3
import sys
from . import app   
from . import analyticsservices

Content of analyticspyengine/__init__.py

#!/usr/bin/python3
import sys, os
sys.path.insert(0, os.path.join(os.path.dirname(__file__)))

from flask import Flask
app = Flask(__name__) 

I'm facing the following problems. Completely helpless and frustrated!!!

**1) Execution is not hitting any breakpoints

2. After launching the app with the above settings, I'm not able to stop the service. i.e, Even after stopping the debugger, the app seems to be running. I can see the requests are being served through terminal output and Postman. The process seems to be alive until VS Code is closed.**

Is it an issue? Could someone shed some light?

Environment:
VS Code 1.31.0
Python Extension - 2019.1.0 (29 Jan 2019)
Python Version 3.7.1 64-bit
Flask Version 1.0.2
Windows 10

[brettcannon]

@iamshivprasad it looks like you stripped out "--no-debugger", "--no-reload" from "run". Try going back to the default and use the following (where all I did was change FLASK_APP):

{
            "name": "Flask",
            "type": "python",
            "request": "launch",
            "module": "flask",
            "env": {
                "FLASK_APP": "analyticspyengine.webapp",
                "FLASK_ENV": "development",
                "FLASK_DEBUG": "0"
            },
            "args": [
                "run",
                "--no-debugger",
                "--no-reload"
            ],
            "jinja": true
        }

[brettcannon]

This was posted simultaneously to Stack Overflow: https://stackoverflow.com/questions/54592727/breakpoints-are-not-hitting-in-vs-code-while-debugging-python-flask-app .

[iamshivprasad]

@iamshivprasad it looks like you stripped out "--no-debugger", "--no-reload" from "run". Try going back to the default and use the following (where all I did was change FLASK_APP):

{
            "name": "Flask",
            "type": "python",
            "request": "launch",
            "module": "flask",
            "env": {
                "FLASK_APP": "analyticspyengine.webapp",
                "FLASK_ENV": "development",
                "FLASK_DEBUG": "0"
            },
            "args": [
                "run",
                "--no-debugger",
                "--no-reload"
            ],
            "jinja": true
        }

@brettcannon Thank you, I think this fixed my issue.

I have taken the config from one of my other apps where I don't face this issue. Surprisingly, I'm still not using these flags there and works perfectly fine. The difference between these two apps is the
way the app object is created (also, app.run(); I'm not using app.run() in the app where I face the issue)

I'm curious to know what exactly went wrong, if you can give a bit of insight. Also, I'd like to know the significance of these flags.

Once again, thank you for saving my day :)

[brettcannon]

Glad it worked out!

[brettcannon]

And the flags basically turn off the automatic reload functionality of Flask which trips up our debugger. We're working on making them work together, but we're not quite there yet.

[iamshivprasad]

@brettcannon Thank you.