How to set environment variables in vscode for debugging?

Inspired by my current area of work - which involved Python.

This is what I do for Flask.

MS Link

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

For any regular Python debugging

Evidence

import os

for key in os.environ.keys():
    print(f"{key}={os.environ.get(key)}")

After doing a F5 in VS Code with a file containing the above snippet:

Update on Feb 18

After receiving a comment I think the OP wants to run a script before debugging the Fask application. The steps that worked for me are below.

Overview

I ended up with the following files:

• Add a PowerShell file dosomething.ps1 (my custom script which I intend to launch before every debug session)
• Add a task.json (launch dosomething.ps1)
• Edit the existing launch.json by linking it with the task in task.json

The file dosomething.ps1

Write-Host "Inside do something"
Write-Host "The value of the environment variable TEMP is $env:TEMPcls"
Write-Host "The current path of the script is $PSScriptroot"

The file tasks.json

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "my script task",
            "type": "shell",
            "windows": {
                "command": "pwsh -f dosomething.ps1"
            },
            "problemMatcher": []
        }
    ]
}

Linking the launch.json with task.json

After pressing F5

What if my environment variable is a secret that I do not want to add to launch.json ?

In my team, we place all confidential variables in a .env file and add the file to .gitignore. As per design of VS Code, it will look for a .env file in the root of the current workspace and load those variables before launching your Python script. Please refer documentaion from MS here: https://code.visualstudio.com/docs/python/environments

By default, the Python extension looks for and loads a file named .env in the current workspace folder, then applies those definitions. The file is identified by the default entry "python.envFile": "${workspaceFolder}/.env" in your user settings (see General Python settings). You can change the python.envFile setting at any time to use a different definitions file