Use environment variables defined in `.env` file when running code in a terminal

@brettcannon I’ve been using PYTHONPATH variable in .env for debugging using experimental debugger (without having to pip install PTVSD). However running in terminal doesn’t inherit these variables, I’ve had to export them manually.

What do you think about this feature?

Technical solution outlined in #4310 Need spec to provide UX (prompting users to load env, etc)

[joeparis]

I would like to ask for some clarification on this issue, please. As of 2he VS Code documentation on Python Environments as of 8/2/20 says:

An environment variable definitions file is a simple text file containing key-value pairs in the form of environment_variable=value, with # used for comments…

…

By default, the Python extension looks for and loads a file named .env in the current workspace folder, then applies those definitions…

I interpret this to mean that when VS Code finds a .env in the root of the workspace it will read the file and set any environment variables found in it in the current shell before the code is executed.

I have a .env file in the root of my workspace as follows:

DB_USER=my_db_user
DB_PASS=my_db_password_123!

I also have a file, envtest.py, in the root of the workspace that looks like this:

import os

db_user = os.environ.get("DB_USER")
db_password = os.environ.get("DB_PASS")

print(db_user)
print(db_password)

When I run this code in the integrated terminal (either Powershell or WSL) or if I remote into WSL I get output like the following:

(venv-win) PS C:\Users\joe\Dev\temp3> & c:/Users/joe/Dev/temp3/venv-win/Scripts/python.exe c:/Users/joe/Dev/temp3/envtest.py
DB_USER = None
DB_PASS = None

😖

When I run this code in the debugger I get the expected output; i.e. the environment variables are set and their values are printed to the screen.

(venv-win) PS C:\Users\joe\Dev\temp3>  cd 'c:\Users\joe\Dev\temp3'; & 'c:\Users\joe\Dev\temp3\venv-win\Scripts\python.exe' 'c:\Users\joe\.vscode\extensions\ms-python.python-2020.7.96456\pythonFiles\lib\python\debugpy\launcher' '51594' '--' 'c:\Users\joe\Dev\temp3\envtest.py'
DB_USER = my_db_user
DB_PASS = my_db_password_123!

😕

This behavior is maddeningly inconsistent and seemingly contradicts the documentation. 😠 Is there any plan to standardize the behavior and/or correct the documentation?

[dakotahawkins]

The whole "python.envFile" feature needs much better documentation/support (#544)…

I don’t know if or how it works, I don’t know if I can or how to refer to other variables inside .env (e.g. Does PYTHONPATH=${PYTHONPATH}:${workspaceFolder}/utility work?), etc.

From an hour of trying to use it, it appears nobody on the internet knows what’s going on. It’s either people who can’t get it to work either or people saying it does work but not giving realistic examples… grrr!!!