Add a general API to get env variables or commands required to activate environment

[karrtikr]

Deprecate existing Jupyter-specific getActivatedEnvironmentVariables along with this.

Activating environments may be done using:

• Activated env variables
• Activation commands
• A combination of both

We've yet to figure out the exact details on the general extension API. Blocked on #20492.

[DonJayamanne]

Ask 1 - site packages

Note: I've found that when using globally installed python environments (like HomeBew Python on Mac, Python Org Python on Mac, apt-get install python3 on ubuntu and Windows Store), we still need to update some path variables.
When you install packages like so <python> pip install jupyter notebook, then warning messages are logged in the console indicating the fact that some paths are not added into the PATH variable.
& sure enough things fail to load a result of not updating the PATH variable.

I.e. even for global envs, we need some PATH variables to be updated.

@brettcannon you might have more information about this, i.e. why users need to manually update their PATH when installing with
--user flag.

Ask 2 - venv created from pyenv (pyenv not in current path)

When dealing with pyenv can we ensure the necessary path variables are added
I.e. add the following into the PATH

/Users/mv/.pyenv/shims
/Users/mv/.pyenv

See microsoft/vscode-jupyter#12542

Ask 3 - Add exec directory to path for globals

In Jupyter extension when ever we run any python env, we always add the python exec directory into the current path
I.e. PATH=dirname(PythonEnvironment.executable):$PATH

This is the default behaviour for virtual envs, conda and the like. I.e. the executable directory is the first in the PATH
However there's no activation of global envs, hence this needs to be added by us (Jupyter ext) manually.

If we're going to off load getting activated env variables of Global envs as well, then this would have to be done for globals as well (i.e. all envs regardless of its activation mechanism)

[brettcannon]

I've found that when using globally installed python environments (like HomeBew Python on Mac, Python Org Python on Mac, apt-get install python3 on ubuntu and Windows Store), we still need to update some path variables.

I've never had a specific issue with e.g. Homebrew with anything like this. But honestly, if you're installing globally you're already asking for trouble and should probably be installing Jupyter via your OS and not Python itself.

why users need to manually update their PATH when installing with
--user flag.

That's only if you are trying to reach a binary that a package installed, not to simply use a library. And it's typically necessary because --user installs to ~/.local/bin on Unix which is not traditionally on PATH. So it's really up to you and/or OS to place that on PATH.

When dealing with pyenv can we ensure the necessary path variables are added

What exactly is in that shim directory? If that's dynamically updated by pyenv then we don't want to add that as we don't control what e.g. python will point to and it can change from underneath us. But I believe we already have support for https://github.com/pyenv/pyenv-virtualenv .

In Jupyter extension when ever we run any python env, we always add the python exec directory into the current path
I.e. PATH=dirname(PythonEnvironment.executable):$PATH

Can I ask why you do that? That's not typical Python behaviour if something is globally installed because it will be found on PATH naturally. And that change to PATH for virtual environments only happens if you activate it, not if you just run Python itself directly. Remember, virtual environment activation is a convenience, not a requirement and people should not be coding as if it's guaranteed to occur.

And can you make those separate asks separate issues? They don't have anything to do with each other and will require their own consideration/solution.

[DonJayamanne]

So it's really up to you and/or OS to place that on PATH.

Got it, thanks, looks like we (Jupyter) will do this.
A lot of the packages (i think binaries) are in special directories and when installing via Pip there were a number of warnings indicating the fact that a particular directory is not in path

f you're installing globally you're already asking for trouble and should probably be installing Jupyter via your OS and not Python itself.

Not sure what you mean by installing jupyter via your OS

at? That's not typical Python behaviour if something is globally installed because it will be found on PATH naturally. And that change to PATH for virtual

Aah yes, agreed, this is specific to Jupyter
Basically users run shell commands within a kernel as python -m pip list at this point ptyhon shoudl point to the same executable that points to the kernel. Similar if a user were to run java -h then java executable shoudl be launched form the same directory where python is
& yes this is specifiv to jupyter

I think we'll continue special casing this in Jupyter ext

@brettcannon thanks for the responses, I will hide these comments as resolved.

[karthiknadig]

This now exists in the new environments extension.

[karthiknadig]

You can even get shell specific activation commands. Or activated run command if such exist for the environment type.