Pass environment variables to the python interpreter

[lud-wj]

I would like to know how I can pass environment variables dynamically. It seems that the interpreter inherits environment variables from where the application is booted. But is there a way to add some (from loaded .env file in runtime.exs) or remove/overwrite some, to avoid leaking sensitive data or swap an API key for another ?

Thank you :)

(oh and not worth its own issue: how do you pass a pid to send_tagged_objects ? The encoder does not support passing pids in globals)

[jonatanklosko]

Yes, when the BEAM starts Erlang uses the process env vars to initialise it's internal env vars store, but further modifications such as System.put_env only affect the Erlang data structure. I think the same applies to Python when modifying sys.environ dict. So System.put_env will not be visible to Python, even if it happens before initialization.

I think it would be reasonable for us to pass System.get_env() when initializing Python and set sys.environ to match it exactly. I will have a look at that.

(oh and not worth its own issue: how do you pass a pid to send_tagged_objects ? The encoder does not support passing pids in globals)

You should be able to pass pid via globals, the encoder was added together with send_tagged_objects, however note that those are only available if you install Pythonx from main, not on latest. We have been waiting on feedback regarding send_tagged_objects before making a release.

[jonatanklosko]

We decided to not mirror the env vars. Setting os.environ in Python automatically sets the OS process environment variables, so the side-effects can go beyond Python. See #43 (comment). On a sidenote, there is a number of gotchas to make it work on Windows.

Instead we documented the current behaviour (#44).

If you want to mirror specific env vars, you can do Pythonx.eval and set os.environ keys accordingly. A good place to do that may be you def start in your Application, so it happens after Python is initialized, and before you start any processes relying on it.