posting here because it proposes a change to the options sys

Question

posting here because it proposes a change to the options system <https github com pantsbuild pants issues 10885 issuecomment 701431374> basically it seems like it might be good to allow users to configure environment variables that affect the tools pants invokes but we generally run those tools with a stripped environment so this normal method of configuration doesn t really work particularly in the case of pex we have to introduce pants options to cover each new pex option which causes options fatigue as well as annoying variance in what s deprecated over time i think we could introduce a `Subsystem` subclass `EnvironmentPropagator` which doesn t register any options itself but allows environment variables in the form `PANTS PEX ` to be converted to just `PEX ` environment variables when we go to run a process where `PEX` is the value of a class level string field `EnvironmentPropagator environment sub component` making this a subsystem or not and using some other method means we could hook it up to ` pants help` and allow the user to see what variables are in their environment which would affect a pants execution and we could also incorporate the tool s own help text for its environment variables posting here because i made the comment specifically regarding using this for pex in the issue and i want to see what response i get to that before trying to make a more general issue

enough-analyst-54434 · Answer

This exists already here <https github com pantsbuild pants blob efef4c54d36e50ee2e14ad476ede8f3891dfa3f5 src python pants core util rules subprocess environment py L62 L75|https github com pantsbuild pants blob efef4c54d36e50ee2e14ad476ede8f3891dfa3f5 src python pants core util rules subprocess environment py L62 L75>

aloof-angle-91616 · Answer

thank you will review

aloof-angle-91616 · Answer

given that is there value in maintaining options like ` verbosity` in the totally separate `PexEnvironment` subsystem i am also somewhat interested in the idea of displaying the options that are available in ` pants help` as well as pulling the env vars help output from pex itself since it s mostly trivial to use pex to pull down the version of pex that pants is using then invoking its help in the command line but not entirely trivial

aloof-angle-91616 · Answer

pex s env var help being parseable allows for this it may not be very generalizable

aloof-angle-91616 · Answer

it also has a nice TODO that relates 100 to my thoughts here ``` TODO We may want to support different sets of env vars for different types of process Can be done via scoped subsystems possibly However we should only do this if there is a real need ```