Add entry point support for remote auth plugin

[asherf]

This will remove the need to specify the remote_auth_plugin in the pants config and will allow the auth plugin to be auto discovered using the entry point mechanism.

Once the updated Toolchain Pants Plugin with the entry point support is released and updated in this repo I will mark the [GLOBAL].remote_auth_plugin as deprecated.

not adding a label for now in order to prevent CI from running. will do that after the PR this change is on top of lands.

[stuhood]

Thanks!

[stuhood]

Won't __name__ always be remote_auth, since it is required to be for loading? You'll probably want to use the module here instead.

[asherf]

updated

[stuhood]

Having a fully specified Protocol for this type would be good.

[asherf]

I tried to do it, but this feels like a rabbit hole which is out of scope for this PR.
since arguments are named, if I do:

AuthPluginFunctionProtocol = Callable[[Dict[str, str], Dict[str, str], Options, Mapping[str, str], Union[AuthPluginResult, None]],   AuthPluginResult]

and use that instead of callable, mypy complains:

src/python/pants/option/global_options.py:391:30: error: Unexpected keyword
argument "initial_execution_headers"  [call-arg]
            auth_plugin_result = remote_auth_plugin_func(
                                 ^
src/python/pants/option/global_options.py:391:30: error: Unexpected keyword
argument "initial_store_headers"  [call-arg]
            auth_plugin_result = remote_auth_plugin_func(
                                 ^
src/python/pants/option/global_options.py:391:30: error: Unexpected keyword
argument "options"  [call-arg]
            auth_plugin_result = remote_auth_plugin_func(
                                 ^
src/python/pants/option/global_options.py:391:30: error: Unexpected keyword
argument "env"  [call-arg]
            auth_plugin_result = remote_auth_plugin_func(
                                 ^
src/python/pants/option/global_options.py:391:30: error: Unexpected keyword
argument "prior_result"  [call-arg]
            auth_plugin_result = remote_auth_plugin_func(
                                 ^
Found 5 errors in 1 file (checked 29 source files)

so this requires usage of NamedArg which is available only in mypy_extensions currently not used in the pants repo.

beside all that, since this is runtime behavior thing, any type checks here are somewhat pointless since the auth plugin function is loaded at runtime and any validation mypy does in the pants repo itself feels pointless and I don't see what kind of errors the additional and more accurate typing information will prevent.

[stuhood]

Sorry, I meant literally Protocol: https://mypy.readthedocs.io/en/stable/protocols.html#simple-user-defined-protocols

[asherf]

Not sure how to use here since the function is implemented as a function and not a class and from a quick read of the docs you linked to, it seems that Protocol is intended to be use in class based interfaces.

At any case, as I said, this still feels out of scope for this PR (we don't have it with the current implementation) and I don't see the benefit (since this is a runtime behavior) what kind of bugs do you think this kind of annotation will prevent ?

[stuhood]

To make a Protocol for a Callable you define the __call__ method: an example:

pants/src/python/pants/pantsd/pants_daemon_core.py

Lines 28 to 34 in 258ab26

	class PantsServicesConstructor(Protocol):
	def __call__(
	self,
	bootstrap_options: OptionValueContainer,
	graph_scheduler: GraphScheduler,
	) -> PantsServices:
	...

But yea, as you said: we don't define this API yet, so I'm fine with it being out of scope.

[asherf]

got it, I'll have a follow up PR for this.
since if we this type is exposed from pants, then the plugin implementation can use it.