Add variadic arguments to metric exporter/reader interfaces

[ocelotl]

Fixes #2650

[lzchen]

What about adding kwargs to the constructors of all these public components?

[ocelotl]

What about adding kwargs to the constructors of all these public components?

Not sure if that is necessary, the idea is that we need kwargs to receive extra arguments that we may decide to add in the future to an existing method call that we have now. For example here we have a call to shutdown. If in the future we want to pass an extra argument to that call, we need the underlying exporter stored in self._exporter there to have a method shutdown that can receive extra arguments. We don't have calls that instantiate these classes in our existing code so, I don't think we need to add them to the constructors.

I guess in the future we could have that constructor call and in theory every method could be in this situation, so the "right" policy would be to add kwargs to all methods, but I don't think we want that.

[lzchen]

@ocelotl

the idea is that we need kwargs to receive extra arguments that we may decide to add in the future to an existing method call that we have now

Is that what the original issue is about? The original issue says add args and kwargs to "user implementable interfaces". The constructors should be part of that no?

I guess in the future we could have that constructor call and in theory every method could be in this situation, so the "right" policy would be to add kwargs to all methods, but I don't think we want that.

I think this is what we want right? We want to have the flexibility to change the signature of every user exposed interface, including methods.

[ocelotl]

@ocelotl

the idea is that we need kwargs to receive extra arguments that we may decide to add in the future to an existing method call that we have now

Is that what the original issue is about? The original issue says add args and kwargs to "user implementable interfaces". The constructors should be part of that no?

If that is the case we should mark the constructor with abstractmethod.