Opentelemetry-java: Rename `contrib` and `sdk_contrib`

[tylerbenson]

contrib is causing a bit of confusion around the intention. Perhaps something like util or ext instead?

[iNikem]

@tylerbenson What IS the intention of those submodules?

[tylerbenson]

This was explained on a call by @bogdandrutu but I forgot what he said.

[iNikem]

I would love to start transferring some tribal knowledge from peoples head into more readable documentation. I totally feel the pain of new contributor and want to help future generations. So if somebody can explain their meaning to me, I will augment CONTRIBUTING.md. And I can make the actual PR of renaming folders, if needed :)

[bogdandrutu]

• contrib has functionality that depends only on the API
• contrib_sdk has functionality that depends on the API (may by just indirect via the SDK dep) + SDK

For the moment these were the only rules we applied, but based on the specification https://github.com/open-telemetry/opentelemetry-specification/pull/539 we should split the contrib into instrumentation (will have all the instrumentation that depends on the API only) and contrib (will contain any helper packages that depend on the API but are not instrumentations like the WithSpan annotation)

[bogdandrutu]

@iNikem you got it :)

[iNikem]

@bogdandrutu but I still don't quite understand what does contrib part of those names mean? And I think just renaming them to util will not bring any clarity into their intention.

[bogdandrutu]

What name do you expect for some utility artifacts? We choose to call them contrib, it is a naming decision (maybe a better name can be used). I am not sure what is unclear.

[iNikem]

E.g. what are criteria for the decision to put some functionality into contrib/util and not into API/SDK proper? If we just say "this is a bunch of utility/helper artefacts", then I am afraid it will become what every util package becomes: big ball of mud :)

[iNikem]

Talked to Bogdan during SIG meeting and we agreed on the name extra and sdk_extra.

[carlosalberto]

I don't like the names of extra and sdk_extra. What is the rationale behind this?

[iNikem]

They contain additional, utility functionality that some users may want, while others don't. They are not "contributed" by some external third party, but are maintained by the same "team" (in loos OSS sense of word) as api or sdk proper.

[trask]

I also find the name contrib confusing. It gives me the impression that it is a grouping for things that are contributed (and possibly maintained) by other people.

Maybe extensions and sdk_extensions? (based on @tylerbenson's ext proposal above)