Add client-benchmark-noop-api-plugin to stress clients even more in benchmarks

[danielmitterdorfer]

With this PR we add a noop plugin for Elasticsearch. It is needed to reduce the amount of request processing that is done on server-side to avoid introducing accidental bottlenecks and uncertainty on server side in order to stress clients in client-side benchmarks.

[rjernst]

@danielmitterdorfer Could we instead have a dummy http server (not even using ES) that responds on the expected paths? I think it would be a lot more transparent (no possibility of accidentally not setting/changing something in ES which results in real work being done). If that doesn't work, then can we at least have a better, more descriptive name than "noop"? Something that makes it clear it is for benchmarking, and makes indexing requests noops...but I would still prefer just not using ES at all for this, since it does not seem necessary.

[danielmitterdorfer]

@rjernst I can change name, sure. Regarding the plugin's purpose: We could use a dummy HTTP server but the thing is that this is also used for benchmarking the transport client and there is no substitute for that. Also, using ES for the server-side component ensures that the interaction model stays as close as possible to a real use case.

[danielmitterdorfer]

I've renamed the plugin now to "client-benchmark-noop-api-plugin" to indicate that it provides a no operation (No op) API and its purpose (benchmarking clients).

[danielmitterdorfer]

@rjernst Are you otherwise fine with the change (especially after my explanation why the plugin is needed at all)?

[rjernst]

just curious, why isn't this called "indexing"?

[danielmitterdorfer]

No special reason tbh. I just used the specific indexing approach as name.

[rjernst]

LGTM

[danielmitterdorfer]

Thanks for your review Ryan.