local rate limiter: backport the non-timer based bucket

[nfuden]

backport the first 3 rate limit pieces of upstream's 34774 issue

This allows us to run local rate limiting not on the main thread if an environment variable is set to true.

In the future can be disabled via envoy_reloadable_features_no_timer_based_rate_limit_token_bucket
for now can be ENABLED via envoy_reloadable_features_no_timer_based_rate_limit_token_bucket

[solo-changelog-bot]

Issues linked to changelog:
solo-io/gloo#9564

[ashishb-solo]

I'm not sure exactly how to review/test this so any guidance you have would be appreciated. So far, envoy-static seems to compile successfully. I'm also looking at the tests that were modified in the patch. It looks like here's a list of test files that were updated:

test/common/common/BUILD
test/common/common/token_bucket_impl_test.cc
test/extensions/filters/common/local_ratelimit/BUILD
test/extensions/filters/common/local_ratelimit/local_ratelimit_test.cc
test/extensions/filters/http/local_ratelimit/BUILD
test/extensions/filters/http/local_ratelimit/config_test.cc
test/extensions/filters/http/local_ratelimit/filter_test.cc
test/extensions/filters/http/local_ratelimit/local_ratelimit_integration_test.cc
test/extensions/filters/listener/local_ratelimit/local_ratelimit_test.cc
test/extensions/filters/network/local_ratelimit/local_ratelimit_integration_test.cc
test/extensions/filters/network/local_ratelimit/local_ratelimit_test.cc

So we can test this by running

bazel test \
@envoy//test/common/common:token_bucket_impl_test \
@envoy//test/extensions/filters/common/local_ratelimit/... \
@envoy//test/extensions/filters/http/local_ratelimit/... \
@envoy//test/extensions/filters/listener/local_ratelimit/... \
@envoy//test/extensions/filters/network/local_ratelimit/...

I'm in the process of running this locally. If it's possible to add this to CI, that would be amazing, but if it's too much of a lift, then don't worry about it.

I'm also wondering if we want to do some sort of performance test before merging this into Gloo and/or releasing it. Do you have any thoughts here?

[nfuden]

solo-io/gloo#9822 shows that basic local rate limit works with this change

[ashishb-solo]

Looking good to me. I don't see any major issues and found a couple tiny nits.

My biggest question at the moment is what the role of lbucket.iff is. Is this something that we need in this patch/branch? Was it added by mistake?

For future reference, it looks like the majority of the complexity in the diffs here lies in these two files:

source/extensions/filters/common/local_ratelimit/local_ratelimit_impl.cc
source/extensions/filters/http/local_ratelimit/local_ratelimit.cc

(and their associated headers too, of course).

[ashishb-solo]

added a few more comments surrounding testing

[nfuden]

/kick aml-cpp

[ashishb-solo]

looks great! i really like having additional actions like this to test the veracity of the upstream patches that we backport

[nfuden]

/kick 92f51882