Support multiples of units for rate limits

[harpunius]

Title: Support multiples of units for rate limits

Description:

We want to be able to specify rate limit intervals more flexibly than per-minute or per-second, for example per 30 seconds or per 10 minutes. Concretely, we have some bursts over 2-3 minutes that we want to restrict. We can only do this by rate limiting per-minute or per-hour, the former not reflecting continuous load and the latter not re-allowing traffic until a full hour has passed.

This is also described in envoyproxy/ratelimit#190 and I planned to contribute this feature for envoyproxy/ratelimit but got stuck at the centralised protobuf definition, hence this issue.

My proposed solution would simply be to extend RateLimit with a new field:

uint32 unitMultiplier = 4;

Relevant Links:
The relevant call (for redis) is https://github.com/envoyproxy/ratelimit/blob/main/src/redis/fixed_cache_impl.go#L155. The ratelimit service iterates over a list of internal limits []*config.RateLimit objects, that each contain a Limit struct (https://github.com/envoyproxy/ratelimit/blob/3654bfd73dc728debfc280b2097664f595036197/src/config/config.go#L22), pointing to the generated pb.go file (https://github.com/envoyproxy/go-control-plane/blob/main/envoy/service/ratelimit/v3/rls.pb.go#L357-L367).

[soulxu]

cc @esmet @mattklein123

[harpunius]

I added my implementation built on the proposed Limit.UnitMultiplier field in envoyproxy/ratelimit#552. Can you please have a look? ping: @esmet @mattklein123

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[harpunius]

Hey @mattklein123 @esmet, this is still relevant. I had a brief look into the c++ ratelimit headers. I guess we would need to extend those as well?

envoy/source/extensions/filters/http/ratelimit/ratelimit_headers.cc

Line 32 in f580ed0

const uint32_t window = convertRateLimitUnit(status.current_limit().unit());

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[harpunius]

Not stale, waiting for input.

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[github-actions]

This issue has been automatically closed because it has not had activity in the last 37 days. If this issue is still valid, please ping a maintainer and ask them to label it as "help wanted" or "no stalebot". Thank you for your contributions.

[ashish-quillbot]

Waiting for this feature

[dnbn]

Waiting for it too

[Martin-happy]

in need of this !
help wanted

[harpunius]

Not stale. Ping @esmet @mattklein123, can you please have a look?

@soulxu can you please mark this as not stale again? Thanks!

[ramaraochavali]

@harpunius Can you please make the necessary API change and propose a PR?