filter: add ratelimit log

[zirain]

Commit Message: add ratelimt log
Additional Description:
add some log to help debug ratelimt filter, in following cases specially:

• ratelimt Status Error due when timeout was set to small, refer to istio PR
• call grpc server onFailure

Risk Level: Low
Testing: manual testing
Docs Changes:
Release Notes:
Platform Specific Features:
[Optional Runtime guard:]
[Optional Fixes #Issue]
[Optional Deprecated:]
[Optional API Considerations:]

[repokitteh-read-only]

Hi @zirain, welcome and thank you for your contribution.

We will try to review your Pull Request as quickly as possible.

In the meantime, please take a look at the contribution guidelines if you have not done so already.

🐱

Caused by: #17902 was opened by zirain.

see: more, trace.

[wbpcode]

Please add signature for every commit by git commit -s.

[wbpcode]

Thanks. We do need some logs to help us to debug rate limit filter.

I add some initial comments to help us to complete this.

[davinci26]

thanks! Got a small question. Please take a look at the format and DCO

[davinci26]

/wait

[zirain]

/wait

do we still wait something else?

[davinci26]

Is the CI is passing the DCO and the format check?

[davinci26]

You will need to apply the DCO on the first commit (follow the instructions here) which would require rewritting the git history of your PR.

Also take a look at https://dev.azure.com/cncf/envoy/_build/results?buildId=87580&view=logs&j=55bc2ab9-36c1-5ab8-58a6-8c258728eeff&t=33b57bf9-ef13-58c8-bc2b-f804aeb16d39 which indicates that you have some format errors

[wbpcode]

Please add signature for every commit by git commit -s.

And we need to format this code by tools/code_format/check_format.py fix.

These are the remaining problems.

[zirain]

Please add signature for every commit by git commit -s.

And we need to format this code by tools/code_format/check_format.py fix.

These are the remaining problems.

All checks have passed.

[davinci26]

Thanks, LGTM @envoyproxy/senior-maintainers for a second review

[wbpcode]

Thanks. And waiting senior-maintainers to merge it.

[mattklein123]

Thanks, small comment.

/wait

[mattklein123]

This will log spam at high volume if the upstream RL server is having issues which I don't think is what we want. I would switch this to debug. There should already be a failure stat. If not we can add one?

[zirain]

there's nothing record right now when the upstream RL server is having issues, I think 'warn' is suitable in this scenario

[mattklein123]

As I said it's not suitable for log spamming reasons. If there is no other stat, you can also potentially use ENVOY_LOG_EVERY_POW_2 or similar.

[zirain]

switch it to debug

[zirain]

Thanks, small comment.

/wait

@mattklein123 please check the code again

[mattklein123]

Thanks!