envoyproxy/envoy

Make grpc client cache eviction period configurable

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#29,982 opened on Oct 5, 2023

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area/ext_authzarea/grpcenhancementhelp wanted

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Description

Envoy is currently hardcoded to evict thread-local GRPC clients from its cache if there is no activity for 50s. Due to the low QPS and high number of Envoy worker threads, it is very easy to cross this interval between consecutive requests on the same worker thread. Hence, many authorization requests from worker threads will incur a connection restablishment latency, resulting in high client-side authorization delays.

To avoid this issue, we would like to be able to use a longer cache eviction timeout. It would be preferable if this timeout is configurable per proxy.

Contributor guide

Research direction
Find the hardcoded 50s timeout for gRPC client cache eviction in the Envoy codebase and make it configurable via a new option in the proxy configuration.
Tech stack
cppgrpc
Domain
backendinfrastructure
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++Envoy internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40