Prathyush PV 4d86357adc Close stale gRPC connections in downstream client caches (#10250) ...

## What changed?
Both downstream client caches now close a cached `*grpc.ClientConn` when
its host leaves the membership ring, instead of holding it until gRPC's
idle timeout:
- History `connectionPool` subscribes to the history ring and closes
departed hosts' conns.
- Matching `ClientCache` gains `Evict` + a per-entry release fn;
`matching.NewClient` subscribes to the matching ring and evicts departed
hosts.

Both wait a configurable drain delay before closing — new
`history.connectionCloseDelay` / `matching.connectionCloseDelay`
settings (default 30s) — so in-flight RPCs can finish. The eviction
goroutines are tied to the owning client via `runtime.AddCleanup`.

## Why?
After #9277 removed the RPCFactory cache, these downstream caches still
held `*grpc.ClientConn` forever, so #8719's dial-timeout log spam just
moved down a layer. Closing conns on ring departure fixes it at the
source.

## How did you test it?
- [x] built
- [x] covered by existing tests

## Potential risks
`CachingRedirector` (non-default;
`HistoryClientOwnershipCachingEnabled=false`) is unchanged and still
relies on gRPC's idle timeout for stale-conn cleanup, same as today.

---------

Co-authored-by: David Reiss <david@temporal.io>

2026-06-06 01:18:45 +00:00

..

server

dynamic config: enhance update with metrics etc (#9366)

2026-03-10 01:50:54 +00:00

tools

Close stale gRPC connections in downstream client caches (#10250)

2026-06-06 01:18:45 +00:00