[konlue]

Fixes #7778.

Summary

In cluster mode, POST /instance/beat is absent from the ClusterForwardFilter forward list, so a follower handles the heartbeat locally: only that JVM's in-memory map is refreshed, while the master — the node that persists instance state — keeps aging the instance to OFFLINE.

Modifications

• Add /instance/beat to the cluster forward-list, making the master the single authority for instance heartbeats: isMaster() short-circuits locally (no forwarding loops), and the filter forwards the POST body and headers verbatim, so master-side validation and handling are unchanged.
• Scope is the beat endpoint only; dashboard reads (GET /instance, /instance/analysis/**) stay local.
• Add ClusterForwardFilterTest, the cluster filter module's first test.

Verifying this change

• ClusterForwardFilterTest: master handles locally; a follower forwards /instance/beat to the elected master with body and Content-Type intact and does not run the local chain; unlisted paths are handled locally; the shipped application.yml keeps the path in the forward list.

• Red-green: removing the yml entry fails the yml assertion (instance heartbeats must be forwarded to the master admin); restoring it passes (4/4).

• Targeted tests pass:

  ./mvnw -B -ntp -pl shenyu-admin test -Dtest=ClusterForwardFilterTest

  4/4 green.

• Checkstyle passes:

  ./mvnw -B -ntp -pl shenyu-admin checkstyle:check

  clean.

Notes

Forward failures (master unreachable) behave like every other forwarded path — no new fallback is introduced here. /instance/beat is not in the shiro white list, and the filter forwards the original headers including credentials, so authentication behaviour is unchanged.

[Aias00]

Approved.

In cluster mode a worker admin should not persist instance heartbeats locally; forwarding /instance/beat to the master keeps the master authoritative for instance data, consistent with the existing forward-list pattern (shenyu-client, configs, etc.). The change is config-only plus the new ClusterForwardFilterTest, which covers local handling on master, forwarding to master, unlisted paths, and a YAML assertion that the forward-list includes /instance/beat.

CI is green on this branch.