Export ClusterStats to JMX

[choiwaiyiu]

Exports ClusterStats to JMX.

Release notes

( x) This is not user-visible or is docs only, and no release notes are required.

*  Export ClusterStats to JMX

[oneonestar]

We can test it using /metrics added by #429

diff --git a/gateway-ha/src/test/java/io/trino/gateway/ha/TestGatewayHaMultipleBackend.java b/gateway-ha/src/test/java/io/trino/gateway/ha/TestGatewayHaMultipleBackend.java
index af680a6..f124e9d 100644
--- a/gateway-ha/src/test/java/io/trino/gateway/ha/TestGatewayHaMultipleBackend.java
+++ b/gateway-ha/src/test/java/io/trino/gateway/ha/TestGatewayHaMultipleBackend.java
@@ -338,6 +338,22 @@ final class TestGatewayHaMultipleBackend
         assertThat(callbackResponse.code()).isEqualTo(500);
     }
 
+    @Test
+    void testClusterStatsJMX()
+            throws Exception
+    {
+        Thread.sleep(5000);     // Wait for first health check to run
+        Request request = new Request.Builder()
+                .url("http://localhost:" + routerPort + "/metrics")
+                .get()
+                .build();
+        Response response = httpClient.newCall(request).execute();
+        String body = response.body().string();
+        System.out.println(body);
+        assertThat(body).contains("trino1_Healthy");
+        assertThat(body).contains("trino2_Healthy");
+    }
+
     @AfterAll
     void cleanup()
     {
diff --git a/gateway-ha/src/test/resources/test-config-template.yml b/gateway-ha/src/test/resources/test-config-template.yml
index beafe30..80ab3f3 100644
--- a/gateway-ha/src/test/resources/test-config-template.yml
+++ b/gateway-ha/src/test/resources/test-config-template.yml
@@ -11,6 +11,11 @@ dataStore:
 
 modules:
   - io.trino.gateway.ha.module.HaGatewayProviderModule
+  - io.trino.gateway.ha.module.ClusterStateListenerModule
+  - io.trino.gateway.ha.module.ClusterStatsMonitorModule
+
+managedApps:
+  - io.trino.gateway.ha.clustermonitor.ActiveClusterMonitor
 
 extraWhitelistPaths:
   - '/v1/custom.*'
@@ -23,3 +28,6 @@ gatewayCookieConfiguration:
 oauth2GatewayCookieConfiguration:
   deletePaths:
     - "/custom/logout"
+
+monitor:
+  taskDelaySeconds: 1

[willmostly]

@choiwaiyiu I just skimmed and this looks good overall. Can you add a test as suggested by @oneonestar?

Please update the description to suggest a simple release note as well.

[choiwaiyiu]

@willmostly @oneonestar
Sorry for the late response. I have added a test as suggested.

[ebyhr]

@willmostly @oneonestar @choiwaiyiu What's the current status of this PR?

[oneonestar]

Is it possible to make updateExport() takes List<ClusterStats> from ClusterStatsObserver? In that case we don't have to inject BackendStateManager and don't need to add getAllBackendStates().

[oneonestar]

Suggested change

	ClusterStatsJMX clusterStatsJMX = backendStates.get(clusterId);
	clusterStatsJMX.setFrom(clusterStats);
	backendStates.get(clusterId).setFrom(clusterStats);