NIFI-16298 Expose Primary Node and Cluster Coordinator role as Prometheus metrics

nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/prometheusutil/ClusterMetricsRegistry.java

@@ -48,5 +48,17 @@ public ClusterMetricsRegistry() {
                 .help("The total number of nodes in this cluster")
                 .labelNames("instance")
                 .register(registry));
+
+        nameToGaugeMap.put("IS_PRIMARY_NODE", Gauge.build()
+                .name("cluster_is_primary_node")
+                .help("Whether this NiFi instance is the Primary Node. Values are 0 or 1")
+                .labelNames("instance")
+                .register(registry));
+
+        nameToGaugeMap.put("IS_CLUSTER_COORDINATOR", Gauge.build()
+                .name("cluster_is_cluster_coordinator")
+                .help("Whether this NiFi instance is the Cluster Coordinator. Values are 0 or 1")
+                .labelNames("instance")
+                .register(registry));
     }
 }

nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/prometheusutil/PrometheusMetricsUtil.java

@@ -500,12 +500,15 @@ public static void createVersionInfoMetrics(final VersionInfoRegistry versionInf
     }
 
     public static CollectorRegistry createClusterMetrics(final ClusterMetricsRegistry clusterMetricsRegistry, final String instId, final boolean isClustered, final boolean isConnectedToCluster,
-                                                         final String connectedNodes, final int connectedNodeCount, final int totalNodeCount) {
+                                                         final String connectedNodes, final int connectedNodeCount, final int totalNodeCount,
+                                                         final boolean isPrimaryNode, final boolean isClusterCoordinator) {
         final String instanceId = StringUtils.isEmpty(instId) ? DEFAULT_LABEL_STRING : instId;
         clusterMetricsRegistry.setDataPoint(isClustered ? 1 : 0, "IS_CLUSTERED", instanceId);
         clusterMetricsRegistry.setDataPoint(isConnectedToCluster ? 1 : 0, "IS_CONNECTED_TO_CLUSTER", instanceId);
         clusterMetricsRegistry.setDataPoint(connectedNodeCount, "CONNECTED_NODE_COUNT", instanceId, connectedNodes);
         clusterMetricsRegistry.setDataPoint(totalNodeCount, "TOTAL_NODE_COUNT", instanceId);
+        clusterMetricsRegistry.setDataPoint(isPrimaryNode ? 1 : 0, "IS_PRIMARY_NODE", instanceId);
+        clusterMetricsRegistry.setDataPoint(isClusterCoordinator ? 1 : 0, "IS_CLUSTER_COORDINATOR", instanceId);
 
         return clusterMetricsRegistry.getRegistry();
     }

nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/StandardNiFiServiceFacade.java

@@ -8171,7 +8171,8 @@ protected Collection<AbstractMetricsRegistry> populateFlowMetrics(FlowMetricsRep
         }
         final boolean isClustered = clusterCoordinator != null;
         final boolean isConnectedToCluster = isClustered() && clusterCoordinator.isConnected();
-        PrometheusMetricsUtil.createClusterMetrics(clusterMetricsRegistry, instanceId, isClustered, isConnectedToCluster, connectedNodesLabel, connectedNodeCount, totalNodeCount);
+        PrometheusMetricsUtil.createClusterMetrics(clusterMetricsRegistry, instanceId, isClustered, isConnectedToCluster, connectedNodesLabel, connectedNodeCount, totalNodeCount,
+                controllerFacade.isPrimary(), controllerFacade.isClusterCoordinator());
         Collection<AbstractMetricsRegistry> metricsRegistries = Arrays.asList(
                 nifiMetricsRegistry,
                 jvmMetricsRegistry,

nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/main/java/org/apache/nifi/web/controller/ControllerFacade.java

@@ -494,6 +494,20 @@ public boolean isClustered() {
         return flowController.isClustered();
     }
 
+    /**
+     * @return true if this node is the Primary Node
+     */
+    public boolean isPrimary() {
+        return flowController.isPrimary();
+    }
+
+    /**
+     * @return true if this node is the Cluster Coordinator
+     */
+    public boolean isClusterCoordinator() {
+        return flowController.isClusterCoordinator();
+    }
+
     /**
      * Gets the name of this controller.
      *

nifi-framework-bundle/nifi-framework/nifi-web/nifi-web-api/src/test/java/org/apache/nifi/web/api/TestFlowResource.java

@@ -276,13 +276,13 @@ public void testGetFlowMetricsPrometheusAsJson() throws IOException {
         assertTrue(metrics.containsKey(ROOT_FIELD_NAME));
 
         final List<Sample> registryList = metrics.get(ROOT_FIELD_NAME);
-        assertEquals(13, registryList.size());
+        assertEquals(15, registryList.size());
 
         final Map<String, Long> result = getResult(registryList);
         assertEquals(3L, result.get(SAMPLE_NAME_JVM));
         assertEquals(4L, result.get(SAMPLE_LABEL_VALUES_PROCESS_GROUP));
         assertEquals(2L, result.get(SAMPLE_LABEL_VALUES_ROOT_PROCESS_GROUP));
-        assertEquals(4L, result.get(CLUSTER_LABEL_KEY));
+        assertEquals(6L, result.get(CLUSTER_LABEL_KEY));
     }
 
     @Test
@@ -836,6 +836,8 @@ private static CollectorRegistry getClusterMetricsRegistry() {
         clusterMetricsRegistry.setDataPoint(1, "IS_CONNECTED_TO_CLUSTER", "B1Id");
         clusterMetricsRegistry.setDataPoint(2, "CONNECTED_NODE_COUNT", "B1Id", "2 / 3");
         clusterMetricsRegistry.setDataPoint(3, "TOTAL_NODE_COUNT", "B1Id");
+        clusterMetricsRegistry.setDataPoint(1, "IS_PRIMARY_NODE", "B1Id");
+        clusterMetricsRegistry.setDataPoint(0, "IS_CLUSTER_COORDINATOR", "B1Id");
 
         return clusterMetricsRegistry.getRegistry();
     }