NIFI-15979 Add Connector reporting-task visibility

src/main/java/org/apache/nifi/controller/status/ConnectorStatus.java

@@ -0,0 +1,90 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.controller.status;
+
+/**
+ * The status of a Connector, including the status of its managed root Process Group.
+ *
+ * <p>
+ *     Connector-managed flows live outside the controller's root Process Group, so reporting tasks that wish to observe
+ *     metrics for them must consult {@link org.apache.nifi.reporting.EventAccess#getConnectorStatuses()} in addition to
+ *     {@link org.apache.nifi.reporting.EventAccess#getControllerStatus()}. Each {@link ConnectorStatus} exposes the
+ *     Connector's identity along with the {@link ProcessGroupStatus} for its managed root group.
+ * </p>
+ *
+ * <p>
+ *     The Connector API is experimental and this type is expected to grow over time to surface connector-level metrics
+ *     that do not exist at the Process Group level (e.g. connector-wide backlog or idle time).
+ * </p>
+ */
+public class ConnectorStatus implements Cloneable {
+
+    private String id;
+    private String name;
+    private ProcessGroupStatus rootGroupStatus;
+
+    /**
+     * @return the identifier of the Connector
+     */
+    public String getId() {
+        return id;
+    }
+
+    public void setId(final String id) {
+        this.id = id;
+    }
+
+    /**
+     * @return the name of the Connector
+     */
+    public String getName() {
+        return name;
+    }
+
+    public void setName(final String name) {
+        this.name = name;
+    }
+
+    /**
+     * @return the status of the Connector's managed root Process Group, or {@code null} if the Connector has no
+     *         active managed flow at the time the status was captured
+     */
+    public ProcessGroupStatus getRootGroupStatus() {
+        return rootGroupStatus;
+    }
+
+    public void setRootGroupStatus(final ProcessGroupStatus rootGroupStatus) {
+        this.rootGroupStatus = rootGroupStatus;
+    }
+
+    @Override
+    public ConnectorStatus clone() {
+        final ConnectorStatus clonedObj = new ConnectorStatus();
+        clonedObj.id = id;
+        clonedObj.name = name;
+        clonedObj.rootGroupStatus = rootGroupStatus == null ? null : rootGroupStatus.clone();
+        return clonedObj;
+    }
+
+    @Override
+    public String toString() {
+        return "ConnectorStatus [id=" + id
+                + ", name=" + name
+                + ", rootGroupStatus=" + rootGroupStatus
+                + "]";
+    }
+}

src/main/java/org/apache/nifi/reporting/EventAccess.java

@@ -17,12 +17,15 @@
 package org.apache.nifi.reporting;
 
 import org.apache.nifi.action.Action;
+import org.apache.nifi.controller.status.ConnectorStatus;
 import org.apache.nifi.controller.status.ProcessGroupStatus;
 import org.apache.nifi.diagnostics.StorageUsage;
 import org.apache.nifi.provenance.ProvenanceEventRecord;
 import org.apache.nifi.provenance.ProvenanceEventRepository;
 
 import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -39,6 +42,24 @@ public interface EventAccess {
      */
     ProcessGroupStatus getGroupStatus(final String groupId);
 
+    /**
+     * Returns one {@link ConnectorStatus} per Connector currently registered with the runtime. Each
+     * {@link ConnectorStatus} carries the Connector's identity together with the {@link ProcessGroupStatus} for the
+     * Connector's managed root Process Group. Connector-managed groups are siblings of the controller's root Process
+     * Group (they have no parent and are not reachable from {@link #getControllerStatus()}), so reporting tasks that
+     * wish to surface metrics for connector-managed flows must consult this method in addition to
+     * {@link #getControllerStatus()}.
+     *
+     * The default implementation returns an empty collection so that runtimes without Connector support — and existing
+     * callers compiled against earlier versions of this interface — continue to work unchanged.
+     *
+     * @return one status per Connector; empty if no Connectors are registered or if the runtime does not support
+     *         Connectors
+     */
+    default Collection<ConnectorStatus> getConnectorStatuses() {
+        return Collections.emptyList();
+    }
+
     /**
      * Convenience method to obtain Provenance Events starting with (and
      * including) the given ID. If no event exists with that ID, the first event