Github user olegz commented on a diff in the pull request:
https://github.com/apache/nifi/pull/323#discussion_r59995310
--- Diff:
nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-framework-cluster/src/main/java/org/apache/nifi/cluster/coordination/heartbeat/CuratorHeartbeatMonitor.java
---
@@ -0,0 +1,376 @@
+/*
+ * 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.cluster.coordination.heartbeat;
+
+import java.io.ByteArrayInputStream;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.Unmarshaller;
+
+import org.apache.curator.RetryPolicy;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.CuratorFrameworkFactory;
+import org.apache.curator.retry.RetryForever;
+import org.apache.nifi.cluster.coordination.ClusterCoordinator;
+import org.apache.nifi.cluster.coordination.node.DisconnectionCode;
+import org.apache.nifi.cluster.coordination.node.NodeConnectionState;
+import org.apache.nifi.cluster.coordination.node.NodeConnectionStatus;
+import org.apache.nifi.cluster.protocol.NodeIdentifier;
+import org.apache.nifi.cluster.protocol.message.HeartbeatMessage;
+import org.apache.nifi.controller.cluster.ZooKeeperClientConfig;
+import org.apache.nifi.engine.FlowEngine;
+import org.apache.nifi.reporting.Severity;
+import org.apache.nifi.util.FormatUtils;
+import org.apache.nifi.util.NiFiProperties;
+import org.apache.nifi.util.StopWatch;
+import org.apache.zookeeper.KeeperException.NoNodeException;
+import org.apache.zookeeper.data.Stat;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Uses Apache Curator to monitor heartbeats from nodes
+ */
+public class CuratorHeartbeatMonitor implements HeartbeatMonitor {
+ private static final Logger logger =
LoggerFactory.getLogger(CuratorHeartbeatMonitor.class);
+ private static final Unmarshaller unmarshaller;
+
+ private final ClusterCoordinator clusterCoordinator;
+ private final ZooKeeperClientConfig zkClientConfig;
+ private final String heartbeatPath;
+ private final int heartbeatIntervalMillis;
+
+ private volatile CuratorFramework curatorClient;
+ private volatile ScheduledFuture<?> future;
+ private volatile Map<NodeIdentifier, NodeHeartbeat>
latestHeartbeatMessages;
+ private volatile long latestHeartbeatTime;
+
+ private final FlowEngine flowEngine = new FlowEngine(1, "Heartbeat
Monitor", true);
+
+ static {
+ try {
+ final JAXBContext jaxbContext =
JAXBContext.newInstance(HeartbeatMessage.class);
+ unmarshaller = jaxbContext.createUnmarshaller();
+ } catch (final Exception e) {
+ throw new RuntimeException("Failed to create an Unmarshaller
for unmarshalling Heartbeat Messages", e);
+ }
+ }
+
+ public CuratorHeartbeatMonitor(final ClusterCoordinator
clusterCoordinator, final Properties properties) {
+ this.clusterCoordinator = clusterCoordinator;
+ this.zkClientConfig =
ZooKeeperClientConfig.createConfig(properties);
+ this.heartbeatPath =
zkClientConfig.resolvePath("cluster/heartbeats");
+
+ final String heartbeatInterval =
properties.getProperty(NiFiProperties.CLUSTER_PROTOCOL_HEARTBEAT_INTERVAL,
+ NiFiProperties.DEFAULT_CLUSTER_PROTOCOL_HEARTBEAT_INTERVAL);
+
+ this.heartbeatIntervalMillis = (int)
FormatUtils.getTimeDuration(heartbeatInterval, TimeUnit.MILLISECONDS);
+ }
+
+ @Override
+ public void start() {
+ final RetryPolicy retryPolicy = new RetryForever(5000);
+ curatorClient =
CuratorFrameworkFactory.newClient(zkClientConfig.getConnectString(),
+ zkClientConfig.getSessionTimeoutMillis(),
zkClientConfig.getConnectionTimeoutMillis(), retryPolicy);
+ curatorClient.start();
+
+ this.future = flowEngine.scheduleWithFixedDelay(new Runnable() {
+ @Override
+ public void run() {
+ try {
+ monitorHeartbeats();
+ } catch (final Exception e) {
+ clusterCoordinator.reportEvent(null, Severity.ERROR,
"Failed to process heartbeats from nodes due to " + e.toString());
+ logger.error("Failed to process heartbeats", e);
+ }
+ }
+ }, heartbeatIntervalMillis, heartbeatIntervalMillis,
TimeUnit.MILLISECONDS);
+ }
+
+ private CuratorFramework getClient() {
+ return curatorClient;
+ }
+
+ @Override
+ public void stop() {
+ final CuratorFramework client = getClient();
+ if (client != null) {
+ client.close();
+ }
+
+ if (future != null) {
+ future.cancel(true);
+ }
+ }
+
+ @Override
+ public NodeHeartbeat getLatestHeartbeat(final NodeIdentifier nodeId) {
+ return latestHeartbeatMessages.get(nodeId);
+ }
+
+
+ /**
+ * Fetches all of the latest heartbeats from ZooKeeper
+ * and updates the Cluster Coordinator as appropriate,
+ * based on the heartbeats received.
+ *
+ * Visible for testing.
+ */
+ synchronized void monitorHeartbeats() {
+ final StopWatch fetchStopWatch = new StopWatch(true);
+ final Map<NodeIdentifier, NodeHeartbeat> latestHeartbeats =
fetchHeartbeats();
+ if (latestHeartbeats == null || latestHeartbeats.isEmpty()) {
+ // failed to fetch heartbeats from ZooKeeper; don't change
anything.
+ clusterCoordinator.reportEvent(null, Severity.WARNING, "Failed
to retrieve any new heartbeat information for nodes from ZooKeeper. "
+ + "Will not make any decisions based on heartbeats.");
+ return;
+ }
+
+ this.latestHeartbeatMessages = new HashMap<>(latestHeartbeats);
+ fetchStopWatch.stop();
+
+ final StopWatch procStopWatch = new StopWatch(true);
+ for (final NodeHeartbeat heartbeat : latestHeartbeats.values()) {
+ try {
+ processHeartbeat(heartbeat);
+ } catch (final Exception e) {
+ clusterCoordinator.reportEvent(null, Severity.ERROR,
+ "Received heartbeat from " +
heartbeat.getNodeIdentifier() + " but failed to process heartbeat due to " + e);
+ logger.error("Failed to process heartbeat from {} due to
{}", heartbeat.getNodeIdentifier(), e.toString());
+ logger.error("", e);
+ }
+ }
+
+ procStopWatch.stop();
+ logger.info("Finished processing {} heartbeats in {} (fetch took
an additional {})",
+ latestHeartbeats.size(), procStopWatch.getDuration(),
fetchStopWatch.getDuration());
+
+ // Disconnect any node that hasn't sent a heartbeat in a long time
(8 times the heartbeat interval)
+ for (final NodeHeartbeat heartbeat : latestHeartbeats.values()) {
+ final long maxMillis = heartbeatIntervalMillis * 1000L * 8;
+ final long threshold = latestHeartbeatTime - maxMillis;
--- End diff --
Do those need to be recomputed for each iteration?
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