/*
* 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.node;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.charset.StandardCharsets;
import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.RetryNTimes;
import org.apache.nifi.cluster.exception.NoClusterCoordinatorException;
import org.apache.nifi.cluster.protocol.AbstractNodeProtocolSender;
import org.apache.nifi.cluster.protocol.ProtocolContext;
import org.apache.nifi.cluster.protocol.ProtocolException;
import org.apache.nifi.cluster.protocol.message.ProtocolMessage;
import org.apache.nifi.controller.cluster.ZooKeeperClientConfig;
import org.apache.nifi.io.socket.SocketConfiguration;
import org.apache.nifi.util.NiFiProperties;
import org.apache.zookeeper.KeeperException.NoNodeException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Uses Apache Curator to determine the address of the current cluster
* coordinator
*/
public class CuratorNodeProtocolSender extends AbstractNodeProtocolSender {
private static final Logger logger = LoggerFactory.getLogger(CuratorNodeProtocolSender.class);
private final String coordinatorPath;
private final ZooKeeperClientConfig zkConfig;
private InetSocketAddress coordinatorAddress;
public CuratorNodeProtocolSender(final SocketConfiguration socketConfig, final ProtocolContext<ProtocolMessage> protocolContext, final NiFiProperties nifiProperties) {
super(socketConfig, protocolContext);
zkConfig = ZooKeeperClientConfig.createConfig(nifiProperties);
coordinatorPath = zkConfig.resolvePath("cluster/nodes/coordinator");
}
@Override
protected synchronized InetSocketAddress getServiceAddress() throws IOException {
if (coordinatorAddress != null) {
return coordinatorAddress;
}
final RetryPolicy retryPolicy = new RetryNTimes(0, 0);
final CuratorFramework curatorClient = CuratorFrameworkFactory.newClient(zkConfig.getConnectString(),
zkConfig.getSessionTimeoutMillis(), zkConfig.getConnectionTimeoutMillis(), retryPolicy);
curatorClient.start();
try {
// Get coordinator address and add watcher to change who we are heartbeating to if the value changes.
final byte[] coordinatorAddressBytes = curatorClient.getData().usingWatcher(new Watcher() {
@Override
public void process(final WatchedEvent event) {
coordinatorAddress = null;
}
}).forPath(coordinatorPath);
if (coordinatorAddressBytes == null || coordinatorAddressBytes.length == 0) {
throw new NoClusterCoordinatorException("No node has yet been elected Cluster Coordinator. Cannot establish connection to cluster yet.");
}
final String address = new String(coordinatorAddressBytes, StandardCharsets.UTF_8);
final String[] splits = address.split(":");
if (splits.length != 2) {
final String message = String.format("Attempted to determine Cluster Coordinator address. Zookeeper indicates "
+ "that address is %s, but this is not in the expected format of <hostname>:<port>", address);
logger.error(message);
throw new ProtocolException(message);
}
logger.info("Determined that Cluster Coordinator is located at {}; will use this address for sending heartbeat messages", address);
final String hostname = splits[0];
final int port;
try {
port = Integer.parseInt(splits[1]);
if (port < 1 || port > 65535) {
throw new NumberFormatException("Port must be in the range of 1 - 65535 but got " + port);
}
} catch (final NumberFormatException nfe) {
final String message = String.format("Attempted to determine Cluster Coordinator address. Zookeeper indicates "
+ "that address is %s, but the port is not a valid port number", address);
logger.error(message);
throw new ProtocolException(message);
}
final InetSocketAddress socketAddress = InetSocketAddress.createUnresolved(hostname, port);
coordinatorAddress = socketAddress;
return socketAddress;
} catch (final NoNodeException nne) {
logger.info("No node has yet been elected Cluster Coordinator. Cannot establish connection to cluster yet.");
throw new NoClusterCoordinatorException("No node has yet been elected Cluster Coordinator. Cannot establish connection to cluster yet.");
} catch (final NoClusterCoordinatorException ncce) {
throw ncce;
} catch (Exception e) {
throw new IOException("Unable to determine Cluster Coordinator from ZooKeeper", e);
} finally {
curatorClient.close();
}
}
}