/**
* 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.cassandra.contrib.circuit;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import javax.management.JMX;
import javax.management.MBeanServerConnection;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
import org.apache.cassandra.dht.Range;
import org.apache.cassandra.service.StorageServiceMBean;
/**
* This class provides data abstraction for the JMX instrumentation
* of Cassandra nodes.
*/
public class RingModel
{
public static final int defaultPort = 8080;
private static final String fmtUrl = "service:jmx:rmi:///jndi/rmi://%s:%d/jmxrmi";
private static final String ssObjName = "org.apache.cassandra.service:type=StorageService";
private String seedName;
private String seedAddr;
private int seedPort;
private List<Node> nodes;
/**
* Constructs a RingModel using the named reference host and port number.
*
* @param seedName the hostname or IP of the startup node
* @param seedPort JMX port number
* @throws IOException if unable to setup the JMX connection
*/
public RingModel(String seedName, int seedPort)
{
this.seedName = seedName;
this.seedPort = seedPort;
try
{
seedAddr = InetAddress.getByName(seedName).getHostAddress();
}
catch (UnknownHostException e)
{
System.err.println("Error unknown host: " + seedName);
seedAddr = seedName;
}
}
/**
* Constructs a RingModel using the named reference host .
*
* @param seedName the hostname or IP of the startup node
*/
public RingModel(String seedName) throws IOException
{
this(seedName, defaultPort);
}
// @throws IOException if unable to setup the JMX connection
private static List<Node> retrieveRingData(String seedAddress, String remoteHost, int port) throws IOException
{
JMXServiceURL jmxUrl = new JMXServiceURL(String.format(fmtUrl, remoteHost, port));
JMXConnector jmxc = JMXConnectorFactory.connect(jmxUrl, null);
StorageServiceMBean ssProxy;
MBeanServerConnection mbeanServerConn = jmxc.getMBeanServerConnection();
try
{
ObjectName name = new ObjectName(ssObjName);
ssProxy = JMX.newMBeanProxy(mbeanServerConn, name, StorageServiceMBean.class);
} catch (MalformedObjectNameException e)
{
throw new RuntimeException(
"Invalid ObjectName? Please report this as a bug.", e);
}
Map<Range, List<String>> rangeMap = ssProxy.getRangeToEndpointMap(null);
List<Range> ranges = new ArrayList<Range>(rangeMap.keySet());
Collections.sort(ranges);
List<Node> nodes = new ArrayList<Node>();
for (Range r : ranges)
{
String host = rangeMap.get(r).get(0);
NodeStatus status;
if (host.equals(seedAddress))
status = NodeStatus.ISSEED;
else
status = NodeStatus.OK;
String token = r.left.toString();
nodes.add(new Node(host, status, token));
}
return nodes;
}
private List<Node> retrieveRingData(String remoteHost) throws IOException
{
return retrieveRingData(seedAddr, remoteHost, seedPort);
}
/**
* Retrieves the nodes that are known to the reference host.
* @return the list of nodes seen by the reference host.
*/
public List<Node> getNodes()
{
if (this.nodes == null)
{
List<Node> nodes = new ArrayList<Node>();
try
{
nodes = retrieveRingData(seedAddr, seedName, seedPort);
}
catch (IOException ex)
{
ex.printStackTrace();
nodes.add(new Node(seedName, NodeStatus.UNKNOWN, null));
}
this.nodes = nodes;
}
return nodes;
}
/**
* Query the specified host for a list of nodes.
*
* @param remoteHost the hostname or IP address of a node
* @return the list of nodes seen by the specified host
* @throws IOException if an error is encountered communicating with the node
*/
public List<Node> getRemoteNodes(String remoteHost) throws IOException
{
return retrieveRingData(remoteHost);
}
}
/**
* Represents a node in the cluster.
*/
class Node
{
public String host;
public volatile NodeStatus nodeStatus;
public String startToken;
public volatile boolean isSelected;
public Node(String host, NodeStatus status, String startToken)
{
this.host = host;
this.nodeStatus = status;
this.startToken = startToken;
}
public String getStartToken()
{
return startToken;
}
public String getHost()
{
return host;
}
public NodeStatus getStatus()
{
return nodeStatus;
}
public String toString()
{
return host;
}
public boolean isSelected()
{
return isSelected;
}
public void setSelected(boolean isSelected)
{
this.isSelected = isSelected;
}
public boolean isSeed()
{
return nodeStatus == NodeStatus.ISSEED ? true : false;
}
public void setStatus(NodeStatus status)
{
nodeStatus = status;
}
public boolean equals(Object o)
{
if (!(o instanceof Node))
return false;
Node other = (Node)o;
return other.getHost().equals(host);
}
public int hashCode()
{
return (startToken + host).hashCode();
}
}
enum NodeStatus
{
OK,
ISSEED,
SHORT,
LONG,
UNKNOWN,
}