/**
* Copyright 2005-2014 Red Hat, Inc.
*
* Red Hat 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 io.fabric8.zookeeper.jgroups;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.util.ArrayList;
import java.util.List;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.utils.ZKPaths;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.jgroups.Address;
import org.jgroups.Event;
import org.jgroups.protocols.FILE_PING;
import org.jgroups.protocols.PingData;
import org.jgroups.util.Util;
public abstract class AbstractZooKeeperPing extends FILE_PING {
private static final String ROOT_PATH = "/fabric/registry/jgroups/";
private volatile String discoveryPath;
private volatile String localNodePath;
protected CuratorFramework curator;
protected abstract CuratorFramework createCurator() throws KeeperException;
protected CreateMode getCreateMode() throws KeeperException {
return CreateMode.EPHEMERAL;
}
@Override
public void init() throws Exception {
curator = createCurator();
super.init();
}
@Override
public void stop() {
try {
removeNode(localNodePath);
} finally {
super.stop();
}
}
public Object down(Event evt) {
switch (evt.getType()) {
case Event.CONNECT:
case Event.CONNECT_USE_FLUSH:
case Event.CONNECT_WITH_STATE_TRANSFER:
case Event.CONNECT_WITH_STATE_TRANSFER_USE_FLUSH:
discoveryPath = ROOT_PATH + evt.getArg();
localNodePath = discoveryPath + "/" + addressAsString(local_addr);
_createRootDir();
break;
}
return super.down(evt);
}
/**
* Creates the root node in ZooKeeper (/fabric/registry/jgroups
*/
@Override
protected void createRootDir() {
// empty on purpose to prevent dir from being created in the local file system
}
protected void _createRootDir() {
try {
if (curator.checkExists().forPath(localNodePath) == null) {
curator.create().creatingParentsIfNeeded().withMode(getCreateMode()).forPath(localNodePath);
}
} catch (Exception e) {
throw new RuntimeException(String.format("Failed to create dir %s in ZooKeeper.", localNodePath), e);
}
}
/**
* Reads all information from the given directory under clustername
*
* @return all data
*/
protected synchronized List<PingData> readAll(String clusterName) {
List<PingData> retval = new ArrayList<>();
try {
for (String node : curator.getChildren().forPath(discoveryPath)) {
String nodePath = ZKPaths.makePath(discoveryPath, node);
PingData nodeData = readPingData(nodePath);
if (nodeData != null) {
retval.add(nodeData);
}
}
} catch (Exception e) {
log.debug(String.format("Failed to read ping data from ZooKeeper for cluster: %s", clusterName), e);
}
return retval;
}
@Override
protected synchronized void writeToFile(PingData data, String clustername) {
writePingData(data);
}
protected synchronized PingData readPingData(String path) {
PingData retval = null;
DataInputStream in = null;
try {
byte[] bytes = curator.getData().forPath(path);
in = new DataInputStream(new ByteArrayInputStream(bytes));
PingData tmp = new PingData();
tmp.readFrom(in);
return tmp;
} catch (Exception e) {
log.debug(String.format("Failed to read ZooKeeper znode: %s", path), e);
} finally {
Util.close(in);
}
return retval;
}
protected synchronized void writePingData(PingData data) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream dos = null;
try {
dos = new DataOutputStream(baos);
data.writeTo(dos);
if (curator.checkExists().forPath(localNodePath) == null) {
curator.create().creatingParentsIfNeeded().withMode(getCreateMode()).forPath(localNodePath, baos.toByteArray());
} else {
curator.setData().forPath(localNodePath, baos.toByteArray());
}
} catch (Exception ex) {
log.error("Error saving ping data", ex);
} finally {
Util.close(dos);
Util.close(baos);
}
}
protected void removeNode(String path) {
try {
curator.delete().forPath(path);
} catch (KeeperException.NoNodeException e) {
// just log this, to keep down to 1 call, instead of 2 (exists + delete)
// coord nodes already remove this in handleView(), hence "expecting" this exception
if (log.isTraceEnabled()) {
log.trace(String.format("Node '%s' already removed: %s", path, e));
}
} catch (Exception e) {
log.error(String.format("Failed removing %s", path), e);
}
}
protected void remove(String clustername, Address addr) {
removeNode(discoveryPath + "/" + addressAsString(addr));
}
}