/*
*
* 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.hadoop.hbase.replication;
import java.io.Closeable;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Abortable;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.replication.ReplicationAdmin;
import org.apache.hadoop.hbase.exceptions.DeserializationException;
import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.zookeeper.ZKUtil;
import org.apache.hadoop.hbase.zookeeper.ZooKeeperNodeTracker;
import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NodeExistsException;
import com.google.protobuf.InvalidProtocolBufferException;
@InterfaceAudience.Private
public class ReplicationPeerZKImpl implements ReplicationPeer, Abortable, Closeable {
private static final Log LOG = LogFactory.getLog(ReplicationPeerZKImpl.class);
private final ReplicationPeerConfig peerConfig;
private final String id;
private volatile PeerState peerState;
private volatile Map<TableName, List<String>> tableCFs = new HashMap<TableName, List<String>>();
private final Configuration conf;
private PeerStateTracker peerStateTracker;
private TableCFsTracker tableCFsTracker;
/**
* Constructor that takes all the objects required to communicate with the
* specified peer, except for the region server addresses.
* @param conf configuration object to this peer
* @param id string representation of this peer's identifier
* @param peerConfig configuration for the replication peer
*/
public ReplicationPeerZKImpl(Configuration conf, String id, ReplicationPeerConfig peerConfig)
throws ReplicationException {
this.conf = conf;
this.peerConfig = peerConfig;
this.id = id;
}
/**
* start a state tracker to check whether this peer is enabled or not
*
* @param zookeeper zk watcher for the local cluster
* @param peerStateNode path to zk node which stores peer state
* @throws KeeperException
*/
public void startStateTracker(ZooKeeperWatcher zookeeper, String peerStateNode)
throws KeeperException {
ensurePeerEnabled(zookeeper, peerStateNode);
this.peerStateTracker = new PeerStateTracker(peerStateNode, zookeeper, this);
this.peerStateTracker.start();
try {
this.readPeerStateZnode();
} catch (DeserializationException e) {
throw ZKUtil.convert(e);
}
}
private void readPeerStateZnode() throws DeserializationException {
this.peerState =
isStateEnabled(this.peerStateTracker.getData(false))
? PeerState.ENABLED
: PeerState.DISABLED;
}
/**
* start a table-cfs tracker to listen the (table, cf-list) map change
*
* @param zookeeper zk watcher for the local cluster
* @param tableCFsNode path to zk node which stores table-cfs
* @throws KeeperException
*/
public void startTableCFsTracker(ZooKeeperWatcher zookeeper, String tableCFsNode)
throws KeeperException {
this.tableCFsTracker = new TableCFsTracker(tableCFsNode, zookeeper,
this);
this.tableCFsTracker.start();
this.readTableCFsZnode();
}
private void readTableCFsZnode() {
String currentTableCFs = Bytes.toString(tableCFsTracker.getData(false));
this.tableCFs = ReplicationAdmin.parseTableCFsFromConfig(currentTableCFs);
}
@Override
public PeerState getPeerState() {
return peerState;
}
/**
* Get the identifier of this peer
* @return string representation of the id (short)
*/
@Override
public String getId() {
return id;
}
/**
* Get the peer config object
* @return the ReplicationPeerConfig for this peer
*/
@Override
public ReplicationPeerConfig getPeerConfig() {
return peerConfig;
}
/**
* Get the configuration object required to communicate with this peer
* @return configuration object
*/
@Override
public Configuration getConfiguration() {
return conf;
}
/**
* Get replicable (table, cf-list) map of this peer
* @return the replicable (table, cf-list) map
*/
@Override
public Map<TableName, List<String>> getTableCFs() {
return this.tableCFs;
}
@Override
public void abort(String why, Throwable e) {
LOG.fatal("The ReplicationPeer coresponding to peer " + peerConfig
+ " was aborted for the following reason(s):" + why, e);
}
@Override
public boolean isAborted() {
// Currently the replication peer is never "Aborted", we just log when the
// abort method is called.
return false;
}
@Override
public void close() throws IOException {
// TODO: stop zkw?
}
/**
* Parse the raw data from ZK to get a peer's state
* @param bytes raw ZK data
* @return True if the passed in <code>bytes</code> are those of a pb serialized ENABLED state.
* @throws DeserializationException
*/
public static boolean isStateEnabled(final byte[] bytes) throws DeserializationException {
ZooKeeperProtos.ReplicationState.State state = parseStateFrom(bytes);
return ZooKeeperProtos.ReplicationState.State.ENABLED == state;
}
/**
* @param bytes Content of a state znode.
* @return State parsed from the passed bytes.
* @throws DeserializationException
*/
private static ZooKeeperProtos.ReplicationState.State parseStateFrom(final byte[] bytes)
throws DeserializationException {
ProtobufUtil.expectPBMagicPrefix(bytes);
int pblen = ProtobufUtil.lengthOfPBMagic();
ZooKeeperProtos.ReplicationState.Builder builder =
ZooKeeperProtos.ReplicationState.newBuilder();
ZooKeeperProtos.ReplicationState state;
try {
state = builder.mergeFrom(bytes, pblen, bytes.length - pblen).build();
return state.getState();
} catch (InvalidProtocolBufferException e) {
throw new DeserializationException(e);
}
}
/**
* Utility method to ensure an ENABLED znode is in place; if not present, we create it.
* @param zookeeper
* @param path Path to znode to check
* @return True if we created the znode.
* @throws NodeExistsException
* @throws KeeperException
*/
private static boolean ensurePeerEnabled(final ZooKeeperWatcher zookeeper, final String path)
throws NodeExistsException, KeeperException {
if (ZKUtil.checkExists(zookeeper, path) == -1) {
// There is a race b/w PeerWatcher and ReplicationZookeeper#add method to create the
// peer-state znode. This happens while adding a peer.
// The peer state data is set as "ENABLED" by default.
ZKUtil.createNodeIfNotExistsAndWatch(zookeeper, path,
ReplicationStateZKBase.ENABLED_ZNODE_BYTES);
return true;
}
return false;
}
/**
* Tracker for state of this peer
*/
public class PeerStateTracker extends ZooKeeperNodeTracker {
public PeerStateTracker(String peerStateZNode, ZooKeeperWatcher watcher,
Abortable abortable) {
super(watcher, peerStateZNode, abortable);
}
@Override
public synchronized void nodeDataChanged(String path) {
if (path.equals(node)) {
super.nodeDataChanged(path);
try {
readPeerStateZnode();
} catch (DeserializationException e) {
LOG.warn("Failed deserializing the content of " + path, e);
}
}
}
}
/**
* Tracker for (table, cf-list) map of this peer
*/
public class TableCFsTracker extends ZooKeeperNodeTracker {
public TableCFsTracker(String tableCFsZNode, ZooKeeperWatcher watcher,
Abortable abortable) {
super(watcher, tableCFsZNode, abortable);
}
@Override
public synchronized void nodeCreated(String path) {
if (path.equals(node)) {
super.nodeCreated(path);
readTableCFsZnode();
}
}
@Override
public synchronized void nodeDataChanged(String path) {
if (path.equals(node)) {
super.nodeDataChanged(path);
}
}
}
}