/**
* 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.client;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.RegionLocations;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.zookeeper.MetaTableLocator;
import org.apache.hadoop.hbase.zookeeper.ZKClusterId;
import org.apache.hadoop.hbase.zookeeper.ZKUtil;
import org.apache.zookeeper.KeeperException;
/**
* A cluster registry that stores to zookeeper.
*/
class ZooKeeperRegistry implements Registry {
static final Log LOG = LogFactory.getLog(ZooKeeperRegistry.class);
// Needs an instance of hci to function. Set after construct this instance.
ConnectionManager.HConnectionImplementation hci;
@Override
public void init(Connection connection) {
if (!(connection instanceof ConnectionManager.HConnectionImplementation)) {
throw new RuntimeException("This registry depends on HConnectionImplementation");
}
this.hci = (ConnectionManager.HConnectionImplementation)connection;
}
@Override
public RegionLocations getMetaRegionLocation() throws IOException {
ZooKeeperKeepAliveConnection zkw = hci.getKeepAliveZooKeeperWatcher();
try {
if (LOG.isTraceEnabled()) {
LOG.trace("Looking up meta region location in ZK," + " connection=" + this);
}
ServerName servername = new MetaTableLocator().blockUntilAvailable(zkw, hci.rpcTimeout);
if (LOG.isTraceEnabled()) {
LOG.trace("Looked up meta region location, connection=" + this +
"; serverName=" + ((servername == null) ? "null" : servername));
}
if (servername == null) return null;
HRegionLocation loc = new HRegionLocation(HRegionInfo.FIRST_META_REGIONINFO, servername, 0);
return new RegionLocations(new HRegionLocation[] {loc});
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
return null;
} finally {
zkw.close();
}
}
private String clusterId = null;
@Override
public String getClusterId() {
if (this.clusterId != null) return this.clusterId;
// No synchronized here, worse case we will retrieve it twice, that's
// not an issue.
ZooKeeperKeepAliveConnection zkw = null;
try {
zkw = hci.getKeepAliveZooKeeperWatcher();
this.clusterId = ZKClusterId.readClusterIdZNode(zkw);
if (this.clusterId == null) {
LOG.info("ClusterId read in ZooKeeper is null");
}
} catch (KeeperException e) {
LOG.warn("Can't retrieve clusterId from Zookeeper", e);
} catch (IOException e) {
LOG.warn("Can't retrieve clusterId from Zookeeper", e);
} finally {
if (zkw != null) zkw.close();
}
return this.clusterId;
}
@Override
public int getCurrentNrHRS() throws IOException {
ZooKeeperKeepAliveConnection zkw = hci.getKeepAliveZooKeeperWatcher();
try {
// We go to zk rather than to master to get count of regions to avoid
// HTable having a Master dependency. See HBase-2828
return ZKUtil.getNumberOfChildren(zkw, zkw.rsZNode);
} catch (KeeperException ke) {
throw new IOException("Unexpected ZooKeeper exception", ke);
} finally {
zkw.close();
}
}
}