/**
*
* 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.zookeeper;
import com.google.protobuf.InvalidProtocolBufferException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.hbase.CoordinatedStateException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.TableStateManager;
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.zookeeper.KeeperException;
import java.io.InterruptedIOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Implementation of TableStateManager which reads, caches and sets state
* up in ZooKeeper. If multiple read/write clients, will make for confusion.
* Code running on client side without consensus context should use
* {@link ZKTableStateClientSideReader} instead.
*
* <p>To save on trips to the zookeeper ensemble, internally we cache table
* state.
*/
@InterfaceAudience.Private
public class ZKTableStateManager implements TableStateManager {
// A znode will exist under the table directory if it is in any of the
// following states: {@link TableState#ENABLING} , {@link TableState#DISABLING},
// or {@link TableState#DISABLED}. If {@link TableState#ENABLED}, there will
// be no entry for a table in zk. Thats how it currently works.
private static final Log LOG = LogFactory.getLog(ZKTableStateManager.class);
private final ZooKeeperWatcher watcher;
/**
* Cache of what we found in zookeeper so we don't have to go to zk ensemble
* for every query. Synchronize access rather than use concurrent Map because
* synchronization needs to span query of zk.
*/
private final Map<TableName, ZooKeeperProtos.Table.State> cache =
new HashMap<TableName, ZooKeeperProtos.Table.State>();
public ZKTableStateManager(final ZooKeeperWatcher zkw) throws KeeperException,
InterruptedException {
super();
this.watcher = zkw;
populateTableStates();
}
/**
* Gets a list of all the tables set as disabled in zookeeper.
* @throws KeeperException, InterruptedException
*/
private void populateTableStates() throws KeeperException, InterruptedException {
synchronized (this.cache) {
List<String> children = ZKUtil.listChildrenNoWatch(this.watcher, this.watcher.tableZNode);
if (children == null) return;
for (String child: children) {
TableName tableName = TableName.valueOf(child);
ZooKeeperProtos.Table.State state = getTableState(this.watcher, tableName);
if (state != null) this.cache.put(tableName, state);
}
}
}
/**
* Sets table state in ZK. Sets no watches.
*
* {@inheritDoc}
*/
@Override
public void setTableState(TableName tableName, ZooKeeperProtos.Table.State state)
throws CoordinatedStateException {
synchronized (this.cache) {
LOG.warn("Moving table " + tableName + " state from " + this.cache.get(tableName)
+ " to " + state);
try {
setTableStateInZK(tableName, state);
} catch (KeeperException e) {
throw new CoordinatedStateException(e);
}
}
}
/**
* Checks and sets table state in ZK. Sets no watches.
* {@inheritDoc}
*/
@Override
public boolean setTableStateIfInStates(TableName tableName,
ZooKeeperProtos.Table.State newState,
ZooKeeperProtos.Table.State... states)
throws CoordinatedStateException {
synchronized (this.cache) {
// Transition ENABLED->DISABLING has to be performed with a hack, because
// we treat empty state as enabled in this case because 0.92- clusters.
if (
(newState == ZooKeeperProtos.Table.State.DISABLING) &&
this.cache.get(tableName) != null && !isTableState(tableName, states) ||
(newState != ZooKeeperProtos.Table.State.DISABLING &&
!isTableState(tableName, states) )) {
return false;
}
try {
setTableStateInZK(tableName, newState);
} catch (KeeperException e) {
throw new CoordinatedStateException(e);
}
return true;
}
}
/**
* Checks and sets table state in ZK. Sets no watches.
* {@inheritDoc}
*/
@Override
public boolean setTableStateIfNotInStates(TableName tableName,
ZooKeeperProtos.Table.State newState,
ZooKeeperProtos.Table.State... states)
throws CoordinatedStateException {
synchronized (this.cache) {
if (isTableState(tableName, states)) {
return false;
}
try {
setTableStateInZK(tableName, newState);
} catch (KeeperException e) {
throw new CoordinatedStateException(e);
}
return true;
}
}
private void setTableStateInZK(final TableName tableName,
final ZooKeeperProtos.Table.State state)
throws KeeperException {
String znode = ZKUtil.joinZNode(this.watcher.tableZNode, tableName.getNameAsString());
if (ZKUtil.checkExists(this.watcher, znode) == -1) {
ZKUtil.createAndFailSilent(this.watcher, znode);
}
synchronized (this.cache) {
ZooKeeperProtos.Table.Builder builder = ZooKeeperProtos.Table.newBuilder();
builder.setState(state);
byte [] data = ProtobufUtil.prependPBMagic(builder.build().toByteArray());
ZKUtil.setData(this.watcher, znode, data);
this.cache.put(tableName, state);
}
}
/**
* Checks if table is marked in specified state in ZK.
*
* {@inheritDoc}
*/
@Override
public boolean isTableState(final TableName tableName,
final ZooKeeperProtos.Table.State... states) {
synchronized (this.cache) {
ZooKeeperProtos.Table.State currentState = this.cache.get(tableName);
return isTableInState(Arrays.asList(states), currentState);
}
}
/**
* Deletes the table in zookeeper. Fails silently if the
* table is not currently disabled in zookeeper. Sets no watches.
*
* {@inheritDoc}
*/
@Override
public void setDeletedTable(final TableName tableName)
throws CoordinatedStateException {
synchronized (this.cache) {
if (this.cache.remove(tableName) == null) {
LOG.warn("Moving table " + tableName + " state to deleted but was " +
"already deleted");
}
try {
ZKUtil.deleteNodeFailSilent(this.watcher,
ZKUtil.joinZNode(this.watcher.tableZNode, tableName.getNameAsString()));
} catch (KeeperException e) {
throw new CoordinatedStateException(e);
}
}
}
/**
* check if table is present.
*
* @param tableName table we're working on
* @return true if the table is present
*/
@Override
public boolean isTablePresent(final TableName tableName) {
synchronized (this.cache) {
ZooKeeperProtos.Table.State state = this.cache.get(tableName);
return !(state == null);
}
}
/**
* Gets a list of all the tables set as disabling in zookeeper.
* @return Set of disabling tables, empty Set if none
* @throws CoordinatedStateException if error happened in underlying coordination engine
*/
@Override
public Set<TableName> getTablesInStates(ZooKeeperProtos.Table.State... states)
throws InterruptedIOException, CoordinatedStateException {
try {
return getAllTables(states);
} catch (KeeperException e) {
throw new CoordinatedStateException(e);
}
}
/**
* {@inheritDoc}
*/
@Override
public void checkAndRemoveTableState(TableName tableName, ZooKeeperProtos.Table.State states,
boolean deletePermanentState)
throws CoordinatedStateException {
synchronized (this.cache) {
if (isTableState(tableName, states)) {
this.cache.remove(tableName);
if (deletePermanentState) {
try {
ZKUtil.deleteNodeFailSilent(this.watcher,
ZKUtil.joinZNode(this.watcher.tableZNode, tableName.getNameAsString()));
} catch (KeeperException e) {
throw new CoordinatedStateException(e);
}
}
}
}
}
/**
* Gets a list of all the tables of specified states in zookeeper.
* @return Set of tables of specified states, empty Set if none
* @throws KeeperException
*/
Set<TableName> getAllTables(final ZooKeeperProtos.Table.State... states)
throws KeeperException, InterruptedIOException {
Set<TableName> allTables = new HashSet<TableName>();
List<String> children =
ZKUtil.listChildrenNoWatch(watcher, watcher.tableZNode);
if(children == null) return allTables;
for (String child: children) {
TableName tableName = TableName.valueOf(child);
ZooKeeperProtos.Table.State state;
try {
state = getTableState(watcher, tableName);
} catch (InterruptedException e) {
throw new InterruptedIOException();
}
for (ZooKeeperProtos.Table.State expectedState: states) {
if (state == expectedState) {
allTables.add(tableName);
break;
}
}
}
return allTables;
}
/**
* Gets table state from ZK.
* @param zkw ZooKeeperWatcher instance to use
* @param tableName table we're checking
* @return Null or {@link ZooKeeperProtos.Table.State} found in znode.
* @throws KeeperException
*/
private ZooKeeperProtos.Table.State getTableState(final ZooKeeperWatcher zkw,
final TableName tableName)
throws KeeperException, InterruptedException {
String znode = ZKUtil.joinZNode(zkw.tableZNode, tableName.getNameAsString());
byte [] data = ZKUtil.getData(zkw, znode);
if (data == null || data.length <= 0) return null;
try {
ProtobufUtil.expectPBMagicPrefix(data);
ZooKeeperProtos.Table.Builder builder = ZooKeeperProtos.Table.newBuilder();
int magicLen = ProtobufUtil.lengthOfPBMagic();
ZooKeeperProtos.Table t = builder.mergeFrom(data, magicLen, data.length - magicLen).build();
return t.getState();
} catch (InvalidProtocolBufferException e) {
KeeperException ke = new KeeperException.DataInconsistencyException();
ke.initCause(e);
throw ke;
} catch (DeserializationException e) {
throw ZKUtil.convert(e);
}
}
/**
* @return true if current state isn't null and is contained
* in the list of expected states.
*/
private boolean isTableInState(final List<ZooKeeperProtos.Table.State> expectedStates,
final ZooKeeperProtos.Table.State currentState) {
return currentState != null && expectedStates.contains(currentState);
}
}