/**
* 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.master;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.NavigableSet;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.NamespaceDescriptor;
import org.apache.hadoop.hbase.NamespaceExistException;
import org.apache.hadoop.hbase.NamespaceNotFoundException;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.ZKNamespaceManager;
import org.apache.hadoop.hbase.MetaTableAccessor;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.constraint.ConstraintException;
import org.apache.hadoop.hbase.master.handler.CreateTableHandler;
import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.FSUtils;
import com.google.common.collect.Sets;
/**
* This is a helper class used to manage the namespace
* metadata that is stored in TableName.NAMESPACE_TABLE_NAME
* It also mirrors updates to the ZK store by forwarding updates to
* {@link org.apache.hadoop.hbase.ZKNamespaceManager}
*/
@InterfaceAudience.Private
public class TableNamespaceManager {
private static final Log LOG = LogFactory.getLog(TableNamespaceManager.class);
private Configuration conf;
private MasterServices masterServices;
private HTable nsTable;
private ZKNamespaceManager zkNamespaceManager;
private boolean initialized;
static final String NS_INIT_TIMEOUT = "hbase.master.namespace.init.timeout";
static final int DEFAULT_NS_INIT_TIMEOUT = 60000;
public TableNamespaceManager(MasterServices masterServices) {
this.masterServices = masterServices;
this.conf = masterServices.getConfiguration();
}
public void start() throws IOException {
if (!MetaTableAccessor.tableExists(masterServices.getShortCircuitConnection(),
TableName.NAMESPACE_TABLE_NAME)) {
LOG.info("Namespace table not found. Creating...");
createNamespaceTable(masterServices);
}
try {
// Wait for the namespace table to be assigned.
// If timed out, we will move ahead without initializing it.
// So that it should be initialized later on lazily.
long startTime = EnvironmentEdgeManager.currentTime();
int timeout = conf.getInt(NS_INIT_TIMEOUT, DEFAULT_NS_INIT_TIMEOUT);
while (!isTableAssigned()) {
if (EnvironmentEdgeManager.currentTime() - startTime + 100 > timeout) {
LOG.warn("Timedout waiting for namespace table to be assigned.");
return;
}
Thread.sleep(100);
}
} catch (InterruptedException e) {
throw (InterruptedIOException)new InterruptedIOException().initCause(e);
}
// initialize namespace table
isTableAvailableAndInitialized();
}
private synchronized Table getNamespaceTable() throws IOException {
if (!isTableAvailableAndInitialized()) {
throw new IOException(this.getClass().getName() + " isn't ready to serve");
}
return nsTable;
}
public synchronized NamespaceDescriptor get(String name) throws IOException {
if (!isTableAvailableAndInitialized()) return null;
return zkNamespaceManager.get(name);
}
public synchronized void create(NamespaceDescriptor ns) throws IOException {
create(getNamespaceTable(), ns);
}
public synchronized void update(NamespaceDescriptor ns) throws IOException {
Table table = getNamespaceTable();
if (get(table, ns.getName()) == null) {
throw new NamespaceNotFoundException(ns.getName());
}
upsert(table, ns);
}
private NamespaceDescriptor get(Table table, String name) throws IOException {
Result res = table.get(new Get(Bytes.toBytes(name)));
if (res.isEmpty()) {
return null;
}
byte[] val = CellUtil.cloneValue(res.getColumnLatestCell(
HTableDescriptor.NAMESPACE_FAMILY_INFO_BYTES, HTableDescriptor.NAMESPACE_COL_DESC_BYTES));
return
ProtobufUtil.toNamespaceDescriptor(
HBaseProtos.NamespaceDescriptor.parseFrom(val));
}
private void create(Table table, NamespaceDescriptor ns) throws IOException {
if (get(table, ns.getName()) != null) {
throw new NamespaceExistException(ns.getName());
}
FileSystem fs = masterServices.getMasterFileSystem().getFileSystem();
fs.mkdirs(FSUtils.getNamespaceDir(
masterServices.getMasterFileSystem().getRootDir(), ns.getName()));
upsert(table, ns);
}
private void upsert(Table table, NamespaceDescriptor ns) throws IOException {
Put p = new Put(Bytes.toBytes(ns.getName()));
p.addImmutable(HTableDescriptor.NAMESPACE_FAMILY_INFO_BYTES,
HTableDescriptor.NAMESPACE_COL_DESC_BYTES,
ProtobufUtil.toProtoNamespaceDescriptor(ns).toByteArray());
table.put(p);
try {
zkNamespaceManager.update(ns);
} catch(IOException ex) {
String msg = "Failed to update namespace information in ZK. Aborting.";
LOG.fatal(msg, ex);
masterServices.abort(msg, ex);
}
}
public synchronized void remove(String name) throws IOException {
if (get(name) == null) {
throw new NamespaceNotFoundException(name);
}
if (NamespaceDescriptor.RESERVED_NAMESPACES.contains(name)) {
throw new ConstraintException("Reserved namespace "+name+" cannot be removed.");
}
int tableCount;
try {
tableCount = masterServices.listTableDescriptorsByNamespace(name).size();
} catch (FileNotFoundException fnfe) {
throw new NamespaceNotFoundException(name);
}
if (tableCount > 0) {
throw new ConstraintException("Only empty namespaces can be removed. " +
"Namespace "+name+" has "+tableCount+" tables");
}
Delete d = new Delete(Bytes.toBytes(name));
getNamespaceTable().delete(d);
//don't abort if cleanup isn't complete
//it will be replaced on new namespace creation
zkNamespaceManager.remove(name);
FileSystem fs = masterServices.getMasterFileSystem().getFileSystem();
for(FileStatus status :
fs.listStatus(FSUtils.getNamespaceDir(
masterServices.getMasterFileSystem().getRootDir(), name))) {
if (!HConstants.HBASE_NON_TABLE_DIRS.contains(status.getPath().getName())) {
throw new IOException("Namespace directory contains table dir: "+status.getPath());
}
}
if (!fs.delete(FSUtils.getNamespaceDir(
masterServices.getMasterFileSystem().getRootDir(), name), true)) {
throw new IOException("Failed to remove namespace: "+name);
}
}
public synchronized NavigableSet<NamespaceDescriptor> list() throws IOException {
NavigableSet<NamespaceDescriptor> ret =
Sets.newTreeSet(NamespaceDescriptor.NAMESPACE_DESCRIPTOR_COMPARATOR);
ResultScanner scanner = getNamespaceTable().getScanner(HTableDescriptor.NAMESPACE_FAMILY_INFO_BYTES);
try {
for(Result r : scanner) {
byte[] val = CellUtil.cloneValue(r.getColumnLatestCell(
HTableDescriptor.NAMESPACE_FAMILY_INFO_BYTES,
HTableDescriptor.NAMESPACE_COL_DESC_BYTES));
ret.add(ProtobufUtil.toNamespaceDescriptor(
HBaseProtos.NamespaceDescriptor.parseFrom(val)));
}
} finally {
scanner.close();
}
return ret;
}
private void createNamespaceTable(MasterServices masterServices) throws IOException {
HRegionInfo newRegions[] = new HRegionInfo[]{
new HRegionInfo(HTableDescriptor.NAMESPACE_TABLEDESC.getTableName(), null, null)};
//we need to create the table this way to bypass
//checkInitialized
masterServices.getExecutorService()
.submit(new CreateTableHandler(masterServices,
masterServices.getMasterFileSystem(),
HTableDescriptor.NAMESPACE_TABLEDESC,
masterServices.getConfiguration(),
newRegions,
masterServices).prepare());
}
/**
* This method checks if the namespace table is assigned and then
* tries to create its HTable. If it was already created before, it also makes
* sure that the connection isn't closed.
* @return true if the namespace table manager is ready to serve, false
* otherwise
* @throws IOException
*/
@SuppressWarnings("deprecation")
public synchronized boolean isTableAvailableAndInitialized() throws IOException {
// Did we already get a table? If so, still make sure it's available
if (initialized) {
if (nsTable.getConnection().isClosed()) {
nsTable = new HTable(conf, TableName.NAMESPACE_TABLE_NAME);
}
return true;
}
// Now check if the table is assigned, if not then fail fast
if (isTableAssigned()) {
try {
nsTable = new HTable(conf, TableName.NAMESPACE_TABLE_NAME);
zkNamespaceManager = new ZKNamespaceManager(masterServices.getZooKeeper());
zkNamespaceManager.start();
if (get(nsTable, NamespaceDescriptor.DEFAULT_NAMESPACE.getName()) == null) {
create(nsTable, NamespaceDescriptor.DEFAULT_NAMESPACE);
}
if (get(nsTable, NamespaceDescriptor.SYSTEM_NAMESPACE.getName()) == null) {
create(nsTable, NamespaceDescriptor.SYSTEM_NAMESPACE);
}
ResultScanner scanner = nsTable.getScanner(HTableDescriptor.NAMESPACE_FAMILY_INFO_BYTES);
try {
for (Result result : scanner) {
byte[] val = CellUtil.cloneValue(result.getColumnLatest(
HTableDescriptor.NAMESPACE_FAMILY_INFO_BYTES,
HTableDescriptor.NAMESPACE_COL_DESC_BYTES));
NamespaceDescriptor ns =
ProtobufUtil.toNamespaceDescriptor(
HBaseProtos.NamespaceDescriptor.parseFrom(val));
zkNamespaceManager.update(ns);
}
} finally {
scanner.close();
}
initialized = true;
return true;
} catch (IOException ie) {
LOG.warn("Caught exception in initializing namespace table manager", ie);
if (nsTable != null) {
nsTable.close();
}
throw ie;
}
}
return false;
}
private boolean isTableAssigned() {
return !masterServices.getAssignmentManager()
.getRegionStates().getRegionsOfTable(TableName.NAMESPACE_TABLE_NAME).isEmpty();
}
}