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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  
20  package org.apache.hadoop.hbase.master.snapshot;
21  
22  import java.io.IOException;
23  import java.util.List;
24  import java.util.concurrent.CancellationException;
25  
26  import org.apache.commons.logging.Log;
27  import org.apache.commons.logging.LogFactory;
28  import org.apache.hadoop.hbase.classification.InterfaceAudience;
29  import org.apache.hadoop.fs.FileSystem;
30  import org.apache.hadoop.fs.Path;
31  import org.apache.hadoop.hbase.TableName;
32  import org.apache.hadoop.hbase.HRegionInfo;
33  import org.apache.hadoop.hbase.HTableDescriptor;
34  import org.apache.hadoop.hbase.NotAllMetaRegionsOnlineException;
35  import org.apache.hadoop.hbase.TableExistsException;
36  import org.apache.hadoop.hbase.errorhandling.ForeignException;
37  import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
38  import org.apache.hadoop.hbase.master.MasterServices;
39  import org.apache.hadoop.hbase.master.MetricsSnapshot;
40  import org.apache.hadoop.hbase.master.SnapshotSentinel;
41  import org.apache.hadoop.hbase.master.handler.CreateTableHandler;
42  import org.apache.hadoop.hbase.monitoring.MonitoredTask;
43  import org.apache.hadoop.hbase.monitoring.TaskMonitor;
44  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
45  import org.apache.hadoop.hbase.snapshot.ClientSnapshotDescriptionUtils;
46  import org.apache.hadoop.hbase.snapshot.RestoreSnapshotException;
47  import org.apache.hadoop.hbase.snapshot.RestoreSnapshotHelper;
48  import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
49  import org.apache.hadoop.hbase.snapshot.SnapshotManifest;
50  
51  import com.google.common.base.Preconditions;
52  
53  /**
54   * Handler to Clone a snapshot.
55   *
56   * <p>Uses {@link RestoreSnapshotHelper} to create a new table with the same
57   * content of the specified snapshot.
58   */
59  @InterfaceAudience.Private
60  public class CloneSnapshotHandler extends CreateTableHandler implements SnapshotSentinel {
61    private static final Log LOG = LogFactory.getLog(CloneSnapshotHandler.class);
62  
63    private final static String NAME = "Master CloneSnapshotHandler";
64  
65    private final SnapshotDescription snapshot;
66    private final boolean restoreAcl;
67  
68    private final ForeignExceptionDispatcher monitor;
69    private final MetricsSnapshot metricsSnapshot = new MetricsSnapshot();
70    private final MonitoredTask status;
71  
72    private RestoreSnapshotHelper.RestoreMetaChanges metaChanges;
73  
74    private volatile boolean stopped = false;
75  
76    public CloneSnapshotHandler(final MasterServices masterServices,
77        final SnapshotDescription snapshot, final HTableDescriptor hTableDescriptor,
78        final boolean restoreAcl) {
79      super(masterServices, masterServices.getMasterFileSystem(), hTableDescriptor,
80        masterServices.getConfiguration(), null, masterServices);
81  
82      // Snapshot information
83      this.snapshot = snapshot;
84      this.restoreAcl = restoreAcl;
85  
86      // Monitor
87      this.monitor = new ForeignExceptionDispatcher();
88      this.status = TaskMonitor.get().createStatus("Cloning  snapshot '" + snapshot.getName() +
89        "' to table " + hTableDescriptor.getTableName());
90    }
91  
92    @Override
93    public CloneSnapshotHandler prepare() throws NotAllMetaRegionsOnlineException,
94        TableExistsException, IOException {
95      return (CloneSnapshotHandler) super.prepare();
96    }
97  
98    /**
99     * Create the on-disk regions, using the tableRootDir provided by the CreateTableHandler.
100    * The cloned table will be created in a temp directory, and then the CreateTableHandler
101    * will be responsible to add the regions returned by this method to hbase:meta and do the assignment.
102    */
103   @Override
104   protected List<HRegionInfo> handleCreateHdfsRegions(final Path tableRootDir,
105       final TableName tableName) throws IOException {
106     status.setStatus("Creating regions for table: " + tableName);
107     FileSystem fs = fileSystemManager.getFileSystem();
108     Path rootDir = fileSystemManager.getRootDir();
109 
110     try {
111       // 1. Execute the on-disk Clone
112       Path snapshotDir = SnapshotDescriptionUtils.getCompletedSnapshotDir(snapshot, rootDir);
113       SnapshotManifest manifest = SnapshotManifest.open(conf, fs, snapshotDir, snapshot);
114       RestoreSnapshotHelper restoreHelper = new RestoreSnapshotHelper(conf, fs,
115           manifest, hTableDescriptor, tableRootDir, monitor, status);
116       metaChanges = restoreHelper.restoreHdfsRegions();
117 
118       // Clone operation should not have stuff to restore or remove
119       Preconditions.checkArgument(!metaChanges.hasRegionsToRestore(),
120           "A clone should not have regions to restore");
121       Preconditions.checkArgument(!metaChanges.hasRegionsToRemove(),
122           "A clone should not have regions to remove");
123 
124       // Clone acl of snapshot into newly created table.
125       if (restoreAcl && snapshot.hasUsersAndPermissions()
126           && snapshot.getUsersAndPermissions() != null
127           && SnapshotDescriptionUtils.isSecurityAvailable(conf)) {
128         RestoreSnapshotHelper.restoreSnapshotACL(snapshot, tableName, conf);
129       }
130 
131       // At this point the clone is complete. Next step is enabling the table.
132       String msg = "Clone snapshot="+ snapshot.getName() +" on table=" + tableName + " completed!";
133       LOG.info(msg);
134       status.setStatus(msg + " Waiting for table to be enabled...");
135 
136       // 2. let the CreateTableHandler add the regions to meta
137       return metaChanges.getRegionsToAdd();
138     } catch (Exception e) {
139       String msg = "clone snapshot=" + ClientSnapshotDescriptionUtils.toString(snapshot) +
140         " failed because " + e.getMessage();
141       LOG.error(msg, e);
142       IOException rse = new RestoreSnapshotException(msg, e, snapshot);
143 
144       // these handlers aren't futures so we need to register the error here.
145       this.monitor.receive(new ForeignException(NAME, rse));
146       throw rse;
147     }
148   }
149 
150   @Override
151   protected void addRegionsToMeta(final List<HRegionInfo> regionInfos,
152       int regionReplication)
153       throws IOException {
154     super.addRegionsToMeta(regionInfos, regionReplication);
155     metaChanges.updateMetaParentRegions(this.server.getConnection(), regionInfos);
156   }
157 
158   @Override
159   protected void completed(final Throwable exception) {
160     this.stopped = true;
161     if (exception != null) {
162       status.abort("Snapshot '" + snapshot.getName() + "' clone failed because " +
163           exception.getMessage());
164     } else {
165       status.markComplete("Snapshot '"+ snapshot.getName() +"' clone completed and table enabled!");
166     }
167     metricsSnapshot.addSnapshotClone(status.getCompletionTimestamp() - status.getStartTime());
168     super.completed(exception);
169   }
170 
171   @Override
172   public boolean isFinished() {
173     return this.stopped;
174   }
175 
176   @Override
177   public long getCompletionTimestamp() {
178     return this.status.getCompletionTimestamp();
179   }
180 
181   @Override
182   public SnapshotDescription getSnapshot() {
183     return snapshot;
184   }
185 
186   @Override
187   public void cancel(String why) {
188     if (this.stopped) return;
189     this.stopped = true;
190     String msg = "Stopping clone snapshot=" + snapshot + " because: " + why;
191     LOG.info(msg);
192     status.abort(msg);
193     this.monitor.receive(new ForeignException(NAME, new CancellationException(why)));
194   }
195 
196   @Override
197   public ForeignException getExceptionIfFailed() {
198     return this.monitor.getException();
199   }
200 
201   @Override
202   public void rethrowExceptionIfFailed() throws ForeignException {
203     monitor.rethrowException();
204   }
205 }