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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.hbase.master.snapshot;
19  
20  import java.io.IOException;
21  import java.util.HashSet;
22  import java.util.List;
23  import java.util.Set;
24  
25  import org.apache.commons.logging.Log;
26  import org.apache.commons.logging.LogFactory;
27  import org.apache.hadoop.classification.InterfaceAudience;
28  import org.apache.hadoop.fs.Path;
29  import org.apache.hadoop.hbase.HRegionInfo;
30  import org.apache.hadoop.hbase.ServerName;
31  import org.apache.hadoop.hbase.errorhandling.ForeignException;
32  import org.apache.hadoop.hbase.master.MasterServices;
33  import org.apache.hadoop.hbase.procedure.Procedure;
34  import org.apache.hadoop.hbase.procedure.ProcedureCoordinator;
35  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
36  import org.apache.hadoop.hbase.regionserver.HRegion;
37  import org.apache.hadoop.hbase.snapshot.HBaseSnapshotException;
38  import org.apache.hadoop.hbase.snapshot.SnapshotDescriptionUtils;
39  import org.apache.hadoop.hbase.util.Pair;
40  
41  import com.google.common.collect.Lists;
42  
43  /**
44   * Handle the master side of taking a snapshot of an online table, regardless of snapshot type.
45   * Uses a {@link Procedure} to run the snapshot across all the involved region servers.
46   * @see ProcedureCoordinator
47   */
48  @InterfaceAudience.Private
49  public class EnabledTableSnapshotHandler extends TakeSnapshotHandler {
50  
51    private static final Log LOG = LogFactory.getLog(EnabledTableSnapshotHandler.class);
52    private final ProcedureCoordinator coordinator;
53  
54    public EnabledTableSnapshotHandler(SnapshotDescription snapshot, MasterServices master,
55        SnapshotManager manager) throws IOException {
56      super(snapshot, master);
57      this.coordinator = manager.getCoordinator();
58    }
59  
60    // TODO consider switching over to using regionnames, rather than server names. This would allow
61    // regions to migrate during a snapshot, and then be involved when they are ready. Still want to
62    // enforce a snapshot time constraints, but lets us be potentially a bit more robust.
63  
64    /**
65     * This method kicks off a snapshot procedure.  Other than that it hangs around for various
66     * phases to complete.
67     */
68    @Override
69    protected void snapshotRegions(List<Pair<HRegionInfo, ServerName>> regions)
70        throws HBaseSnapshotException, IOException {
71      Set<String> regionServers = new HashSet<String>(regions.size());
72      for (Pair<HRegionInfo, ServerName> region : regions) {
73        if (region != null && region.getFirst() != null && region.getSecond() != null) {
74          HRegionInfo hri = region.getFirst();
75          if (hri.isOffline() && (hri.isSplit() || hri.isSplitParent())) continue;
76          regionServers.add(region.getSecond().toString());
77        }
78      }
79  
80      // start the snapshot on the RS
81      Procedure proc = coordinator.startProcedure(this.monitor, this.snapshot.getName(),
82        this.snapshot.toByteArray(), Lists.newArrayList(regionServers));
83      if (proc == null) {
84        String msg = "Failed to submit distributed procedure for snapshot '"
85            + snapshot.getName() + "'";
86        LOG.error(msg);
87        throw new HBaseSnapshotException(msg);
88      }
89  
90      try {
91        // wait for the snapshot to complete.  A timer thread is kicked off that should cancel this
92        // if it takes too long.
93        proc.waitForCompleted();
94        LOG.info("Done waiting - online snapshot for " + this.snapshot.getName());
95  
96        // Take the offline regions as disabled
97        Path snapshotDir = SnapshotDescriptionUtils.getWorkingSnapshotDir(snapshot, rootDir);
98        for (Pair<HRegionInfo, ServerName> region : regions) {
99          HRegionInfo regionInfo = region.getFirst();
100         if (regionInfo.isOffline() && (regionInfo.isSplit() || regionInfo.isSplitParent())) {
101           if (!fs.exists(new Path(snapshotDir, regionInfo.getEncodedName()))) {
102             LOG.info("Take disabled snapshot of offline region=" + regionInfo);
103             snapshotDisabledRegion(regionInfo);
104           }
105         }
106       }
107     } catch (InterruptedException e) {
108       ForeignException ee =
109           new ForeignException("Interrupted while waiting for snapshot to finish", e);
110       monitor.receive(ee);
111       Thread.currentThread().interrupt();
112     } catch (ForeignException e) {
113       monitor.receive(e);
114     }
115   }
116 }