Source code

001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.hbase.master.procedure;
020
021import java.io.FileNotFoundException;
022import java.io.IOException;
023
024import org.apache.hadoop.fs.FileStatus;
025import org.apache.hadoop.fs.FileSystem;
026import org.apache.hadoop.fs.Path;
027import org.apache.hadoop.hbase.HConstants;
028import org.apache.hadoop.hbase.NamespaceDescriptor;
029import org.apache.hadoop.hbase.NamespaceNotFoundException;
030import org.apache.yetus.audience.InterfaceAudience;
031import org.slf4j.Logger;
032import org.slf4j.LoggerFactory;
033import org.apache.hadoop.hbase.constraint.ConstraintException;
034import org.apache.hadoop.hbase.master.MasterFileSystem;
035import org.apache.hadoop.hbase.master.TableNamespaceManager;
036import org.apache.hadoop.hbase.procedure2.ProcedureStateSerializer;
037import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
038import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProcedureProtos;
039import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProcedureProtos.DeleteNamespaceState;
040import org.apache.hadoop.hbase.util.FSUtils;
041
042/**
043 * The procedure to remove a namespace.
044 */
045@InterfaceAudience.Private
046public class DeleteNamespaceProcedure
047    extends AbstractStateMachineNamespaceProcedure<DeleteNamespaceState> {
048  private static final Logger LOG = LoggerFactory.getLogger(DeleteNamespaceProcedure.class);
049
050  private NamespaceDescriptor nsDescriptor;
051  private String namespaceName;
052  private Boolean traceEnabled;
053
054  public DeleteNamespaceProcedure() {
055    this.nsDescriptor = null;
056    this.traceEnabled = null;
057  }
058
059  public DeleteNamespaceProcedure(final MasterProcedureEnv env, final String namespaceName) {
060    this(env, namespaceName, null);
061  }
062
063  public DeleteNamespaceProcedure(final MasterProcedureEnv env, final String namespaceName,
064      final ProcedurePrepareLatch latch) {
065    super(env, latch);
066    this.namespaceName = namespaceName;
067    this.nsDescriptor = null;
068    this.traceEnabled = null;
069  }
070
071  @Override
072  protected Flow executeFromState(final MasterProcedureEnv env, final DeleteNamespaceState state)
073      throws InterruptedException {
074    LOG.info(this.toString());
075    try {
076      switch (state) {
077      case DELETE_NAMESPACE_PREPARE:
078        boolean present = prepareDelete(env);
079        releaseSyncLatch();
080        if (!present) {
081          assert isFailed() : "Delete namespace should have an exception here";
082          return Flow.NO_MORE_STATE;
083        }
084        setNextState(DeleteNamespaceState.DELETE_NAMESPACE_DELETE_FROM_NS_TABLE);
085        break;
086      case DELETE_NAMESPACE_DELETE_FROM_NS_TABLE:
087        deleteFromNSTable(env, namespaceName);
088        setNextState(DeleteNamespaceState.DELETE_NAMESPACE_REMOVE_FROM_ZK);
089        break;
090      case DELETE_NAMESPACE_REMOVE_FROM_ZK:
091        removeFromZKNamespaceManager(env, namespaceName);
092        setNextState(DeleteNamespaceState.DELETE_NAMESPACE_DELETE_DIRECTORIES);
093        break;
094      case DELETE_NAMESPACE_DELETE_DIRECTORIES:
095        deleteDirectory(env, namespaceName);
096        setNextState(DeleteNamespaceState.DELETE_NAMESPACE_REMOVE_NAMESPACE_QUOTA);
097        break;
098      case DELETE_NAMESPACE_REMOVE_NAMESPACE_QUOTA:
099        removeNamespaceQuota(env, namespaceName);
100        return Flow.NO_MORE_STATE;
101      default:
102        throw new UnsupportedOperationException(this + " unhandled state=" + state);
103      }
104    } catch (IOException e) {
105      if (isRollbackSupported(state)) {
106        setFailure("master-delete-namespace", e);
107      } else {
108        LOG.warn("Retriable error trying to delete namespace " + namespaceName +
109          " (in state=" + state + ")", e);
110      }
111    }
112    return Flow.HAS_MORE_STATE;
113  }
114
115  @Override
116  protected void rollbackState(final MasterProcedureEnv env, final DeleteNamespaceState state)
117      throws IOException {
118    if (state == DeleteNamespaceState.DELETE_NAMESPACE_PREPARE) {
119      // nothing to rollback, pre is just table-state checks.
120      // We can fail if the table does not exist or is not disabled.
121      // TODO: coprocessor rollback semantic is still undefined.
122      releaseSyncLatch();
123      return;
124    }
125
126    // The procedure doesn't have a rollback. The execution will succeed, at some point.
127    throw new UnsupportedOperationException("unhandled state=" + state);
128  }
129
130  @Override
131  protected boolean isRollbackSupported(final DeleteNamespaceState state) {
132    switch (state) {
133      case DELETE_NAMESPACE_PREPARE:
134        return true;
135      default:
136        return false;
137    }
138  }
139
140  @Override
141  protected DeleteNamespaceState getState(final int stateId) {
142    return DeleteNamespaceState.valueOf(stateId);
143  }
144
145  @Override
146  protected int getStateId(final DeleteNamespaceState state) {
147    return state.getNumber();
148  }
149
150  @Override
151  protected DeleteNamespaceState getInitialState() {
152    return DeleteNamespaceState.DELETE_NAMESPACE_PREPARE;
153  }
154
155  @Override
156  protected void serializeStateData(ProcedureStateSerializer serializer)
157      throws IOException {
158    super.serializeStateData(serializer);
159
160    MasterProcedureProtos.DeleteNamespaceStateData.Builder deleteNamespaceMsg =
161        MasterProcedureProtos.DeleteNamespaceStateData.newBuilder().setNamespaceName(namespaceName);
162    if (this.nsDescriptor != null) {
163      deleteNamespaceMsg.setNamespaceDescriptor(
164        ProtobufUtil.toProtoNamespaceDescriptor(this.nsDescriptor));
165    }
166    serializer.serialize(deleteNamespaceMsg.build());
167  }
168
169  @Override
170  protected void deserializeStateData(ProcedureStateSerializer serializer)
171      throws IOException {
172    super.deserializeStateData(serializer);
173
174    MasterProcedureProtos.DeleteNamespaceStateData deleteNamespaceMsg =
175        serializer.deserialize(MasterProcedureProtos.DeleteNamespaceStateData.class);
176    namespaceName = deleteNamespaceMsg.getNamespaceName();
177    if (deleteNamespaceMsg.hasNamespaceDescriptor()) {
178      nsDescriptor =
179          ProtobufUtil.toNamespaceDescriptor(deleteNamespaceMsg.getNamespaceDescriptor());
180    }
181  }
182
183  @Override
184  public TableOperationType getTableOperationType() {
185    return TableOperationType.EDIT;
186  }
187
188  @Override
189  protected String getNamespaceName() {
190    return namespaceName;
191  }
192
193  /**
194   * Action before any real action of deleting namespace.
195   * @param env MasterProcedureEnv
196   * @throws IOException
197   */
198  private boolean prepareDelete(final MasterProcedureEnv env) throws IOException {
199    if (getTableNamespaceManager(env).doesNamespaceExist(namespaceName) == false) {
200      setFailure("master-delete-namespace", new NamespaceNotFoundException(namespaceName));
201      return false;
202    }
203    if (NamespaceDescriptor.RESERVED_NAMESPACES.contains(namespaceName)) {
204      setFailure("master-delete-namespace", new ConstraintException(
205          "Reserved namespace "+ namespaceName +" cannot be removed."));
206      return false;
207    }
208
209    int tableCount = 0;
210    try {
211      tableCount = env.getMasterServices().listTableDescriptorsByNamespace(namespaceName).size();
212    } catch (FileNotFoundException fnfe) {
213      setFailure("master-delete-namespace", new NamespaceNotFoundException(namespaceName));
214      return false;
215    }
216    if (tableCount > 0) {
217      setFailure("master-delete-namespace", new ConstraintException(
218          "Only empty namespaces can be removed. Namespace "+ namespaceName + " has "
219          + tableCount +" tables"));
220      return false;
221    }
222
223    // This is used for rollback
224    nsDescriptor = getTableNamespaceManager(env).get(namespaceName);
225    return true;
226  }
227
228  /**
229   * delete the row from namespace table
230   * @param env MasterProcedureEnv
231   * @param namespaceName name of the namespace in string format
232   * @throws IOException
233   */
234  protected static void deleteFromNSTable(
235      final MasterProcedureEnv env,
236      final String namespaceName) throws IOException {
237    getTableNamespaceManager(env).removeFromNSTable(namespaceName);
238  }
239
240  /**
241   * undo the delete
242   * @param env MasterProcedureEnv
243   * @throws IOException
244   */
245  private void undoDeleteFromNSTable(final MasterProcedureEnv env) {
246    try {
247      if (nsDescriptor != null) {
248        CreateNamespaceProcedure.insertIntoNSTable(env, nsDescriptor);
249      }
250    } catch (Exception e) {
251      // Ignore
252      LOG.debug("Rollback of deleteFromNSTable throws exception: " + e);
253    }
254  }
255
256  /**
257   * remove from ZooKeeper.
258   * @param env MasterProcedureEnv
259   * @param namespaceName name of the namespace in string format
260   * @throws IOException
261   */
262  protected static void removeFromZKNamespaceManager(
263      final MasterProcedureEnv env,
264      final String namespaceName) throws IOException {
265    getTableNamespaceManager(env).removeFromZKNamespaceManager(namespaceName);
266  }
267
268  /**
269   * undo the remove from ZooKeeper
270   * @param env MasterProcedureEnv
271   * @throws IOException
272   */
273  private void undoRemoveFromZKNamespaceManager(final MasterProcedureEnv env) {
274    try {
275      if (nsDescriptor != null) {
276        CreateNamespaceProcedure.updateZKNamespaceManager(env, nsDescriptor);
277      }
278    } catch (Exception e) {
279      // Ignore
280      LOG.debug("Rollback of removeFromZKNamespaceManager throws exception: " + e);
281    }
282  }
283
284  /**
285   * Delete the namespace directories from the file system
286   * @param env MasterProcedureEnv
287   * @param namespaceName name of the namespace in string format
288   * @throws IOException
289   */
290  protected static void deleteDirectory(
291      final MasterProcedureEnv env,
292      final String namespaceName) throws IOException {
293    MasterFileSystem mfs = env.getMasterServices().getMasterFileSystem();
294    FileSystem fs = mfs.getFileSystem();
295    Path p = FSUtils.getNamespaceDir(mfs.getRootDir(), namespaceName);
296
297    try {
298      for(FileStatus status : fs.listStatus(p)) {
299        if (!HConstants.HBASE_NON_TABLE_DIRS.contains(status.getPath().getName())) {
300          throw new IOException("Namespace directory contains table dir: " + status.getPath());
301        }
302      }
303      if (!fs.delete(FSUtils.getNamespaceDir(mfs.getRootDir(), namespaceName), true)) {
304        throw new IOException("Failed to remove namespace: " + namespaceName);
305      }
306    } catch (FileNotFoundException e) {
307      // File already deleted, continue
308      LOG.debug("deleteDirectory throws exception: " + e);
309    }
310  }
311
312  /**
313   * undo delete directory
314   * @param env MasterProcedureEnv
315   * @throws IOException
316   */
317  private void rollbackDeleteDirectory(final MasterProcedureEnv env) throws IOException {
318    try {
319      CreateNamespaceProcedure.createDirectory(env, nsDescriptor);
320    } catch (Exception e) {
321      // Ignore exception
322      LOG.debug("Rollback of deleteDirectory throws exception: " + e);
323    }
324  }
325
326  /**
327   * remove quota for the namespace
328   * @param env MasterProcedureEnv
329   * @param namespaceName name of the namespace in string format
330   * @throws IOException
331   **/
332  protected static void removeNamespaceQuota(
333      final MasterProcedureEnv env,
334      final String namespaceName) throws IOException {
335    env.getMasterServices().getMasterQuotaManager().removeNamespaceQuota(namespaceName);
336  }
337
338  /**
339   * undo remove quota for the namespace
340   * @param env MasterProcedureEnv
341   * @throws IOException
342   **/
343  private void rollbacRemoveNamespaceQuota(final MasterProcedureEnv env) throws IOException {
344    try {
345      CreateNamespaceProcedure.setNamespaceQuota(env, nsDescriptor);
346    } catch (Exception e) {
347      // Ignore exception
348      LOG.debug("Rollback of removeNamespaceQuota throws exception: " + e);
349    }
350  }
351
352  private static TableNamespaceManager getTableNamespaceManager(final MasterProcedureEnv env) {
353    return env.getMasterServices().getClusterSchema().getTableNamespaceManager();
354  }
355  /**
356   * The procedure could be restarted from a different machine. If the variable is null, we need to
357   * retrieve it.
358   * @return traceEnabled
359   */
360  private Boolean isTraceEnabled() {
361    if (traceEnabled == null) {
362      traceEnabled = LOG.isTraceEnabled();
363    }
364    return traceEnabled;
365  }
366}