HBASE-7992 provide pre/post region offline hooks for HMaster.offlineRegion() (Rajeshbabu)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1457854 13f79535-47bb-0310-9956-ffa450edef68

hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/BaseMasterObserver.java

@@ -232,6 +232,16 @@ public class BaseMasterObserver implements MasterObserver {
       HRegionInfo regionInfo, boolean force) throws IOException {
   }
 
+  @Override
+  public void preRegionOffline(ObserverContext<MasterCoprocessorEnvironment> ctx,
+    HRegionInfo regionInfo) throws IOException {
+  }
+
+  @Override
+  public void postRegionOffline(ObserverContext<MasterCoprocessorEnvironment> ctx,
+    HRegionInfo regionInfo) throws IOException {
+  }
+
   @Override
   public void preBalance(ObserverContext<MasterCoprocessorEnvironment> ctx)
       throws IOException {

hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java

@@ -440,6 +440,23 @@ public interface MasterObserver extends Coprocessor {
   void postUnassign(final ObserverContext<MasterCoprocessorEnvironment> ctx,
       final HRegionInfo regionInfo, final boolean force) throws IOException;
 
+  /**
+   * Called prior to marking a given region as offline. <code>ctx.bypass()</code> will not have any
+   * impact on this hook.
+   * @param ctx the environment to interact with the framework and master
+   * @param regionInfo
+   */
+  void preRegionOffline(final ObserverContext<MasterCoprocessorEnvironment> ctx,
+      final HRegionInfo regionInfo) throws IOException;
+
+  /**
+   * Called after the region has been marked offline.
+   * @param ctx the environment to interact with the framework and master
+   * @param regionInfo
+   */
+  void postRegionOffline(final ObserverContext<MasterCoprocessorEnvironment> ctx,
+      final HRegionInfo regionInfo) throws IOException;
+
   /**
    * Called prior to requesting rebalancing of the cluster regions, though after
    * the initial checks for regions in transition and the balance switch flag.

hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java

@@ -2252,7 +2252,11 @@ Server {
   }
 
   /**
-   * Special method, only used by hbck.
+   * Offline specified region from master's in-memory state. It will not attempt to
+   * reassign the region as in unassign.
+   *  
+   * This is a special method that should be used by experts or hbck.
+   * 
    */
   @Override
   public OfflineRegionResponse offlineRegion(RpcController controller, OfflineRegionRequest request)
@@ -2269,7 +2273,13 @@ Server {
         MetaReader.getRegion(this.catalogTracker, regionName);
       if (pair == null) throw new UnknownRegionException(Bytes.toStringBinary(regionName));
       HRegionInfo hri = pair.getFirst();
+      if (cpHost != null) {
+        cpHost.preRegionOffline(hri);
+      }
       this.assignmentManager.regionOffline(hri);
+      if (cpHost != null) {
+        cpHost.postRegionOffline(hri);
+      }
     } catch (IOException ioe) {
       throw new ServiceException(ioe);
     }

hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java

@@ -811,6 +811,40 @@ public class MasterCoprocessorHost
     }
   }
 
+  void preRegionOffline(final HRegionInfo regionInfo) throws IOException {
+    ObserverContext<MasterCoprocessorEnvironment> ctx = null;
+    for (MasterEnvironment env : coprocessors) {
+      if (env.getInstance() instanceof MasterObserver) {
+        ctx = ObserverContext.createAndPrepare(env, ctx);
+        try {
+          ((MasterObserver) env.getInstance()).preRegionOffline(ctx, regionInfo);
+        } catch (Throwable e) {
+          handleCoprocessorThrowable(env, e);
+        }
+        if (ctx.shouldComplete()) {
+          break;
+        }
+      }
+    }
+  }
+
+  void postRegionOffline(final HRegionInfo regionInfo) throws IOException {
+    ObserverContext<MasterCoprocessorEnvironment> ctx = null;
+    for (MasterEnvironment env : coprocessors) {
+      if (env.getInstance() instanceof MasterObserver) {
+        ctx = ObserverContext.createAndPrepare(env, ctx);
+        try {
+          ((MasterObserver) env.getInstance()).postRegionOffline(ctx, regionInfo);
+        } catch (Throwable e) {
+          handleCoprocessorThrowable(env, e);
+        }
+        if (ctx.shouldComplete()) {
+          break;
+        }
+      }
+    }
+  }
+
   boolean preBalance() throws IOException {
     boolean bypass = false;
     ObserverContext<MasterCoprocessorEnvironment> ctx = null;

hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AccessController.java

@@ -674,6 +674,17 @@ public class AccessController extends BaseRegionObserver
   public void postUnassign(ObserverContext<MasterCoprocessorEnvironment> c,
       HRegionInfo regionInfo, boolean force) throws IOException {}
 
+  @Override
+  public void preRegionOffline(ObserverContext<MasterCoprocessorEnvironment> c,
+      HRegionInfo regionInfo) throws IOException {
+    requirePermission("regionOffline", regionInfo.getTableName(), null, null, Action.ADMIN);
+  }
+
+  @Override
+  public void postRegionOffline(ObserverContext<MasterCoprocessorEnvironment> c,
+      HRegionInfo regionInfo) throws IOException {
+  }
+
   @Override
   public void preBalance(ObserverContext<MasterCoprocessorEnvironment> c)
       throws IOException {

hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestMasterObserver.java

@@ -90,6 +90,8 @@ public class TestMasterObserver {
     private boolean postAssignCalled;
     private boolean preUnassignCalled;
     private boolean postUnassignCalled;
+    private boolean preRegionOfflineCalled;
+    private boolean postRegionOfflineCalled;
     private boolean preBalanceCalled;
     private boolean postBalanceCalled;
     private boolean preBalanceSwitchCalled;
@@ -151,6 +153,8 @@ public class TestMasterObserver {
       postAssignCalled = false;
       preUnassignCalled = false;
       postUnassignCalled = false;
+      preRegionOfflineCalled = false;
+      postRegionOfflineCalled = false;
       preBalanceCalled = false;
       postBalanceCalled = false;
       preBalanceSwitchCalled = false;
@@ -441,6 +445,26 @@ public class TestMasterObserver {
       return preUnassignCalled && !postUnassignCalled;
     }
 
+    @Override
+    public void preRegionOffline(ObserverContext<MasterCoprocessorEnvironment> env,
+        final HRegionInfo regionInfo) throws IOException {
+      preRegionOfflineCalled = true;
+    }
+
+    @Override
+    public void postRegionOffline(ObserverContext<MasterCoprocessorEnvironment> env,
+        final HRegionInfo regionInfo) throws IOException {
+      postRegionOfflineCalled = true;
+    }
+
+    public boolean wasRegionOfflineCalled() {
+      return preRegionOfflineCalled && postRegionOfflineCalled;
+    }
+
+    public boolean preRegionOfflineCalledOnly() {
+      return preRegionOfflineCalled && !postRegionOfflineCalled;
+    }
+
     @Override
     public void preBalance(ObserverContext<MasterCoprocessorEnvironment> env)
         throws IOException {

hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestAccessController.java

@@ -486,6 +486,29 @@ public class TestAccessController {
     verifyDenied(action, USER_CREATE, USER_RW, USER_RO, USER_NONE);
   }
 
+  @Test
+  public void testRegionOffline() throws Exception {
+    Map<HRegionInfo, ServerName> regions;
+    HTable table = new HTable(TEST_UTIL.getConfiguration(), TEST_TABLE);
+    try {
+      regions = table.getRegionLocations();
+    } finally {
+      table.close();
+    }
+    final Map.Entry<HRegionInfo, ServerName> firstRegion = regions.entrySet().iterator().next();
+
+    PrivilegedExceptionAction action = new PrivilegedExceptionAction() {
+      public Object run() throws Exception {
+        ACCESS_CONTROLLER.preRegionOffline(ObserverContext.createAndPrepare(CP_ENV, null),
+          firstRegion.getKey());
+        return null;
+      }
+    };
+
+    verifyAllowed(action, SUPERUSER, USER_ADMIN, USER_OWNER);
+    verifyDenied(action, USER_CREATE, USER_RW, USER_RO, USER_NONE);
+  }
+
   @Test
   public void testBalance() throws Exception {
     PrivilegedExceptionAction action = new PrivilegedExceptionAction() {