content: /**
   * 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.atlas.hive.hook;
  
  import org.apache.atlas.plugin.classloader.AtlasPluginClassLoader;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hive.metastore.MetaStoreEventListener;
  import org.apache.hadoop.hive.metastore.api.MetaException;
  import org.apache.hadoop.hive.metastore.events.*;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Hive Metastore hook to capture DDL operations for atlas entity registration.
   */
  public class HiveMetastoreHook extends MetaStoreEventListener {
      private static final String ATLAS_PLUGIN_TYPE                        = "hive";
      private static final String ATLAS_HIVE_METASTORE_HOOK_IMPL_CLASSNAME = "org.apache.atlas.hive.hook.HiveMetastoreHookImpl";
      public  static final Logger LOG                                      = LoggerFactory.getLogger(HiveMetastoreHook.class);
  
      private AtlasPluginClassLoader atlasPluginClassLoader = null;
      private MetaStoreEventListener atlasMetastoreHookImpl = null;
      private Configuration          config;
  
      public HiveMetastoreHook(Configuration config) {
          super(config);
  
          this.config   = config;
  
          this.initialize();
      }
  
      private void initialize() {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveMetastoreHook.initialize()");
          }
  
          try {
              atlasPluginClassLoader = AtlasPluginClassLoader.getInstance(ATLAS_PLUGIN_TYPE, this.getClass());
  
              @SuppressWarnings("unchecked")
              Class<MetaStoreEventListener> cls = (Class<MetaStoreEventListener>)
                      Class.forName(ATLAS_HIVE_METASTORE_HOOK_IMPL_CLASSNAME, true, atlasPluginClassLoader);
  
              activatePluginClassLoader();
  
              atlasMetastoreHookImpl = cls.getDeclaredConstructor(Configuration.class).newInstance(config);
          } catch (Exception ex) {
              LOG.error("Error instantiating Atlas hook implementation", ex);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveMetastoreHook.initialize()");
          }
      }
  
      @Override
      public void onCreateTable(CreateTableEvent tableEvent) throws MetaException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveMetastoreHook.onCreateTable()");
          }
  
          try {
              activatePluginClassLoader();
  
              atlasMetastoreHookImpl.onCreateTable(tableEvent);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveMetastoreHook.onCreateTable()");
          }
      }
  
      @Override
      public void onDropTable(DropTableEvent tableEvent) throws MetaException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveMetastoreHook.onDropTable()");
          }
  
          try {
              activatePluginClassLoader();
  
              atlasMetastoreHookImpl.onDropTable(tableEvent);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveMetastoreHook.onDropTable()");
          }
      }
  
      @Override
      public void onAlterTable(AlterTableEvent tableEvent) throws MetaException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveMetastoreHook.onAlterTable()");
          }
  
          try {
              activatePluginClassLoader();
  
              atlasMetastoreHookImpl.onAlterTable(tableEvent);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveMetastoreHook.onAlterTable()");
          }
      }
  
      @Override
      public void onCreateDatabase(CreateDatabaseEvent dbEvent) throws MetaException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveMetastoreHook.onCreateDatabase()");
          }
  
          try {
              activatePluginClassLoader();
  
              atlasMetastoreHookImpl.onCreateDatabase(dbEvent);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveMetastoreHook.onCreateDatabase()");
          }
      }
  
      @Override
      public void onDropDatabase(DropDatabaseEvent dbEvent) throws MetaException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveMetastoreHook.onDropDatabase()");
          }
  
          try {
              activatePluginClassLoader();
  
              atlasMetastoreHookImpl.onDropDatabase(dbEvent);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveMetastoreHook.onDropDatabase()");
          }
      }
  
      @Override
      public void onAlterDatabase(AlterDatabaseEvent dbEvent) throws MetaException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveMetastoreHook.onAlterDatabase()");
          }
  
          try {
              activatePluginClassLoader();
  
              atlasMetastoreHookImpl.onAlterDatabase(dbEvent);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveMetastoreHook.onAlterDatabase()");
          }
      }
  
      private void activatePluginClassLoader() {
          if (atlasPluginClassLoader != null) {
              atlasPluginClassLoader.activate();
          }
      }
  
      private void deactivatePluginClassLoader() {
          if (atlasPluginClassLoader != null) {
              atlasPluginClassLoader.deactivate();
          }
      }
  }