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.ambari.server.events.listeners.alerts;
  
  import java.util.List;
  import java.util.Set;
  
  import org.apache.ambari.server.EagerSingleton;
  import org.apache.ambari.server.events.AlertDefinitionChangedEvent;
  import org.apache.ambari.server.events.AlertDefinitionDeleteEvent;
  import org.apache.ambari.server.events.AlertDefinitionRegistrationEvent;
  import org.apache.ambari.server.events.AlertHashInvalidationEvent;
  import org.apache.ambari.server.events.publishers.AmbariEventPublisher;
  import org.apache.ambari.server.orm.dao.AlertsDAO;
  import org.apache.ambari.server.orm.entities.AlertCurrentEntity;
  import org.apache.ambari.server.orm.entities.AlertHistoryEntity;
  import org.apache.ambari.server.state.alert.AggregateDefinitionMapping;
  import org.apache.ambari.server.state.alert.AlertDefinition;
  import org.apache.ambari.server.state.alert.AlertDefinitionHash;
  import org.apache.ambari.server.state.alert.SourceType;
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.google.common.eventbus.AllowConcurrentEvents;
  import com.google.common.eventbus.Subscribe;
  import com.google.inject.Inject;
  import com.google.inject.Provider;
  import com.google.inject.Singleton;
  
  /**
   * The {@link AlertLifecycleListener} handles events that are part of the alert
   * infrastructure lifecycle such as definition registration events.
   */
  @Singleton
  @EagerSingleton
  public class AlertLifecycleListener {
    /**
     * Logger.
     */
    private static final Logger LOG = LoggerFactory.getLogger(AlertLifecycleListener.class);
  
    /**
     * Used for quick lookups of aggregate alerts.
     */
    @Inject
    private AggregateDefinitionMapping m_aggregateMapping;
  
    /**
     * Invalidates hosts so that they can receive updated alert definition
     * commands.
     */
    @Inject
    private Provider<AlertDefinitionHash> m_alertDefinitionHash;
  
    /**
     * Used to publish events when an alert definition has a lifecycle event.
     */
    @Inject
    private AmbariEventPublisher m_eventPublisher;
  
    /**
     * Used for querying current alerts when an alert definition changes.
     */
    @Inject
    private AlertsDAO m_alertsDao;
  
    /**
     * Constructor.
     *
     * @param publisher
     */
    @Inject
    public AlertLifecycleListener(AmbariEventPublisher publisher) {
      publisher.register(this);
    }
  
    /**
     * Handles {@link AlertDefinitionRegistrationEvent} by performing the
     * following tasks:
     * <ul>
     * <li>Registration with {@link AggregateDefinitionMapping}</li>
     * </ul>
     *
     * @param event
     *          the event being handled.
     */
    @Subscribe
    @AllowConcurrentEvents
    public void onAmbariEvent(AlertDefinitionRegistrationEvent event) {
      LOG.debug("Received event {}", event);
  
      AlertDefinition definition = event.getDefinition();
  
      LOG.debug("Registering alert definition {}", definition);
  
      if (definition.getSource().getType() == SourceType.AGGREGATE) {
        m_aggregateMapping.registerAggregate(event.getClusterId(), definition);
      }
    }
  
    /**
     * Handles {@link AlertDefinitionChangedEvent} by performing the following
     * tasks:
     * <ul>
     * <li>Updating definition with {@link AggregateDefinitionMapping}</li>
     * <li>Updating current alerts with definition label</li>
     * </ul>
     *
     * @param event
     *          the event being handled.
     */
    @Subscribe
    @AllowConcurrentEvents
    public void onAmbariEvent(AlertDefinitionChangedEvent event) {
      LOG.debug("Received event {}", event);
  
      AlertDefinition definition = event.getDefinition();
  
      LOG.debug("Updating alert definition {}", definition);
  
      if (definition.getSource().getType() == SourceType.AGGREGATE) {
        m_aggregateMapping.registerAggregate(event.getClusterId(), definition);
      }
  
      // update any current alerts
      List<AlertCurrentEntity> currentAlerts = m_alertsDao.findCurrentByDefinitionId(definition.getDefinitionId());
      for (AlertCurrentEntity current : currentAlerts) {
        AlertHistoryEntity history = current.getAlertHistory();
  
        // if the definition label changed, update the current alerts
        if (!StringUtils.equals(definition.getLabel(), history.getAlertLabel())) {
          history.setAlertLabel(definition.getLabel());
          m_alertsDao.merge(history);
        }
      }
    }
  
    /**
     * Handles {@link AlertDefinitionDeleteEvent} by performing the following
     * tasks:
     * <ul>
     * <li>Removal from with {@link AggregateDefinitionMapping}</li>
     * <li>{@link AlertDefinitionHash} invalidation</li>
     * </ul>
     *
     * @param event
     *          the event being handled.
     */
    @Subscribe
    @AllowConcurrentEvents
    public void onAmbariEvent(AlertDefinitionDeleteEvent event) {
      LOG.debug("Received event {}", event);
  
      AlertDefinition definition = event.getDefinition();
  
      LOG.debug("Removing alert definition {}", definition);
  
      if (null == definition) {
        return;
      }
  
      m_aggregateMapping.removeAssociatedAggregate(event.getClusterId(),
          definition.getName());
  
      // invalidate and publish
      AlertDefinitionHash hashHelper = m_alertDefinitionHash.get();
      Set<String> invalidatedHosts = hashHelper.invalidateHosts(definition);
      AlertHashInvalidationEvent hashInvalidationEvent = new AlertHashInvalidationEvent(
          definition.getClusterId(), invalidatedHosts);
  
      m_eventPublisher.publish(hashInvalidationEvent);
    }
  }
  