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.alerts;
  
  import java.text.MessageFormat;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.List;
  
  import org.apache.ambari.server.AmbariException;
  import org.apache.ambari.server.orm.entities.AlertDefinitionEntity;
  import org.apache.ambari.server.state.Alert;
  import org.apache.ambari.server.state.AlertState;
  import org.apache.ambari.server.state.Cluster;
  import org.apache.ambari.server.state.Host;
  import org.apache.ambari.server.state.HostState;
  import org.apache.ambari.server.state.services.AmbariServerAlertService;
  
  /**
   * The {@link AgentHeartbeatAlertRunnable} is used by the
   * {@link AmbariServerAlertService} to check agent heartbeats and fire alert
   * events when agents are not reachable.
   */
  public class AgentHeartbeatAlertRunnable extends AlertRunnable {
    /**
     * Agent initializing message.
     */
    private static final String INIT_MSG = "{0} is initializing";
  
    /**
     * Agent healthy message.
     */
    private static final String HEALTHY_MSG = "{0} is healthy";
  
    /**
     * Agent waiting for status updates message.
     */
    private static final String STATUS_UPDATE_MSG = "{0} is waiting for status updates";
  
    /**
     * Agent is not heartbeating message.
     */
    private static final String HEARTBEAT_LOST_MSG = "{0} is not sending heartbeats";
  
    /**
     * Agent is not healthy message.
     */
    private static final String UNHEALTHY_MSG = "{0} is not healthy";
  
    /**
     * Unknown agent state message.
     */
    private static final String UNKNOWN_MSG = "{0} has an unknown state of {1}";
  
    /**
     * Constructor.
     *
     * @param definitionName
     */
    public AgentHeartbeatAlertRunnable(String definitionName) {
      super(definitionName);
    }
  
    /**
     * {@inheritDoc}
     */
    @Override
    List<Alert> execute(Cluster cluster, AlertDefinitionEntity definition)
        throws AmbariException {
      long alertTimestamp = System.currentTimeMillis();
  
      Collection<Host> hosts = cluster.getHosts();
  
      List<Alert> alerts = new ArrayList<>(hosts.size());
      for (Host host : hosts) {
        String hostName = host.getHostName();
  
        String alertText;
        AlertState alertState = AlertState.OK;
        HostState hostState = host.getState();
  
        switch (hostState) {
          case INIT:
            alertText = MessageFormat.format(INIT_MSG, hostName);
            break;
          case HEALTHY:
            alertText = MessageFormat.format(HEALTHY_MSG, hostName);
            break;
          case WAITING_FOR_HOST_STATUS_UPDATES:
            alertText = MessageFormat.format(STATUS_UPDATE_MSG, hostName);
            break;
          case HEARTBEAT_LOST:
            alertState = AlertState.CRITICAL;
            alertText = MessageFormat.format(HEARTBEAT_LOST_MSG, hostName);
            break;
          case UNHEALTHY:
            alertState = AlertState.CRITICAL;
            alertText = MessageFormat.format(UNHEALTHY_MSG, hostName);
            break;
          default:
            alertState = AlertState.UNKNOWN;
            alertText = MessageFormat.format(UNKNOWN_MSG, hostName, hostState);
            break;
        }
  
        Alert alert = new Alert(definition.getDefinitionName(), null, definition.getServiceName(),
            definition.getComponentName(), hostName, alertState);
  
        alert.setLabel(definition.getLabel());
        alert.setText(alertText);
        alert.setTimestamp(alertTimestamp);
        alert.setClusterId(cluster.getClusterId());
  
        alerts.add(alert);
      }
  
      return alerts;
    }
  }
  