package org.apache.helix.controller.stages;
   
   /*
    * 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.
   */
  
  import java.util.Map;
  
  import org.apache.helix.HelixManager;
  import org.apache.helix.HelixManagerProperties;
  import org.apache.helix.controller.pipeline.AbstractBaseStage;
  import org.apache.helix.controller.pipeline.StageException;
  import org.apache.helix.model.LiveInstance;
  import org.apache.log4j.Logger;
  
  /**
   * controller checks if participant version is compatible 
   *
   */
  public class CompatibilityCheckStage extends AbstractBaseStage {
    private static final Logger LOG = Logger
        .getLogger(CompatibilityCheckStage.class.getName());
  
    @Override
    public void process(ClusterEvent event) throws Exception
    {
      HelixManager manager = event.getAttribute("helixmanager");
      ClusterDataCache cache = event.getAttribute("ClusterDataCache");
      if (manager == null || cache == null)
      {
        throw new StageException("Missing attributes in event:" + event
            + ". Requires HelixManager | DataCache");
      }
  
      HelixManagerProperties properties = manager.getProperties();
      Map<String, LiveInstance> liveInstanceMap = cache.getLiveInstances();
      for (LiveInstance liveInstance : liveInstanceMap.values())
      {
        String participantVersion = liveInstance.getHelixVersion();
        if (!properties.isParticipantCompatible(participantVersion))
        {
          String errorMsg = "incompatible participant. pipeline will not continue. "
                          + "controller: " + manager.getInstanceName() 
                          + ", controllerVersion: " + properties.getVersion()
                          + ", minimumSupportedParticipantVersion: " 
                          + properties.getProperty("miminum_supported_version.participant")
                          + ", participant: " + liveInstance.getInstanceName() 
                          + ", participantVersion: " + participantVersion;
          LOG.error(errorMsg);
          throw new StageException(errorMsg);
        }
      }
    }
  }