helix-rest/src/main/java/org/apache/helix/rest/clusterMaintenanceService/HealthCheck.java

package org.apache.helix.rest.clusterMaintenanceService;

/*
 * 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.Arrays;
import java.util.List;

import com.google.common.collect.ImmutableList;


public enum HealthCheck {
  /**
   * Check if instance is alive
   */
  INSTANCE_NOT_ALIVE,
  /**
   * Check if instance is enabled both in instance config and cluster config
   */
  INSTANCE_NOT_ENABLED,
  /**
   * Check if instance is stable
   * Stable means all the ideal state mapping matches external view (view of current state).
   */
  INSTANCE_NOT_STABLE,
  /**
   * Check if instance has 0 resource assigned
   */
  EMPTY_RESOURCE_ASSIGNMENT,
  /**
   * Check if instance has disabled partitions
   */
  HAS_DISABLED_PARTITION,
  /**
   * Check if instance has valid configuration (pre-requisite for all checks)
   */
  INVALID_CONFIG,
  /**
   * Check if instance has error partitions
   */
  HAS_ERROR_PARTITION,
  /**
   * Check if all resources hosted on the instance can still meet the min active replica
   * constraint if this instance is shutdown
   */
  MIN_ACTIVE_REPLICA_CHECK_FAILED;

  /**
   * Pre-defined list of checks to test if an instance can be stopped at runtime
   */
  public static List<HealthCheck> STOPPABLE_CHECK_LIST = Arrays.asList(HealthCheck.values());
  /**
   * Pre-defined list of checks to test if an instance is in healthy running state
   */
  public static List<HealthCheck> STARTED_AND_HEALTH_CHECK_LIST = ImmutableList
      .of(INVALID_CONFIG, INSTANCE_NOT_ALIVE, INSTANCE_NOT_ENABLED, INSTANCE_NOT_STABLE,
          EMPTY_RESOURCE_ASSIGNMENT);
}