server/base/src/main/java/org/apache/accumulo/server/util/AccumuloStatus.java

/*
 * 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.accumulo.server.util;

import java.io.IOException;

import org.apache.accumulo.core.Constants;
import org.apache.accumulo.fate.zookeeper.ZooReader;
import org.apache.zookeeper.KeeperException;

public class AccumuloStatus {
  /**
   * Determines if there could be an accumulo instance running via zookeeper lock checking
   *
   * @return true iff all servers show no indication of being registered in zookeeper, otherwise
   *         false
   * @throws IOException
   *           if there are issues connecting to ZooKeeper to determine service status
   */
  public static boolean isAccumuloOffline(ZooReader reader, String rootPath) throws IOException {
    try {
      for (String child : reader.getChildren(rootPath + Constants.ZTSERVERS)) {
        if (!reader.getChildren(rootPath + Constants.ZTSERVERS + "/" + child).isEmpty())
          return false;
      }
      if (!reader.getChildren(rootPath + Constants.ZMANAGER_LOCK).isEmpty())
        return false;
      if (!reader.getChildren(rootPath + Constants.ZMONITOR_LOCK).isEmpty())
        return false;
      if (!reader.getChildren(rootPath + Constants.ZGC_LOCK).isEmpty())
        return false;
    } catch (KeeperException | InterruptedException e) {
      throw new IOException("Issues contacting ZooKeeper to get Accumulo status.", e);
    }
    return true;
  }

}