/*
    * 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.omid.zk;
  
  import org.apache.curator.RetryPolicy;
  import org.apache.curator.framework.CuratorFramework;
  import org.apache.curator.framework.CuratorFrameworkFactory;
  import org.apache.curator.retry.ExponentialBackoffRetry;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.util.concurrent.TimeUnit;
  
  public class ZKUtils {
  
      private static final Logger LOG = LoggerFactory.getLogger(ZKUtils.class);
  
      public static CuratorFramework initZKClient(String zkCluster, String namespace, int zkConnectionTimeoutInSec)
              throws IOException {
  
          LOG.info("Creating Zookeeper Client connecting to {}", zkCluster);
  
          RetryPolicy retryPolicy = new ExponentialBackoffRetry(1000, 3);
          CuratorFramework zkClient = CuratorFrameworkFactory.builder()
                  .namespace(namespace)
                  .connectString(zkCluster)
                  .retryPolicy(retryPolicy)
                  .build();
  
          zkClient.start();
  
          try {
              if (zkClient.blockUntilConnected(zkConnectionTimeoutInSec, TimeUnit.SECONDS)) {
                  LOG.info("Connected to ZK cluster '{}', client in state: [{}]", zkCluster, zkClient.getState());
              } else {
                  String errorMsg = String.format("Can't contact ZK cluster '%s' after %d seconds",
                                                  zkCluster, zkConnectionTimeoutInSec);
                  throw new IOException(errorMsg);
              }
          } catch (InterruptedException ex) {
              throw new IOException(String.format("Interrupted whilst connecting to ZK cluster '%s'", zkCluster));
          }
  
          return zkClient;
  
      }
  
  }