001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.ipc;
019
020import java.net.InetSocketAddress;
021import java.util.HashMap;
022import java.util.Iterator;
023import java.util.LinkedList;
024import java.util.Map;
025
026import org.apache.hadoop.conf.Configuration;
027import org.apache.yetus.audience.InterfaceAudience;
028import org.slf4j.Logger;
029import org.slf4j.LoggerFactory;
030import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
031import org.apache.hadoop.hbase.util.Pair;
032
033/**
034 * A class to manage a list of servers that failed recently.
035 */
036@InterfaceAudience.Private
037public class FailedServers {
038  private final Map<String, Long> failedServers = new HashMap<String, Long>();
039  private long latestExpiry = 0;
040  private final int recheckServersTimeout;
041  private static final Logger LOG = LoggerFactory.getLogger(FailedServers.class);
042
043  public FailedServers(Configuration conf) {
044    this.recheckServersTimeout = conf.getInt(
045        RpcClient.FAILED_SERVER_EXPIRY_KEY, RpcClient.FAILED_SERVER_EXPIRY_DEFAULT);
046  }
047
048  /**
049   * Add an address to the list of the failed servers list.
050   */
051  public synchronized void addToFailedServers(InetSocketAddress address, Throwable throwable) {
052    final long expiry = EnvironmentEdgeManager.currentTime() + recheckServersTimeout;
053    this.failedServers.put(address.toString(), expiry);
054    this.latestExpiry = expiry;
055    if (LOG.isDebugEnabled()) {
056      LOG.debug(
057        "Added failed server with address " + address.toString() + " to list caused by "
058            + throwable.toString());
059    }
060  }
061
062  /**
063   * Check if the server should be considered as bad. Clean the old entries of the list.
064   *
065   * @return true if the server is in the failed servers list
066   */
067  public synchronized boolean isFailedServer(final InetSocketAddress address) {
068    if (failedServers.isEmpty()) {
069      return false;
070    }
071    final long now = EnvironmentEdgeManager.currentTime();
072    if (now > this.latestExpiry) {
073      failedServers.clear();
074      return false;
075    }
076    String key = address.toString();
077    Long expiry = this.failedServers.get(key);
078    if (expiry == null) {
079      return false;
080    }
081    if (expiry >= now) {
082      return true;
083    } else {
084      this.failedServers.remove(key);
085    }
086    return false;
087  }
088}