| // 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 |
| // 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 com.cloud.utils.db; |
| |
| import java.sql.SQLException; |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Properties; |
| |
| import org.apache.log4j.Logger; |
| |
| import com.mysql.jdbc.BalanceStrategy; |
| import com.mysql.jdbc.Connection; |
| import com.mysql.jdbc.ConnectionImpl; |
| import com.mysql.jdbc.LoadBalancingConnectionProxy; |
| import com.mysql.jdbc.SQLError; |
| |
| public class StaticStrategy implements BalanceStrategy { |
| private static final Logger s_logger = Logger.getLogger(StaticStrategy.class); |
| |
| public StaticStrategy() { |
| } |
| |
| @Override |
| public void destroy() { |
| // we don't have anything to clean up |
| } |
| |
| @Override |
| public void init(Connection conn, Properties props) throws SQLException { |
| // we don't have anything to initialize |
| } |
| |
| @Override |
| public ConnectionImpl pickConnection(LoadBalancingConnectionProxy proxy, List<String> configuredHosts, Map<String, ConnectionImpl> liveConnections, |
| long[] responseTimes, int numRetries) throws SQLException { |
| int numHosts = configuredHosts.size(); |
| |
| SQLException ex = null; |
| |
| List<String> whiteList = new ArrayList<String>(numHosts); |
| whiteList.addAll(configuredHosts); |
| |
| Map<String, Long> blackList = proxy.getGlobalBlacklist(); |
| |
| whiteList.removeAll(blackList.keySet()); |
| |
| Map<String, Integer> whiteListMap = this.getArrayIndexMap(whiteList); |
| |
| for (int attempts = 0; attempts < numRetries;) { |
| if (whiteList.size() == 0) { |
| throw SQLError.createSQLException("No hosts configured", null); |
| } |
| |
| String hostPortSpec = whiteList.get(0); //Always take the first host |
| |
| ConnectionImpl conn = liveConnections.get(hostPortSpec); |
| |
| if (conn == null) { |
| try { |
| conn = proxy.createConnectionForHost(hostPortSpec); |
| } catch (SQLException sqlEx) { |
| ex = sqlEx; |
| |
| if (proxy.shouldExceptionTriggerFailover(sqlEx)) { |
| |
| Integer whiteListIndex = whiteListMap.get(hostPortSpec); |
| |
| // exclude this host from being picked again |
| if (whiteListIndex != null) { |
| whiteList.remove(whiteListIndex.intValue()); |
| whiteListMap = this.getArrayIndexMap(whiteList); |
| } |
| proxy.addToGlobalBlacklist(hostPortSpec); |
| |
| if (whiteList.size() == 0) { |
| attempts++; |
| try { |
| Thread.sleep(250); |
| } catch (InterruptedException e) { |
| s_logger.debug("[ignored] interupted while fail over in progres."); |
| } |
| |
| // start fresh |
| whiteListMap = new HashMap<String, Integer>(numHosts); |
| whiteList.addAll(configuredHosts); |
| blackList = proxy.getGlobalBlacklist(); |
| |
| whiteList.removeAll(blackList.keySet()); |
| whiteListMap = this.getArrayIndexMap(whiteList); |
| } |
| |
| continue; |
| } |
| |
| throw sqlEx; |
| } |
| } |
| |
| return conn; |
| } |
| |
| if (ex != null) { |
| throw ex; |
| } |
| |
| return null; // we won't get here, compiler can't tell |
| } |
| |
| private Map<String, Integer> getArrayIndexMap(List<String> l) { |
| Map<String, Integer> m = new HashMap<String, Integer>(l.size()); |
| for (int i = 0; i < l.size(); i++) { |
| m.put(l.get(i), Integer.valueOf(i)); |
| } |
| return m; |
| |
| } |
| |
| } |