Java tutorial
/** * Copyright The Apache Software Foundation * * 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 com.alibaba.wasp.zookeeper; import com.alibaba.wasp.FConstants; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.util.StringUtils; import java.io.IOException; import java.io.InputStream; import java.net.InetAddress; import java.net.UnknownHostException; import java.util.ArrayList; import java.util.List; import java.util.Map.Entry; import java.util.Properties; /** * Utility methods for reading, parsing, and building zookeeper configuration. */ public class ZKConfig { private static final Log LOG = LogFactory.getLog(ZKConfig.class); private static final String VARIABLE_START = "${"; private static final int VARIABLE_START_LENGTH = VARIABLE_START.length(); private static final String VARIABLE_END = "}"; private static final int VARIABLE_END_LENGTH = VARIABLE_END.length(); /** * Make a Properties object holding ZooKeeper config equivalent to zoo.cfg. * If there is a zoo.cfg in the classpath, simply read it in. Otherwise parse * the corresponding config options from the Wasp XML configs and generate * the appropriate ZooKeeper properties. * @param conf Configuration to read from. * @return Properties holding mappings representing ZooKeeper zoo.cfg file. */ public static Properties makeZKProps(Configuration conf) { // First check if there is a zoo.cfg in the CLASSPATH. If so, simply read // it and grab its configuration properties. ClassLoader cl = FQuorumPeer.class.getClassLoader(); final InputStream inputStream = cl.getResourceAsStream(FConstants.ZOOKEEPER_CONFIG_NAME); if (inputStream != null) { try { return parseZooCfg(conf, inputStream); } catch (IOException e) { LOG.warn("Cannot read " + FConstants.ZOOKEEPER_CONFIG_NAME + ", loading from XML files", e); } } // Otherwise, use the configuration options from Wasp's XML files. Properties zkProperties = new Properties(); // Directly map all of the wasp.zookeeper.property.KEY properties. for (Entry<String, String> entry : conf) { String key = entry.getKey(); if (key.startsWith(FConstants.ZK_CFG_PROPERTY_PREFIX)) { String zkKey = key.substring(FConstants.ZK_CFG_PROPERTY_PREFIX_LEN); String value = entry.getValue(); // If the value has variables substitutions, need to do a get. if (value.contains(VARIABLE_START)) { value = conf.get(key); } zkProperties.put(zkKey, value); } } // If clientPort is not set, assign the default. if (zkProperties.getProperty(FConstants.CLIENT_PORT_STR) == null) { zkProperties.put(FConstants.CLIENT_PORT_STR, FConstants.DEFAULT_ZOOKEPER_CLIENT_PORT); } // Create the server.X properties. int peerPort = conf.getInt("wasp.zookeeper.peerport", 2888); int leaderPort = conf.getInt("wasp.zookeeper.leaderport", 3888); final String[] serverHosts = conf.getStrings(FConstants.ZOOKEEPER_QUORUM, FConstants.LOCALHOST); for (int i = 0; i < serverHosts.length; ++i) { String serverHost = serverHosts[i]; String address = serverHost + ":" + peerPort + ":" + leaderPort; String key = "server." + i; zkProperties.put(key, address); } return zkProperties; } /** * Parse ZooKeeper's zoo.cfg, injecting Wasp Configuration variables in. * This method is used for testing so we can pass our own InputStream. * @param conf WaspConfiguration to use for injecting variables. * @param inputStream InputStream to read from. * @return Properties parsed from config stream with variables substituted. * @throws java.io.IOException if anything goes wrong parsing config */ public static Properties parseZooCfg(Configuration conf, InputStream inputStream) throws IOException { Properties properties = new Properties(); try { properties.load(inputStream); } catch (IOException e) { final String msg = "fail to read properties from " + FConstants.ZOOKEEPER_CONFIG_NAME; LOG.fatal(msg); throw new IOException(msg, e); } for (Entry<Object, Object> entry : properties.entrySet()) { String value = entry.getValue().toString().trim(); String key = entry.getKey().toString().trim(); StringBuilder newValue = new StringBuilder(); int varStart = value.indexOf(VARIABLE_START); int varEnd = 0; while (varStart != -1) { varEnd = value.indexOf(VARIABLE_END, varStart); if (varEnd == -1) { String msg = "variable at " + varStart + " has no end marker"; LOG.fatal(msg); throw new IOException(msg); } String variable = value.substring(varStart + VARIABLE_START_LENGTH, varEnd); String substituteValue = System.getProperty(variable); if (substituteValue == null) { substituteValue = conf.get(variable); } if (substituteValue == null) { String msg = "variable " + variable + " not set in system property " + "or wasp configs"; LOG.fatal(msg); throw new IOException(msg); } newValue.append(substituteValue); varEnd += VARIABLE_END_LENGTH; varStart = value.indexOf(VARIABLE_START, varEnd); } // Special case for 'wasp.cluster.distributed' property being 'true' if (key.startsWith("server.")) { boolean mode = conf.getBoolean(FConstants.CLUSTER_DISTRIBUTED, FConstants.DEFAULT_CLUSTER_DISTRIBUTED); if (mode == FConstants.CLUSTER_IS_DISTRIBUTED && value.startsWith(FConstants.LOCALHOST)) { String msg = "The server in zoo.cfg cannot be set to localhost " + "in a fully-distributed setup because it won't be reachable. " + "See \"Getting Started\" for more information."; LOG.fatal(msg); throw new IOException(msg); } } newValue.append(value.substring(varEnd)); properties.setProperty(key, newValue.toString()); } return properties; } /** * Return the ZK Quorum servers string given zk properties returned by * makeZKProps * @param properties * @return Quorum servers String */ public static String getZKQuorumServersString(Properties properties) { String clientPort = null; List<String> servers = new ArrayList<String>(); // The clientPort option may come after the server.X hosts, so we need to // grab everything and then create the final host:port comma separated list. boolean anyValid = false; for (Entry<Object, Object> property : properties.entrySet()) { String key = property.getKey().toString().trim(); String value = property.getValue().toString().trim(); if (key.equals("clientPort")) { clientPort = value; } else if (key.startsWith("server.")) { String host = value.substring(0, value.indexOf(':')); servers.add(host); try { //noinspection ResultOfMethodCallIgnored InetAddress.getByName(host); anyValid = true; } catch (UnknownHostException e) { LOG.warn(StringUtils.stringifyException(e)); } } } if (!anyValid) { LOG.error("no valid quorum servers found in " + FConstants.ZOOKEEPER_CONFIG_NAME); return null; } if (clientPort == null) { LOG.error("no clientPort found in " + FConstants.ZOOKEEPER_CONFIG_NAME); return null; } if (servers.isEmpty()) { LOG.fatal("No server.X lines found in conf/zoo.cfg. Wasp must have a " + "ZooKeeper cluster configured for its operation."); return null; } StringBuilder hostPortBuilder = new StringBuilder(); for (int i = 0; i < servers.size(); ++i) { String host = servers.get(i); if (i > 0) { hostPortBuilder.append(','); } hostPortBuilder.append(host); hostPortBuilder.append(':'); hostPortBuilder.append(clientPort); } return hostPortBuilder.toString(); } /** * Return the ZK Quorum servers string given the specified configuration. * @param conf * @return Quorum servers */ public static String getZKQuorumServersString(Configuration conf) { return getZKQuorumServersString(makeZKProps(conf)); } }