/**
    *
    * 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.hadoop.hbase.zookeeper;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map.Entry;
  import java.util.Properties;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HConstants;
  
  /**
   * Utility methods for reading, and building the ZooKeeper configuration.
   *
   * The order and priority for reading the config are as follows:
   * (1). zoo.cfg if ""hbase.config.read.zookeeper.config" is true
   * (2). Property with "hbase.zookeeper.property." prefix from HBase XML
   * (3). other zookeeper related properties in HBASE XML
   */
  @InterfaceAudience.Private
  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.
     * Parses the corresponding config options from the HBase XML configs
     * and generates the appropriate ZooKeeper properties.
     * @param conf Configuration to read from.
     * @return Properties holding mappings representing ZooKeeper config file.
     */
    public static Properties makeZKProps(Configuration conf) {
      Properties zkProperties = makeZKPropsFromZooCfg(conf);
  
      if (zkProperties == null) {
        // Otherwise, use the configuration options from HBase's XML files.
        zkProperties = makeZKPropsFromHbaseConfig(conf);
      }
      return zkProperties;
    }
  
    /**
     * Parses the corresponding config options from the zoo.cfg file
     * and make a Properties object holding the Zookeeper config.
     *
     * @param conf Configuration to read from.
     * @return Properties holding mappings representing the ZooKeeper config file or null if
     * the HBASE_CONFIG_READ_ZOOKEEPER_CONFIG is false or the file does not exist.
     */
    private static Properties makeZKPropsFromZooCfg(Configuration conf) {
      if (conf.getBoolean(HConstants.HBASE_CONFIG_READ_ZOOKEEPER_CONFIG, false)) {
        LOG.warn(
            "Parsing ZooKeeper's " + HConstants.ZOOKEEPER_CONFIG_NAME +
            " file for ZK properties " +
            "has been deprecated. Please instead place all ZK related HBase " +
            "configuration under the hbase-site.xml, using prefixes " +
            "of the form '" + HConstants.ZK_CFG_PROPERTY_PREFIX + "', and " +
            "set property '" + HConstants.HBASE_CONFIG_READ_ZOOKEEPER_CONFIG +
            "' to false");
        // First check if there is a zoo.cfg in the CLASSPATH. If so, simply read
        // it and grab its configuration properties.
        ClassLoader cl = HQuorumPeer.class.getClassLoader();
        final InputStream inputStream =
          cl.getResourceAsStream(HConstants.ZOOKEEPER_CONFIG_NAME);
        if (inputStream != null) {
          try {
            return parseZooCfg(conf, inputStream);
          } catch (IOException e) {
            LOG.warn("Cannot read " + HConstants.ZOOKEEPER_CONFIG_NAME +
                     ", loading from XML files", e);
          }
        }
      } else {
       if (LOG.isTraceEnabled()) {
         LOG.trace("Skipped reading ZK properties file '" + HConstants.ZOOKEEPER_CONFIG_NAME +
           "' since '" + HConstants.HBASE_CONFIG_READ_ZOOKEEPER_CONFIG + "' was not set to true");
       }
     }
 
     return null;
   }
 
   /**
    * Make a Properties object holding ZooKeeper config.
    * Parses the corresponding config options from the HBase XML configs
    * and generates the appropriate ZooKeeper properties.
    *
    * @param conf Configuration to read from.
    * @return Properties holding mappings representing ZooKeeper config file.
    */
   private static Properties makeZKPropsFromHbaseConfig(Configuration conf) {
     Properties zkProperties = new Properties();
 
     // Directly map all of the hbase.zookeeper.property.KEY properties.
     // Synchronize on conf so no loading of configs while we iterate
     synchronized (conf) {
       for (Entry<String, String> entry : conf) {
         String key = entry.getKey();
         if (key.startsWith(HConstants.ZK_CFG_PROPERTY_PREFIX)) {
           String zkKey = key.substring(HConstants.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(HConstants.CLIENT_PORT_STR) == null) {
       zkProperties.put(HConstants.CLIENT_PORT_STR,
           HConstants.DEFAULT_ZOOKEPER_CLIENT_PORT);
     }
 
     // Create the server.X properties.
     int peerPort = conf.getInt("hbase.zookeeper.peerport", 2888);
     int leaderPort = conf.getInt("hbase.zookeeper.leaderport", 3888);
 
     final String[] serverHosts = conf.getStrings(HConstants.ZOOKEEPER_QUORUM,
                                                  HConstants.LOCALHOST);
     String serverHost;
     String address;
     String key;
     for (int i = 0; i < serverHosts.length; ++i) {
       if (serverHosts[i].contains(":")) {
         serverHost = serverHosts[i].substring(0, serverHosts[i].indexOf(':'));
       } else {
         serverHost = serverHosts[i];
       }
       address = serverHost + ":" + peerPort + ":" + leaderPort;
       key = "server." + i;
       zkProperties.put(key, address);
     }
 
     return zkProperties;
   }
 
   /**
    * Parse ZooKeeper's zoo.cfg, injecting HBase Configuration variables in.
    * This method is used for testing so we can pass our own InputStream.
    * @param conf HBaseConfiguration to use for injecting variables.
    * @param inputStream InputStream to read from.
    * @return Properties parsed from config stream with variables substituted.
    * @throws IOException if anything goes wrong parsing config
    * @deprecated in 0.96 onwards. HBase will no longer rely on zoo.cfg
    * availability.
    */
   @Deprecated
   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 "
         + HConstants.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 hbase configs";
           LOG.fatal(msg);
           throw new IOException(msg);
         }
 
         newValue.append(substituteValue);
 
         varEnd += VARIABLE_END_LENGTH;
         varStart = value.indexOf(VARIABLE_START, varEnd);
       }
       // Special case for 'hbase.cluster.distributed' property being 'true'
       if (key.startsWith("server.")) {
         boolean mode =
             conf.getBoolean(HConstants.CLUSTER_DISTRIBUTED, HConstants.DEFAULT_CLUSTER_DISTRIBUTED);
         if (mode == HConstants.CLUSTER_IS_DISTRIBUTED && value.startsWith(HConstants.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
    */
   private 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);
         anyValid = true;
       }
     }
 
     if (!anyValid) {
       LOG.error("no valid quorum servers found in " + HConstants.ZOOKEEPER_CONFIG_NAME);
       return null;
     }
 
     if (clientPort == null) {
       LOG.error("no clientPort found in " + HConstants.ZOOKEEPER_CONFIG_NAME);
       return null;
     }
 
     if (servers.isEmpty()) {
       LOG.fatal("No servers were found in provided ZooKeeper configuration. " +
           "HBase must have a ZooKeeper cluster configured for its " +
           "operation. Ensure that you've configured '" +
           HConstants.ZOOKEEPER_QUORUM + "' properly.");
       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 String
    */
   private static String getZKQuorumServersStringFromHbaseConfig(Configuration conf) {
     String defaultClientPort = Integer.toString(
         conf.getInt(HConstants.ZOOKEEPER_CLIENT_PORT, HConstants.DEFAULT_ZOOKEPER_CLIENT_PORT));
 
     // Build the ZK quorum server string with "server:clientport" list, separated by ','
     final String[] serverHosts =
         conf.getStrings(HConstants.ZOOKEEPER_QUORUM, HConstants.LOCALHOST);
     return buildQuorumServerString(serverHosts, defaultClientPort);
   }
 
   /**
    * Build the ZK quorum server string with "server:clientport" list, separated by ','
    *
    * @param serverHosts a list of servers for ZK quorum
    * @param clientPort the default client port
    * @return the string for a list of "server:port" separated by ","
    */
   public static String buildQuorumServerString(String[] serverHosts, String clientPort) {
     StringBuilder quorumStringBuilder = new StringBuilder();
     String serverHost;
     for (int i = 0; i < serverHosts.length; ++i) {
       if (serverHosts[i].contains(":")) {
         serverHost = serverHosts[i]; // just use the port specified from the input
       } else {
         serverHost = serverHosts[i] + ":" + clientPort;
       }
       if (i > 0) {
         quorumStringBuilder.append(',');
       }
       quorumStringBuilder.append(serverHost);
     }
     return quorumStringBuilder.toString();
   }
 
   /**
    * Return the ZK Quorum servers string given the specified configuration.
    * @param conf
    * @return Quorum servers
    */
   public static String getZKQuorumServersString(Configuration conf) {
     // First try zoo.cfg; if not applicable, then try config XML.
     Properties zkProperties = makeZKPropsFromZooCfg(conf);
 
     if (zkProperties != null) {
       return getZKQuorumServersString(zkProperties);
     }
 
     return getZKQuorumServersStringFromHbaseConfig(conf);
   }
 }