/*
    *
    * 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.BufferedReader;
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.InterruptedIOException;
  import java.io.OutputStream;
  import java.io.Reader;
  import java.net.BindException;
  import java.net.InetSocketAddress;
  import java.net.Socket;
  import java.nio.charset.StandardCharsets;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Random;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.zookeeper.server.NIOServerCnxnFactory;
  import org.apache.zookeeper.server.ZooKeeperServer;
  import org.apache.zookeeper.server.persistence.FileTxnLog;
  
  /**
   * TODO: Most of the code in this class is ripped from ZooKeeper tests. Instead
   * of redoing it, we should contribute updates to their code which let us more
   * easily access testing helper objects.
   */
  @InterfaceAudience.Public
  @InterfaceStability.Evolving
  public class MiniZooKeeperCluster {
    private static final Log LOG = LogFactory.getLog(MiniZooKeeperCluster.class);
  
    private static final int TICK_TIME = 2000;
    private static final int DEFAULT_CONNECTION_TIMEOUT = 30000;
    private int connectionTimeout;
  
    private boolean started;
  
    /** The default port. If zero, we use a random port. */
    private int defaultClientPort = 0;
  
    private List<NIOServerCnxnFactory> standaloneServerFactoryList;
    private List<ZooKeeperServer> zooKeeperServers;
    private List<Integer> clientPortList;
  
    private int activeZKServerIndex;
    private int tickTime = 0;
  
    private Configuration configuration;
  
    public MiniZooKeeperCluster() {
      this(new Configuration());
    }
  
    public MiniZooKeeperCluster(Configuration configuration) {
      this.started = false;
      this.configuration = configuration;
      activeZKServerIndex = -1;
      zooKeeperServers = new ArrayList<ZooKeeperServer>();
      clientPortList = new ArrayList<Integer>();
      standaloneServerFactoryList = new ArrayList<NIOServerCnxnFactory>();
      connectionTimeout = configuration.getInt(HConstants.ZK_SESSION_TIMEOUT + ".localHBaseCluster",
        DEFAULT_CONNECTION_TIMEOUT);
    }
  
    /**
     * Add a client port to the list.
     *
     * @param clientPort the specified port
     */
    public void addClientPort(int clientPort) {
      clientPortList.add(clientPort);
    }
  
    /**
    * Get the list of client ports.
    * @return clientPortList the client port list
    */
   @InterfaceAudience.Private
   public List<Integer> getClientPortList() {
     return clientPortList;
   }
 
   /**
    * Check whether the client port in a specific position of the client port list is valid.
    *
    * @param index the specified position
    */
   private boolean hasValidClientPortInList(int index) {
     return (clientPortList.size() > index && clientPortList.get(index) > 0);
   }
 
   public void setDefaultClientPort(int clientPort) {
     if (clientPort <= 0) {
       throw new IllegalArgumentException("Invalid default ZK client port: "
           + clientPort);
     }
     this.defaultClientPort = clientPort;
   }
 
   /**
    * Selects a ZK client port.
    *
    * @param seedPort the seed port to start with; -1 means first time.
    * @Returns a valid and unused client port
    */
   private int selectClientPort(int seedPort) {
     int i;
     int returnClientPort = seedPort + 1;
     if (returnClientPort == 0) {
       // If the new port is invalid, find one - starting with the default client port.
       // If the default client port is not specified, starting with a random port.
       // The random port is selected from the range between 49152 to 65535. These ports cannot be
       // registered with IANA and are intended for dynamic allocation (see http://bit.ly/dynports).
       if (defaultClientPort > 0) {
         returnClientPort = defaultClientPort;
       } else {
         returnClientPort = 0xc000 + new Random().nextInt(0x3f00);
       }
     }
     // Make sure that the port is unused.
     while (true) {
       for (i = 0; i < clientPortList.size(); i++) {
         if (returnClientPort == clientPortList.get(i)) {
           // Already used. Update the port and retry.
           returnClientPort++;
           break;
         }
       }
       if (i == clientPortList.size()) {
         break; // found a unused port, exit
       }
     }
     return returnClientPort;
   }
 
   public void setTickTime(int tickTime) {
     this.tickTime = tickTime;
   }
 
   public int getBackupZooKeeperServerNum() {
     return zooKeeperServers.size()-1;
   }
 
   public int getZooKeeperServerNum() {
     return zooKeeperServers.size();
   }
 
   // / XXX: From o.a.zk.t.ClientBase
   private static void setupTestEnv() {
     // during the tests we run with 100K prealloc in the logs.
     // on windows systems prealloc of 64M was seen to take ~15seconds
     // resulting in test failure (client timeout on first session).
     // set env and directly in order to handle static init/gc issues
     System.setProperty("zookeeper.preAllocSize", "100");
     FileTxnLog.setPreallocSize(100 * 1024);
     // allow all 4 letter words
     System.setProperty("zookeeper.4lw.commands.whitelist","*");
   }
 
   public int startup(File baseDir) throws IOException, InterruptedException {
     int numZooKeeperServers = clientPortList.size();
     if (numZooKeeperServers == 0) {
       numZooKeeperServers = 1; // need at least 1 ZK server for testing
     }
     return startup(baseDir, numZooKeeperServers);
   }
 
   /**
    * @param baseDir
    * @param numZooKeeperServers
    * @return ClientPort server bound to, -1 if there was a
    *         binding problem and we couldn't pick another port.
    * @throws IOException
    * @throws InterruptedException
    */
   public int startup(File baseDir, int numZooKeeperServers) throws IOException,
       InterruptedException {
     if (numZooKeeperServers <= 0)
       return -1;
 
     setupTestEnv();
     shutdown();
 
     int tentativePort = -1; // the seed port
     int currentClientPort;
 
     // running all the ZK servers
     for (int i = 0; i < numZooKeeperServers; i++) {
       File dir = new File(baseDir, "zookeeper_"+i).getAbsoluteFile();
       createDir(dir);
       int tickTimeToUse;
       if (this.tickTime > 0) {
         tickTimeToUse = this.tickTime;
       } else {
         tickTimeToUse = TICK_TIME;
       }
 
       // Set up client port - if we have already had a list of valid ports, use it.
       if (hasValidClientPortInList(i)) {
         currentClientPort = clientPortList.get(i);
       } else {
         tentativePort = selectClientPort(tentativePort); // update the seed
         currentClientPort = tentativePort;
       }
 
       ZooKeeperServer server = new ZooKeeperServer(dir, dir, tickTimeToUse);
       // Setting {min,max}SessionTimeout defaults to be the same as in Zookeeper
       server.setMinSessionTimeout(configuration.getInt("hbase.zookeeper.property.minSessionTimeout", -1));
       server.setMaxSessionTimeout(configuration.getInt("hbase.zookeeper.property.maxSessionTimeout", -1));
       NIOServerCnxnFactory standaloneServerFactory;
       while (true) {
         try {
           standaloneServerFactory = new NIOServerCnxnFactory();
           standaloneServerFactory.configure(
             new InetSocketAddress(currentClientPort),
             configuration.getInt(HConstants.ZOOKEEPER_MAX_CLIENT_CNXNS, 1000));
         } catch (BindException e) {
           LOG.debug("Failed binding ZK Server to client port: " +
               currentClientPort, e);
           // We're told to use some port but it's occupied, fail
           if (hasValidClientPortInList(i)) {
             return -1;
           }
           // This port is already in use, try to use another.
           tentativePort = selectClientPort(tentativePort);
           currentClientPort = tentativePort;
           continue;
         }
         break;
       }
 
       // Start up this ZK server
       standaloneServerFactory.startup(server);
       // Runs a 'stat' against the servers.
       if (!waitForServerUp(currentClientPort, connectionTimeout)) {
         throw new IOException("Waiting for startup of standalone server");
       }
 
       // We have selected a port as a client port.  Update clientPortList if necessary.
       if (clientPortList.size() <= i) { // it is not in the list, add the port
         clientPortList.add(currentClientPort);
       }
       else if (clientPortList.get(i) <= 0) { // the list has invalid port, update with valid port
         clientPortList.remove(i);
         clientPortList.add(i, currentClientPort);
       }
 
       standaloneServerFactoryList.add(standaloneServerFactory);
       zooKeeperServers.add(server);
     }
 
     // set the first one to be active ZK; Others are backups
     activeZKServerIndex = 0;
     started = true;
     int clientPort = clientPortList.get(activeZKServerIndex);
     LOG.info("Started MiniZooKeeperCluster and ran successful 'stat' " +
         "on client port=" + clientPort);
     return clientPort;
   }
 
   private void createDir(File dir) throws IOException {
     try {
       if (!dir.exists()) {
         dir.mkdirs();
       }
     } catch (SecurityException e) {
       throw new IOException("creating dir: " + dir, e);
     }
   }
 
   /**
    * @throws IOException
    */
   public void shutdown() throws IOException {
     // shut down all the zk servers
     for (int i = 0; i < standaloneServerFactoryList.size(); i++) {
       NIOServerCnxnFactory standaloneServerFactory =
         standaloneServerFactoryList.get(i);
       int clientPort = clientPortList.get(i);
 
       standaloneServerFactory.shutdown();
       if (!waitForServerDown(clientPort, connectionTimeout)) {
         throw new IOException("Waiting for shutdown of standalone server");
       }
     }
     standaloneServerFactoryList.clear();
 
     for (ZooKeeperServer zkServer: zooKeeperServers) {
       //explicitly close ZKDatabase since ZookeeperServer does not close them
       zkServer.getZKDatabase().close();
     }
     zooKeeperServers.clear();
 
     // clear everything
     if (started) {
       started = false;
       activeZKServerIndex = 0;
       clientPortList.clear();
       LOG.info("Shutdown MiniZK cluster with all ZK servers");
     }
   }
 
   /**@return clientPort return clientPort if there is another ZK backup can run
    *         when killing the current active; return -1, if there is no backups.
    * @throws IOException
    * @throws InterruptedException
    */
   public int killCurrentActiveZooKeeperServer() throws IOException,
                                         InterruptedException {
     if (!started || activeZKServerIndex < 0) {
       return -1;
     }
 
     // Shutdown the current active one
     NIOServerCnxnFactory standaloneServerFactory =
       standaloneServerFactoryList.get(activeZKServerIndex);
     int clientPort = clientPortList.get(activeZKServerIndex);
 
     standaloneServerFactory.shutdown();
     if (!waitForServerDown(clientPort, connectionTimeout)) {
       throw new IOException("Waiting for shutdown of standalone server");
     }
 
     zooKeeperServers.get(activeZKServerIndex).getZKDatabase().close();
 
     // remove the current active zk server
     standaloneServerFactoryList.remove(activeZKServerIndex);
     clientPortList.remove(activeZKServerIndex);
     zooKeeperServers.remove(activeZKServerIndex);
     LOG.info("Kill the current active ZK servers in the cluster " +
         "on client port: " + clientPort);
 
     if (standaloneServerFactoryList.size() == 0) {
       // there is no backup servers;
       return -1;
     }
     clientPort = clientPortList.get(activeZKServerIndex);
     LOG.info("Activate a backup zk server in the cluster " +
         "on client port: " + clientPort);
     // return the next back zk server's port
     return clientPort;
   }
 
   /**
    * Kill one back up ZK servers
    * @throws IOException
    * @throws InterruptedException
    */
   public void killOneBackupZooKeeperServer() throws IOException,
                                         InterruptedException {
     if (!started || activeZKServerIndex < 0 ||
         standaloneServerFactoryList.size() <= 1) {
       return ;
     }
 
     int backupZKServerIndex = activeZKServerIndex+1;
     // Shutdown the current active one
     NIOServerCnxnFactory standaloneServerFactory =
       standaloneServerFactoryList.get(backupZKServerIndex);
     int clientPort = clientPortList.get(backupZKServerIndex);
 
     standaloneServerFactory.shutdown();
     if (!waitForServerDown(clientPort, connectionTimeout)) {
       throw new IOException("Waiting for shutdown of standalone server");
     }
 
     zooKeeperServers.get(backupZKServerIndex).getZKDatabase().close();
 
     // remove this backup zk server
     standaloneServerFactoryList.remove(backupZKServerIndex);
     clientPortList.remove(backupZKServerIndex);
     zooKeeperServers.remove(backupZKServerIndex);
     LOG.info("Kill one backup ZK servers in the cluster " +
         "on client port: " + clientPort);
   }
 
   // XXX: From o.a.zk.t.ClientBase
   private static boolean waitForServerDown(int port, long timeout) throws IOException {
     long start = System.currentTimeMillis();
     while (true) {
       try {
         Socket sock = new Socket("localhost", port);
         try {
           OutputStream outstream = sock.getOutputStream();
           outstream.write(Bytes.toBytes("stat"));
           outstream.flush();
         } finally {
           sock.close();
         }
       } catch (IOException e) {
         return true;
       }
 
       if (System.currentTimeMillis() > start + timeout) {
         break;
       }
       try {
         Thread.sleep(250);
       } catch (InterruptedException e) {
         throw (InterruptedIOException)new InterruptedIOException().initCause(e);
       }
     }
     return false;
   }
 
   // XXX: From o.a.zk.t.ClientBase
   private static boolean waitForServerUp(int port, long timeout) throws IOException {
     long start = System.currentTimeMillis();
     while (true) {
       try {
         Socket sock = new Socket("localhost", port);
         BufferedReader reader = null;
         try {
           OutputStream outstream = sock.getOutputStream();
           outstream.write(Bytes.toBytes("stat"));
           outstream.flush();
 
           Reader isr = new InputStreamReader(sock.getInputStream(), StandardCharsets.UTF_8);
           reader = new BufferedReader(isr);
           String line = reader.readLine();
           if (line != null && line.startsWith("Zookeeper version:")) {
             return true;
           }
         } finally {
           sock.close();
           if (reader != null) {
             reader.close();
           }
         }
       } catch (IOException e) {
         // ignore as this is expected
         LOG.info("server localhost:" + port + " not up " + e);
       }
 
       if (System.currentTimeMillis() > start + timeout) {
         break;
       }
       try {
         Thread.sleep(250);
       } catch (InterruptedException e) {
         throw (InterruptedIOException)new InterruptedIOException().initCause(e);
       }
     }
     return false;
   }
 
   public int getClientPort() {
     return activeZKServerIndex < 0 || activeZKServerIndex >= clientPortList.size() ? -1
         : clientPortList.get(activeZKServerIndex);
   }
 }