/**
    * 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;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.Locale;
  import java.util.Map;
  
  import org.apache.commons.lang.StringUtils;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.conf.Configured;
  import org.apache.hadoop.hbase.HBaseClusterManager.CommandProvider.Operation;
  import org.apache.hadoop.hbase.util.Pair;
  import org.apache.hadoop.hbase.util.RetryCounter;
  import org.apache.hadoop.hbase.util.RetryCounter.RetryConfig;
  import org.apache.hadoop.hbase.util.RetryCounterFactory;
  import org.apache.hadoop.util.Shell;
  
  /**
   * A default cluster manager for HBase. Uses SSH, and hbase shell scripts
   * to manage the cluster. Assumes Unix-like commands are available like 'ps',
   * 'kill', etc. Also assumes the user running the test has enough "power" to start & stop
   * servers on the remote machines (for example, the test user could be the same user as the
   * user the daemon is running as)
   */
  @InterfaceAudience.Private
  public class HBaseClusterManager extends Configured implements ClusterManager {
    private static final String SIGKILL = "SIGKILL";
    private static final String SIGSTOP = "SIGSTOP";
    private static final String SIGCONT = "SIGCONT";
  
    protected static final Log LOG = LogFactory.getLog(HBaseClusterManager.class);
    private String sshUserName;
    private String sshOptions;
  
    /**
     * The command format that is used to execute the remote command. Arguments:
     * 1 SSH options, 2 user name , 3 "@" if username is set, 4 host,
     * 5 original command, 6 service user.
     */
    private static final String DEFAULT_TUNNEL_CMD =
        "/usr/bin/ssh %1$s %2$s%3$s%4$s \"sudo -u %6$s %5$s\"";
    private String tunnelCmd;
  
    private static final String RETRY_ATTEMPTS_KEY = "hbase.it.clustermanager.retry.attempts";
    private static final int DEFAULT_RETRY_ATTEMPTS = 5;
  
    private static final String RETRY_SLEEP_INTERVAL_KEY = "hbase.it.clustermanager.retry.sleep.interval";
    private static final int DEFAULT_RETRY_SLEEP_INTERVAL = 1000;
  
    protected RetryCounterFactory retryCounterFactory;
  
    @Override
    public void setConf(Configuration conf) {
      super.setConf(conf);
      if (conf == null) {
        // Configured gets passed null before real conf. Why? I don't know.
        return;
      }
      sshUserName = conf.get("hbase.it.clustermanager.ssh.user", "");
      String extraSshOptions = conf.get("hbase.it.clustermanager.ssh.opts", "");
      sshOptions = System.getenv("HBASE_SSH_OPTS");
      if (!extraSshOptions.isEmpty()) {
        sshOptions = StringUtils.join(new Object[] { sshOptions, extraSshOptions }, " ");
      }
      sshOptions = (sshOptions == null) ? "" : sshOptions;
      sshUserName = (sshUserName == null) ? "" : sshUserName;
      tunnelCmd = conf.get("hbase.it.clustermanager.ssh.cmd", DEFAULT_TUNNEL_CMD);
      // Print out ssh special config if any.
      if ((sshUserName != null && sshUserName.length() > 0) ||
          (sshOptions != null && sshOptions.length() > 0)) {
        LOG.info("Running with SSH user [" + sshUserName + "] and options [" + sshOptions + "]");
      }
  
      this.retryCounterFactory = new RetryCounterFactory(new RetryConfig()
          .setMaxAttempts(conf.getInt(RETRY_ATTEMPTS_KEY, DEFAULT_RETRY_ATTEMPTS))
          .setSleepInterval(conf.getLong(RETRY_SLEEP_INTERVAL_KEY, DEFAULT_RETRY_SLEEP_INTERVAL)));
    }
  
   private String getServiceUser(ServiceType service) {
     Configuration conf = getConf();
     switch (service) {
       case HADOOP_DATANODE:
         return conf.get("hbase.it.clustermanager.hadoop.hdfs.user", "hdfs");
       case ZOOKEEPER_SERVER:
         return conf.get("hbase.it.clustermanager.zookeeper.user", "zookeeper");
       default:
         return conf.get("hbase.it.clustermanager.hbase.user", "hbase");
     }
   }
 
   /**
    * Executes commands over SSH
    */
   protected class RemoteShell extends Shell.ShellCommandExecutor {
     private String hostname;
     private String user;
 
     public RemoteShell(String hostname, String[] execString, File dir, Map<String, String> env,
         long timeout) {
       super(execString, dir, env, timeout);
       this.hostname = hostname;
     }
 
     public RemoteShell(String hostname, String[] execString, File dir, Map<String, String> env) {
       super(execString, dir, env);
       this.hostname = hostname;
     }
 
     public RemoteShell(String hostname, String[] execString, File dir) {
       super(execString, dir);
       this.hostname = hostname;
     }
 
     public RemoteShell(String hostname, String[] execString) {
       super(execString);
       this.hostname = hostname;
     }
 
     public RemoteShell(String hostname, String user, String[] execString) {
       super(execString);
       this.hostname = hostname;
       this.user = user;
     }
 
     @Override
     public String[] getExecString() {
       String at = sshUserName.isEmpty() ? "" : "@";
       String remoteCmd = StringUtils.join(super.getExecString(), " ");
       String cmd = String.format(tunnelCmd, sshOptions, sshUserName, at, hostname, remoteCmd, user);
       LOG.info("Executing full command [" + cmd + "]");
       return new String[] { "/usr/bin/env", "bash", "-c", cmd };
     }
 
     @Override
     public void execute() throws IOException {
       super.execute();
     }
   }
 
   /**
    * Provides command strings for services to be executed by Shell. CommandProviders are
    * pluggable, and different deployments(windows, bigtop, etc) can be managed by
    * plugging-in custom CommandProvider's or ClusterManager's.
    */
   static abstract class CommandProvider {
 
     enum Operation {
       START, STOP, RESTART
     }
 
     public abstract String getCommand(ServiceType service, Operation op);
 
     public String isRunningCommand(ServiceType service) {
       return findPidCommand(service);
     }
 
     protected String findPidCommand(ServiceType service) {
       return String.format("ps ux | grep proc_%s | grep -v grep | tr -s ' ' | cut -d ' ' -f2",
           service);
     }
 
     public String signalCommand(ServiceType service, String signal) {
       return String.format("%s | xargs kill -s %s", findPidCommand(service), signal);
     }
   }
 
   /**
    * CommandProvider to manage the service using bin/hbase-* scripts
    */
   static class HBaseShellCommandProvider extends CommandProvider {
     private final String hbaseHome;
     private final String confDir;
 
     HBaseShellCommandProvider(Configuration conf) {
       hbaseHome = conf.get("hbase.it.clustermanager.hbase.home",
         System.getenv("HBASE_HOME"));
       String tmp = conf.get("hbase.it.clustermanager.hbase.conf.dir",
         System.getenv("HBASE_CONF_DIR"));
       if (tmp != null) {
         confDir = String.format("--config %s", tmp);
       } else {
         confDir = "";
       }
     }
 
     @Override
     public String getCommand(ServiceType service, Operation op) {
       return String.format("%s/bin/hbase-daemon.sh %s %s %s", hbaseHome, confDir,
           op.toString().toLowerCase(Locale.ROOT), service);
     }
   }
 
   /**
    * CommandProvider to manage the service using sbin/hadoop-* scripts.
    */
   static class HadoopShellCommandProvider extends CommandProvider {
     private final String hadoopHome;
     private final String confDir;
 
     HadoopShellCommandProvider(Configuration conf) throws IOException {
       hadoopHome = conf.get("hbase.it.clustermanager.hadoop.home",
           System.getenv("HADOOP_HOME"));
       String tmp = conf.get("hbase.it.clustermanager.hadoop.conf.dir",
           System.getenv("HADOOP_CONF_DIR"));
       if (hadoopHome == null) {
         throw new IOException("Hadoop home configuration parameter i.e. " +
           "'hbase.it.clustermanager.hadoop.home' is not configured properly.");
       }
       if (tmp != null) {
         confDir = String.format("--config %s", tmp);
       } else {
         confDir = "";
       }
     }
 
     @Override
     public String getCommand(ServiceType service, Operation op) {
       return String.format("%s/sbin/hadoop-daemon.sh %s %s %s", hadoopHome, confDir,
           op.toString().toLowerCase(Locale.ROOT), service);
     }
   }
 
   /**
    * CommandProvider to manage the service using bin/zk* scripts.
    */
   static class ZookeeperShellCommandProvider extends CommandProvider {
     private final String zookeeperHome;
     private final String confDir;
 
     ZookeeperShellCommandProvider(Configuration conf) throws IOException {
       zookeeperHome = conf.get("hbase.it.clustermanager.zookeeper.home",
           System.getenv("ZOOBINDIR"));
       String tmp = conf.get("hbase.it.clustermanager.zookeeper.conf.dir",
           System.getenv("ZOOCFGDIR"));
       if (zookeeperHome == null) {
         throw new IOException("Zookeeper home configuration parameter i.e. " +
           "'hbase.it.clustermanager.zookeeper.home' is not configured properly.");
       }
       if (tmp != null) {
         confDir = String.format("--config %s", tmp);
       } else {
         confDir = "";
       }
     }
 
     @Override
     public String getCommand(ServiceType service, Operation op) {
       return String.format("%s/bin/zkServer.sh %s", zookeeperHome, op.toString().toLowerCase(Locale.ROOT));
     }
 
     @Override
     protected String findPidCommand(ServiceType service) {
       return String.format("ps ux | grep %s | grep -v grep | tr -s ' ' | cut -d ' ' -f2",
         service);
     }
   }
 
   public HBaseClusterManager() {
   }
 
   protected CommandProvider getCommandProvider(ServiceType service) throws IOException {
     switch (service) {
       case HADOOP_DATANODE:
         return new HadoopShellCommandProvider(getConf());
       case ZOOKEEPER_SERVER:
         return new ZookeeperShellCommandProvider(getConf());
       default:
         return new HBaseShellCommandProvider(getConf());
     }
   }
 
   /**
    * Execute the given command on the host using SSH
    * @return pair of exit code and command output
    * @throws IOException if something goes wrong.
    */
   private Pair<Integer, String> exec(String hostname, ServiceType service, String... cmd)
     throws IOException {
     LOG.info("Executing remote command: " + StringUtils.join(cmd, " ") + " , hostname:" + hostname);
 
     RemoteShell shell = new RemoteShell(hostname, getServiceUser(service), cmd);
     try {
       shell.execute();
     } catch (Shell.ExitCodeException ex) {
       // capture the stdout of the process as well.
       String output = shell.getOutput();
       // add output for the ExitCodeException.
       throw new Shell.ExitCodeException(ex.getExitCode(), "stderr: " + ex.getMessage()
         + ", stdout: " + output);
     }
 
     LOG.info("Executed remote command, exit code:" + shell.getExitCode()
         + " , output:" + shell.getOutput());
 
     return new Pair<Integer, String>(shell.getExitCode(), shell.getOutput());
   }
 
   private Pair<Integer, String> execWithRetries(String hostname, ServiceType service, String... cmd)
       throws IOException {
     RetryCounter retryCounter = retryCounterFactory.create();
     while (true) {
       try {
         return exec(hostname, service, cmd);
       } catch (IOException e) {
         retryOrThrow(retryCounter, e, hostname, cmd);
       }
       try {
         retryCounter.sleepUntilNextRetry();
       } catch (InterruptedException ex) {
         // ignore
         LOG.warn("Sleep Interrupted:" + ex);
       }
     }
   }
 
   private <E extends Exception> void retryOrThrow(RetryCounter retryCounter, E ex,
       String hostname, String[] cmd) throws E {
     if (retryCounter.shouldRetry()) {
       LOG.warn("Remote command: " + StringUtils.join(cmd, " ") + " , hostname:" + hostname
         + " failed at attempt " + retryCounter.getAttemptTimes() + ". Retrying until maxAttempts: "
           + retryCounter.getMaxAttempts() + ". Exception: " + ex.getMessage());
       return;
     }
     throw ex;
   }
 
   private void exec(String hostname, ServiceType service, Operation op) throws IOException {
     execWithRetries(hostname, service, getCommandProvider(service).getCommand(service, op));
   }
 
   @Override
   public void start(ServiceType service, String hostname, int port) throws IOException {
     exec(hostname, service, Operation.START);
   }
 
   @Override
   public void stop(ServiceType service, String hostname, int port) throws IOException {
     exec(hostname, service, Operation.STOP);
   }
 
   @Override
   public void restart(ServiceType service, String hostname, int port) throws IOException {
     exec(hostname, service, Operation.RESTART);
   }
 
   public void signal(ServiceType service, String signal, String hostname) throws IOException {
     execWithRetries(hostname, service, getCommandProvider(service).signalCommand(service, signal));
   }
 
   @Override
   public boolean isRunning(ServiceType service, String hostname, int port) throws IOException {
     String ret = execWithRetries(hostname, service,
       getCommandProvider(service).isRunningCommand(service)).getSecond();
     return ret.length() > 0;
   }
 
   @Override
   public void kill(ServiceType service, String hostname, int port) throws IOException {
     signal(service, SIGKILL, hostname);
   }
 
   @Override
   public void suspend(ServiceType service, String hostname, int port) throws IOException {
     signal(service, SIGSTOP, hostname);
   }
 
   @Override
   public void resume(ServiceType service, String hostname, int port) throws IOException {
     signal(service, SIGCONT, hostname);
   }
 }