/*
 * Copyright 2012 LinkedIn Corp.
 *
 * Licensed 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 azkaban.jobtype;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.nio.charset.StandardCharsets;
import java.security.PrivilegedExceptionAction;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.yarn.api.records.ApplicationId;
import org.apache.hadoop.yarn.client.api.YarnClient;
import org.apache.hadoop.yarn.conf.YarnConfiguration;
import org.apache.hadoop.yarn.exceptions.YarnException;
import org.apache.log4j.Logger;

import azkaban.security.commons.HadoopSecurityManager;
import azkaban.security.commons.HadoopSecurityManagerException;
import azkaban.utils.Props;

/**
 * <pre>
 * There are many common methods that's required by the Hadoop*Job.java's. They are all consolidated
 * here.
 *
 * Methods here include getting/setting hadoop tokens,
 * methods for manipulating lib folder paths and jar paths passed in from Azkaban prop file,
 * and finally methods for helping to parse logs for application ids,
 * and kill the applications via Yarn (very helpful during the cancel method)
 *
 * </pre>
 *
 *
 * @see azkaban.jobtype.HadoopSparkJob
 * @see HadoopHiveJob
 * @see HadoopPigJob
 * @see HadoopJavaJob
 */

public class HadoopJobUtils {
  public static String MATCH_ALL_REGEX = ".*";

  public static String MATCH_NONE_REGEX = ".^";

  public static final String HADOOP_SECURITY_MANAGER_CLASS_PARAM = "hadoop.security.manager.class";

  // the regex to look for while looking for application id's in the hadoop log
  public static final Pattern APPLICATION_ID_PATTERN = Pattern
          .compile("^(application_\\d+_\\d+).*");

  // Azkaban built in property name
  public static final String JOBTYPE_GLOBAL_JVM_ARGS = "jobtype.global.jvm.args";

  // Azkaban built in property name
  public static final String JOBTYPE_JVM_ARGS = "jobtype.jvm.args";

  // Azkaban built in property name
  public static final String JVM_ARGS = "jvm.args";

  // MapReduce config for specifying additional namenodes for delegation tokens
  public static final String MAPREDUCE_JOB_OTHER_NAMENODES = "mapreduce.job.hdfs-servers";

  // Azkaban property for listing additional namenodes for delegation tokens
  private static final String OTHER_NAMENODES_PROPERTY = "other_namenodes";

  /**
   * Invalidates a Hadoop authentication token file
   *
   * @param hadoopSecurityManager
   * @param userToProxy
   * @param tokenFile
   * @param log
   */
  public static void cancelHadoopTokens(HadoopSecurityManager hadoopSecurityManager,
          String userToProxy, File tokenFile, Logger log) {
    try {
      hadoopSecurityManager.cancelTokens(tokenFile, userToProxy, log);
    } catch (HadoopSecurityManagerException e) {
      log.error(e.getCause() + e.getMessage());
    } catch (Exception e) {
      log.error(e.getCause() + e.getMessage());
    }
  }

  /**
   * Based on the HADOOP_SECURITY_MANAGER_CLASS_PARAM setting in the incoming props, finds the
   * correct HadoopSecurityManager Java class
   *
   * @param props
   * @param log
   * @return a HadoopSecurityManager object. Will throw exception if any errors occur (including not
   *         finding a class)
   * @throws RuntimeException
   *           : If any errors happen along the way.
   */
  public static HadoopSecurityManager loadHadoopSecurityManager(Props props, Logger log)
          throws RuntimeException {

    Class<?> hadoopSecurityManagerClass = props.getClass(HADOOP_SECURITY_MANAGER_CLASS_PARAM, true,
            HadoopJobUtils.class.getClassLoader());
    log.info("Loading hadoop security manager " + hadoopSecurityManagerClass.getName());
    HadoopSecurityManager hadoopSecurityManager = null;

    try {
      Method getInstanceMethod = hadoopSecurityManagerClass.getMethod("getInstance", Props.class);
      hadoopSecurityManager = (HadoopSecurityManager) getInstanceMethod.invoke(
              hadoopSecurityManagerClass, props);
    } catch (InvocationTargetException e) {
      String errMsg = "Could not instantiate Hadoop Security Manager "
              + hadoopSecurityManagerClass.getName() + e.getCause();
      log.error(errMsg);
      throw new RuntimeException(errMsg, e);
    } catch (Exception e) {
      throw new RuntimeException(e);
    }

    return hadoopSecurityManager;

  }

  /**
   * The same as {@link #addAdditionalNamenodesToProps}, but assumes that the
   * calling job is MapReduce-based and so uses the
   * {@link #MAPREDUCE_JOB_OTHER_NAMENODES} from a {@link Configuration} object
   * to get the list of additional namenodes.
   * @param props Props to add the new Namenode URIs to.
   * @see #addAdditionalNamenodesToProps(Props, String)
   */
  public static void addAdditionalNamenodesToPropsFromMRJob(Props props, Logger log) {
    String additionalNamenodes =
        (new Configuration()).get(MAPREDUCE_JOB_OTHER_NAMENODES);
    if (additionalNamenodes != null && additionalNamenodes.length() > 0) {
      log.info("Found property " + MAPREDUCE_JOB_OTHER_NAMENODES +
          " = " + additionalNamenodes + "; setting additional namenodes");
      HadoopJobUtils.addAdditionalNamenodesToProps(props, additionalNamenodes);
    }
  }

  /**
   * Takes the list of other Namenodes from which to fetch delegation tokens,
   * the {@link #OTHER_NAMENODES_PROPERTY} property, from Props and inserts it
   * back with the addition of the the potentially JobType-specific Namenode URIs
   * from additionalNamenodes. Modifies props in-place.
   * @param props Props to add the new Namenode URIs to.
   * @param additionalNamenodes Comma-separated list of Namenode URIs from which to fetch
   *                            delegation tokens.
   */
  public static void addAdditionalNamenodesToProps(Props props, String additionalNamenodes) {
    String otherNamenodes = props.get(OTHER_NAMENODES_PROPERTY);
    if (otherNamenodes != null && otherNamenodes.length() > 0) {
      props.put(OTHER_NAMENODES_PROPERTY, otherNamenodes + "," + additionalNamenodes);
    } else {
      props.put(OTHER_NAMENODES_PROPERTY, additionalNamenodes);
    }
  }

  /**
   * Fetching token with the Azkaban user
   *
   * @param hadoopSecurityManager
   * @param props
   * @param log
   * @return
   * @throws HadoopSecurityManagerException
   */
  public static File getHadoopTokens(HadoopSecurityManager hadoopSecurityManager, Props props,
          Logger log) throws HadoopSecurityManagerException {

    File tokenFile = null;
    try {
      tokenFile = File.createTempFile("mr-azkaban", ".token");
    } catch (Exception e) {
      throw new HadoopSecurityManagerException("Failed to create the token file.", e);
    }

    hadoopSecurityManager.prefetchToken(tokenFile, props, log);

    return tokenFile;
  }

  /**
   * <pre>
   * If there's a * specification in the "jar" argument (e.g. jar=./lib/*,./lib2/*),
   * this method helps to resolve the * into actual jar names inside the folder, and in order.
   * This is due to the requirement that Spark 1.4 doesn't seem to do the resolution for users
   *
   * </pre>
   *
   * @param unresolvedJarSpec
   * @return jar file list, comma separated, all .../* expanded into actual jar names in order
   *
   */
  public static String resolveWildCardForJarSpec(String workingDirectory, String unresolvedJarSpec,
          Logger log) {

    log.debug("resolveWildCardForJarSpec: unresolved jar specification: " + unresolvedJarSpec);
    log.debug("working directory: " + workingDirectory);

    if (unresolvedJarSpec == null || unresolvedJarSpec.isEmpty())
      return "";

    StringBuilder resolvedJarSpec = new StringBuilder();

    String[] unresolvedJarSpecList = unresolvedJarSpec.split(",");
    for (String s : unresolvedJarSpecList) {
      // if need resolution
      if (s.endsWith("*")) {
        // remove last 2 characters to get to the folder
        String dirName = String.format("%s/%s", workingDirectory, s.substring(0, s.length() - 2));

        File[] jars = null;
        try {
          jars = getFilesInFolderByRegex(new File(dirName), ".*jar");
        } catch (FileNotFoundException fnfe) {
          log.warn("folder does not exist: " + dirName);
          continue;
        }

        // if the folder is there, add them to the jar list
        for (File jar : jars) {
          resolvedJarSpec.append(jar.toString()).append(",");
        }
      } else { // no need for resolution
        resolvedJarSpec.append(s).append(",");
      }
    }

    log.debug("resolveWildCardForJarSpec: resolvedJarSpec: " + resolvedJarSpec);

    // remove the trailing comma
    int lastCharIndex = resolvedJarSpec.length() - 1;
    if (lastCharIndex >= 0 && resolvedJarSpec.charAt(lastCharIndex) == ',') {
      resolvedJarSpec.deleteCharAt(lastCharIndex);
    }

    return resolvedJarSpec.toString();
  }

  /**
   * <pre>
   * Spark-submit accepts a execution jar or a python file.
   * This method looks for the proper user execution jar or a python file.
   * The user input is expected in the following 3 formats:
   *   1. ./lib/abc
   *   2. ./lib/abc.jar
   *   3. ./lib/abc.py
   *
   * This method will use prefix matching to find any jar/py that is the form of abc*.(jar|py),
   * so that users can bump jar versions without doing modifications to their Hadoop DSL.
   *
   * This method will throw an Exception if more than one jar that matches the prefix is found
   *
   * @param workingDirectory
   * @param userSpecifiedJarName
   * @return the resolved actual jar/py file name to execute
   */
  public static String resolveExecutionJarName(String workingDirectory,
          String userSpecifiedJarName, Logger log) {

    if (log.isDebugEnabled()) {
      String debugMsg = String.format(
              "Resolving execution jar name: working directory: %s,  user specified name: %s",
              workingDirectory, userSpecifiedJarName);
      log.debug(debugMsg);
    }

    // in case user decides to specify with abc.jar, instead of only abc
    if (userSpecifiedJarName.endsWith(".jar")) {
      userSpecifiedJarName = userSpecifiedJarName.replace(".jar", "");
    } else if (userSpecifiedJarName.endsWith(".py")) {
      userSpecifiedJarName = userSpecifiedJarName.replace(".py", "");
    }

    // can't use java 1.7 stuff, reverting to a slightly ugly implementation
    String userSpecifiedJarPath = String.format("%s/%s", workingDirectory, userSpecifiedJarName);
    int lastIndexOfSlash = userSpecifiedJarPath.lastIndexOf("/");
    final String jarPrefix = userSpecifiedJarPath.substring(lastIndexOfSlash + 1);
    final String dirName = userSpecifiedJarPath.substring(0, lastIndexOfSlash);

    if (log.isDebugEnabled()) {
      String debugMsg = String.format("Resolving execution jar name: dirname: %s, jar name: %s",
              dirName, jarPrefix);
      log.debug(debugMsg);
    }

    File[] potentialExecutionJarList;
    try {
      potentialExecutionJarList = getFilesInFolderByRegex(new File(dirName), jarPrefix + ".*(jar|py)");
    } catch (FileNotFoundException e) {
      throw new IllegalStateException(
              "execution jar is suppose to be in this folder, but the folder doesn't exist: "
                      + dirName);
    }

    if (potentialExecutionJarList.length == 0) {
      throw new IllegalStateException("unable to find execution jar for Spark at path: "
              + userSpecifiedJarPath + "*.(jar|py)");
    } else if (potentialExecutionJarList.length > 1) {
      throw new IllegalStateException(
              "I find more than one matching instance of the execution jar at the path, don't know which one to use: "
                      + userSpecifiedJarPath + "*.(jar|py)");
    }

    String resolvedJarName = potentialExecutionJarList[0].toString();
    log.info("Resolving execution jar/py name: resolvedJarName: " + resolvedJarName);
    return resolvedJarName;
  }

  /**
   *
   * @return a list of files in the given folder that matches the regex. It may be empty, but will
   *         never return a null
   * @throws FileNotFoundException
   */
  private static File[] getFilesInFolderByRegex(File folder, final String regex)
          throws FileNotFoundException {
    // sanity check

    if (!folder.exists()) {
      throw new FileNotFoundException();

    }
    if (!folder.isDirectory()) {
      throw new IllegalStateException(
              "execution jar is suppose to be in this folder, but the object present is not a directory: "
                      + folder);
    }

    File[] matchingFiles = folder.listFiles(new FilenameFilter() {
      @Override
      public boolean accept(File dir, String name) {
        if (name.matches(regex))
          return true;
        else
          return false;
      }
    });

    if (matchingFiles == null) {
      throw new IllegalStateException(
              "the File[] matchingFiles variable is null.  This means an IOException occured while doing listFiles.  Please check disk availability and retry again");
    }

    return matchingFiles;
  }

/**
 * This method is a decorator around the KillAllSpawnedHadoopJobs method.
 * This method takes additional parameters to determine whether KillAllSpawnedHadoopJobs needs to be executed
 * using doAs as a different user
 *
 * @param logFilePath Azkaban log file path
 * @param jobProps Azkaban job props
 * @param tokenFile Pass in the tokenFile if value is known.  It is ok to skip if the token file is in the environmental variable
 * @param log a usable logger
 */
  public static void proxyUserKillAllSpawnedHadoopJobs(final String logFilePath, Props jobProps, File tokenFile, final Logger log) {
    Properties properties = new Properties();
    properties.putAll(jobProps.getFlattened());

    try {
      if (HadoopSecureWrapperUtils.shouldProxy(properties)) {
        UserGroupInformation proxyUser =
            HadoopSecureWrapperUtils.setupProxyUser(properties,
                tokenFile.getAbsolutePath(), log);
        proxyUser.doAs(new PrivilegedExceptionAction<Void>() {
          @Override
          public Void run() throws Exception {
            HadoopJobUtils.killAllSpawnedHadoopJobs(logFilePath, log);
            return null;
          }
        });
      } else {
        HadoopJobUtils.killAllSpawnedHadoopJobs(logFilePath, log);
      }
    } catch (Throwable t) {
      log.warn("something happened while trying to kill all spawned jobs", t);
    }
  }


  /**
   * Pass in a log file, this method will find all the hadoop jobs it has launched, and kills it
   *
   * Only works with Hadoop2
   *
   * @param logFilePath
   * @param log
   * @return a Set<String>. The set will contain the applicationIds that this job tried to kill.
   */
  public static Set<String> killAllSpawnedHadoopJobs(String logFilePath, Logger log) {
    Set<String> allSpawnedJobs = findApplicationIdFromLog(logFilePath, log);
    log.info("applicationIds to kill: " + allSpawnedJobs);

    for (String appId : allSpawnedJobs) {
      try {
        killJobOnCluster(appId, log);
      } catch (Throwable t) {
        log.warn("something happened while trying to kill this job: " + appId, t);
      }
    }

    return allSpawnedJobs;
  }

  /**
   * <pre>
   * Takes in a log file, will grep every line to look for the application_id pattern.
   * If it finds multiple, it will return all of them, de-duped (this is possible in the case of pig jobs)
   * This can be used in conjunction with the @killJobOnCluster method in this file.
   * </pre>
   *
   * @param logFilePath
   * @return a Set. May be empty, but will never be null
   */
  public static Set<String> findApplicationIdFromLog(String logFilePath, Logger log) {

    File logFile = new File(logFilePath);

    if (!logFile.exists()) {
      throw new IllegalArgumentException("the logFilePath does not exist: " + logFilePath);
    }
    if (!logFile.isFile()) {
      throw new IllegalArgumentException("the logFilePath specified  is not a valid file: "
              + logFilePath);
    }
    if (!logFile.canRead()) {
      throw new IllegalArgumentException("unable to read the logFilePath specified: " + logFilePath);
    }

    BufferedReader br = null;
    Set<String> applicationIds = new HashSet<String>();

    try {
//      br = new BufferedReader(new FileReader(logFile));
      br = new BufferedReader(new InputStreamReader(
          new FileInputStream(logFile), StandardCharsets.UTF_8));
      String line;

      // finds all the application IDs
      while ((line = br.readLine()) != null) {
        String [] inputs = line.split("\\s");
        if (inputs != null) {
          for (String input : inputs) {
            Matcher m = APPLICATION_ID_PATTERN.matcher(input);
            if (m.find()) {
              String appId = m.group(1);
              applicationIds.add(appId);
            }
          }
        }
      }
    } catch (IOException e) {
      log.error("Error while trying to find applicationId for log", e);
    } finally {
      try {
        if (br != null)
          br.close();
      } catch (Exception e) {
        // do nothing
      }
    }
    return applicationIds;
  }

  /**
   * <pre>
   * Uses YarnClient to kill the job on HDFS.
   * Using JobClient only works partially:
   *   If yarn container has started but spark job haven't, it will kill
   *   If spark job has started, the cancel will hang until the spark job is complete
   *   If the spark job is complete, it will return immediately, with a job not found on job tracker
   * </pre>
   *
   * @param applicationId
   * @throws IOException
   * @throws YarnException
   */
  public static void killJobOnCluster(String applicationId, Logger log) throws YarnException,
          IOException {

    YarnConfiguration yarnConf = new YarnConfiguration();
    YarnClient yarnClient = YarnClient.createYarnClient();
    yarnClient.init(yarnConf);
    yarnClient.start();

    String[] split = applicationId.split("_");
    ApplicationId aid = ApplicationId.newInstance(Long.parseLong(split[1]),
            Integer.parseInt(split[2]));

    log.info("start klling application: " + aid);
    yarnClient.killApplication(aid);
    log.info("successfully killed application: " + aid);
  }

  /**
   * <pre>
   * constructions a javaOpts string based on the Props, and the key given, will return
   *  String.format("-D%s=%s", key, value);
   * </pre>
   *
   * @param props
   * @param key
   * @return will return String.format("-D%s=%s", key, value). Throws RuntimeException if props not
   *         present
   */
  public static String javaOptStringFromAzkabanProps(Props props, String key) {
    String value = props.get(key);
    if (value == null) {
      throw new RuntimeException(String.format("Cannot find property [%s], in azkaban props: [%s]",
              key, value));
    }
    return String.format("-D%s=%s", key, value);
  }

  /**
   * Filter a collection of String commands to match a whitelist regex and not match a blacklist
   * regex.
   *
   * @param commands
   *          Collection of commands to be filtered
   * @param whitelistRegex
   *          whitelist regex to work as inclusion criteria
   * @param blacklistRegex
   *          blacklist regex to work as exclusion criteria
   * @param log
   *          logger to report violation
   * @return filtered list of matching. Empty list if no command match all the criteria.
   */
  public static List<String> filterCommands(Collection<String> commands, String whitelistRegex,
          String blacklistRegex, Logger log) {
    List<String> filteredCommands = new LinkedList<String>();
    Pattern whitelistPattern = Pattern.compile(whitelistRegex);
    Pattern blacklistPattern = Pattern.compile(blacklistRegex);
    for (String command : commands) {
      if (whitelistPattern.matcher(command).matches()
              && !blacklistPattern.matcher(command).matches()) {
        filteredCommands.add(command);
      } else {
        log.warn(String.format("Removing restricted command: %s", command));
      }
    }
    return filteredCommands;
  }

  /**
   * <pre>
   * constructions a javaOpts string based on the Props, and the key given, will return
   *  String.format("-D%s=%s", key, value);
   * </pre>
   *
   * @param conf
   * @param key
   * @return will return String.format("-D%s=%s", key, value). Throws RuntimeException if props not
   *         present
   */
  public static String javaOptStringFromHadoopConfiguration(Configuration conf, String key) {
    String value = conf.get(key);
    if (value == null) {
      throw new RuntimeException(String.format("Cannot find property [%s], in Hadoop configuration: [%s]",
              key, value));
    }
    return String.format("-D%s=%s", key, value);
  }
}
