/**
    * 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.util;
  
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.io.InterruptedIOException;
  import java.lang.reflect.Method;
  import java.net.InetSocketAddress;
  import java.net.URI;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  import java.util.Collection;
  
  import com.google.common.collect.Sets;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.classification.InterfaceStability;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hdfs.DistributedFileSystem;
  import org.apache.hadoop.hdfs.server.namenode.LeaseExpiredException;
  
  
  /**
   * Implementation for hdfs
   */
  @InterfaceAudience.Private
  @InterfaceStability.Evolving
  public class FSHDFSUtils extends FSUtils {
    private static final Log LOG = LogFactory.getLog(FSHDFSUtils.class);
    private static Class dfsUtilClazz;
    private static Method getNNAddressesMethod;
  
    /**
     * @param fs
     * @param conf
     * @return A set containing all namenode addresses of fs
     */
    private static Set<InetSocketAddress> getNNAddresses(DistributedFileSystem fs,
                                                        Configuration conf) {
      Set<InetSocketAddress> addresses = new HashSet<InetSocketAddress>();
      String serviceName = fs.getCanonicalServiceName();
  
      if (serviceName.startsWith("ha-hdfs")) {
        try {
          if (dfsUtilClazz == null) {
            dfsUtilClazz = Class.forName("org.apache.hadoop.hdfs.DFSUtil");
          }
          if (getNNAddressesMethod == null) {
            try {
              // getNNServiceRpcAddressesForCluster is available only in version
              // equal to or later than Hadoop 2.6
              getNNAddressesMethod =
                  dfsUtilClazz.getMethod("getNNServiceRpcAddressesForCluster", Configuration.class);
            } catch (NoSuchMethodException e) {
              // If hadoop version is older than hadoop 2.6
              getNNAddressesMethod =
                  dfsUtilClazz.getMethod("getNNServiceRpcAddresses", Configuration.class);
            }
  
          }
  
          Map<String, Map<String, InetSocketAddress>> addressMap =
                  (Map<String, Map<String, InetSocketAddress>>) getNNAddressesMethod
                          .invoke(null, conf);
          for (Map.Entry<String, Map<String, InetSocketAddress>> entry : addressMap.entrySet()) {
            Map<String, InetSocketAddress> nnMap = entry.getValue();
            for (Map.Entry<String, InetSocketAddress> e2 : nnMap.entrySet()) {
              InetSocketAddress addr = e2.getValue();
              addresses.add(addr);
            }
          }
        } catch (Exception e) {
          LOG.warn("DFSUtil.getNNServiceRpcAddresses failed. serviceName=" + serviceName, e);
        }
      } else {
        URI uri = fs.getUri();
        int port = uri.getPort();
        if (port < 0) {
         int idx = serviceName.indexOf(':');
         port = Integer.parseInt(serviceName.substring(idx+1));
       }
       InetSocketAddress addr = new InetSocketAddress(uri.getHost(), port);
       addresses.add(addr);
     }
 
     return addresses;
   }
 
   /**
    * @param conf the Configuration of HBase
    * @param srcFs
    * @param desFs
    * @return Whether srcFs and desFs are on same hdfs or not
    */
   public static boolean isSameHdfs(Configuration conf, FileSystem srcFs, FileSystem desFs) {
     // By getCanonicalServiceName, we could make sure both srcFs and desFs
     // show a unified format which contains scheme, host and port.
     String srcServiceName = srcFs.getCanonicalServiceName();
     String desServiceName = desFs.getCanonicalServiceName();
 
     if (srcServiceName == null || desServiceName == null) {
       return false;
     }
     if (srcServiceName.equals(desServiceName)) {
       return true;
     }
     if (srcServiceName.startsWith("ha-hdfs") && desServiceName.startsWith("ha-hdfs")) {
       Collection<String> internalNameServices =
           conf.getTrimmedStringCollection("dfs.internal.nameservices");
       if (!internalNameServices.isEmpty()) {
         if (internalNameServices.contains(srcServiceName.split(":")[1])) {
           return true;
         } else {
           return false;
         }
       }
     }
     if (srcFs instanceof DistributedFileSystem && desFs instanceof DistributedFileSystem) {
       //If one serviceName is an HA format while the other is a non-HA format,
       // maybe they refer to the same FileSystem.
       //For example, srcFs is "ha-hdfs://nameservices" and desFs is "hdfs://activeNamenode:port"
       Set<InetSocketAddress> srcAddrs = getNNAddresses((DistributedFileSystem) srcFs, conf);
       Set<InetSocketAddress> desAddrs = getNNAddresses((DistributedFileSystem) desFs, conf);
       if (Sets.intersection(srcAddrs, desAddrs).size() > 0) {
         return true;
       }
     }
 
     return false;
   }
 
   /**
    * Recover the lease from HDFS, retrying multiple times.
    */
   @Override
   public void recoverFileLease(final FileSystem fs, final Path p,
       Configuration conf, CancelableProgressable reporter)
   throws IOException {
     // lease recovery not needed for local file system case.
     if (!(fs instanceof DistributedFileSystem)) return;
     recoverDFSFileLease((DistributedFileSystem)fs, p, conf, reporter);
   }
 
   /*
    * Run the dfs recover lease. recoverLease is asynchronous. It returns:
    *    -false when it starts the lease recovery (i.e. lease recovery not *yet* done)
    *    - true when the lease recovery has succeeded or the file is closed.
    * But, we have to be careful.  Each time we call recoverLease, it starts the recover lease
    * process over from the beginning.  We could put ourselves in a situation where we are
    * doing nothing but starting a recovery, interrupting it to start again, and so on.
    * The findings over in HBASE-8354 have it that the namenode will try to recover the lease
    * on the file's primary node.  If all is well, it should return near immediately.  But,
    * as is common, it is the very primary node that has crashed and so the namenode will be
    * stuck waiting on a socket timeout before it will ask another datanode to start the
    * recovery. It does not help if we call recoverLease in the meantime and in particular,
    * subsequent to the socket timeout, a recoverLease invocation will cause us to start
    * over from square one (possibly waiting on socket timeout against primary node).  So,
    * in the below, we do the following:
    * 1. Call recoverLease.
    * 2. If it returns true, break.
    * 3. If it returns false, wait a few seconds and then call it again.
    * 4. If it returns true, break.
    * 5. If it returns false, wait for what we think the datanode socket timeout is
    * (configurable) and then try again.
    * 6. If it returns true, break.
    * 7. If it returns false, repeat starting at step 5. above.
    *
    * If HDFS-4525 is available, call it every second and we might be able to exit early.
    */
   boolean recoverDFSFileLease(final DistributedFileSystem dfs, final Path p,
       final Configuration conf, final CancelableProgressable reporter)
   throws IOException {
     LOG.info("Recover lease on dfs file " + p);
     long startWaiting = EnvironmentEdgeManager.currentTime();
     // Default is 15 minutes. It's huge, but the idea is that if we have a major issue, HDFS
     // usually needs 10 minutes before marking the nodes as dead. So we're putting ourselves
     // beyond that limit 'to be safe'.
     long recoveryTimeout = conf.getInt("hbase.lease.recovery.timeout", 900000) + startWaiting;
     // This setting should be a little bit above what the cluster dfs heartbeat is set to.
     long firstPause = conf.getInt("hbase.lease.recovery.first.pause", 4000);
     // This should be set to how long it'll take for us to timeout against primary datanode if it
     // is dead.  We set it to 61 seconds, 1 second than the default READ_TIMEOUT in HDFS, the
     // default value for DFS_CLIENT_SOCKET_TIMEOUT_KEY. If recovery is still failing after this
     // timeout, then further recovery will take liner backoff with this base, to avoid endless
     // preemptions when this value is not properly configured.
     long subsequentPauseBase = conf.getLong("hbase.lease.recovery.dfs.timeout", 61 * 1000);
 
     Method isFileClosedMeth = null;
     // whether we need to look for isFileClosed method
     boolean findIsFileClosedMeth = true;
     boolean recovered = false;
     // We break the loop if we succeed the lease recovery, timeout, or we throw an exception.
     for (int nbAttempt = 0; !recovered; nbAttempt++) {
       recovered = recoverLease(dfs, nbAttempt, p, startWaiting);
       if (recovered) break;
       checkIfCancelled(reporter);
       if (checkIfTimedout(conf, recoveryTimeout, nbAttempt, p, startWaiting)) break;
       try {
         // On the first time through wait the short 'firstPause'.
         if (nbAttempt == 0) {
           Thread.sleep(firstPause);
         } else {
           // Cycle here until (subsequentPause * nbAttempt) elapses.  While spinning, check
           // isFileClosed if available (should be in hadoop 2.0.5... not in hadoop 1 though.
           long localStartWaiting = EnvironmentEdgeManager.currentTime();
           while ((EnvironmentEdgeManager.currentTime() - localStartWaiting) <
               subsequentPauseBase * nbAttempt) {
             Thread.sleep(conf.getInt("hbase.lease.recovery.pause", 1000));
             if (findIsFileClosedMeth) {
               try {
                 isFileClosedMeth = dfs.getClass().getMethod("isFileClosed",
                   new Class[]{ Path.class });
               } catch (NoSuchMethodException nsme) {
                 LOG.debug("isFileClosed not available");
               } finally {
                 findIsFileClosedMeth = false;
               }
             }
             if (isFileClosedMeth != null && isFileClosed(dfs, isFileClosedMeth, p)) {
               recovered = true;
               break;
             }
             checkIfCancelled(reporter);
           }
         }
       } catch (InterruptedException ie) {
         InterruptedIOException iioe = new InterruptedIOException();
         iioe.initCause(ie);
         throw iioe;
       }
     }
     return recovered;
   }
 
   boolean checkIfTimedout(final Configuration conf, final long recoveryTimeout,
       final int nbAttempt, final Path p, final long startWaiting) {
     if (recoveryTimeout < EnvironmentEdgeManager.currentTime()) {
       LOG.warn("Cannot recoverLease after trying for " +
         conf.getInt("hbase.lease.recovery.timeout", 900000) +
         "ms (hbase.lease.recovery.timeout); continuing, but may be DATALOSS!!!; " +
         getLogMessageDetail(nbAttempt, p, startWaiting));
       return true;
     }
     return false;
   }
 
   /**
    * Try to recover the lease.
    * @param dfs
    * @param nbAttempt
    * @param p
    * @param startWaiting
    * @return True if dfs#recoverLease came by true.
    * @throws FileNotFoundException
    */
   boolean recoverLease(final DistributedFileSystem dfs, final int nbAttempt, final Path p,
       final long startWaiting)
   throws FileNotFoundException {
     boolean recovered = false;
     try {
       recovered = dfs.recoverLease(p);
       LOG.info((recovered? "Recovered lease, ": "Failed to recover lease, ") +
         getLogMessageDetail(nbAttempt, p, startWaiting));
     } catch (IOException e) {
       if (e instanceof LeaseExpiredException && e.getMessage().contains("File does not exist")) {
         // This exception comes out instead of FNFE, fix it
         throw new FileNotFoundException("The given WAL wasn't found at " + p);
       } else if (e instanceof FileNotFoundException) {
         throw (FileNotFoundException)e;
       }
       LOG.warn(getLogMessageDetail(nbAttempt, p, startWaiting), e);
     }
     return recovered;
   }
 
   /**
    * @param nbAttempt
    * @param p
    * @param startWaiting
    * @return Detail to append to any log message around lease recovering.
    */
   private String getLogMessageDetail(final int nbAttempt, final Path p, final long startWaiting) {
     return "attempt=" + nbAttempt + " on file=" + p + " after " +
       (EnvironmentEdgeManager.currentTime() - startWaiting) + "ms";
   }
 
   /**
    * Call HDFS-4525 isFileClosed if it is available.
    * @param dfs
    * @param m
    * @param p
    * @return True if file is closed.
    */
   private boolean isFileClosed(final DistributedFileSystem dfs, final Method m, final Path p) {
     try {
       return (Boolean) m.invoke(dfs, p);
     } catch (SecurityException e) {
       LOG.warn("No access", e);
     } catch (Exception e) {
       LOG.warn("Failed invocation for " + p.toString(), e);
     }
     return false;
   }
 
   void checkIfCancelled(final CancelableProgressable reporter)
   throws InterruptedIOException {
     if (reporter == null) return;
     if (!reporter.progress()) throw new InterruptedIOException("Operation cancelled");
   }
 }