/**
    * 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.procedure.flush;
  
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.ThreadPoolExecutor;
  
  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.HBaseInterfaceAudience;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.MetaTableAccessor;
  import org.apache.hadoop.hbase.errorhandling.ForeignException;
  import org.apache.hadoop.hbase.errorhandling.ForeignExceptionDispatcher;
  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
  import org.apache.hadoop.hbase.master.MasterServices;
  import org.apache.hadoop.hbase.master.MetricsMaster;
  import org.apache.hadoop.hbase.procedure.MasterProcedureManager;
  import org.apache.hadoop.hbase.procedure.Procedure;
  import org.apache.hadoop.hbase.procedure.ProcedureCoordinator;
  import org.apache.hadoop.hbase.procedure.ProcedureCoordinatorRpcs;
  import org.apache.hadoop.hbase.procedure.ZKProcedureCoordinatorRpcs;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.ProcedureDescription;
  import org.apache.hadoop.hbase.util.Pair;
  import org.apache.hadoop.hbase.zookeeper.MetaTableLocator;
  import org.apache.zookeeper.KeeperException;
  
  import com.google.common.collect.Lists;
  
  @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
  public class MasterFlushTableProcedureManager extends MasterProcedureManager {
  
    public static final String FLUSH_TABLE_PROCEDURE_SIGNATURE = "flush-table-proc";
  
    private static final String FLUSH_TIMEOUT_MILLIS_KEY = "hbase.flush.master.timeoutMillis";
    private static final int FLUSH_TIMEOUT_MILLIS_DEFAULT = 60000;
    private static final String FLUSH_WAKE_MILLIS_KEY = "hbase.flush.master.wakeMillis";
    private static final int FLUSH_WAKE_MILLIS_DEFAULT = 500;
  
    private static final String FLUSH_PROC_POOL_THREADS_KEY =
        "hbase.flush.procedure.master.threads";
    private static final int FLUSH_PROC_POOL_THREADS_DEFAULT = 1;
  
    private static final Log LOG = LogFactory.getLog(MasterFlushTableProcedureManager.class);
  
    private MasterServices master;
    private ProcedureCoordinator coordinator;
    private Map<TableName, Procedure> procMap = new HashMap<TableName, Procedure>();
    private boolean stopped;
  
    public MasterFlushTableProcedureManager() {};
  
    @Override
    public void stop(String why) {
      LOG.info("stop: " + why);
      this.stopped = true;
    }
  
    @Override
    public boolean isStopped() {
      return this.stopped;
    }
  
    @Override
    public void initialize(MasterServices master, MetricsMaster metricsMaster)
        throws KeeperException, IOException, UnsupportedOperationException {
      this.master = master;
  
      // get the configuration for the coordinator
      Configuration conf = master.getConfiguration();
      long wakeFrequency = conf.getInt(FLUSH_WAKE_MILLIS_KEY, FLUSH_WAKE_MILLIS_DEFAULT);
      long timeoutMillis = conf.getLong(FLUSH_TIMEOUT_MILLIS_KEY, FLUSH_TIMEOUT_MILLIS_DEFAULT);
      int threads = conf.getInt(FLUSH_PROC_POOL_THREADS_KEY, FLUSH_PROC_POOL_THREADS_DEFAULT);
  
      // setup the procedure coordinator
     String name = master.getServerName().toString();
     ThreadPoolExecutor tpool = ProcedureCoordinator.defaultPool(name, threads);
     ProcedureCoordinatorRpcs comms = new ZKProcedureCoordinatorRpcs(
         master.getZooKeeper(), getProcedureSignature(), name);
 
     this.coordinator = new ProcedureCoordinator(comms, tpool, timeoutMillis, wakeFrequency);
   }
 
   @Override
   public String getProcedureSignature() {
     return FLUSH_TABLE_PROCEDURE_SIGNATURE;
   }
 
   @Override
   public void execProcedure(ProcedureDescription desc) throws IOException {
 
     TableName tableName = TableName.valueOf(desc.getInstance());
 
     // call pre coproc hook
     MasterCoprocessorHost cpHost = master.getMasterCoprocessorHost();
     if (cpHost != null) {
       cpHost.preTableFlush(tableName);
     }
 
     // Get the list of region servers that host the online regions for table.
     // We use the procedure instance name to carry the table name from the client.
     // It is possible that regions may move after we get the region server list.
     // Each region server will get its own online regions for the table.
     // We may still miss regions that need to be flushed.
     List<Pair<HRegionInfo, ServerName>> regionsAndLocations;
 
     if (TableName.META_TABLE_NAME.equals(tableName)) {
       regionsAndLocations = new MetaTableLocator().getMetaRegionsAndLocations(
         master.getZooKeeper());
     } else {
       regionsAndLocations = MetaTableAccessor.getTableRegionsAndLocations(
         master.getZooKeeper(), master.getConnection(), tableName, false);
     }
 
     Set<String> regionServers = new HashSet<String>(regionsAndLocations.size());
     for (Pair<HRegionInfo, ServerName> region : regionsAndLocations) {
       if (region != null && region.getFirst() != null && region.getSecond() != null) {
         HRegionInfo hri = region.getFirst();
         if (hri.isOffline() && (hri.isSplit() || hri.isSplitParent())) continue;
         regionServers.add(region.getSecond().toString());
       }
     }
 
     ForeignExceptionDispatcher monitor = new ForeignExceptionDispatcher(desc.getInstance());
 
     // Kick of the global procedure from the master coordinator to the region servers.
     // We rely on the existing Distributed Procedure framework to prevent any concurrent
     // procedure with the same name.
     Procedure proc = coordinator.startProcedure(monitor, desc.getInstance(),
       new byte[0], Lists.newArrayList(regionServers));
     monitor.rethrowException();
     if (proc == null) {
       String msg = "Failed to submit distributed procedure " + desc.getSignature() + " for '"
           + desc.getInstance() + "'. " + "Another flush procedure is running?";
       LOG.error(msg);
       throw new IOException(msg);
     }
 
     procMap.put(tableName, proc);
 
     try {
       // wait for the procedure to complete.  A timer thread is kicked off that should cancel this
       // if it takes too long.
       proc.waitForCompleted();
       LOG.info("Done waiting - exec procedure " + desc.getSignature() + " for '"
           + desc.getInstance() + "'");
       LOG.info("Master flush table procedure is successful!");
     } catch (InterruptedException e) {
       ForeignException ee =
           new ForeignException("Interrupted while waiting for flush table procdure to finish", e);
       monitor.receive(ee);
       Thread.currentThread().interrupt();
     } catch (ForeignException e) {
       ForeignException ee =
           new ForeignException("Exception while waiting for flush table procdure to finish", e);
       monitor.receive(ee);
     }
     monitor.rethrowException();
   }
 
   @Override
   public synchronized boolean isProcedureDone(ProcedureDescription desc) throws IOException {
     // Procedure instance name is the table name.
     TableName tableName = TableName.valueOf(desc.getInstance());
     Procedure proc = procMap.get(tableName);
     if (proc == null) {
       // The procedure has not even been started yet.
       // The client would request the procedure and call isProcedureDone().
       // The HBaseAdmin.execProcedure() wraps both request and isProcedureDone().
       return false;
     }
     // We reply on the existing Distributed Procedure framework to give us the status.
     return proc.isCompleted();
   }
 
 }