/**
    *
    * 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.master.handler;
  
  import java.io.IOException;
  import java.io.InterruptedIOException;
  import java.util.ArrayList;
  import java.util.List;
  
  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.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.CoordinatedStateException;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.NotAllMetaRegionsOnlineException;
  import org.apache.hadoop.hbase.Server;
  import org.apache.hadoop.hbase.TableExistsException;
  import org.apache.hadoop.hbase.client.RegionReplicaUtil;
  import org.apache.hadoop.hbase.MetaTableAccessor;
  import org.apache.hadoop.hbase.executor.EventHandler;
  import org.apache.hadoop.hbase.executor.EventType;
  import org.apache.hadoop.hbase.ipc.RpcServer;
  import org.apache.hadoop.hbase.master.AssignmentManager;
  import org.apache.hadoop.hbase.master.HMaster;
  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
  import org.apache.hadoop.hbase.master.MasterFileSystem;
  import org.apache.hadoop.hbase.master.MasterServices;
  import org.apache.hadoop.hbase.master.TableLockManager;
  import org.apache.hadoop.hbase.master.TableLockManager.TableLock;
  import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
  import org.apache.hadoop.hbase.security.User;
  import org.apache.hadoop.hbase.security.UserProvider;
  import org.apache.hadoop.hbase.util.FSTableDescriptors;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.util.ModifyRegionUtils;
  import org.apache.hadoop.hbase.util.ServerRegionReplicaUtil;
  
  /**
   * Handler to create a table.
   */
  @InterfaceAudience.Private
  public class CreateTableHandler extends EventHandler {
    private static final Log LOG = LogFactory.getLog(CreateTableHandler.class);
    protected final MasterFileSystem fileSystemManager;
    protected final HTableDescriptor hTableDescriptor;
    protected final Configuration conf;
    private final AssignmentManager assignmentManager;
    private final TableLockManager tableLockManager;
    private final HRegionInfo [] newRegions;
    private final TableLock tableLock;
    private User activeUser;
  
    public CreateTableHandler(Server server, MasterFileSystem fileSystemManager,
        HTableDescriptor hTableDescriptor, Configuration conf, HRegionInfo [] newRegions,
        MasterServices masterServices) {
      super(server, EventType.C_M_CREATE_TABLE);
  
      this.fileSystemManager = fileSystemManager;
      this.hTableDescriptor = hTableDescriptor;
      this.conf = conf;
      this.newRegions = newRegions;
      this.assignmentManager = masterServices.getAssignmentManager();
      this.tableLockManager = masterServices.getTableLockManager();
  
      this.tableLock = this.tableLockManager.writeLock(this.hTableDescriptor.getTableName()
          , EventType.C_M_CREATE_TABLE.toString());
    }
  
    @Override
    public CreateTableHandler prepare()
        throws NotAllMetaRegionsOnlineException, TableExistsException, IOException {
      int timeout = conf.getInt("hbase.client.catalog.timeout", 10000);
      // Need hbase:meta availability to create a table
      try {
        if (server.getMetaTableLocator().waitMetaRegionLocation(
            server.getZooKeeper(), timeout) == null) {
          throw new NotAllMetaRegionsOnlineException();
        }
       // If we are creating the table in service to an RPC request, record the
       // active user for later, so proper permissions will be applied to the
       // new table by the AccessController if it is active
       this.activeUser = RpcServer.getRequestUser();
       if (this.activeUser == null) {
         this.activeUser = UserProvider.instantiate(conf).getCurrent();
       }
     } catch (InterruptedException e) {
       LOG.warn("Interrupted waiting for meta availability", e);
       InterruptedIOException ie = new InterruptedIOException(e.getMessage());
       ie.initCause(e);
       throw ie;
     }
 
     //acquire the table write lock, blocking. Make sure that it is released.
     this.tableLock.acquire();
     boolean success = false;
     try {
       TableName tableName = this.hTableDescriptor.getTableName();
       if (MetaTableAccessor.tableExists(this.server.getConnection(), tableName)) {
         throw new TableExistsException(tableName);
       }
 
       // During master initialization, the ZK state could be inconsistent from failed DDL
       // in the past. If we fail here, it would prevent master to start.  We should force
       // setting the system table state regardless the table state.
       boolean skipTableStateCheck =
           !((HMaster) this.server).isInitialized() && tableName.isSystemTable();
       checkAndSetEnablingTable(assignmentManager, tableName, skipTableStateCheck);
       success = true;
     } finally {
       if (!success) {
         releaseTableLock();
       }
     }
     return this;
   }
 
   static void checkAndSetEnablingTable(final AssignmentManager assignmentManager,
       final TableName tableName, boolean skipTableStateCheck) throws IOException {
     // If we have multiple client threads trying to create the table at the
     // same time, given the async nature of the operation, the table
     // could be in a state where hbase:meta table hasn't been updated yet in
     // the process() function.
     // Use enabling state to tell if there is already a request for the same
     // table in progress. This will introduce a new zookeeper call. Given
     // createTable isn't a frequent operation, that should be ok.
     // TODO: now that we have table locks, re-evaluate above -- table locks are not enough.
     // We could have cleared the hbase.rootdir and not zk.  How can we detect this case?
     // Having to clean zk AND hdfs is awkward.
     try {
       if (skipTableStateCheck) {
         assignmentManager.getTableStateManager().setTableState(
           tableName,
           ZooKeeperProtos.Table.State.ENABLING);
       } else if (!assignmentManager.getTableStateManager().setTableStateIfNotInStates(
         tableName,
         ZooKeeperProtos.Table.State.ENABLING,
         ZooKeeperProtos.Table.State.ENABLING,
         ZooKeeperProtos.Table.State.ENABLED)) {
         throw new TableExistsException(tableName);
       }
     } catch (CoordinatedStateException e) {
       throw new IOException("Unable to ensure that the table will be" +
         " enabling because of a ZooKeeper issue", e);
     }
   }
 
   static void removeEnablingTable(final AssignmentManager assignmentManager,
       final TableName tableName) {
     // Try deleting the enabling node in case of error
     // If this does not happen then if the client tries to create the table
     // again with the same Active master
     // It will block the creation saying TableAlreadyExists.
     try {
       assignmentManager.getTableStateManager().checkAndRemoveTableState(tableName,
         ZooKeeperProtos.Table.State.ENABLING, false);
     } catch (CoordinatedStateException e) {
       // Keeper exception should not happen here
       LOG.error("Got a keeper exception while removing the ENABLING table znode "
           + tableName, e);
     }
   }
 
   @Override
   public String toString() {
     String name = "UnknownServerName";
     if(server != null && server.getServerName() != null) {
       name = server.getServerName().toString();
     }
     return getClass().getSimpleName() + "-" + name + "-" + getSeqid() + "-" +
       this.hTableDescriptor.getTableName();
   }
 
   @Override
   public void process() {
     TableName tableName = this.hTableDescriptor.getTableName();
     LOG.info("Create table " + tableName);
     HMaster master = ((HMaster) this.server);
     try {
       final MasterCoprocessorHost cpHost = master.getMasterCoprocessorHost();
       if (cpHost != null) {
         cpHost.preCreateTableHandler(this.hTableDescriptor, this.newRegions, activeUser);
       }
       handleCreateTable(tableName);
       completed(null);
       if (cpHost != null) {
         cpHost.postCreateTableHandler(hTableDescriptor, newRegions, activeUser);
       }
     } catch (Throwable e) {
       LOG.error("Error trying to create the table " + tableName, e);
       if (master.isInitialized()) {
         try {
           ((HMaster) this.server).getMasterQuotaManager().removeTableFromNamespaceQuota(
             hTableDescriptor.getTableName());
         } catch (IOException e1) {
           LOG.error("Error trying to update namespace quota " + e1);
         }
       }
       completed(e);
     }
   }
 
   /**
    * Called after that process() is completed.
    * @param exception null if process() is successful or not null if something has failed.
    */
   protected void completed(final Throwable exception) {
     releaseTableLock();
     LOG.info("Table, " + this.hTableDescriptor.getTableName() + ", creation " +
         (exception == null ? "successful" : "failed. " + exception));
     if (exception != null) {
       removeEnablingTable(this.assignmentManager, this.hTableDescriptor.getTableName());
     }
   }
 
   /**
    * Responsible of table creation (on-disk and META) and assignment.
    * - Create the table directory and descriptor (temp folder)
    * - Create the on-disk regions (temp folder)
    *   [If something fails here: we've just some trash in temp]
    * - Move the table from temp to the root directory
    *   [If something fails here: we've the table in place but some of the rows required
    *    present in META. (hbck needed)]
    * - Add regions to META
    *   [If something fails here: we don't have regions assigned: table disabled]
    * - Assign regions to Region Servers
    *   [If something fails here: we still have the table in disabled state]
    * - Update ZooKeeper with the enabled state
    */
   private void handleCreateTable(TableName tableName)
       throws IOException, CoordinatedStateException {
     Path tempdir = fileSystemManager.getTempDir();
     FileSystem fs = fileSystemManager.getFileSystem();
 
     // 1. Create Table Descriptor
     Path tempTableDir = FSUtils.getTableDir(tempdir, tableName);
     new FSTableDescriptors(this.conf).createTableDescriptorForTableDirectory(
       tempTableDir, this.hTableDescriptor, false);
     Path tableDir = FSUtils.getTableDir(fileSystemManager.getRootDir(), tableName);
 
     // 2. Create Regions
     List<HRegionInfo> regionInfos = handleCreateHdfsRegions(tempdir, tableName);
     // 3. Move Table temp directory to the hbase root location
     if (!fs.rename(tempTableDir, tableDir)) {
       throw new IOException("Unable to move table from temp=" + tempTableDir +
         " to hbase root=" + tableDir);
     }
 
     if (regionInfos != null && regionInfos.size() > 0) {
       // 4. Add regions to META
       addRegionsToMeta(regionInfos, hTableDescriptor.getRegionReplication());
       // 5. Add replicas if needed
       regionInfos = addReplicas(hTableDescriptor, regionInfos);
 
       // 6. Setup replication for region replicas if needed
       if (hTableDescriptor.getRegionReplication() > 1) {
         ServerRegionReplicaUtil.setupRegionReplicaReplication(conf);
       }
 
       // 7. Trigger immediate assignment of the regions in round-robin fashion
       ModifyRegionUtils.assignRegions(assignmentManager, regionInfos);
     }
 
     // 8. Set table enabled flag up in zk.
     try {
       assignmentManager.getTableStateManager().setTableState(tableName,
         ZooKeeperProtos.Table.State.ENABLED);
     } catch (CoordinatedStateException e) {
       throw new IOException("Unable to ensure that " + tableName + " will be" +
         " enabled because of a ZooKeeper issue", e);
     }
 
     // 8. Update the tabledescriptor cache.
     ((HMaster) this.server).getTableDescriptors().get(tableName);
   }
 
   /**
    * Create any replicas for the regions (the default replicas that was
    * already created is passed to the method)
    * @param hTableDescriptor
    * @param regions default replicas
    * @return the combined list of default and non-default replicas
    */
   protected List<HRegionInfo> addReplicas(HTableDescriptor hTableDescriptor,
       List<HRegionInfo> regions) {
     int numRegionReplicas = hTableDescriptor.getRegionReplication() - 1;
     if (numRegionReplicas <= 0) {
       return regions;
     }
     List<HRegionInfo> hRegionInfos =
         new ArrayList<HRegionInfo>((numRegionReplicas+1)*regions.size());
     for (int i = 0; i < regions.size(); i++) {
       for (int j = 1; j <= numRegionReplicas; j++) {
         hRegionInfos.add(RegionReplicaUtil.getRegionInfoForReplica(regions.get(i), j));
       }
     }
     hRegionInfos.addAll(regions);
     return hRegionInfos;
   }
 
   private void releaseTableLock() {
     if (this.tableLock != null) {
       try {
         this.tableLock.release();
       } catch (IOException ex) {
         LOG.warn("Could not release the table lock", ex);
       }
     }
   }
 
   /**
    * Create the on-disk structure for the table, and returns the regions info.
    * @param tableRootDir directory where the table is being created
    * @param tableName name of the table under construction
    * @return the list of regions created
    */
   protected List<HRegionInfo> handleCreateHdfsRegions(final Path tableRootDir,
     final TableName tableName)
       throws IOException {
     return ModifyRegionUtils.createRegions(conf, tableRootDir,
         hTableDescriptor, newRegions, null);
   }
 
   /**
    * Add the specified set of regions to the hbase:meta table.
    */
   protected void addRegionsToMeta(final List<HRegionInfo> regionInfos, int regionReplication)
       throws IOException {
     MetaTableAccessor.addRegionsToMeta(this.server.getConnection(), regionInfos, regionReplication);
   }
 }