/**
    * 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.procedure;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.NamespaceDescriptor;
  import org.apache.hadoop.hbase.NamespaceExistException;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.master.MasterFileSystem;
  import org.apache.hadoop.hbase.master.TableNamespaceManager;
  import org.apache.hadoop.hbase.procedure2.StateMachineProcedure;
  import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProcedureProtos;
  import org.apache.hadoop.hbase.protobuf.generated.MasterProcedureProtos.CreateNamespaceState;
  import org.apache.hadoop.hbase.util.FSUtils;
  
  /**
   * The procedure to create a new namespace.
   */
  @InterfaceAudience.Private
  public class CreateNamespaceProcedure
      extends StateMachineProcedure<MasterProcedureEnv, CreateNamespaceState>
      implements TableProcedureInterface {
    private static final Log LOG = LogFactory.getLog(CreateNamespaceProcedure.class);
  
    private final AtomicBoolean aborted = new AtomicBoolean(false);
  
    private NamespaceDescriptor nsDescriptor;
    private Boolean traceEnabled;
  
    public CreateNamespaceProcedure() {
      this.traceEnabled = null;
    }
  
    public CreateNamespaceProcedure(final MasterProcedureEnv env,
        final NamespaceDescriptor nsDescriptor) {
      this.nsDescriptor = nsDescriptor;
      this.traceEnabled = null;
      this.setOwner(env.getRequestUser().getUGI().getShortUserName());
    }
  
    @Override
    protected Flow executeFromState(final MasterProcedureEnv env, final CreateNamespaceState state)
        throws InterruptedException {
      if (isTraceEnabled()) {
        LOG.trace(this + " execute state=" + state);
      }
  
      try {
        switch (state) {
        case CREATE_NAMESPACE_PREPARE:
          prepareCreate(env);
          setNextState(CreateNamespaceState.CREATE_NAMESPACE_CREATE_DIRECTORY);
          break;
        case CREATE_NAMESPACE_CREATE_DIRECTORY:
          createDirectory(env, nsDescriptor);
          setNextState(CreateNamespaceState.CREATE_NAMESPACE_INSERT_INTO_NS_TABLE);
          break;
        case CREATE_NAMESPACE_INSERT_INTO_NS_TABLE:
          insertIntoNSTable(env, nsDescriptor);
          setNextState(CreateNamespaceState.CREATE_NAMESPACE_UPDATE_ZK);
          break;
        case CREATE_NAMESPACE_UPDATE_ZK:
          updateZKNamespaceManager(env, nsDescriptor);
          setNextState(CreateNamespaceState.CREATE_NAMESPACE_SET_NAMESPACE_QUOTA);
          break;
        case CREATE_NAMESPACE_SET_NAMESPACE_QUOTA:
          setNamespaceQuota(env, nsDescriptor);
          return Flow.NO_MORE_STATE;
        default:
          throw new UnsupportedOperationException(this + " unhandled state=" + state);
        }
      } catch (IOException e) {
        LOG.warn("Error trying to create the namespace" + nsDescriptor.getName()
          + " (in state=" + state + ")", e);
  
       setFailure("master-create-namespace", e);
     }
     return Flow.HAS_MORE_STATE;
   }
 
   @Override
   protected void rollbackState(final MasterProcedureEnv env, final CreateNamespaceState state)
       throws IOException {
     if (isTraceEnabled()) {
       LOG.trace(this + " rollback state=" + state);
     }
     try {
       switch (state) {
       case CREATE_NAMESPACE_SET_NAMESPACE_QUOTA:
         rollbackSetNamespaceQuota(env);
         break;
       case CREATE_NAMESPACE_UPDATE_ZK:
         rollbackZKNamespaceManagerChange(env);
         break;
       case CREATE_NAMESPACE_INSERT_INTO_NS_TABLE:
         rollbackInsertIntoNSTable(env);
         break;
       case CREATE_NAMESPACE_CREATE_DIRECTORY:
         rollbackCreateDirectory(env);
         break;
       case CREATE_NAMESPACE_PREPARE:
         break; // nothing to do
       default:
         throw new UnsupportedOperationException(this + " unhandled state=" + state);
       }
     } catch (IOException e) {
       // This will be retried. Unless there is a bug in the code,
       // this should be just a "temporary error" (e.g. network down)
       LOG.warn("Failed rollback attempt step " + state + " for creating the namespace "
           + nsDescriptor.getName(), e);
       throw e;
     }
   }
 
   @Override
   protected CreateNamespaceState getState(final int stateId) {
     return CreateNamespaceState.valueOf(stateId);
   }
 
   @Override
   protected int getStateId(final CreateNamespaceState state) {
     return state.getNumber();
   }
 
   @Override
   protected CreateNamespaceState getInitialState() {
     return CreateNamespaceState.CREATE_NAMESPACE_PREPARE;
   }
 
   @Override
   protected void setNextState(CreateNamespaceState state) {
     if (aborted.get()) {
       setAbortFailure("create-namespace", "abort requested");
     } else {
       super.setNextState(state);
     }
   }
 
   @Override
   public boolean abort(final MasterProcedureEnv env) {
     aborted.set(true);
     return true;
   }
 
   @Override
   public void serializeStateData(final OutputStream stream) throws IOException {
     super.serializeStateData(stream);
 
     MasterProcedureProtos.CreateNamespaceStateData.Builder createNamespaceMsg =
         MasterProcedureProtos.CreateNamespaceStateData.newBuilder().setNamespaceDescriptor(
           ProtobufUtil.toProtoNamespaceDescriptor(this.nsDescriptor));
     createNamespaceMsg.build().writeDelimitedTo(stream);
   }
 
   @Override
   public void deserializeStateData(final InputStream stream) throws IOException {
     super.deserializeStateData(stream);
 
     MasterProcedureProtos.CreateNamespaceStateData createNamespaceMsg =
         MasterProcedureProtos.CreateNamespaceStateData.parseDelimitedFrom(stream);
     nsDescriptor = ProtobufUtil.toNamespaceDescriptor(createNamespaceMsg.getNamespaceDescriptor());
   }
 
   @Override
   public void toStringClassDetails(StringBuilder sb) {
     sb.append(getClass().getSimpleName());
     sb.append(" (Namespace=");
     sb.append(nsDescriptor.getName());
     sb.append(")");
   }
 
   private boolean isBootstrapNamespace() {
     return nsDescriptor.equals(NamespaceDescriptor.DEFAULT_NAMESPACE) ||
         nsDescriptor.equals(NamespaceDescriptor.SYSTEM_NAMESPACE);
   }
 
   @Override
   protected boolean acquireLock(final MasterProcedureEnv env) {
     if (!env.getMasterServices().isInitialized()) {
       // Namespace manager might not be ready if master is not fully initialized,
       // return false to reject user namespace creation; return true for default
       // and system namespace creation (this is part of master initialization).
       if (!isBootstrapNamespace() && env.waitInitialized(this)) {
         return false;
       }
     }
     return env.getProcedureQueue().tryAcquireNamespaceExclusiveLock(this, getNamespaceName());
   }
 
   @Override
   protected void releaseLock(final MasterProcedureEnv env) {
     env.getProcedureQueue().releaseNamespaceExclusiveLock(this, getNamespaceName());
   }
 
   @Override
   public TableName getTableName() {
     return TableName.NAMESPACE_TABLE_NAME;
   }
 
   @Override
   public TableOperationType getTableOperationType() {
     return TableOperationType.EDIT;
   }
 
   private String getNamespaceName() {
     return nsDescriptor.getName();
   }
 
   /**
    * Action before any real action of creating namespace.
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void prepareCreate(final MasterProcedureEnv env) throws IOException {
     if (getTableNamespaceManager(env).doesNamespaceExist(nsDescriptor.getName())) {
       throw new NamespaceExistException(nsDescriptor.getName());
     }
     getTableNamespaceManager(env).validateTableAndRegionCount(nsDescriptor);
   }
 
   /**
    * Create the namespace directory
    * @param env MasterProcedureEnv
    * @param nsDescriptor NamespaceDescriptor
    * @throws IOException
    */
   protected static void createDirectory(
       final MasterProcedureEnv env,
       final NamespaceDescriptor nsDescriptor) throws IOException {
     MasterFileSystem mfs = env.getMasterServices().getMasterFileSystem();
     mfs.getFileSystem().mkdirs(
       FSUtils.getNamespaceDir(mfs.getRootDir(), nsDescriptor.getName()));
   }
 
   /**
    * undo create directory
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void rollbackCreateDirectory(final MasterProcedureEnv env) throws IOException {
     try {
       DeleteNamespaceProcedure.deleteDirectory(env, nsDescriptor.getName());
     } catch (Exception e) {
       // Ignore exception
       LOG.debug("Rollback of createDirectory throws exception: " + e);
     }
   }
 
   /**
    * Insert the row into ns table
    * @param env MasterProcedureEnv
    * @param nsDescriptor NamespaceDescriptor
    * @throws IOException
    */
   protected static void insertIntoNSTable(
       final MasterProcedureEnv env,
       final NamespaceDescriptor nsDescriptor) throws IOException {
     getTableNamespaceManager(env).insertIntoNSTable(nsDescriptor);
   }
 
   /**
    * Undo the insert.
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void rollbackInsertIntoNSTable(final MasterProcedureEnv env) throws IOException {
     try {
       DeleteNamespaceProcedure.deleteFromNSTable(env, nsDescriptor.getName());
     } catch (Exception e) {
       // Ignore exception
       LOG.debug("Rollback of insertIntoNSTable throws exception: " + e);
     }
   }
 
   /**
    * Update Zookeeper.
    * @param env MasterProcedureEnv
    * @param nsDescriptor NamespaceDescriptor
    * @throws IOException
    */
   protected static void updateZKNamespaceManager(
       final MasterProcedureEnv env,
       final NamespaceDescriptor nsDescriptor) throws IOException {
     getTableNamespaceManager(env).updateZKNamespaceManager(nsDescriptor);
   }
 
   /**
    * rollback Zookeeper update.
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   private void rollbackZKNamespaceManagerChange(final MasterProcedureEnv env) throws IOException {
     try {
       DeleteNamespaceProcedure.removeFromZKNamespaceManager(env, nsDescriptor.getName());
     } catch (Exception e) {
       // Ignore exception
       LOG.debug("Rollback of updateZKNamespaceManager throws exception: " + e);
     }
   }
 
   /**
    * Set quota for the namespace
    * @param env MasterProcedureEnv
    * @param nsDescriptor NamespaceDescriptor
    * @throws IOException
    **/
   protected static void setNamespaceQuota(
       final MasterProcedureEnv env,
       final NamespaceDescriptor nsDescriptor) throws IOException {
     if (env.getMasterServices().isInitialized()) {
       env.getMasterServices().getMasterQuotaManager().setNamespaceQuota(nsDescriptor);
     }
   }
 
   /**
    * remove quota for the namespace if exists
    * @param env MasterProcedureEnv
    * @throws IOException
    **/
   private void rollbackSetNamespaceQuota(final MasterProcedureEnv env) throws IOException {
     try {
       DeleteNamespaceProcedure.removeNamespaceQuota(env, nsDescriptor.getName());
     } catch (Exception e) {
       // Ignore exception
       LOG.debug("Rollback of setNamespaceQuota throws exception: " + e);
     }
   }
 
   private static TableNamespaceManager getTableNamespaceManager(final MasterProcedureEnv env) {
     return env.getMasterServices().getTableNamespaceManager();
   }
 
   /**
    * The procedure could be restarted from a different machine. If the variable is null, we need to
    * retrieve it.
    * @return traceEnabled
    */
   private Boolean isTraceEnabled() {
     if (traceEnabled == null) {
       traceEnabled = LOG.isTraceEnabled();
     }
     return traceEnabled;
   }
 
   @Override
   protected boolean shouldWaitClientAck(MasterProcedureEnv env) {
     // hbase and default namespaces are created on bootstrap internally by the system
     // the client does not know about this procedures.
     return !isBootstrapNamespace();
   }
 }