/**
    * 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.security.PrivilegedExceptionAction;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.MetaTableAccessor;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.TableNotDisabledException;
  import org.apache.hadoop.hbase.TableNotFoundException;
  import org.apache.hadoop.hbase.TableStateManager;
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.hbase.executor.EventType;
  import org.apache.hadoop.hbase.exceptions.HBaseException;
  import org.apache.hadoop.hbase.master.AssignmentManager;
  import org.apache.hadoop.hbase.master.BulkAssigner;
  import org.apache.hadoop.hbase.master.GeneralBulkAssigner;
  import org.apache.hadoop.hbase.master.MasterCoprocessorHost;
  import org.apache.hadoop.hbase.master.MasterServices;
  import org.apache.hadoop.hbase.master.RegionStates;
  import org.apache.hadoop.hbase.master.ServerManager;
  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.EnableTableState;
  import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos;
  import org.apache.hadoop.hbase.util.Pair;
  import org.apache.hadoop.hbase.zookeeper.MetaTableLocator;
  import org.apache.hadoop.security.UserGroupInformation;
  
  @InterfaceAudience.Private
  public class EnableTableProcedure
      extends StateMachineProcedure<MasterProcedureEnv, EnableTableState>
      implements TableProcedureInterface {
    private static final Log LOG = LogFactory.getLog(EnableTableProcedure.class);
  
    private final AtomicBoolean aborted = new AtomicBoolean(false);
  
    // This is for back compatible with 1.0 asynchronized operations.
    private final ProcedurePrepareLatch syncLatch;
  
    private TableName tableName;
    private boolean skipTableStateCheck;
    private UserGroupInformation user;
  
    private Boolean traceEnabled = null;
  
    public EnableTableProcedure() {
      syncLatch = null;
    }
  
    /**
     * Constructor
     * @param env MasterProcedureEnv
     * @param tableName the table to operate on
     * @param skipTableStateCheck whether to check table state
     */
    public EnableTableProcedure(final MasterProcedureEnv env, final TableName tableName,
        final boolean skipTableStateCheck) {
      this(env, tableName, skipTableStateCheck, null);
    }
  
    /**
     * Constructor
     * @param env MasterProcedureEnv
     * @throws IOException
     * @param tableName the table to operate on
     * @param skipTableStateCheck whether to check table state
     */
    public EnableTableProcedure(final MasterProcedureEnv env, final TableName tableName,
        final boolean skipTableStateCheck, final ProcedurePrepareLatch syncLatch) {
     this.tableName = tableName;
     this.skipTableStateCheck = skipTableStateCheck;
     this.user = env.getRequestUser().getUGI();
     this.setOwner(this.user.getShortUserName());
 
     // Compatible with 1.0: We use latch to make sure that this procedure implementation is
     // compatible with 1.0 asynchronized operations. We need to lock the table and check
     // whether the Enable operation could be performed (table exists and offline; table state
     // is DISABLED). Once it is done, we are good to release the latch and the client can
     // start asynchronously wait for the operation.
     //
     // Note: the member syncLatch could be null if we are in failover or recovery scenario.
     // This is ok for backward compatible, as 1.0 client would not able to peek at procedure.
     this.syncLatch = syncLatch;
   }
 
   @Override
   protected Flow executeFromState(final MasterProcedureEnv env, final EnableTableState state) {
     if (isTraceEnabled()) {
       LOG.trace(this + " execute state=" + state);
     }
 
     try {
       switch (state) {
       case ENABLE_TABLE_PREPARE:
         if (prepareEnable(env)) {
           setNextState(EnableTableState.ENABLE_TABLE_PRE_OPERATION);
         } else {
           assert isFailed() : "enable should have an exception here";
           return Flow.NO_MORE_STATE;
         }
         break;
       case ENABLE_TABLE_PRE_OPERATION:
         preEnable(env, state);
         setNextState(EnableTableState.ENABLE_TABLE_SET_ENABLING_TABLE_STATE);
         break;
       case ENABLE_TABLE_SET_ENABLING_TABLE_STATE:
         setTableStateToEnabling(env, tableName);
         setNextState(EnableTableState.ENABLE_TABLE_MARK_REGIONS_ONLINE);
         break;
       case ENABLE_TABLE_MARK_REGIONS_ONLINE:
         markRegionsOnline(env, tableName, true);
         setNextState(EnableTableState.ENABLE_TABLE_SET_ENABLED_TABLE_STATE);
         break;
       case ENABLE_TABLE_SET_ENABLED_TABLE_STATE:
         setTableStateToEnabled(env, tableName);
         setNextState(EnableTableState.ENABLE_TABLE_POST_OPERATION);
         break;
       case ENABLE_TABLE_POST_OPERATION:
         postEnable(env, state);
         return Flow.NO_MORE_STATE;
       default:
         throw new UnsupportedOperationException("unhandled state=" + state);
       }
     } catch (InterruptedException|HBaseException|IOException e) {
       LOG.error("Error trying to enable table=" + tableName + " state=" + state, e);
       setFailure("master-enable-table", e);
     }
     return Flow.HAS_MORE_STATE;
   }
 
   @Override
   protected void rollbackState(final MasterProcedureEnv env, final EnableTableState state)
       throws IOException {
     if (isTraceEnabled()) {
       LOG.trace(this + " rollback state=" + state);
     }
     try {
       switch (state) {
       case ENABLE_TABLE_POST_OPERATION:
         // TODO-MAYBE: call the coprocessor event to undo (eg. DisableTableProcedure.preDisable())?
         break;
       case ENABLE_TABLE_SET_ENABLED_TABLE_STATE:
         DisableTableProcedure.setTableStateToDisabling(env, tableName);
         break;
       case ENABLE_TABLE_MARK_REGIONS_ONLINE:
         markRegionsOfflineDuringRecovery(env);
         break;
       case ENABLE_TABLE_SET_ENABLING_TABLE_STATE:
         DisableTableProcedure.setTableStateToDisabled(env, tableName);
         break;
       case ENABLE_TABLE_PRE_OPERATION:
         // TODO-MAYBE: call the coprocessor event to undo (eg. DisableTableProcedure.postDisable())?
         break;
       case ENABLE_TABLE_PREPARE:
         // Nothing to undo for this state.
         // We do need to count down the latch count so that we don't stuck.
         ProcedurePrepareLatch.releaseLatch(syncLatch, this);
         break;
       default:
         throw new UnsupportedOperationException("unhandled state=" + state);
       }
     } catch (HBaseException e) {
       LOG.warn("Failed enable table rollback attempt step=" + state + " table=" + tableName, e);
       throw new IOException(e);
     } 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 enable table rollback attempt step=" + state + " table=" + tableName, e);
       throw e;
     }
   }
 
   @Override
   protected EnableTableState getState(final int stateId) {
     return EnableTableState.valueOf(stateId);
   }
 
   @Override
   protected int getStateId(final EnableTableState state) {
     return state.getNumber();
   }
 
   @Override
   protected EnableTableState getInitialState() {
     return EnableTableState.ENABLE_TABLE_PREPARE;
   }
 
   @Override
   protected void setNextState(final EnableTableState state) {
     if (aborted.get()) {
       setAbortFailure("Enable-table", "abort requested");
     } else {
       super.setNextState(state);
     }
   }
 
   @Override
   public boolean abort(final MasterProcedureEnv env) {
     aborted.set(true);
     return true;
   }
 
   @Override
   protected boolean acquireLock(final MasterProcedureEnv env) {
     if (!env.isInitialized()) return false;
     return env.getProcedureQueue().tryAcquireTableWrite(
       tableName,
       EventType.C_M_ENABLE_TABLE.toString());
   }
 
   @Override
   protected void releaseLock(final MasterProcedureEnv env) {
     env.getProcedureQueue().releaseTableWrite(tableName);
   }
 
   @Override
   public void serializeStateData(final OutputStream stream) throws IOException {
     super.serializeStateData(stream);
 
     MasterProcedureProtos.EnableTableStateData.Builder enableTableMsg =
         MasterProcedureProtos.EnableTableStateData.newBuilder()
             .setUserInfo(MasterProcedureUtil.toProtoUserInfo(user))
             .setTableName(ProtobufUtil.toProtoTableName(tableName))
             .setSkipTableStateCheck(skipTableStateCheck);
 
     enableTableMsg.build().writeDelimitedTo(stream);
   }
 
   @Override
   public void deserializeStateData(final InputStream stream) throws IOException {
     super.deserializeStateData(stream);
 
     MasterProcedureProtos.EnableTableStateData enableTableMsg =
         MasterProcedureProtos.EnableTableStateData.parseDelimitedFrom(stream);
     user = MasterProcedureUtil.toUserInfo(enableTableMsg.getUserInfo());
     tableName = ProtobufUtil.toTableName(enableTableMsg.getTableName());
     skipTableStateCheck = enableTableMsg.getSkipTableStateCheck();
   }
 
   @Override
   public void toStringClassDetails(StringBuilder sb) {
     sb.append(getClass().getSimpleName());
     sb.append(" (table=");
     sb.append(tableName);
     sb.append(")");
   }
 
   @Override
   public TableName getTableName() {
     return tableName;
   }
 
   @Override
   public TableOperationType getTableOperationType() {
     return TableOperationType.ENABLE;
   }
 
 
   /**
    * Action before any real action of enabling table. Set the exception in the procedure instead
    * of throwing it.  This approach is to deal with backward compatible with 1.0.
    * @param env MasterProcedureEnv
    * @return whether the table passes the necessary checks
    * @throws IOException
    */
   private boolean prepareEnable(final MasterProcedureEnv env) throws IOException {
     boolean canTableBeEnabled = true;
 
     // Check whether table exists
     if (!MetaTableAccessor.tableExists(env.getMasterServices().getConnection(), tableName)) {
       setFailure("master-enable-table", new TableNotFoundException(tableName));
       canTableBeEnabled = false;
     } else if (!skipTableStateCheck) {
       // There could be multiple client requests trying to disable or enable
       // the table at the same time. Ensure only the first request is honored
       // After that, no other requests can be accepted until the table reaches
       // DISABLED or ENABLED.
       //
       // Note: in 1.0 release, we called TableStateManager.setTableStateIfInStates() to set
       // the state to ENABLING from DISABLED. The implementation was done before table lock
       // was implemented. With table lock, there is no need to set the state here (it will
       // set the state later on). A quick state check should be enough for us to move forward.
       TableStateManager tsm = env.getMasterServices().getAssignmentManager().getTableStateManager();
       if (!tsm.isTableState(tableName, ZooKeeperProtos.Table.State.DISABLED)) {
         LOG.info("Table " + tableName + " isn't disabled; skipping enable");
         setFailure("master-enable-table", new TableNotDisabledException(this.tableName));
         canTableBeEnabled = false;
       }
     }
 
     // We are done the check. Future actions in this procedure could be done asynchronously.
     ProcedurePrepareLatch.releaseLatch(syncLatch, this);
 
     return canTableBeEnabled;
   }
 
   /**
    * Action before enabling table.
    * @param env MasterProcedureEnv
    * @param state the procedure state
    * @throws IOException
    * @throws InterruptedException
    */
   private void preEnable(final MasterProcedureEnv env, final EnableTableState state)
       throws IOException, InterruptedException {
     runCoprocessorAction(env, state);
   }
 
   /**
    * Mark table state to Enabling
    * @param env MasterProcedureEnv
    * @param tableName the target table
    * @throws IOException
    */
   protected static void setTableStateToEnabling(
       final MasterProcedureEnv env,
       final TableName tableName) throws HBaseException, IOException {
     // Set table disabling flag up in zk.
     LOG.info("Attempting to enable the table " + tableName);
     env.getMasterServices().getAssignmentManager().getTableStateManager().setTableState(
       tableName,
       ZooKeeperProtos.Table.State.ENABLING);
   }
 
   /**
    * Mark offline regions of the table online with retry
    * @param env MasterProcedureEnv
    * @param tableName the target table
    * @param retryRequired whether to retry if the first run failed
    * @throws IOException
    */
   protected static void markRegionsOnline(
       final MasterProcedureEnv env,
       final TableName tableName,
       final Boolean retryRequired) throws IOException {
     // This is best effort approach to make all regions of a table online.  If we fail to do
     // that, it is ok that the table has some offline regions; user can fix it manually.
 
     // Dev consideration: add a config to control max number of retry. For now, it is hard coded.
     int maxTry = (retryRequired ? 10 : 1);
     boolean done = false;
 
     do {
       try {
         done = markRegionsOnline(env, tableName);
         if (done) {
           break;
         }
         maxTry--;
       } catch (Exception e) {
         LOG.warn("Received exception while marking regions online. tries left: " + maxTry, e);
         maxTry--;
         if (maxTry > 0) {
           continue; // we still have some retry left, try again.
         }
         throw e;
       }
     } while (maxTry > 0);
 
     if (!done) {
       LOG.warn("Some or all regions of the Table '" + tableName + "' were offline");
     }
   }
 
   /**
    * Mark offline regions of the table online
    * @param env MasterProcedureEnv
    * @param tableName the target table
    * @return whether the operation is fully completed or being interrupted.
    * @throws IOException
    */
   private static boolean markRegionsOnline(final MasterProcedureEnv env, final TableName tableName)
       throws IOException {
     final AssignmentManager assignmentManager = env.getMasterServices().getAssignmentManager();
     final MasterServices masterServices = env.getMasterServices();
     final ServerManager serverManager = masterServices.getServerManager();
     boolean done = false;
     // Get the regions of this table. We're done when all listed
     // tables are onlined.
     List<Pair<HRegionInfo, ServerName>> tableRegionsAndLocations;
 
     if (TableName.META_TABLE_NAME.equals(tableName)) {
       tableRegionsAndLocations =
           new MetaTableLocator().getMetaRegionsAndLocations(masterServices.getZooKeeper());
     } else {
       tableRegionsAndLocations =
           MetaTableAccessor.getTableRegionsAndLocations(
             masterServices.getZooKeeper(), masterServices.getConnection(), tableName, true);
     }
 
     int countOfRegionsInTable = tableRegionsAndLocations.size();
     Map<HRegionInfo, ServerName> regionsToAssign =
         regionsToAssignWithServerName(env, tableRegionsAndLocations);
 
     // need to potentially create some regions for the replicas
     List<HRegionInfo> unrecordedReplicas =
         AssignmentManager.replicaRegionsNotRecordedInMeta(new HashSet<HRegionInfo>(
             regionsToAssign.keySet()), masterServices);
     Map<ServerName, List<HRegionInfo>> srvToUnassignedRegs =
         assignmentManager.getBalancer().roundRobinAssignment(unrecordedReplicas,
           serverManager.getOnlineServersList());
     if (srvToUnassignedRegs != null) {
       for (Map.Entry<ServerName, List<HRegionInfo>> entry : srvToUnassignedRegs.entrySet()) {
         for (HRegionInfo h : entry.getValue()) {
           regionsToAssign.put(h, entry.getKey());
         }
       }
     }
 
     int offlineRegionsCount = regionsToAssign.size();
 
     LOG.info("Table '" + tableName + "' has " + countOfRegionsInTable + " regions, of which "
         + offlineRegionsCount + " are offline.");
     if (offlineRegionsCount == 0) {
       return true;
     }
 
     List<ServerName> onlineServers = serverManager.createDestinationServersList();
     Map<ServerName, List<HRegionInfo>> bulkPlan =
         env.getMasterServices().getAssignmentManager().getBalancer()
             .retainAssignment(regionsToAssign, onlineServers);
     if (bulkPlan != null) {
       LOG.info("Bulk assigning " + offlineRegionsCount + " region(s) across " + bulkPlan.size()
           + " server(s), retainAssignment=true");
 
       BulkAssigner ba = new GeneralBulkAssigner(masterServices, bulkPlan, assignmentManager, true);
       try {
         if (ba.bulkAssign()) {
           done = true;
         }
       } catch (InterruptedException e) {
         LOG.warn("Enable operation was interrupted when enabling table '" + tableName + "'");
         // Preserve the interrupt.
         Thread.currentThread().interrupt();
       }
     } else {
       LOG.info("Balancer was unable to find suitable servers for table " + tableName
           + ", leaving unassigned");
     }
     return done;
   }
 
   /**
    * Mark regions of the table offline during recovery
    * @param env MasterProcedureEnv
    */
   private void markRegionsOfflineDuringRecovery(final MasterProcedureEnv env) {
     try {
       // This is a best effort attempt. We will move on even it does not succeed. We will retry
       // several times until we giving up.
       DisableTableProcedure.markRegionsOffline(env, tableName, true);
     } catch (Exception e) {
       LOG.debug("Failed to offline all regions of table " + tableName + ". Ignoring", e);
     }
   }
 
   /**
    * Mark table state to Enabled
    * @param env MasterProcedureEnv
    * @throws IOException
    */
   protected static void setTableStateToEnabled(
       final MasterProcedureEnv env,
       final TableName tableName) throws HBaseException, IOException {
     // Flip the table to Enabled
     env.getMasterServices().getAssignmentManager().getTableStateManager().setTableState(
       tableName,
       ZooKeeperProtos.Table.State.ENABLED);
     LOG.info("Table '" + tableName + "' was successfully enabled.");
   }
 
   /**
    * Action after enabling table.
    * @param env MasterProcedureEnv
    * @param state the procedure state
    * @throws IOException
    * @throws InterruptedException
    */
   private void postEnable(final MasterProcedureEnv env, final EnableTableState state)
       throws IOException, InterruptedException {
     runCoprocessorAction(env, state);
   }
 
   /**
    * 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;
   }
 
   /**
    * @param regionsInMeta
    * @return List of regions neither in transition nor assigned.
    * @throws IOException
    */
   private static Map<HRegionInfo, ServerName> regionsToAssignWithServerName(
       final MasterProcedureEnv env,
       final List<Pair<HRegionInfo, ServerName>> regionsInMeta) throws IOException {
     Map<HRegionInfo, ServerName> regionsToAssign =
         new HashMap<HRegionInfo, ServerName>(regionsInMeta.size());
     RegionStates regionStates = env.getMasterServices().getAssignmentManager().getRegionStates();
     for (Pair<HRegionInfo, ServerName> regionLocation : regionsInMeta) {
       HRegionInfo hri = regionLocation.getFirst();
       ServerName sn = regionLocation.getSecond();
       if (regionStates.isRegionOffline(hri)) {
         regionsToAssign.put(hri, sn);
       } else {
         if (LOG.isDebugEnabled()) {
           LOG.debug("Skipping assign for the region " + hri + " during enable table "
               + hri.getTable() + " because its already in tranition or assigned.");
         }
       }
     }
     return regionsToAssign;
   }
 
   /**
    * Coprocessor Action.
    * @param env MasterProcedureEnv
    * @param state the procedure state
    * @throws IOException
    * @throws InterruptedException
    */
   private void runCoprocessorAction(final MasterProcedureEnv env, final EnableTableState state)
       throws IOException, InterruptedException {
     final MasterCoprocessorHost cpHost = env.getMasterCoprocessorHost();
     if (cpHost != null) {
       user.doAs(new PrivilegedExceptionAction<Void>() {
         @Override
         public Void run() throws Exception {
           switch (state) {
           case ENABLE_TABLE_PRE_OPERATION:
             cpHost.preEnableTableHandler(getTableName());
             break;
           case ENABLE_TABLE_POST_OPERATION:
             cpHost.postEnableTableHandler(getTableName());
             break;
           default:
             throw new UnsupportedOperationException(this + " unhandled state=" + state);
           }
           return null;
         }
       });
     }
   }
 }