content: /*
   * 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.cassandra.tcm.transformations;
  
  import java.io.IOException;
  import java.net.UnknownHostException;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Set;
  import java.util.stream.Collectors;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.db.TypeSizes;
  import org.apache.cassandra.io.util.DataInputPlus;
  import org.apache.cassandra.io.util.DataOutputPlus;
  import org.apache.cassandra.locator.InetAddressAndPort;
  import org.apache.cassandra.tcm.ClusterMetadata;
  import org.apache.cassandra.tcm.ClusterMetadataService;
  import org.apache.cassandra.tcm.Transformation;
  import org.apache.cassandra.tcm.membership.Directory;
  import org.apache.cassandra.tcm.membership.Location;
  import org.apache.cassandra.tcm.membership.NodeId;
  import org.apache.cassandra.tcm.ownership.DataPlacements;
  import org.apache.cassandra.tcm.ownership.PlacementProvider;
  import org.apache.cassandra.tcm.sequences.LockedRanges;
  import org.apache.cassandra.tcm.serialization.AsymmetricMetadataSerializer;
  import org.apache.cassandra.tcm.serialization.Version;
  
  import static org.apache.cassandra.exceptions.ExceptionCode.INVALID;
  
  public class AlterTopology implements Transformation
  {
      private static final Logger logger = LoggerFactory.getLogger(AlterTopology.class);
      public static final Serializer serializer = new Serializer();
  
      private final Map<NodeId, Location> updates;
      private final PlacementProvider placementProvider;
  
      public AlterTopology(Map<NodeId, Location> updates, PlacementProvider placementProvider)
      {
          this.updates = updates;
          this.placementProvider = placementProvider;
      }
  
      public static Map<NodeId, Location> parseArgs(String args, Directory directory)
      {
          Map<NodeId, Location> asMap = new HashMap<>();
          for (String change : args.split(","))
          {
              String[] parts = change.trim().split("=");
              if (parts.length != 2)
                  throw new IllegalArgumentException("Invalid specification: " + change);
  
              if (parts[0].isEmpty() || parts[1].isEmpty())
                  throw new IllegalArgumentException("Invalid specification: " + change);
  
              NodeId id = getNodeIdFromString(parts[0].trim(), directory);
              if (asMap.containsKey(id))
                  throw new IllegalArgumentException("Multiple updates for node " + id + " (" + parts[0].trim() + " )");
              asMap.put(getNodeIdFromString(parts[0].trim(), directory), Location.fromString(parts[1].trim()));
          }
          return asMap;
      }
  
      private static NodeId getNodeIdFromString(String s, Directory directory)
      {
          // first try to parse the id as a node id, either in UUID or int form
          try
          {
              return NodeId.fromString(s);
          }
          catch (Exception e)
          {
              // fall back to trying the supplied id as an endpoint
              try
              {
                  InetAddressAndPort endpoint = InetAddressAndPort.getByName(s);
                  return directory.peerId(endpoint);
              }
              catch (UnknownHostException u)
              {
                  throw new IllegalArgumentException("Invalid node identifier supplied: " + s);
              }
  
          }
      }
  
      @Override
      public Kind kind()
      {
          return Kind.ALTER_TOPOLOGY;
      }
  
      @Override
      public Result execute(ClusterMetadata prev)
      {
          // Check no inflight range movements
          if (!prev.lockedRanges.locked.isEmpty())
              return new Rejected(INVALID, "The requested topology changes cannot be executed while there are ongoing range movements.");
  
          Directory dir = prev.directory;
          // Check all node ids are present
          Set<NodeId> missing = updates.keySet()
                                       .stream()
                                       .filter(location -> (null == dir.location(location)))
                                       .collect(Collectors.toSet());
          if (!missing.isEmpty())
              return new Rejected(INVALID, String.format("Some updates specify an unregistered node: %s", missing));
  
          // Validate there will be no change to placements
          Directory updated = prev.directory;
          for (Map.Entry<NodeId, Location> update : updates.entrySet())
              updated = updated.withUpdatedRackAndDc(update.getKey(), update.getValue());
          ClusterMetadata proposed = prev.transformer().with(updated).build().metadata;
          DataPlacements proposedPlacements = placementProvider.calculatePlacements(prev.placements.lastModified(),
                                                                                    proposed.tokenMap.toRanges(),
                                                                                    proposed,
                                                                                    proposed.schema.getKeyspaces());
          if (!proposedPlacements.equivalentTo(prev.placements))
          {
              logger.info("Rejecting topology modifications which would materially change data placements: {}", updates);
              return new Rejected(INVALID, "Proposed updates modify data placements, violating consistency guarantees");
          }
  
          ClusterMetadata.Transformer next = prev.transformer().with(updated);
          return Transformation.success(next, LockedRanges.AffectedRanges.EMPTY);
      }
  
  
      @Override
      public String toString()
      {
          return "AlterTopology{" +
                 "updates=" + updates +
                 '}';
      }
  
      static class Serializer implements AsymmetricMetadataSerializer<Transformation, AlterTopology>
      {
          public void serialize(Transformation t, DataOutputPlus out, Version version) throws IOException
          {
              assert t instanceof AlterTopology;
              AlterTopology alterTopology = (AlterTopology)t;
              int size = alterTopology.updates.size();
              out.writeInt(size);
              for (Map.Entry<NodeId, Location> entry : alterTopology.updates.entrySet())
              {
                  NodeId.serializer.serialize(entry.getKey(), out, version);
                  Location.serializer.serialize(entry.getValue(), out, version);
              }
          }
  
          public AlterTopology deserialize(DataInputPlus in, Version version) throws IOException
          {
              int size = in.readInt();
              Map<NodeId, Location> updates = new HashMap<>(size);
              for (int i = 0; i < size; i++)
                  updates.put(NodeId.serializer.deserialize(in, version), Location.serializer.deserialize(in, version));
              return new AlterTopology(updates, ClusterMetadataService.instance().placementProvider());
          }
  
          public long serializedSize(Transformation t, Version version)
          {
              assert t instanceof AlterTopology;
              AlterTopology alterTopology = (AlterTopology) t;
              long size = TypeSizes.sizeof(alterTopology.updates.size());
              for (Map.Entry<NodeId, Location> entry : alterTopology.updates.entrySet())
              {
                  size += NodeId.serializer.serializedSize(entry.getKey(), version);
                  size += Location.serializer.serializedSize(entry.getValue(), version);
              }
              return size;
          }
      }
  }