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.service;
  
  import java.nio.ByteBuffer;
  
  import com.google.common.collect.Iterables;
  
  import org.apache.cassandra.schema.TableMetadata;
  import org.apache.cassandra.service.paxos.Ballot;
  import org.apache.cassandra.service.paxos.v1.PrepareVerbHandler;
  import org.apache.cassandra.service.paxos.v1.ProposeVerbHandler;
  
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.Future;
  import java.util.concurrent.TimeUnit;
  import java.util.function.Supplier;
  
  import org.apache.cassandra.dht.Murmur3Partitioner;
  import org.apache.cassandra.exceptions.ReadTimeoutException;
  import org.apache.cassandra.service.paxos.PaxosOperationLock;
  import org.junit.AfterClass;
  import org.junit.Assert;
  import org.junit.BeforeClass;
  import org.junit.Test;
  
  import org.apache.cassandra.SchemaLoader;
  import org.apache.cassandra.Util;
  import org.apache.cassandra.db.*;
  import org.apache.cassandra.db.rows.Row;
  import org.apache.cassandra.db.partitions.PartitionUpdate;
  import org.apache.cassandra.gms.Gossiper;
  import org.apache.cassandra.service.paxos.Commit;
  import org.apache.cassandra.service.paxos.PaxosState;
  import org.apache.cassandra.utils.ByteBufferUtil;
  import org.apache.cassandra.utils.FBUtilities;
  
  import static org.apache.cassandra.service.paxos.Ballot.Flag.NONE;
  import static org.apache.cassandra.service.paxos.BallotGenerator.Global.atUnixMicros;
  import static org.apache.cassandra.utils.Clock.Global.nanoTime;
  import static org.junit.Assert.*;
  
  public class PaxosStateTest
  {
      @BeforeClass
      public static void setUpClass() throws Throwable
      {
          SchemaLoader.loadSchema();
          SchemaLoader.schemaDefinition("PaxosStateTest");
      }
  
      @AfterClass
      public static void stopGossiper()
      {
          Gossiper.instance.stop();
      }
  
      @Test
      public void testCommittingAfterTruncation() throws Exception
      {
          ColumnFamilyStore cfs = Keyspace.open("PaxosStateTestKeyspace1").getColumnFamilyStore("Standard1");
          String key = "key" + nanoTime();
          ByteBuffer value = ByteBufferUtil.bytes(0);
          RowUpdateBuilder builder = new RowUpdateBuilder(cfs.metadata(), FBUtilities.timestampMicros(), key);
          builder.clustering("a").add("val", value);
          PartitionUpdate update = Iterables.getOnlyElement(builder.build().getPartitionUpdates());
  
          // CFS should be empty initially
          assertNoDataPresent(cfs, Util.dk(key));
  
          // Commit the proposal & verify the data is present
          Commit beforeTruncate = newProposal(0, update);
          PaxosState.commitDirect(beforeTruncate);
          assertDataPresent(cfs, Util.dk(key), "val", value);
  
          // Truncate then attempt to commit again, mutation should
          // be ignored as the proposal predates the truncation
          cfs.truncateBlocking();
          PaxosState.commitDirect(beforeTruncate);
          assertNoDataPresent(cfs, Util.dk(key));
  
          // Now try again with a ballot created after the truncation
          long timestamp = SystemKeyspace.getTruncatedAt(update.metadata().id) + 1;
          Commit afterTruncate = newProposal(timestamp, update);
          PaxosState.commitDirect(afterTruncate);
          assertDataPresent(cfs, Util.dk(key), "val", value);
      }
  
      private Commit newProposal(long ballotMicros, PartitionUpdate update)
      {
          return Commit.newProposal(atUnixMicros(ballotMicros, NONE), update);
      }
  
      private void assertDataPresent(ColumnFamilyStore cfs, DecoratedKey key, String name, ByteBuffer value)
      {
          Row row = Util.getOnlyRowUnfiltered(Util.cmd(cfs, key).build());
          assertEquals(0, ByteBufferUtil.compareUnsigned(value,
                  row.getCell(cfs.metadata().getColumn(ByteBufferUtil.bytes(name))).buffer()));
      }
  
      private void assertNoDataPresent(ColumnFamilyStore cfs, DecoratedKey key)
      {
          Util.assertEmpty(Util.cmd(cfs, key).build());
      }
  
      @Test
      public void testPrepareProposePaxos() throws Throwable
      {
          ColumnFamilyStore cfs = Keyspace.open("PaxosStateTestKeyspace1").getColumnFamilyStore("Standard1");
          String key = "key" + nanoTime();
          ByteBuffer value = ByteBufferUtil.bytes(0);
          RowUpdateBuilder builder = new RowUpdateBuilder(cfs.metadata(), FBUtilities.timestampMicros(), key);
          builder.clustering("a").add("val", value);
          PartitionUpdate update = Iterables.getOnlyElement(builder.build().getPartitionUpdates());
  
          // CFS should be empty initially
          assertNoDataPresent(cfs, Util.dk(key));
  
          Ballot ballot = atUnixMicros(1000 * System.currentTimeMillis(), NONE);
  
          Commit commit = Commit.newPrepare(Util.dk(key), cfs.metadata(), ballot);
  
          assertTrue("paxos prepare stage failed", PrepareVerbHandler.doPrepare(commit).promised);
          assertTrue("paxos propose stage failed", ProposeVerbHandler.doPropose(commit));
      }
  
      public void testPaxosLock() throws ExecutionException, InterruptedException, ExecutionException
      {
          DecoratedKey key = new BufferDecoratedKey(Murmur3Partitioner.MINIMUM, ByteBufferUtil.EMPTY_BYTE_BUFFER);
          TableMetadata metadata = Keyspace.open("PaxosStateTestKeyspace1").getColumnFamilyStore("Standard1").metadata.get();
          Supplier<PaxosOperationLock> locker = () -> PaxosState.lock(key, metadata, System.nanoTime() + TimeUnit.SECONDS.toNanos(1L), ConsistencyLevel.SERIAL, false);
          ExecutorService executor = Executors.newFixedThreadPool(1);
          Future<?> future;
          try (PaxosOperationLock lock = locker.get())
          {
              try
              {
                  try (PaxosOperationLock lock2 = locker.get())
                  {
                      Assert.fail();
                  }
              }
              catch (ReadTimeoutException rte)
              {
              }
  
              future = executor.submit(() -> {
                  try (PaxosOperationLock lock2 = locker.get())
                  {
                  }
              });
          }
          finally
          {
              executor.shutdown();
          }
          future.get();
      }
  }
  