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.distributed.test.repair;
  
  import java.util.concurrent.Callable;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.junit.Test;
  
  import net.bytebuddy.ByteBuddy;
  import net.bytebuddy.dynamic.loading.ClassLoadingStrategy;
  import net.bytebuddy.implementation.MethodDelegation;
  import net.bytebuddy.implementation.bind.annotation.SuperCall;
  import org.apache.cassandra.distributed.Cluster;
  import org.apache.cassandra.distributed.api.ConsistencyLevel;
  import org.apache.cassandra.distributed.api.NodeToolResult;
  import org.apache.cassandra.distributed.test.TestBaseImpl;
  import org.apache.cassandra.repair.ValidationTask;
  import org.apache.cassandra.utils.MerkleTrees;
  
  import static net.bytebuddy.matcher.ElementMatchers.named;
  import static org.apache.cassandra.distributed.api.Feature.GOSSIP;
  import static org.apache.cassandra.distributed.api.Feature.NETWORK;
  
  /**
   * Verifies that the config property {@code concurrent_merkle_tree_requests} limits the number of concurrent validation
   * requests.
   */
  public class ConcurrentValidationRequestsTest extends TestBaseImpl
  {
      private static final int NODES = 4;
      private static final int RF = 3;
      private static final int TABLES = 5;
      private static final int ROWS = 100;
      private static final int MAX_REQUESTS = 1;
  
      @Test
      public void testConcurrentValidations() throws Throwable
      {
          try (Cluster cluster = init(builder().withNodes(NODES)
                                               .withInstanceInitializer(ConcurrentValidationRequestsTest.BBHelper::install)
                                               .withConfig(c -> c.set("concurrent_merkle_tree_requests", MAX_REQUESTS)
                                                                 .with(NETWORK, GOSSIP))
                                               .start(), RF))
          {
              for (int t = 1; t <= TABLES; t++)
                  cluster.schemaChange(withKeyspace("CREATE TABLE %s.t" + t + " (k int PRIMARY KEY, v int)"));
  
              int v = 0;
              for (int k = 0; k < ROWS; k++)
              {
                  v++;
                  for (int t = 1; t <= TABLES; t++)
                  {
                      String insert = withKeyspace("INSERT INTO %s.t" + t + " (k, v) VALUES (?, ?)");
                      cluster.coordinator(1).execute(insert, ConsistencyLevel.ALL, k, v);
                  }
              }
              cluster.forEach(x -> x.flush(KEYSPACE));
  
              NodeToolResult res = cluster.get(1).nodetoolResult("repair", "-j=4", KEYSPACE);
              res.asserts().success();
          }
      }
  
      public static class BBHelper
      {
          /**
           * Keeps track of the number of concurrent validation requests, which should never be greater than RF times
           * the value of the {@code concurrent_merkle_tree_requests} config property.
           */
          public static volatile AtomicInteger requests = new AtomicInteger(0);
  
          public static void install(ClassLoader cl, int node)
          {
              if (node != 1)
                  return;
  
              new ByteBuddy().rebase(ValidationTask.class)
                             .method(named("run"))
                             .intercept(MethodDelegation.to(ConcurrentValidationRequestsTest.BBHelper.class))
                             .method(named("treesReceived"))
                             .intercept(MethodDelegation.to(ConcurrentValidationRequestsTest.BBHelper.class))
                             .make()
                             .load(cl, ClassLoadingStrategy.Default.INJECTION);
          }
  
          @SuppressWarnings("unused")
          public static void run(@SuperCall Callable<Void> zuper)
          {
              try
              {
                  zuper.call();
              }
              catch (Exception e)
              {
                  throw new RuntimeException(e);
              }
  
              int requests = BBHelper.requests.incrementAndGet();
              if (requests > MAX_REQUESTS * RF)
                  throw new AssertionError("Too many concurrent validation requests: " + requests);
          }
  
          @SuppressWarnings("unused")
          public static void treesReceived(MerkleTrees trees, @SuperCall Callable<Void> zuperCall)
          {
              requests.decrementAndGet();
  
              try
              {
                  zuperCall.call();
              }
              catch (Exception e)
              {
                  throw new RuntimeException(e);
              }
          }
      }
  }