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.arrow.flight;
  
  import static org.apache.arrow.flight.FlightTestUtil.LOCALHOST;
  import static org.apache.arrow.flight.Location.forGrpcInsecure;
  
  import java.util.Arrays;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.TimeUnit;
  import org.apache.arrow.memory.BufferAllocator;
  import org.apache.arrow.memory.RootAllocator;
  import org.apache.arrow.vector.Float8Vector;
  import org.apache.arrow.vector.VectorSchemaRoot;
  import org.apache.arrow.vector.types.FloatingPointPrecision;
  import org.apache.arrow.vector.types.pojo.ArrowType;
  import org.apache.arrow.vector.types.pojo.Field;
  import org.apache.arrow.vector.types.pojo.Schema;
  import org.junit.jupiter.api.Test;
  
  /** Tests for scenarios where Flight could leak memory. */
  public class TestLeak {
  
    private static final int ROWS = 2048;
  
    private static Schema getSchema() {
      return new Schema(
          Arrays.asList(
              Field.nullable("0", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("1", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("2", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("3", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("4", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("5", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("6", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("7", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("8", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("9", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE)),
              Field.nullable("10", new ArrowType.FloatingPoint(FloatingPointPrecision.DOUBLE))));
    }
  
    /**
     * Ensure that if the client cancels, the server does not leak memory.
     *
     * <p>In gRPC, canceling the stream from the client sends an event to the server. Once processed,
     * gRPC will start silently rejecting messages sent by the server. However, Flight depends on gRPC
     * processing these messages in order to free the associated memory.
     */
    @Test
    public void testCancelingDoGetDoesNotLeak() throws Exception {
      final CountDownLatch callFinished = new CountDownLatch(1);
      try (final BufferAllocator allocator = new RootAllocator(Long.MAX_VALUE);
          final FlightServer s =
              FlightServer.builder(
                      allocator,
                      forGrpcInsecure(LOCALHOST, 0),
                      new LeakFlightProducer(allocator, callFinished))
                  .build()
                  .start();
          final FlightClient client = FlightClient.builder(allocator, s.getLocation()).build()) {
  
        final FlightStream stream = client.getStream(new Ticket(new byte[0]));
        stream.getRoot();
        stream.cancel("Cancel", null);
  
        // Wait for the call to finish. (Closing the allocator while a call is ongoing is a guaranteed
        // leak.)
        callFinished.await(60, TimeUnit.SECONDS);
  
        s.shutdown();
        s.awaitTermination();
      }
    }
  
    @Test
    public void testCancelingDoPutDoesNotBlock() throws Exception {
      final CountDownLatch callFinished = new CountDownLatch(1);
      try (final BufferAllocator allocator = new RootAllocator(Long.MAX_VALUE);
          final FlightServer s =
              FlightServer.builder(
                      allocator,
                      forGrpcInsecure(LOCALHOST, 0),
                      new LeakFlightProducer(allocator, callFinished))
                  .build()
                  .start();
          final FlightClient client = FlightClient.builder(allocator, s.getLocation()).build()) {
  
        try (final VectorSchemaRoot root = VectorSchemaRoot.create(getSchema(), allocator)) {
          final FlightDescriptor descriptor = FlightDescriptor.command(new byte[0]);
          final SyncPutListener listener = new SyncPutListener();
          final FlightClient.ClientStreamListener stream =
              client.startPut(descriptor, root, listener);
          // Wait for the server to cancel
          callFinished.await(60, TimeUnit.SECONDS);
  
          for (int col = 0; col < 11; col++) {
            final Float8Vector vector = (Float8Vector) root.getVector(Integer.toString(col));
            vector.allocateNew();
            for (int row = 0; row < ROWS; row++) {
              vector.setSafe(row, 10.);
            }
          }
          root.setRowCount(ROWS);
          // Unlike DoGet, this method fairly reliably will write the message to the stream, so even
          // without the fix
          // for ARROW-7343, this won't leak memory.
          // However, it will block if FlightClient doesn't check for cancellation.
          stream.putNext();
          stream.completed();
        }
  
        s.shutdown();
        s.awaitTermination();
      }
    }
  
    /** A FlightProducer that always produces a fixed data stream with metadata on the side. */
    private static class LeakFlightProducer extends NoOpFlightProducer {
  
      private final BufferAllocator allocator;
      private final CountDownLatch callFinished;
  
      public LeakFlightProducer(BufferAllocator allocator, CountDownLatch callFinished) {
        this.allocator = allocator;
        this.callFinished = callFinished;
      }
  
      @Override
      public void getStream(CallContext context, Ticket ticket, ServerStreamListener listener) {
        BufferAllocator childAllocator = allocator.newChildAllocator("foo", 0, Long.MAX_VALUE);
        VectorSchemaRoot root = VectorSchemaRoot.create(TestLeak.getSchema(), childAllocator);
        root.allocateNew();
        listener.start(root);
  
        // We can't poll listener#isCancelled since gRPC has two distinct "is cancelled" flags.
        // TODO: should we continue leaking gRPC semantics? Can we even avoid this?
        listener.setOnCancelHandler(
            () -> {
              try {
                for (int col = 0; col < 11; col++) {
                  final Float8Vector vector = (Float8Vector) root.getVector(Integer.toString(col));
                  vector.allocateNew();
                  for (int row = 0; row < ROWS; row++) {
                    vector.setSafe(row, 10.);
                  }
                }
                root.setRowCount(ROWS);
                // Once the call is "really cancelled" (setOnCancelListener has run/is running), this
                // call is actually a
                // no-op on the gRPC side and will leak the ArrowMessage unless Flight checks for
                // this.
                listener.putNext();
                listener.completed();
              } finally {
                try {
                  root.close();
                  childAllocator.close();
                } finally {
                  // Don't let the test hang if we throw above
                  callFinished.countDown();
                }
              }
            });
      }
  
      @Override
      public Runnable acceptPut(
          CallContext context, FlightStream flightStream, StreamListener<PutResult> ackStream) {
        return () -> {
          flightStream.getRoot();
          ackStream.onError(CallStatus.CANCELLED.withDescription("CANCELLED").toRuntimeException());
          callFinished.countDown();
          ackStream.onCompleted();
        };
      }
    }
  }
  