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.net.proxy;
  
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.concurrent.atomic.AtomicLong;
  import java.util.function.Consumer;
  
  import org.junit.Assert;
  import org.junit.Test;
  
  import io.netty.bootstrap.Bootstrap;
  import io.netty.bootstrap.ServerBootstrap;
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.Unpooled;
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.channel.ChannelInitializer;
  import io.netty.channel.ChannelOption;
  import io.netty.channel.EventLoopGroup;
  import io.netty.channel.local.LocalAddress;
  import io.netty.channel.local.LocalChannel;
  import io.netty.channel.local.LocalServerChannel;
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.handler.logging.LogLevel;
  import io.netty.handler.logging.LoggingHandler;
  
  public class ProxyHandlerTest
  {
      private final Object PAYLOAD = new Object();
  
      @Test
      public void testLatency() throws Throwable
      {
          test((proxyHandler, testHandler, channel) -> {
              int count = 1;
              long latency = 100;
              CountDownLatch latch = new CountDownLatch(count);
              long start = System.currentTimeMillis();
              testHandler.onRead = new Consumer<Object>()
              {
                  int last = -1;
                  public void accept(Object o)
                  {
                      // Make sure that order is preserved
                      Assert.assertEquals(last + 1, o);
                      last = (int) o;
  
                      long elapsed = System.currentTimeMillis() - start;
                      Assert.assertTrue("Latency was:" + elapsed, elapsed > latency);
                      latch.countDown();
                  }
              };
  
              proxyHandler.withLatency(latency, TimeUnit.MILLISECONDS);
  
              for (int i = 0; i < count; i++)
              {
                  ByteBuf bb = Unpooled.buffer(Integer.BYTES);
                  bb.writeInt(i);
                  channel.writeAndFlush(i);
              }
  
              Assert.assertTrue(latch.await(10, TimeUnit.SECONDS));
          });
      }
  
      @Test
      public void testNormalDelivery() throws Throwable
      {
          test((proxyHandler, testHandler, channelPipeline) -> {
              int count = 10;
              CountDownLatch latch = new CountDownLatch(count);
              AtomicLong end = new AtomicLong();
              testHandler.onRead = (o) -> {
                  end.set(System.currentTimeMillis());
                  latch.countDown();
              };
  
              for (int i = 0; i < count; i++)
                  channelPipeline.writeAndFlush(PAYLOAD);
              Assert.assertTrue(latch.await(10, TimeUnit.SECONDS));
  
          });
      }
  
      @Test
      public void testLatencyForMany() throws Throwable
      {
          class Event {
              private final long latency;
              private final long start;
              private final int idx;
  
              Event(long latency, int idx)
              {
                  this.latency = latency;
                  this.start = System.currentTimeMillis();
                  this.idx = idx;
              }
          }
  
          test((proxyHandler, testHandler, channel) -> {
              int count = 150;
              CountDownLatch latch = new CountDownLatch(count);
              AtomicInteger counter = new AtomicInteger();
              testHandler.onRead = new Consumer<Object>()
              {
                  int lastSeen = -1;
                  public void accept(Object o)
                  {
                      Event e = (Event) o;
                      Assert.assertEquals(lastSeen + 1, e.idx);
                      lastSeen = e.idx;
                      long elapsed = System.currentTimeMillis() - e.start;
                      Assert.assertTrue(elapsed >= e.latency);
                      counter.incrementAndGet();
                      latch.countDown();
                  }
              };
  
              int idx = 0;
              for (int i = 0; i < count / 3; i++)
              {
                  for (long latency : new long[]{ 100, 200, 0 })
                  {
                      proxyHandler.withLatency(latency, TimeUnit.MILLISECONDS);
                      CountDownLatch read = new CountDownLatch(1);
                      proxyHandler.onRead(read::countDown);
                      channel.writeAndFlush(new Event(latency, idx++));
                      Assert.assertTrue(read.await(10, TimeUnit.SECONDS));
                  }
              }
  
              Assert.assertTrue(latch.await(10, TimeUnit.SECONDS));
              Assert.assertEquals(counter.get(), count);
          });
      }
  
      private interface DoTest
      {
          public void doTest(InboundProxyHandler.Controller proxy, TestHandler testHandler, Channel channel) throws Throwable;
      }
  
  
      public void test(DoTest test) throws Throwable
      {
          EventLoopGroup serverGroup = new NioEventLoopGroup(1);
          EventLoopGroup clientGroup = new NioEventLoopGroup(1);
  
          InboundProxyHandler.Controller controller = new InboundProxyHandler.Controller();
          InboundProxyHandler proxyHandler = new InboundProxyHandler(controller);
          TestHandler testHandler = new TestHandler();
  
          ServerBootstrap sb = new ServerBootstrap();
          sb.group(serverGroup)
            .channel(LocalServerChannel.class)
            .childHandler(new ChannelInitializer<LocalChannel>() {
                @Override
                public void initChannel(LocalChannel ch)
                {
                    ch.pipeline()
                      .addLast(proxyHandler)
                      .addLast(testHandler);
                }
            })
            .childOption(ChannelOption.AUTO_READ, false);
  
          Bootstrap cb = new Bootstrap();
          cb.group(clientGroup)
            .channel(LocalChannel.class)
            .handler(new ChannelInitializer<LocalChannel>() {
                @Override
                public void initChannel(LocalChannel ch) throws Exception {
                    ch.pipeline()
                      .addLast(new LoggingHandler(LogLevel.TRACE));
                }
            });
  
          final LocalAddress addr = new LocalAddress("test");
  
          Channel serverChannel = sb.bind(addr).sync().channel();
  
          Channel clientChannel = cb.connect(addr).sync().channel();
          test.doTest(controller, testHandler, clientChannel);
  
          clientChannel.close();
          serverChannel.close();
          serverGroup.shutdownGracefully();
          clientGroup.shutdownGracefully();
      }
  
  
      public static class TestHandler extends ChannelInboundHandlerAdapter
      {
          private Consumer<Object> onRead = (o) -> {};
          @Override
          public void channelRead(ChannelHandlerContext ctx, Object msg)
          {
              onRead.accept(msg);
          }
      }
  }
  