Add check for DefaultFileRegion to calculate size of msg in AbstractTrafficShapingHandler (#10215)

Motivation:

Currently calculateSize method in AbstractTrafficShapingHandler calculates size for object of type ByteBuf or ByteBufHolder. Adding a check for FileRegion, makes it possible to do traffic shaping for FileRegion objects as well

Modification:

Check if object to be sent is of type FileRegion, if yes calculate the size using its count() method.

Co-authored-by: Dinesh Joshi <dinesh.joshi@apple.com>

handler/src/main/java/io/netty/handler/traffic/AbstractTrafficShapingHandler.java

@@ -23,6 +23,7 @@ import io.netty.channel.ChannelHandler;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelOutboundBuffer;
 import io.netty.channel.ChannelPromise;
+import io.netty.channel.FileRegion;
 import io.netty.util.Attribute;
 import io.netty.util.AttributeKey;
 import io.netty.util.internal.logging.InternalLogger;
@@ -643,7 +644,8 @@ public abstract class AbstractTrafficShapingHandler implements ChannelHandler {
     /**
      * Calculate the size of the given {@link Object}.
      *
-     * This implementation supports {@link ByteBuf} and {@link ByteBufHolder}. Sub-classes may override this.
+     * This implementation supports {@link ByteBuf}, {@link ByteBufHolder} and {@link FileRegion}.
+     * Sub-classes may override this.
      * @param msg the msg for which the size should be calculated.
      * @return size the size of the msg or {@code -1} if unknown.
      */
@@ -654,6 +656,9 @@ public abstract class AbstractTrafficShapingHandler implements ChannelHandler {
         if (msg instanceof ByteBufHolder) {
             return ((ByteBufHolder) msg).content().readableBytes();
         }
+        if (msg instanceof FileRegion) {
+            return ((FileRegion) msg).count();
+        }
         return -1;
     }
 }

handler/src/test/java/io/netty/handler/traffic/FileRegionThrottleTest.java

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2020 The Netty Project
+ *
+ * The Netty Project 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 io.netty.handler.traffic;
+
+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.ChannelFuture;
+import io.netty.channel.ChannelHandler;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelInitializer;
+import io.netty.channel.DefaultFileRegion;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.MultithreadEventLoopGroup;
+import io.netty.channel.nio.NioHandler;
+import io.netty.channel.socket.SocketChannel;
+import io.netty.channel.socket.nio.NioServerSocketChannel;
+import io.netty.channel.socket.nio.NioSocketChannel;
+import io.netty.handler.codec.LineBasedFrameDecoder;
+import io.netty.util.CharsetUtil;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.net.SocketAddress;
+import java.nio.charset.Charset;
+import java.util.Random;
+import java.util.concurrent.CountDownLatch;
+
+import static org.junit.Assert.assertTrue;
+
+public class FileRegionThrottleTest {
+    private static final byte[] BYTES = new byte[64 * 1024 * 4];
+    private static final long WRITE_LIMIT = 64 * 1024;
+    private static File tmp;
+    private EventLoopGroup group;
+
+    @BeforeClass
+    public static void beforeClass() throws IOException {
+        final Random r = new Random();
+        for (int i = 0; i < BYTES.length; i++) {
+            BYTES[i] = (byte) r.nextInt(255);
+        }
+
+        tmp = File.createTempFile("netty-traffic", ".tmp");
+        tmp.deleteOnExit();
+        try (FileOutputStream out = new FileOutputStream(tmp)) {
+            out.write(BYTES);
+            out.flush();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Before
+    public void setUp() {
+        group = new MultithreadEventLoopGroup(NioHandler.newFactory());
+    }
+
+    @After
+    public void tearDown() {
+        group.shutdownGracefully();
+    }
+
+    @Test
+    public void testGlobalWriteThrottle() throws Exception {
+        final CountDownLatch latch = new CountDownLatch(1);
+        final GlobalTrafficShapingHandler gtsh = new GlobalTrafficShapingHandler(group, WRITE_LIMIT, 0);
+        ServerBootstrap bs = new ServerBootstrap();
+        bs.group(group).channel(NioServerSocketChannel.class).childHandler(new ChannelInitializer<SocketChannel>() {
+            @Override
+            protected void initChannel(SocketChannel ch) {
+                ch.pipeline().addLast(new LineBasedFrameDecoder(Integer.MAX_VALUE));
+                ch.pipeline().addLast(new MessageDecoder());
+                ch.pipeline().addLast(gtsh);
+            }
+        });
+        Channel sc = bs.bind(0).sync().channel();
+        Channel cc = clientConnect(sc.localAddress(), new ReadHandler(latch)).channel();
+
+        long start = TrafficCounter.milliSecondFromNano();
+        cc.writeAndFlush(Unpooled.copiedBuffer("send-file\n", CharsetUtil.US_ASCII)).sync();
+        latch.await();
+        long timeTaken = TrafficCounter.milliSecondFromNano() - start;
+        assertTrue("Data streamed faster than expected", timeTaken > 3000);
+        sc.close().sync();
+        cc.close().sync();
+    }
+
+    private ChannelFuture clientConnect(final SocketAddress server, final ReadHandler readHandler) throws Exception {
+        Bootstrap bc = new Bootstrap();
+        bc.group(group).channel(NioSocketChannel.class).handler(new ChannelInitializer<SocketChannel>() {
+            @Override
+            protected void initChannel(SocketChannel ch) {
+                ch.pipeline().addLast(readHandler);
+            }
+        });
+        return bc.connect(server).sync();
+    }
+
+    private static final class MessageDecoder implements ChannelHandler {
+        @Override
+        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+            if (msg instanceof ByteBuf) {
+                ByteBuf buf = (ByteBuf) msg;
+                String message = buf.toString(Charset.defaultCharset());
+                buf.release();
+                if (message.equals("send-file")) {
+                    RandomAccessFile raf = new RandomAccessFile(tmp, "r");
+                    ctx.channel().writeAndFlush(new DefaultFileRegion(raf.getChannel(), 0, tmp.length()));
+                }
+            }
+        }
+    }
+
+    private static final class ReadHandler implements ChannelHandler {
+        private long bytesTransferred;
+        private CountDownLatch latch;
+
+        ReadHandler(CountDownLatch latch) {
+            this.latch = latch;
+        }
+
+        @Override
+        public void channelRead(ChannelHandlerContext ctx, Object msg) {
+            if (msg instanceof ByteBuf) {
+                ByteBuf buf = (ByteBuf) msg;
+                bytesTransferred += buf.readableBytes();
+                buf.release();
+                if (bytesTransferred == tmp.length()) {
+                    latch.countDown();
+                }
+            }
+        }
+    }
+}