experimental introduction of a bounded queue and rejection handler

lib/logstash/inputs/beats.rb

@@ -163,7 +163,7 @@ def register
   end # def register
 
   def create_server
-    server = org.logstash.beats.Server.new(@host, @port, @client_inactivity_timeout, @executor_threads)
+    server = org.logstash.beats.Server.new(@host, @port, @client_inactivity_timeout, @executor_threads, 5)
     if @ssl
 
       begin

src/main/java/org/logstash/beats/CustomRejectedExecutionHandler.java

@@ -0,0 +1,18 @@
+package org.logstash.beats;
+
+import io.netty.util.concurrent.RejectedExecutionHandler;
+import io.netty.util.concurrent.SingleThreadEventExecutor;
+
+public class CustomRejectedExecutionHandler implements RejectedExecutionHandler {
+
+    @Override
+    public void rejected(Runnable task, SingleThreadEventExecutor executor) {
+        System.out.println("Requeueing the message");
+        try {
+            Thread.sleep(100);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        executor.execute(task);
+    }
+}

src/main/java/org/logstash/beats/DaemonThreadFactory.java

@@ -0,0 +1,30 @@
+package org.logstash.beats;
+
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class DaemonThreadFactory implements ThreadFactory {
+
+    final ThreadGroup group;
+    final AtomicInteger threadNumber = new AtomicInteger(1);
+    final String namePrefix;
+
+    DaemonThreadFactory(String namePrefix) {
+        this.namePrefix = namePrefix;
+        group = Thread.currentThread().getThreadGroup();
+    }
+
+    @Override
+    public Thread newThread(Runnable r) {
+        Thread t = new Thread(group, r,
+                namePrefix + "[T#" + threadNumber.getAndIncrement() + "]",
+                0);
+        t.setDaemon(true);
+        return t;
+    }
+
+    public static ThreadFactory daemonThreadFactory(String namePrefix) {
+        return new DaemonThreadFactory(namePrefix);
+    }
+
+}

src/main/java/org/logstash/beats/Runner.java

@@ -18,7 +18,7 @@ static public void main(String[] args) throws Exception {
         // Check for leaks.
         // ResourceLeakDetector.setLevel(ResourceLeakDetector.Level.PARANOID);
 
-        Server server = new Server("0.0.0.0", DEFAULT_PORT, 15, Runtime.getRuntime().availableProcessors());
+        Server server = new Server("0.0.0.0", DEFAULT_PORT, 15, Runtime.getRuntime().availableProcessors(), 128);
 
             if(args.length > 0 && args[0].equals("ssl")) {
             logger.debug("Using SSL");

src/main/java/org/logstash/beats/Server.java

@@ -16,25 +16,33 @@
 import java.io.IOException;
 import java.security.NoSuchAlgorithmException;
 import java.security.cert.CertificateException;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import static org.logstash.beats.DaemonThreadFactory.daemonThreadFactory;
 
 public class Server {
     private final static Logger logger = LogManager.getLogger(Server.class);
 
     private final int port;
     private final String host;
-    private final int beatsHeandlerThreadCount;
+    private final int beatsHandlerThreadCount;
+    private final int maxPendingRequests;
     private NioEventLoopGroup workGroup;
     private IMessageListener messageListener = new MessageListener();
     private SslSimpleBuilder sslBuilder;
     private BeatsInitializer beatsInitializer;
+    private final int connectionBacklog = 128;
 
     private final int clientInactivityTimeoutSeconds;
 
-    public Server(String host, int p, int timeout, int threadCount) {
+    public Server(String host, int p, int timeout, int threadCount, int maxPendingRequests) {
         this.host = host;
         port = p;
         clientInactivityTimeoutSeconds = timeout;
-        beatsHeandlerThreadCount = threadCount;
+        beatsHandlerThreadCount = threadCount;
+        this.maxPendingRequests = maxPendingRequests;
     }
 
     public void enableSSL(SslSimpleBuilder builder) {
@@ -54,11 +62,12 @@ public Server listen() throws InterruptedException {
         try {
             logger.info("Starting server on port: {}", this.port);
 
-            beatsInitializer = new BeatsInitializer(isSslEnable(), messageListener, clientInactivityTimeoutSeconds, beatsHeandlerThreadCount);
+            beatsInitializer = new BeatsInitializer(isSslEnable(), messageListener, clientInactivityTimeoutSeconds, beatsHandlerThreadCount, maxPendingRequests);
 
             ServerBootstrap server = new ServerBootstrap();
             server.group(workGroup)
                     .channel(NioServerSocketChannel.class)
+                    .option(ChannelOption.SO_BACKLOG, connectionBacklog)
                     .childOption(ChannelOption.SO_LINGER, 0) // Since the protocol doesn't support yet a remote close from the server and we don't want to have 'unclosed' socket lying around we have to use `SO_LINGER` to force the close of the socket.
                     .childHandler(beatsInitializer);
 
@@ -114,14 +123,14 @@ private class BeatsInitializer extends ChannelInitializer<SocketChannel> {
         private final int localClientInactivityTimeoutSeconds;
         private final boolean localEnableSSL;
 
-        BeatsInitializer(Boolean enableSSL, IMessageListener messageListener, int clientInactivityTimeoutSeconds, int beatsHandlerThread) {
+        BeatsInitializer(Boolean enableSSL, IMessageListener messageListener, int clientInactivityTimeoutSeconds, int beatsHandlerThread, int maxPendingRequests) {
             // Keeps a local copy of Server settings, so they can't be modified once it starts listening
             this.localEnableSSL = enableSSL;
             this.localMessageListener = messageListener;
             this.localClientInactivityTimeoutSeconds = clientInactivityTimeoutSeconds;
             idleExecutorGroup = new DefaultEventExecutorGroup(DEFAULT_IDLESTATEHANDLER_THREAD);
-            beatsHandlerExecutorGroup = new DefaultEventExecutorGroup(beatsHandlerThread);
-
+            beatsHandlerExecutorGroup = new DefaultEventExecutorGroup(beatsHandlerThread, daemonThreadFactory("beats-input-handler-executor"), maxPendingRequests, new CustomRejectedExecutionHandler());
+            //beatsHandlerExecutorGroup = new DefaultEventExecutorGroup(beatsHandlerThread);
         }
 
         public void initChannel(SocketChannel socket) throws IOException, NoSuchAlgorithmException, CertificateException {
@@ -136,6 +145,7 @@ public void initChannel(SocketChannel socket) throws IOException, NoSuchAlgorith
             pipeline.addLast(BEATS_ACKER, new AckEncoder());
             pipeline.addLast(CONNECTION_HANDLER, new ConnectionHandler());
             pipeline.addLast(beatsHandlerExecutorGroup, new BeatsParser(), new BeatsHandler(localMessageListener));
+
         }
 
         @Override

src/test/java/org/logstash/beats/ServerTest.java

@@ -34,6 +34,7 @@ public class ServerTest {
     private EventLoopGroup group;
     private final String host = "0.0.0.0";
     private final int threadCount = 10;
+    private final int maxPendingRequests = 128;
 
     @Before
     public void setUp() {
@@ -50,7 +51,7 @@ public void testServerShouldTerminateConnectionWhenExceptionHappen() throws Inte
 
         final CountDownLatch latch = new CountDownLatch(concurrentConnections);
 
-        final Server server = new Server(host, randomPort, inactivityTime, threadCount);
+        final Server server = new Server(host, randomPort, inactivityTime, threadCount, maxPendingRequests);
         final AtomicBoolean otherCause = new AtomicBoolean(false);
         server.setMessageListener(new MessageListener() {
             public void onNewConnection(ChannelHandlerContext ctx) {
@@ -114,7 +115,7 @@ public void testServerShouldTerminateConnectionIdleForTooLong() throws Interrupt
 
         final CountDownLatch latch = new CountDownLatch(concurrentConnections);
         final AtomicBoolean exceptionClose = new AtomicBoolean(false);
-        final Server server = new Server(host, randomPort, inactivityTime, threadCount);
+        final Server server = new Server(host, randomPort, inactivityTime, threadCount, maxPendingRequests);
         server.setMessageListener(new MessageListener() {
             @Override
             public void onNewConnection(ChannelHandlerContext ctx) {
@@ -170,7 +171,7 @@ public void run() {
 
     @Test
     public void testServerShouldAcceptConcurrentConnection() throws InterruptedException {
-        final Server server = new Server(host, randomPort, 30, threadCount);
+        final Server server = new Server(host, randomPort, 30, threadCount, maxPendingRequests);
         SpyListener listener = new SpyListener();
         server.setMessageListener(listener);
         Runnable serverTask = new Runnable() {