io.netty.channel.ChannelFactory Java Examples

@Test
public void responseConnectionReused_shouldReleaseChannel() throws Exception {

    ChannelFactory channelFactory = mock(ChannelFactory.class);
    EventLoopGroup customEventLoopGroup = new NioEventLoopGroup(1);
    NioSocketChannel channel = new NioSocketChannel();

    when(channelFactory.newChannel()).thenAnswer((Answer<NioSocketChannel>) invocationOnMock -> channel);
    SdkEventLoopGroup eventLoopGroup = SdkEventLoopGroup.create(customEventLoopGroup, channelFactory);

    NettyNioAsyncHttpClient customClient =
        (NettyNioAsyncHttpClient) NettyNioAsyncHttpClient.builder()
                                                         .eventLoopGroup(eventLoopGroup)
                                                         .maxConcurrency(1)
                                                         .build();

    makeSimpleRequest(customClient);
    verifyChannelRelease(channel);
    assertThat(channel.isShutdown()).isFalse();

    customClient.close();
    eventLoopGroup.eventLoopGroup().shutdownGracefully().awaitUninterruptibly();
}
 

private NettyClientTransport newTransport(ProtocolNegotiator negotiator, int maxMsgSize,
    int maxHeaderListSize, String userAgent, boolean enableKeepAlive, long keepAliveTimeNano,
    long keepAliveTimeoutNano, ChannelFactory<? extends Channel> channelFactory,
    EventLoopGroup group) {
  if (!enableKeepAlive) {
    keepAliveTimeNano = KEEPALIVE_TIME_NANOS_DISABLED;
  }
  NettyClientTransport transport = new NettyClientTransport(
      address, channelFactory, new HashMap<ChannelOption<?>, Object>(), group,
      negotiator, false, DEFAULT_WINDOW_SIZE, maxMsgSize, maxHeaderListSize,
      keepAliveTimeNano, keepAliveTimeoutNano,
      false, authority, userAgent, tooManyPingsRunnable,
      new TransportTracer(), eagAttributes, new SocketPicker(), new FakeChannelLogger(), false);
  transports.add(transport);
  return transport;
}
 

@Test
public void customChannelFactoryIsUsed() throws Exception {

    ChannelFactory channelFactory = mock(ChannelFactory.class);

    when(channelFactory.newChannel()).thenAnswer((Answer<NioSocketChannel>) invocationOnMock -> new NioSocketChannel());
    EventLoopGroup customEventLoopGroup = new NioEventLoopGroup();

    SdkAsyncHttpClient customClient =
        NettyNioAsyncHttpClient.builder()
                               .eventLoopGroup(SdkEventLoopGroup.create(customEventLoopGroup, channelFactory))
                               .build();

    makeSimpleRequest(customClient);
    customClient.close();

    Mockito.verify(channelFactory, atLeastOnce()).newChannel();
    assertThat(customEventLoopGroup.isShuttingDown()).isFalse();
    customEventLoopGroup.shutdownGracefully().awaitUninterruptibly();
}
 

NettyTransportFactory(ProtocolNegotiator protocolNegotiator,
    ChannelFactory<? extends Channel> channelFactory,
    Map<ChannelOption<?>, ?> channelOptions, ObjectPool<? extends EventLoopGroup> groupPool,
    boolean autoFlowControl, int flowControlWindow, int maxMessageSize, int maxHeaderListSize,
    long keepAliveTimeNanos, long keepAliveTimeoutNanos, boolean keepAliveWithoutCalls,
    TransportTracer.Factory transportTracerFactory, LocalSocketPicker localSocketPicker,
    boolean useGetForSafeMethods) {
  this.protocolNegotiator = checkNotNull(protocolNegotiator, "protocolNegotiator");
  this.channelFactory = channelFactory;
  this.channelOptions = new HashMap<ChannelOption<?>, Object>(channelOptions);
  this.groupPool = groupPool;
  this.group = groupPool.getObject();
  this.autoFlowControl = autoFlowControl;
  this.flowControlWindow = flowControlWindow;
  this.maxMessageSize = maxMessageSize;
  this.maxHeaderListSize = maxHeaderListSize;
  this.keepAliveTimeNanos = new AtomicBackoff("keepalive time nanos", keepAliveTimeNanos);
  this.keepAliveTimeoutNanos = keepAliveTimeoutNanos;
  this.keepAliveWithoutCalls = keepAliveWithoutCalls;
  this.transportTracerFactory = transportTracerFactory;
  this.localSocketPicker =
      localSocketPicker != null ? localSocketPicker : new LocalSocketPicker();
  this.useGetForSafeMethods = useGetForSafeMethods;
}
 

@Test
public void testChannelFactoryFailureNotifiesPromise() throws Exception {
    final RuntimeException exception = new RuntimeException("newChannel crash");

    final Bootstrap bootstrap = new Bootstrap()
            .handler(dummyHandler)
            .group(groupA)
            .channelFactory(new ChannelFactory<Channel>() {
        @Override
        public Channel newChannel() {
            throw exception;
        }
    });

    ChannelFuture connectFuture = bootstrap.connect(LocalAddress.ANY);

    // Should fail with the RuntimeException.
    assertThat(connectFuture.await(10000), is(true));
    assertThat(connectFuture.cause(), sameInstance((Throwable) exception));
    assertThat(connectFuture.channel(), is(not(nullValue())));
}
 

/**
 * Attempts to determine the {@link ChannelFactory} class that corresponds to the given
 * event loop group.
 *
 * @param eventLoopGroup the event loop group to determine the {@link ChannelFactory} for
 * @return A {@link ChannelFactory} instance for the given event loop group.
 */
@SuppressWarnings("unchecked")
public static ChannelFactory<? extends Channel> resolveSocketChannelFactory(EventLoopGroup eventLoopGroup) {
    if (eventLoopGroup instanceof DelegatingEventLoopGroup) {
        return resolveSocketChannelFactory(((DelegatingEventLoopGroup) eventLoopGroup).getDelegate());
    }

    if (eventLoopGroup instanceof NioEventLoopGroup) {
        return NioSocketChannel::new;
    }
    if (eventLoopGroup instanceof EpollEventLoopGroup) {
        return EpollSocketChannel::new;
    }

    String socketFqcn = KNOWN_EL_GROUPS.get(eventLoopGroup.getClass().getName());
    if (socketFqcn == null) {
        throw new IllegalArgumentException("Unknown event loop group : " + eventLoopGroup.getClass());
    }

    return invokeSafely(() -> new ReflectiveChannelFactory(Class.forName(socketFqcn)));
}
 

@Override
public EventLoopGroup init(Bootstrap bootstrap, final DockerClientConfig dockerClientConfig) {
    EventLoopGroup nioEventLoopGroup = new NioEventLoopGroup(0, new DefaultThreadFactory(threadPrefix));

    InetAddress addr = InetAddress.getLoopbackAddress();

    final SocketAddress proxyAddress = new InetSocketAddress(addr, 8008);

    Security.addProvider(new BouncyCastleProvider());

    ChannelFactory<NioSocketChannel> factory = () -> configure(new NioSocketChannel());

    bootstrap.group(nioEventLoopGroup).channelFactory(factory)
            .handler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(final SocketChannel channel) throws Exception {
                    // channel.pipeline().addLast(new
                    // HttpProxyHandler(proxyAddress));
                    channel.pipeline().addLast(new HttpClientCodec());
                    channel.pipeline().addLast(new HttpContentDecompressor());
                }
            });

    return nioEventLoopGroup;
}
 

public EventLoopGroup epollGroup() {
    EventLoopGroup epollEventLoopGroup = new EpollEventLoopGroup(0, new DefaultThreadFactory(threadPrefix));

    ChannelFactory<EpollDomainSocketChannel> factory = () -> configure(new EpollDomainSocketChannel());

    bootstrap.group(epollEventLoopGroup).channelFactory(factory).handler(new ChannelInitializer<UnixChannel>() {
        @Override
        protected void initChannel(final UnixChannel channel) throws Exception {
            channel.pipeline().addLast(new HttpClientCodec());
            channel.pipeline().addLast(new HttpContentDecompressor());
        }
    });
    return epollEventLoopGroup;
}
 

@Test
public void responseConnectionClosed_shouldCloseAndReleaseChannel() throws Exception {

    ChannelFactory channelFactory = mock(ChannelFactory.class);
    EventLoopGroup customEventLoopGroup = new NioEventLoopGroup(1);
    NioSocketChannel channel = new NioSocketChannel();

    when(channelFactory.newChannel()).thenAnswer((Answer<NioSocketChannel>) invocationOnMock -> channel);

    URI uri = URI.create("http://localhost:" + mockServer.port());
    SdkHttpRequest request = createRequest(uri);
    RecordingResponseHandler recorder = new RecordingResponseHandler();

    SdkEventLoopGroup eventLoopGroup = SdkEventLoopGroup.create(customEventLoopGroup, channelFactory);

    NettyNioAsyncHttpClient customClient =
        (NettyNioAsyncHttpClient) NettyNioAsyncHttpClient.builder()
                                                         .eventLoopGroup(eventLoopGroup)
                                                         .maxConcurrency(1)
                                                         .build();

    String body = randomAlphabetic(10);

    stubFor(any(urlPathEqualTo("/")).willReturn(aResponse().withBody(body)
                                                           .withStatus(500)
                                                           .withHeader("Connection", "close")
    ));

    customClient.execute(AsyncExecuteRequest.builder()
                                            .request(request)
                                            .requestContentPublisher(createProvider(""))
                                            .responseHandler(recorder).build());
    recorder.completeFuture.get(5, TimeUnit.SECONDS);

    verifyChannelRelease(channel);
    assertThat(channel.isShutdown()).isTrue();

    customClient.close();
    eventLoopGroup.eventLoopGroup().shutdownGracefully().awaitUninterruptibly();
}
 

@Test
public void closeMethodClosesOpenedChannels() throws InterruptedException, TimeoutException, ExecutionException {
    String body = randomAlphabetic(10);
    URI uri = URI.create("https://localhost:" + mockServer.httpsPort());
    stubFor(any(urlPathEqualTo("/")).willReturn(aResponse().withHeader("Some-Header", "With Value").withBody(body)));

    SdkHttpFullRequest request = createRequest(uri, "/", body, SdkHttpMethod.POST, Collections.emptyMap());
    RecordingResponseHandler recorder = new RecordingResponseHandler();

    CompletableFuture<Boolean> channelClosedFuture = new CompletableFuture<>();
    ChannelFactory<NioSocketChannel> channelFactory = new ChannelFactory<NioSocketChannel>() {
        @Override
        public NioSocketChannel newChannel() {
            return new NioSocketChannel() {
                @Override
                public ChannelFuture close() {
                    ChannelFuture cf = super.close();
                    channelClosedFuture.complete(true);
                    return cf;
                }
            };
        }
    };

    SdkAsyncHttpClient customClient = NettyNioAsyncHttpClient.builder()
            .eventLoopGroup(new SdkEventLoopGroup(new NioEventLoopGroup(1), channelFactory))
            .buildWithDefaults(mapWithTrustAllCerts());

    try {
        customClient.execute(AsyncExecuteRequest.builder()
                .request(request)
                .requestContentPublisher(createProvider(body))
                .responseHandler(recorder).build())
                .join();
    } finally {
        customClient.close();
    }

    assertThat(channelClosedFuture.get(5, TimeUnit.SECONDS)).isTrue();
}
 

private void createServer(Listener listener, EventLoopGroup eventLoopGroup, ChannelFactory<? extends DatagramChannel> channelFactory) {
    this.eventLoopGroup = eventLoopGroup;
    try {
        Bootstrap b = new Bootstrap();
        b.group(eventLoopGroup)//默认是根据机器情况创建Channel,如果机器支持ipv6,则无法使用ipv4的地址加入组播
                .channelFactory(channelFactory)
                .option(ChannelOption.SO_BROADCAST, true)
                .handler(getChannelHandler());

        initOptions(b);

        //直接绑定端口，不要指定host，不然收不到组播消息
        b.bind(port).addListener(future -> {
            if (future.isSuccess()) {
                logger.info("udp server start success on:{}", port);
                if (listener != null) listener.onSuccess(port);
            } else {
                logger.error("udp server start failure on:{}", port, future.cause());
                if (listener != null) listener.onFailure(future.cause());
            }
        });
    } catch (Exception e) {
        logger.error("udp server start exception", e);
        if (listener != null) listener.onFailure(e);
        throw new ServiceException("udp server start exception, port=" + port, e);
    }
}
 

@Override
protected ChannelFactory<? extends Channel> connectionFactory(EventLoopGroup elg, boolean isDomainSocket) {
	if (isDomainSocket) {
		throw new UnsupportedOperationException();
	}
	if (isPreferNative()) {
		return () -> loopResources().onChannel(DatagramChannel.class, elg);
	}
	else {
		return () -> new NioDatagramChannel(family());
	}
}
 

@Override
protected ChannelFactory<? extends Channel> connectionFactory(EventLoopGroup elg, boolean isDomainSocket) {
	if (isDomainSocket) {
		throw new UnsupportedOperationException();
	}
	if (isPreferNative()) {
		return () -> loopResources().onChannel(DatagramChannel.class, elg);
	}
	else {
		return () -> new NioDatagramChannel(family());
	}
}
 

@Test
public void defaultServerChannelFactory_whenEpollIsAvailable() {
  assume().that(Utils.isEpollAvailable()).isTrue();

  ChannelFactory<? extends ServerChannel> channelFactory = Utils.DEFAULT_SERVER_CHANNEL_FACTORY;

  assertThat(channelFactory.toString())
      .isEqualTo("ReflectiveChannelFactory(EpollServerSocketChannel.class)");
}
 

NettyClientTransport(
    SocketAddress address, ChannelFactory<? extends Channel> channelFactory,
    Map<ChannelOption<?>, ?> channelOptions, EventLoopGroup group,
    ProtocolNegotiator negotiator, boolean autoFlowControl, int flowControlWindow,
    int maxMessageSize, int maxHeaderListSize,
    long keepAliveTimeNanos, long keepAliveTimeoutNanos,
    boolean keepAliveWithoutCalls, String authority, @Nullable String userAgent,
    Runnable tooManyPingsRunnable, TransportTracer transportTracer, Attributes eagAttributes,
    LocalSocketPicker localSocketPicker, ChannelLogger channelLogger,
    boolean useGetForSafeMethods) {
  this.negotiator = Preconditions.checkNotNull(negotiator, "negotiator");
  this.negotiationScheme = this.negotiator.scheme();
  this.remoteAddress = Preconditions.checkNotNull(address, "address");
  this.group = Preconditions.checkNotNull(group, "group");
  this.channelFactory = channelFactory;
  this.channelOptions = Preconditions.checkNotNull(channelOptions, "channelOptions");
  this.autoFlowControl = autoFlowControl;
  this.flowControlWindow = flowControlWindow;
  this.maxMessageSize = maxMessageSize;
  this.maxHeaderListSize = maxHeaderListSize;
  this.keepAliveTimeNanos = keepAliveTimeNanos;
  this.keepAliveTimeoutNanos = keepAliveTimeoutNanos;
  this.keepAliveWithoutCalls = keepAliveWithoutCalls;
  this.authorityString = authority;
  this.authority = new AsciiString(authority);
  this.userAgent = new AsciiString(GrpcUtil.getGrpcUserAgent("netty", userAgent));
  this.tooManyPingsRunnable =
      Preconditions.checkNotNull(tooManyPingsRunnable, "tooManyPingsRunnable");
  this.transportTracer = Preconditions.checkNotNull(transportTracer, "transportTracer");
  this.eagAttributes = Preconditions.checkNotNull(eagAttributes, "eagAttributes");
  this.localSocketPicker = Preconditions.checkNotNull(localSocketPicker, "localSocketPicker");
  this.logId = InternalLogId.allocate(getClass(), remoteAddress.toString());
  this.channelLogger = Preconditions.checkNotNull(channelLogger, "channelLogger");
  this.useGetForSafeMethods = useGetForSafeMethods;
}
 

private static ChannelFactory<ServerChannel> nioServerChannelFactory() {
  return new ChannelFactory<ServerChannel>() {
    @Override
    public ServerChannel newChannel() {
      return new NioServerSocketChannel();
    }
  };
}
 

@Test
public void assertEventLoopAndChannelType_onlyFactoryProvided() {
  NettyChannelBuilder builder = NettyChannelBuilder.forTarget("fakeTarget");
  builder.channelFactory(new ChannelFactory<Channel>() {
    @Override
    public Channel newChannel() {
      return null;
    }
  });
  thrown.expect(IllegalStateException.class);
  thrown.expectMessage("Both EventLoopGroup and ChannelType should be provided");

  builder.assertEventLoopAndChannelType();
}
 

public List<BootstrapComboFactory<Bootstrap, Bootstrap>> datagram() {
    // Make the list of Bootstrap factories.
    List<BootstrapFactory<Bootstrap>> bfs = Arrays.asList(
            new BootstrapFactory<Bootstrap>() {
                @Override
                public Bootstrap newInstance() {
                    return new Bootstrap().group(nioWorkerGroup).channelFactory(new ChannelFactory<Channel>() {
                        @Override
                        public Channel newChannel() {
                            return new NioDatagramChannel(InternetProtocolFamily.IPv4);
                        }

                        @Override
                        public String toString() {
                            return NioDatagramChannel.class.getSimpleName() + ".class";
                        }
                    });
                }
            },
            new BootstrapFactory<Bootstrap>() {
                @Override
                public Bootstrap newInstance() {
                    return new Bootstrap().group(oioWorkerGroup).channel(OioDatagramChannel.class)
                            .option(ChannelOption.SO_TIMEOUT, OIO_SO_TIMEOUT);
                }
            }
    );

    // Populare the combinations.
    return combo(bfs, bfs);
}
 

@Test
public void connectionInactive_shouldReleaseChannel() throws Exception {

    ChannelFactory channelFactory = mock(ChannelFactory.class);
    EventLoopGroup customEventLoopGroup = new NioEventLoopGroup(1);
    NioSocketChannel channel = new NioSocketChannel();

    when(channelFactory.newChannel()).thenAnswer((Answer<NioSocketChannel>) invocationOnMock -> channel);
    SdkEventLoopGroup eventLoopGroup = SdkEventLoopGroup.create(customEventLoopGroup, channelFactory);

    NettyNioAsyncHttpClient customClient =
        (NettyNioAsyncHttpClient) NettyNioAsyncHttpClient.builder()
                                                         .eventLoopGroup(eventLoopGroup)
                                                         .maxConcurrency(1)
                                                         .build();


    String body = randomAlphabetic(10);
    URI uri = URI.create("http://localhost:" + mockServer.port());
    SdkHttpRequest request = createRequest(uri);
    RecordingResponseHandler recorder = new RecordingResponseHandler();


    stubFor(any(urlPathEqualTo("/")).willReturn(aResponse().withBody(body)
                                                           .withStatus(500)
                                                           .withFault(Fault.RANDOM_DATA_THEN_CLOSE)));

    customClient.execute(AsyncExecuteRequest.builder()
                                            .request(request)
                                            .requestContentPublisher(createProvider(""))
                                            .responseHandler(recorder).build());

    verifyChannelRelease(channel);
    assertThat(channel.isShutdown()).isTrue();

    customClient.close();
    eventLoopGroup.eventLoopGroup().shutdownGracefully().awaitUninterruptibly();
}
 

/**
 * @deprecated Override {@link #newNameResolver(EventLoop, ChannelFactory, DnsServerAddressStreamProvider)}.
 */
@Deprecated
protected AddressResolver<InetSocketAddress> newResolver(
        EventLoop eventLoop, ChannelFactory<? extends DatagramChannel> channelFactory,
        DnsServerAddressStreamProvider nameServerProvider) throws Exception {

    final NameResolver<InetAddress> resolver = new InflightNameResolver<InetAddress>(
            eventLoop,
            newNameResolver(eventLoop, channelFactory, nameServerProvider),
            resolvesInProgress,
            resolveAllsInProgress);

    return newAddressResolver(eventLoop, resolver);
}
 

/**
 * Creates a new {@link NameResolver}. Override this method to create an alternative {@link NameResolver}
 * implementation or override the default configuration.
 */
protected NameResolver<InetAddress> newNameResolver(EventLoop eventLoop,
                                                    ChannelFactory<? extends DatagramChannel> channelFactory,
                                                    DnsServerAddressStreamProvider nameServerProvider)
        throws Exception {
    return new DnsNameResolverBuilder(eventLoop)
            .channelFactory(channelFactory)
            .nameServerProvider(nameServerProvider)
            .build();
}
 

@Override
public List<TestsuitePermutation.BootstrapComboFactory<Bootstrap, Bootstrap>> datagram() {
    // Make the list of Bootstrap factories.
    @SuppressWarnings("unchecked")
    List<BootstrapFactory<Bootstrap>> bfs = Arrays.asList(
            new BootstrapFactory<Bootstrap>() {
                @Override
                public Bootstrap newInstance() {
                    return new Bootstrap().group(nioWorkerGroup).channelFactory(new ChannelFactory<Channel>() {
                        @Override
                        public Channel newChannel() {
                            return new NioDatagramChannel(InternetProtocolFamily.IPv4);
                        }

                        @Override
                        public String toString() {
                            return NioDatagramChannel.class.getSimpleName() + ".class";
                        }
                    });
                }
            },
            new BootstrapFactory<Bootstrap>() {
                @Override
                public Bootstrap newInstance() {
                    return new Bootstrap().group(KQUEUE_WORKER_GROUP).channel(KQueueDatagramChannel.class);
                }
            }
    );
    return combo(bfs, bfs);
}
 

@Override
public List<TestsuitePermutation.BootstrapComboFactory<Bootstrap, Bootstrap>> datagram() {
    // Make the list of Bootstrap factories.
    @SuppressWarnings("unchecked")
    List<BootstrapFactory<Bootstrap>> bfs = Arrays.asList(
            new BootstrapFactory<Bootstrap>() {
                @Override
                public Bootstrap newInstance() {
                    return new Bootstrap().group(nioWorkerGroup).channelFactory(new ChannelFactory<Channel>() {
                        @Override
                        public Channel newChannel() {
                            return new NioDatagramChannel(InternetProtocolFamily.IPv4);
                        }

                        @Override
                        public String toString() {
                            return NioDatagramChannel.class.getSimpleName() + ".class";
                        }
                    });
                }
            },
            new BootstrapFactory<Bootstrap>() {
                @Override
                public Bootstrap newInstance() {
                    return new Bootstrap().group(EPOLL_WORKER_GROUP).channel(EpollDatagramChannel.class);
                }
            }
    );
    return combo(bfs, bfs);
}
 

public static void main(String[] args) throws Exception {
    ApplicationContext context = new ClassPathXmlApplicationContext("classpath:netty-gateway.xml");
    PORT = ((GatewayOptions) context.getBean("options")).getGatewayPort();

    dumpSystemInfo(new PrintWriter(System.out));

    EventLoopGroup bossGroup = new NioEventLoopGroup(1, new DefaultThreadFactory("netty.gateway.boss", Thread.MAX_PRIORITY));
    EventLoopGroup workerGroup = new NioEventLoopGroup(GATEWAY_OPTION_PARALLEL, new DefaultThreadFactory("netty.gateway.worker", Thread.MAX_PRIORITY));

    try {
        ServerBootstrap b = new ServerBootstrap();
        b.group(bossGroup, workerGroup)
                .channelFactory(new ChannelFactory<NioServerSocketChannel>() {
                    @Override
                    public NioServerSocketChannel newChannel() {
                        return new NioServerSocketChannel(SelectorProvider.provider());
                    }
                })
                .handler(new LoggingHandler(LogLevel.INFO))
                .childHandler(new GatewayServerInitializer());
        Channel ch = b.bind(PORT).sync().channel();
        ch.closeFuture().sync();
    } finally {
        bossGroup.shutdownGracefully();
        workerGroup.shutdownGracefully();
    }
}
 

public DnsAddressResolverGroup(
        ChannelFactory<? extends DatagramChannel> channelFactory,
        DnsServerAddressStreamProvider nameServerProvider) {
    this.channelFactory = channelFactory;
    this.nameServerProvider = nameServerProvider;
}
 

public RoundRobinDnsAddressResolverGroup(
        ChannelFactory<? extends DatagramChannel> channelFactory,
        DnsServerAddressStreamProvider nameServerProvider) {
    super(channelFactory, nameServerProvider);
}
 

NettyServer(
    SocketAddress address, ChannelFactory<? extends ServerChannel> channelFactory,
    Map<ChannelOption<?>, ?> channelOptions,
    Map<ChannelOption<?>, ?> childChannelOptions,
    ObjectPool<? extends EventLoopGroup> bossGroupPool,
    ObjectPool<? extends EventLoopGroup> workerGroupPool,
    boolean forceHeapBuffer,
    ProtocolNegotiator protocolNegotiator,
    List<? extends ServerStreamTracer.Factory> streamTracerFactories,
    TransportTracer.Factory transportTracerFactory,
    int maxStreamsPerConnection, boolean autoFlowControl, int flowControlWindow,
    int maxMessageSize, int maxHeaderListSize,
    long keepAliveTimeInNanos, long keepAliveTimeoutInNanos,
    long maxConnectionIdleInNanos,
    long maxConnectionAgeInNanos, long maxConnectionAgeGraceInNanos,
    boolean permitKeepAliveWithoutCalls, long permitKeepAliveTimeInNanos,
    InternalChannelz channelz) {
  this.address = address;
  this.channelFactory = checkNotNull(channelFactory, "channelFactory");
  checkNotNull(channelOptions, "channelOptions");
  this.channelOptions = new HashMap<ChannelOption<?>, Object>(channelOptions);
  checkNotNull(childChannelOptions, "childChannelOptions");
  this.childChannelOptions = new HashMap<ChannelOption<?>, Object>(childChannelOptions);
  this.bossGroupPool = checkNotNull(bossGroupPool, "bossGroupPool");
  this.workerGroupPool = checkNotNull(workerGroupPool, "workerGroupPool");
  this.forceHeapBuffer = forceHeapBuffer;
  this.bossGroup = bossGroupPool.getObject();
  this.workerGroup = workerGroupPool.getObject();
  this.protocolNegotiator = checkNotNull(protocolNegotiator, "protocolNegotiator");
  this.streamTracerFactories = checkNotNull(streamTracerFactories, "streamTracerFactories");
  this.transportTracerFactory = transportTracerFactory;
  this.maxStreamsPerConnection = maxStreamsPerConnection;
  this.autoFlowControl = autoFlowControl;
  this.flowControlWindow = flowControlWindow;
  this.maxMessageSize = maxMessageSize;
  this.maxHeaderListSize = maxHeaderListSize;
  this.keepAliveTimeInNanos = keepAliveTimeInNanos;
  this.keepAliveTimeoutInNanos = keepAliveTimeoutInNanos;
  this.maxConnectionIdleInNanos = maxConnectionIdleInNanos;
  this.maxConnectionAgeInNanos = maxConnectionAgeInNanos;
  this.maxConnectionAgeGraceInNanos = maxConnectionAgeGraceInNanos;
  this.permitKeepAliveWithoutCalls = permitKeepAliveWithoutCalls;
  this.permitKeepAliveTimeInNanos = permitKeepAliveTimeInNanos;
  this.channelz = Preconditions.checkNotNull(channelz);
  this.logId =
      InternalLogId.allocate(getClass(), address != null ? address.toString() : "No address");
}
 

public static ChannelFactory<? extends ServerChannel> getServerSocketChannelFactory() {
    if (epoll)
        return EpollServerSocketChannel::new;
    else
        return NioServerSocketChannel::new;
}
 

@SuppressWarnings("FutureReturnValueIgnored")
static Mono<Channel> doInitAndRegister(
		TransportConfig config,
		ChannelInitializer<Channel> channelInitializer,
		boolean isDomainSocket) {
	EventLoopGroup elg = config.eventLoopGroup();

	ChannelFactory<? extends Channel> channelFactory = config.connectionFactory(elg, isDomainSocket);

	Channel channel = null;
	try {
		channel = channelFactory.newChannel();
		if (channelInitializer instanceof ServerTransport.AcceptorInitializer) {
			((ServerTransport.AcceptorInitializer) channelInitializer).acceptor.enableAutoReadTask(channel);
		}
		channel.pipeline().addLast(channelInitializer);
		setChannelOptions(channel, config.options, isDomainSocket);
		setAttributes(channel, config.attrs);
	}
	catch (Throwable t) {
		if (channel != null) {
			channel.unsafe().closeForcibly();
		}
		return Mono.error(t);
	}

	MonoChannelPromise monoChannelPromise = new MonoChannelPromise(channel);
	channel.unsafe().register(elg.next(), monoChannelPromise);
	Throwable cause = monoChannelPromise.cause();
	if (cause != null) {
		if (channel.isRegistered()) {
			// "FutureReturnValueIgnored" this is deliberate
			channel.close();
		}
		else {
			channel.unsafe().closeForcibly();
		}
	}

	return monoChannelPromise;
}
 

@Override
public void connect() throws Exception {

    try {
        channelLock.writeLock().lock();
           LinkedHashMap<String, ChannelHandler> handlers = getChannelHandlers();

           String interfaceIp = getSettings().getInterfaceIp();
           String mcastIp = getSettings().getMulticastIp();
           int mcastPort = getSettings().getMulticastPort();

           this.localNetworkInterface = NetworkInterface.getByInetAddress(Inet4Address.getByName(interfaceIp));

           if (this.localNetworkInterface == null) {
               throw new ServiceException("Failed to resolve network interface via IP: " + interfaceIp);
           }

           this.multicastGroup = new InetSocketAddress(InetAddress.getByName(mcastIp), mcastPort);

           Bootstrap cb = new Bootstrap();
           // Fixme: use ITaskExecutor ?
           cb.group(nioEventLoopGroup);
           cb.channelFactory(new ChannelFactory<Channel>() {
               @Override
               public Channel newChannel() {
                   // Force IPv4
                   return new NioDatagramChannel(InternetProtocolFamily.IPv4);
               }
           });
           cb.option(ChannelOption.SO_REUSEADDR, true);
           cb.option(ChannelOption.IP_MULTICAST_IF, localNetworkInterface);
           cb.option(ChannelOption.IP_MULTICAST_TTL, getSettings().getTtl());
           cb.localAddress(new InetSocketAddress(InetAddress.getByName(mcastIp), mcastPort));
           // we can configure java -Dio.netty.allocator.numDirectArenas=... -Dio.netty.allocator.numHeapArenas=...
           cb.option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT);
           cb.handler(new ChannelInitializer<Channel>() {
               @Override
               protected void initChannel(Channel ch) throws Exception {
                   handlers.forEach((key, value) -> ch.pipeline().addLast(key, value));
                   // add exception handler for inbound messages
                   // outbound exceptions will be routed here by ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE
                   ch.pipeline().addLast(new ExceptionInboundHandler(nettySession::onExceptionCaught));

               }
           });

           Channel localChannel = cb.bind().addListener(new ChannelFutureListener() {
               @Override
               public void operationComplete(ChannelFuture bindFuture) throws Exception {
                   if (!bindFuture.isSuccess()) {
                       return;
                   }
                   DatagramChannel channel = (DatagramChannel) bindFuture.channel();
                   // TODO: heartbeat loss detection

                   ChannelFuture future;
                   String sourceIP = getSettings().getSourceIp();
                   if (sourceIP == null) {
                       future = channel.joinGroup(multicastGroup, localNetworkInterface);
                   } else {
                       future = channel.joinGroup(multicastGroup.getAddress(), localNetworkInterface, InetAddress.getByName(sourceIP));
                   }
                   future.addListener(ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE).addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
               }
           }).addListener(ChannelFutureListener.CLOSE_ON_FAILURE).syncUninterruptibly().channel();

           localChannel.closeFuture().addListener((ChannelFutureListener) future -> changeStatus(ServiceStatus.DISPOSED, "Connection closed", null));
           setChannel(localChannel);
       } finally {
        channelLock.writeLock().unlock();
       }
}