net.kuujo.copycat.io.transport.NettyServer.java Source code

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Here is the source code for net.kuujo.copycat.io.transport.NettyServer.java

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/*
 * Copyright 2015 the original author or authors.
 *
 * Licensed 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 net.kuujo.copycat.io.transport;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.PooledByteBufAllocator;
import io.netty.channel.*;
import io.netty.channel.epoll.EpollEventLoopGroup;
import io.netty.channel.epoll.EpollServerSocketChannel;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.util.concurrent.GlobalEventExecutor;
import net.kuujo.copycat.util.Assert;
import net.kuujo.copycat.util.concurrent.Context;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Map;
import java.util.UUID;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Consumer;

/**
 * Netty server.
 *
 * @author <a href="http://github.com/kuujo">Jordan Halterman</a>
 */
public class NettyServer implements Server {
    private static final Logger LOGGER = LoggerFactory.getLogger(NettyServer.class);
    private static final ByteBufAllocator ALLOCATOR = new PooledByteBufAllocator(true);
    private static final ChannelHandler FIELD_PREPENDER = new LengthFieldPrepender(2);

    private final UUID id;
    private final EventLoopGroup eventLoopGroup;
    private final Map<Channel, NettyConnection> connections = new ConcurrentHashMap<>();
    private ServerHandler handler;
    private ChannelGroup channelGroup;
    private volatile boolean listening;
    private CompletableFuture<Void> listenFuture;

    public NettyServer(UUID id, EventLoopGroup eventLoopGroup) {
        this.id = id;
        this.eventLoopGroup = eventLoopGroup;
    }

    @Override
    public UUID id() {
        return id;
    }

    /**
     * Returns the current execution context.
     */
    private Context getContext() {
        Context context = Context.currentContext();
        if (context == null) {
            throw new IllegalStateException("not on a Copycat thread");
        }
        return context;
    }

    @Override
    public CompletableFuture<Void> listen(Address address, Consumer<Connection> listener) {
        Assert.notNull(address, "address");
        Assert.notNull(listener, "listener");
        if (listening)
            return CompletableFuture.completedFuture(null);

        Context context = getContext();
        synchronized (this) {
            if (listenFuture == null) {
                listenFuture = new CompletableFuture<>();
                listen(address, listener, context);
            }
        }
        return listenFuture;
    }

    /**
     * Starts listening for the given member.
     */
    private void listen(Address address, Consumer<Connection> listener, Context context) {
        channelGroup = new DefaultChannelGroup("copycat-acceptor-channels", GlobalEventExecutor.INSTANCE);

        handler = new ServerHandler(connections, listener, context);

        final ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(eventLoopGroup)
                .channel(eventLoopGroup instanceof EpollEventLoopGroup ? EpollServerSocketChannel.class
                        : NioServerSocketChannel.class)
                .handler(new LoggingHandler(LogLevel.DEBUG)).childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    public void initChannel(SocketChannel channel) throws Exception {
                        ChannelPipeline pipeline = channel.pipeline();
                        pipeline.addLast(FIELD_PREPENDER);
                        pipeline.addLast(new LengthFieldBasedFrameDecoder(1024 * 32, 0, 2, 0, 2));
                        pipeline.addLast(handler);
                    }
                }).option(ChannelOption.SO_BACKLOG, 128).option(ChannelOption.TCP_NODELAY, true)
                .option(ChannelOption.SO_REUSEADDR, true).childOption(ChannelOption.ALLOCATOR, ALLOCATOR)
                .childOption(ChannelOption.SO_KEEPALIVE, true);

        LOGGER.info("Binding to {}", address);

        ChannelFuture bindFuture = bootstrap.bind(address.socketAddress());
        bindFuture.addListener((ChannelFutureListener) channelFuture -> {
            if (channelFuture.isSuccess()) {
                listening = true;
                context.executor().execute(() -> {
                    LOGGER.info("Listening at {}", bindFuture.channel().localAddress());
                    listenFuture.complete(null);
                });
            } else {
                context.execute(() -> listenFuture.completeExceptionally(channelFuture.cause()));
            }
        });
        channelGroup.add(bindFuture.channel());
    }

    @Override
    public CompletableFuture<Void> close() {
        int i = 0;
        CompletableFuture[] futures = new CompletableFuture[connections.size()];
        for (Connection connection : connections.values()) {
            futures[i++] = connection.close();
        }
        return CompletableFuture.allOf(futures);
    }

    /**
     * Server handler.
     */
    @ChannelHandler.Sharable
    private static class ServerHandler extends NettyHandler {

        private ServerHandler(Map<Channel, NettyConnection> connections, Consumer<Connection> listener,
                Context context) {
            super(connections, listener, context);
        }

    }

}