com.spotify.heroic.rpc.nativerpc.NativeRpcClientSession.java Source code

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Here is the source code for com.spotify.heroic.rpc.nativerpc.NativeRpcClientSession.java

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/*
 * Copyright (c) 2015 Spotify AB.
 *
 * 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 com.spotify.heroic.rpc.nativerpc;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.spotify.heroic.rpc.nativerpc.message.NativeRpcError;
import com.spotify.heroic.rpc.nativerpc.message.NativeRpcHeartBeat;
import com.spotify.heroic.rpc.nativerpc.message.NativeRpcResponse;
import eu.toolchain.async.ResolvableFuture;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.util.Timeout;
import io.netty.util.Timer;
import io.netty.util.TimerTask;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

@Slf4j
@RequiredArgsConstructor
public class NativeRpcClientSession<R> extends ChannelInitializer<Channel> {
    private final ObjectMapper mapper;
    private final Timer timer;
    private final long heartbeatInterval;
    private final int maxFrameSize;
    private final InetSocketAddress address;
    private final AtomicReference<Timeout> heartbeatTimeout;

    private final ResolvableFuture<R> future;
    private final Class<R> expected;

    @Override
    protected void initChannel(final Channel ch) throws Exception {
        final ChannelPipeline pipeline = ch.pipeline();

        pipeline.addLast(new ChannelInboundHandlerAdapter() {
            @Override
            public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
                bumpTimeout(ctx);
                ctx.fireChannelRead(msg);
            }
        });

        // first four bytes are length prefix of message, strip first four bytes.
        pipeline.addLast(new LengthFieldBasedFrameDecoder(maxFrameSize, 0, 4, 0, 4));
        pipeline.addLast(new NativeRpcDecoder());
        pipeline.addLast(new SimpleChannelInboundHandler<Object>() {
            @Override
            protected void channelRead0(final ChannelHandlerContext ctx, final Object msg) throws Exception {
                if (msg instanceof NativeRpcError) {
                    final NativeRpcError error = (NativeRpcError) msg;

                    if (log.isTraceEnabled()) {
                        log.trace("[{}] remote error: {}", ctx.channel(), error.getMessage());
                    }

                    future.fail(new NativeRpcRemoteException(address, error.getMessage()));
                    ctx.channel().close();
                    return;
                }

                if (msg instanceof NativeRpcResponse) {
                    if (log.isTraceEnabled()) {
                        log.trace("[{}] response: cancelling heartbeat", ctx.channel());
                    }

                    try {
                        handleResponse((NativeRpcResponse) msg);
                    } catch (Exception e) {
                        future.fail(new Exception("Failed to handle response", e));
                    }

                    return;
                }

                if (msg instanceof NativeRpcHeartBeat) {
                    if (log.isTraceEnabled()) {
                        log.trace("[{}] heartbeat: delaying timeout by {}ms", ctx.channel(), heartbeatInterval);
                    }

                    bumpTimeout(ctx);
                    return;
                }

                throw new IllegalArgumentException("unable to handle type: " + msg);
            }

            @Override
            public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
                future.fail(cause);
                ctx.channel().close();
            }
        });

        pipeline.addLast(new LengthFieldPrepender(4));
        pipeline.addLast(new NativeRpcEncoder());
    }

    private void unsetTimeout() {
        final Timeout old = heartbeatTimeout.getAndSet(null);

        if (old != null) {
            old.cancel();
        }
    }

    private void bumpTimeout(final ChannelHandlerContext ctx) {
        final Timeout timeout = timer.newTimeout(heartbeatTimeout(ctx.channel(), future), heartbeatInterval,
                TimeUnit.MILLISECONDS);

        final Timeout old = heartbeatTimeout.getAndSet(timeout);

        if (old != null) {
            old.cancel();
        }
    }

    private void handleResponse(final NativeRpcResponse response)
            throws IOException, JsonParseException, JsonMappingException {
        unsetTimeout();

        final byte[] bytes = NativeUtils.decodeBody(response.getOptions(), response.getSize(), response.getBody());

        final R responseBody = mapper.readValue(bytes, expected);

        future.resolve(responseBody);
    }

    private TimerTask heartbeatTimeout(final Channel ch, final ResolvableFuture<?> future) {
        return new TimerTask() {
            @Override
            public void run(Timeout timeout) throws Exception {
                future.fail(new Exception("request timed out (missing heartbeat)"));
                ch.close();
            }
        };
    }
}