graylog 的InputBuffer 简单说明

InputBuffer 是graylog 实际处理日志的部分，内部处理基于了Disruptor，同时还依赖了Journalling 能力
内部实际处理是依赖LocalKafka的（而且是推荐的）

InputBuffer 处理的几个模式

目前主要包含了3大类 DirectMessageHandler,RawMessageEncoderHandler,JournallingMessageHandler
构造(InputBufferImpl 构造函数)

final Disruptor<RawMessageEvent> disruptor = new Disruptor<>(
                RawMessageEvent.FACTORY,
                configuration.getInputBufferRingSize(),
                threadFactory(metricRegistry),
                ProducerType.MULTI,
                configuration.getInputBufferWaitStrategy());
        disruptor.setDefaultExceptionHandler(new LoggingExceptionHandler(LOG));
        // 处理器核心是disruptor 的workpool 实现负载均衡能力
        final int numberOfHandlers = configuration.getInputbufferProcessors();
        if (configuration.isMessageJournalEnabled()) {
            LOG.info("Message journal is enabled.");
 
            final RawMessageEncoderHandler[] handlers = new RawMessageEncoderHandler[numberOfHandlers];
            for (int i = 0; i < numberOfHandlers; i++) {
                handlers[i] = rawMessageEncoderHandlerProvider.get();
            }
            disruptor.handleEventsWithWorkerPool(handlers).then(spoolingMessageHandlerProvider.get());
        } else {
            LOG.info("Message journal is disabled.");
            final DirectMessageHandler[] handlers = new DirectMessageHandler[numberOfHandlers];
            for (int i = 0; i < numberOfHandlers; i++) {
                handlers[i] = directMessageHandlerProvider.get();
            }
            disruptor.handleEventsWithWorkerPool(handlers);
        }
 
        ringBuffer = disruptor.start();
JournallingMessageHandler 依赖MessageQueueWriter 能力，核心实现是onEvent 方法，调用MessageQueueWriter 的write
同时也会依赖Filter ，进行过滤处理
DirectMessageHandler 依赖ProcessBuffer ，具体处理后边会介绍 ProcessBuffer 也依赖Disruptor 进行处理

RawMessageEvent.FACTORY,

JournallingMessageHandler 依赖MessageQueueWriter 能力，核心实现是onEvent 方法，调用MessageQueueWriter 的write
同时也会依赖Filter ，进行过滤处理
DirectMessageHandler 依赖ProcessBuffer ，具体处理后边会介绍 ProcessBuffer 也依赖Disruptor 进行处理

insert 处理

通过MessageInput 我们可以知道MessageInput核心是依赖的是InputBuffer 的insert 方法，此处依赖了Disruptor
RingBuffer 的publishEvent 方法，具体消息处理就需要依赖上边的MessageHandler 了

说明

graylog 的InputBuffer 比较依赖Disruptor 进行数据处理，毕竟Disruptor 性能是很不错的，好多高性能框架都依赖这个
进行消息处理

参考资料

​​https://github.com/Graylog2/graylog2-server/blob/626be1f0d80506705b5ba41fbea33c2ec0164bc0/graylog2-server/src/main/java/org/graylog2/shared/buffers/JournallingMessageHandler.java​​​
​​​https://github.com/Graylog2/graylog2-server/blob/626be1f0d80506705b5ba41fbea33c2ec0164bc0/graylog2-server/src/main/java/org/graylog2/shared/buffers/InputBufferImpl.java​​​
​​​https://github.com/Graylog2/graylog2-server/blob/626be1f0d80506705b5ba41fbea33c2ec0164bc0/graylog2-server/src/main/java/org/graylog2/shared/buffers/ProcessBuffer.java​​