Package org.logstash.beats

Class ConnectionHandler

  • All Implemented Interfaces:
    io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler, io.netty.channel.ChannelOutboundHandler
    public class ConnectionHandler
extends io.netty.channel.ChannelDuplexHandler
    Manages the connection state to the beats client.

    • Nested Class Summary

      • Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

        io.netty.channel.ChannelHandler.Sharable

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void channelActive​(io.netty.channel.ChannelHandlerContext ctx)  
      void channelRead​(io.netty.channel.ChannelHandlerContext ctx, Object msg)
      Sets the flag that the keep alive should be sent.
      boolean sendKeepAlive​(io.netty.channel.ChannelHandlerContext ctx)
      Determine if this channel has finished processing it's payload.
      void userEventTriggered​(io.netty.channel.ChannelHandlerContext ctx, Object evt)

      • Methods inherited from class io.netty.channel.ChannelDuplexHandler

        bind, close, connect, deregister, disconnect, flush, read, write

      • Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

        channelInactive, channelReadComplete, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught

      • Methods inherited from class io.netty.channel.ChannelHandlerAdapter

        ensureNotSharable, handlerAdded, handlerRemoved, isSharable

      • Methods inherited from interface io.netty.channel.ChannelHandler

        handlerAdded, handlerRemoved

    • Field Detail

      • CHANNEL_SEND_KEEP_ALIVE

        public static final io.netty.util.AttributeKey<AtomicBoolean> CHANNEL_SEND_KEEP_ALIVE

    • Constructor Detail

      • ConnectionHandler

        public ConnectionHandler()

    • Method Detail

      • channelActive

        public void channelActive​(io.netty.channel.ChannelHandlerContext ctx)
                   throws Exception
        Specified by:
        channelActive in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelActive in class io.netty.channel.ChannelInboundHandlerAdapter
        Throws:
        Exception

      • channelRead

        public void channelRead​(io.netty.channel.ChannelHandlerContext ctx,
                        Object msg)
                 throws Exception
        Sets the flag that the keep alive should be sent. BeatsHandler will un-set it. It is important that this handler comes before the BeatsHandler in the channel pipeline. Note - For large payloads, this method may be called many times more often then the BeatsHandler#channelRead due to decoder aggregating the payload.
        Specified by:
        channelRead in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        channelRead in class io.netty.channel.ChannelInboundHandlerAdapter
        Throws:
        Exception

      • userEventTriggered

        public void userEventTriggered​(io.netty.channel.ChannelHandlerContext ctx,
                               Object evt)
                        throws Exception

        IdleState.WRITER_IDLE
        If no response has been issued after the configured write idle timeout via IdleStateHandler, then start to issue a TCP keep alive. This can happen when the pipeline is blocked. Pending (blocked) batches are in either in the EventLoop attempting to write to the queue, or may be in a taskPending queue waiting for the EventLoop to unblock. This keep alive holds open the TCP connection from the Beats client so that it will not timeout and retry which could result in duplicates.

        IdleState.ALL_IDLE
        If no read or write has been issued after the configured all idle timeout via IdleStateHandler, then close the connection. This is really only happens for beats that are sending sparse amounts of data, and helps to the keep the number of concurrent connections in check. Note that ChannelOption.SO_LINGER = 0 needs to be set to ensure we clean up quickly. Also note that the above keep alive counts as a not-idle, and thus the keep alive will prevent this logic from closing the connection. For this reason, we stop sending keep alives when there are no more pending batches to allow this idle close timer to take effect.

        Specified by:
        userEventTriggered in interface io.netty.channel.ChannelInboundHandler
        Overrides:
        userEventTriggered in class io.netty.channel.ChannelInboundHandlerAdapter
        Throws:
        Exception

      • sendKeepAlive

        public boolean sendKeepAlive​(io.netty.channel.ChannelHandlerContext ctx)
        Determine if this channel has finished processing it's payload. If it has not, send a TCP keep alive. Note - for this to work, the following must be true:
        • This Handler comes before the BeatsHandler in the channel's pipeline
        • This Handler is associated to an EventLoopGroup that has guarantees that the associated EventLoop will never block.
        • The BeatsHandler un-sets only after it has processed this channel's payload.
        Parameters:
        ctx - the ChannelHandlerContext used to curry the flag.
        Returns:
        Returns true if this channel/connection has NOT finished processing it's payload. False otherwise.