1. Zuul1

总体架构：

1.png

Zuul Servlet源码：

2.png
调用流程：
3.png
4.png

2.Zuul2

总体架构：

5.png

调用流程：

10.png
refer link: zuul-2-the-netflix-journey-to-asynchronous-non-blocking-systems

时序图：
以下是 zuul inbound 和 zuul outbound 中任意filter needsBodyBuffered方法 return true时的时序图
图片过大，点击原图查看

zuul2.png
zuul inbound 和 outbound 中所有filter needsBodyBuffered方法 return false时
接收请求：
ProxyEndpoint writeClientRequestToOrigin方法在netty lister成功时被调用（这时zuulRequest，bodyChunks有值）或先被调用（这时zuulRequest，bodyChunks为空），
ZuulFilterChainHandler channelRead方法循环读 HttpContent，
ZuulFilterChainRunner filter方法里 limit >= filters.length invokeNextStage(inMesg, chunk)，
ZuulEndPointRunner filter(zuulReq, chunk)方法里 endpoint.processContentChunk(zuulReq, chunk) 用originConn的channel（netty client）写HttpContent，zuulReq.bufferBodyContents(newChunk)里缓存 HttpContent
origin发送：
ClientResponseWriter chnnelRead方法里，先发送 zuulResponse，再循环写 HttpContent

源码：
Netty Server:

6.png

Http handler &Zuul pipeline:

7.png

GATEWAY SERVER PIPELINE:

0 = "IdleStateHandler#0"
1 = "CloseOnIdleStateHandler#0"
2 = "SourceAddressChannelHandler#0"
3 = "channelMetrics"
4 = "PerEventLoopMetricsChannelHandler$Connections#0"
5 = "ElbProxyProtocolChannelHandler"
6 = "MaxInboundConnectionsHandler#0"
7 = "codec"
8 = "Http1ConnectionCloseHandler#0"
9 = "conn_expiry_handler"
10 = "PassportStateHttpServerHandler#0"
11 = "http_request_read_timeout_handler"
12 = "HttpServerLifecycleChannelHandler#0"
13 = "ClientResponseHttpContentLimitHandler#0"
14 = "HttpBodySizeRecordingChannelHandler#0"
15 = "HttpMetricsChannelHandler#0"
16 = "PerEventLoopMetricsChannelHandler$HttpRequests#0"
17 = "AccessLogChannelHandler#0"
18 = "ServerStatusHeaderHandler#0"
19 = "StripUntrustedProxyHeadersHandler#0"
20 = "logger"
21 = "ClientRequestReceiver#0"
22 = "ClientRequestHttpContentLimitHandler#0"
23 = "ZuulFilterChainHandler#0"
24 = "ClientResponseWriter#0"
25 = "DefaultChannelPipeline$TailContext#0"

Netty Client:

8.png
9.png

GATEWAY CLIENT PIPELINE:

0 = "PassportStateOriginHandler#0"
1 = "codec"
2 = "PassportStateHttpClientHandler"
3 = "readTimeoutHandler"
4 = "originNettyLogger"
5 = "HttpMetricsChannelHandler#0"
6 = "httpLifecycle"
7 = "ClientTimeoutHandler#0"
8 = "_origin_response_receiver"
9 = "connectionPoolHandler"
10 = "DefaultChannelPipeline$TailContext#0"