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commit a96fbeae96f3456a525b327dcfc006e3671dfc99
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Tue Apr 29 20:18:32 2025 +0100
Start to re-do the sequence diagrams for request processing
NIOEndpoint to Processor
---
webapps/docs/architecture/requestProcess.xml | 51 +++++++++--
.../architecture/requestProcess/1_nio.plantuml | 93 +++++++++++++++++++++
webapps/docs/architecture/requestProcess/1_nio.png | Bin 0 -> 105158 bytes
3 files changed, 136 insertions(+), 8 deletions(-)
diff --git a/webapps/docs/architecture/requestProcess.xml
b/webapps/docs/architecture/requestProcess.xml
index 1d8adbceb3..97ec32d73f 100644
--- a/webapps/docs/architecture/requestProcess.xml
+++ b/webapps/docs/architecture/requestProcess.xml
@@ -29,21 +29,56 @@
<body>
+<section name="Introduction">
+<p>
+This page describes how requests flow through Tomcat during processing.
Requests
+start processing in an endpoint, then get passed to the protocol and then the
+Coyote adapter which is the common entry point for all servlet request
+processing.
+</p>
+</section>
-<section name="Request Process Flow">
+<section name="Endpoint implementations">
+<p>
+UML diagrams have been created for each Endpoint implementation to show how
+requests flow from the endpoint to the protocol.
+</p>
+<p>
+<a href="requestProcess/1_nio.png">Diagram 1</a> shows how requests received
via
+an NIO based endpoint are processed upto the point they reach the processor
+instance.
+</p>
+<p>
+NIO2 - TBD.
+</p>
+</section>
+<section name="Protocols">
+<p>
+UML diagrams have been created for each protocol to show how requests flow from
+the processor instance to the CoyoteAdapter.
+</p>
+<p>
+HTTP/1.1 TBD.
+</p>
<p>
-This page describes the process used by Tomcat to handle
-an incoming request. This process is largely defined by
-the Servlet Specification, which outlines the order
-of events that must take place.
+HTTP/2 - TBD.
</p>
+<p>
+AJP - TBD.
+</p>
+</section>
-<subsection name="description">
+<section name="Servlet engine">
<p>
-TODO
+Synchronous - TBD
</p>
-</subsection>
+<p>
+Asynchronous - TBD.
+</p>
+</section>
+
+<section name="Legacy information">
<subsection name="diagrams">
<p>
diff --git a/webapps/docs/architecture/requestProcess/1_nio.plantuml
b/webapps/docs/architecture/requestProcess/1_nio.plantuml
new file mode 100644
index 0000000000..03608a5737
--- /dev/null
+++ b/webapps/docs/architecture/requestProcess/1_nio.plantuml
@@ -0,0 +1,93 @@
+@startuml
+
+' 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.
+
+hide footbox
+skinparam style strictuml
+
+activate Acceptor
+participant NioEndpoint
+participant ServerSocket
+participant SocketChannel
+activate Poller
+participant Selector
+participant Executor
+activate Worker
+
+group Acceptor Loop
+Acceptor -> NioEndpoint ++: serverSocketAccept()
+NioEndpoint -> ServerSocket ++: accept()
+note right of ServerSocket
+ This is where Tomcat
+ waits for incoming
+ connections
+end note
+ServerSocket -->> SocketChannel **:
+return
+return
+
+Acceptor -> NioEndpoint ++: setSocketOptions()
+NioEndpoint -> Poller ++: register()
+return
+return
+end
+
+group Poller Loop (simplified)
+Poller -> Poller ++: events()
+Poller -> SocketChannel ++: register(OP_READ)
+return
+return
+
+Poller -> Selector ++: select()
+return
+
+Poller -> Poller ++: processKey()
+Poller -> NioEndpoint ++: processSocket()
+NioEndpoint -> NioEndpoint ++: createSocketProcessor()
+NioEndpoint -->> SocketProcessor **:
+NioEndpoint -> Executor ++: execute()
+Executor -> Worker ++: run()
+return
+return
+return
+return
+return
+end
+
+Worker -> SocketProcessor ++: run()
+SocketProcessor -> SocketChannel ++: handshake()
+note right of SocketChannel
+ TLS handshake
+end note
+return
+SocketProcessor -> ConnectionHandler ++: process()
+ConnectionHandler -> Protocol ++: createProcessor()
+Protocol -->> Processor **:
+return
+ConnectionHandler -> Processor ++: process()
+Processor -> Processor ++: service()
+note right of Processor
+ More detail of this
+ processing in the
+ protocol specific
+ diagrams
+end note
+return
+return
+return
+return
+
+@enduml
\ No newline at end of file
diff --git a/webapps/docs/architecture/requestProcess/1_nio.png
b/webapps/docs/architecture/requestProcess/1_nio.png
new file mode 100644
index 0000000000..32cf126b80
Binary files /dev/null and b/webapps/docs/architecture/requestProcess/1_nio.png
differ
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