Netty - Network - Application development the easy way

Network - Application development the easy way
@netty_project
http://netty.io
https://github.com/netty/netty

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NORMAN MAURER
Red Hat (JBoss) - EAP Core Team
Former contractor for Apple Inc
Author - Netty in Action
Apache Software Foundation Member
Netty / Vert.x Core-Developer and all things NIO
Java and Scala
Twitter: @normanmaurer
Github: https://github.com/normanmaurer

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WHAT IS NETTY ?
“Netty is a NIO client server framework which
enable quick and easy development of
network applications such as protocol servers
and clients...”

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YET ANOTHER NETWORK FRAMEWORK ?
YES!

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“ @!# WTF, WHY SHOULD I CARE
? ”

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FEATURES

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FEATURES
Asynchronous
Simple and unified API
High-Performing
Listeners and Callbacks supported
Zero-file-copy
Buffer Pooling
Gathering / Scattering
... and many more

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ASYNCHRONOUS, WHAT DOES THIS MEAN ?

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ASYNCHRONOUS...
All I/O Operations don't block!
Get notified once the operation completes
Be able to share one Thread across many connections

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“But synchronous / blocking IO served me
well! Again, why should I care ?”

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BLOCKING-IO MAY NOT SCALE!
GOOD LUCK WITH SERVING 1 MILLION CONCURRENT
CONNECTIONS
“ Usually a Thread takes memory from
256kb to 1mb for the stack space! ”

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NETTY TO THE RESCUE
“Ouch....”

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ASYNCHRONOUS IN ACTION
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TRANSPORTS
NIO
OIO
AIO
Local
Embedded
“And more to come ....”

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SUPPORTED PROTOCOLS
TCP
UDP
SCTP*
UDT
Serial
* O
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d o
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x

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SIMPLE STATE MODEL

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STATE FLOW

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DATA CONTAINERS
ByteBuf
MessageBuf
“ByteBuffer on steroids!”
“Queue like thing which can hold Message of
type T”

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BYTEBUF
Separate index for reader/writer
CompositeByteBuf
Direct and Heap implementations
Resizable with max capacity
Support for reference-counting
Method-Chaining
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MESSAGEBUF
Extend Queue
Support reference-counting
Type-safe!

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CHANNELHANDLER
“Time to process some data, heh ?”

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CHANNELHANDLER
“Your business logic needs a place, and this is
where it belongs too”

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CHANNELHANDLER FACTS
Inbound vs. Outbound
State vs. Operation
Byte or Message based
Always called by the assigned EventExecutor
Type-safe

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EXAMPLE USE CASES
Convert data a.k.a Encoder / Decoder
Business-Logic
Handle state changes

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PROVIDED CODECS
“We have a lot of them!”

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PROVIDED CODECS
HTTP
Websockets
SPDY
Serialization
JBoss Marshalling
Protobufs
SSL
Zlib

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ADAPTERS
ChannelInboundMessageHandlerAdapter
ChannelInboundByteHandlerAdapter
ChannelOutboundMessageHandlerAdapter
ChannelOutboundByteHandlerAdapter
“Makes your life easier”

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ADAPTER IN ACTION
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DECODER
ByteToByteDecoder
ByteToMessageDecoder
MessageToMessageDecoder

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ENCODER
ByteToByteEncoder
MessageToByteEncoder
MessageToMessageEncoder

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HYBRIDS
ByteToByteCodec
ByteToMessageCodec
MessageToMessageCodec

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OTHER OFTEN USEFUL DECODERS
ReplayDecoder
FixedLengthFrameDecoder
LengthFieldBasedFrameDecoder
LineBasedFrameDecoder
DelimiterBasedFrameDecoder

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WATCH OUT!
Repeat with me:
“I promise to never block the IO-Thread!”

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You
“Uhm well.... but my ChannelHandler needs to
block. I'm screwed now ?”

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“Hold on.... Netty is here for the rescue!”

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CHANNELPIPELINE
The home for all your ChannelHandlers

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CHANNELPIPELINE
Holds the ChannelHandlers for a Channel
All events will get passed through it
On the fly modification
One-to-one relation between Channel and ChannelPipeline

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CHANNELPIPELINE
Kind of a unix-pipe-like thing...
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“You see, everything is adjustable!”

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“But my ChannelHandler still block!”
“ Ah yes, I forgot... ”

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ADDING CHANNELHANDLERS
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EVENT-LOOP
Someone needs to do the heavy work!

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EVENT-LOOP
One-to-Many relation between EventLoop and Channel
Process "events" and hand over work to the
ChannelPipeline

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All the submitted Tasks will get executed in
the IO-Thread!
“ Yay, no need to worry about
synchronization! ”

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EVENTLOOP HIERARCHY
“All the ScheduleExecutorService goodies for
free!”

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EVENTLOOP - HOW DOES IT WORK

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RUN A TASK IN THE EVENTLOOP
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BOOTSTRAP YOUR APPLICATION
“It's time to accept some real traffic”

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BOOTSTRAP
Fluent-API a.k.a DSL
Graceful shutdown
Lightweight

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BOOTSTRAP A SERVER
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BOOTSTRAP A CLIENT
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GENERAL
ASL2 license
Hosted at Github
Community-driven

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COMPANIES
Red Hat
Twitter
Facebook
Boundary
Typesafe
“And many more... ”

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OPENSOURCE PROJECTS
HornetQ
Infinispan
Vert.x
Play Framework
Finangle
Cassandra
“And again many more....”

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THINGS TO COME
Chained ChannelPipelines
Native edge-triggered Transport*
Lambda support

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OTHER NIO FRAMEWORKS
Apache MINA
Grizzly
HawtDispatch*
JBoss XNIO*

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GET INVOLVED
Mailinglist
https://groups.google.com/forum/#!forum/netty
IRC
#netty irc.freenode.org
Website
http://netty.io
GitHub
https://github.com/netty/netty/

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TOO LOW LEVEL ?
“You may like Vert.x which is based on Netty
and also polyglot!”

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NOT ENOUGH INFO?
http://www.manning.com/maurer/
“You may want to buy my book...”

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“Questions please!”

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THANKS!

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Netty - Network - Application development the easy way

Netty - Network - Application development the easy way

Norman Maurer

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