Netty at Twitter with Finagle

@TwitterAds | Conﬁdential Evan Meagher (@evanm) 7/28/14 Netty at Twitter
with Finagle

@Twitter 2 Agenda Why and what is Finagle? What does
it do? What are we working on now?

@Twitter 3 What is Finagle?

@Twitter 4 An open source, protocol-agnostic, asynchronous RPC library for
the JVM

@Twitter 5 Why did we build Finagle?

@Twitter 6 In the beginning…

@Twitter 7 Monolithic Rails app MySQL

@Twitter 8 Monolithic Rails app MySQL Monolithic Rails app MySQL
Monolithic Rails app MySQL … Monolithic Rails app MySQL … …

@Twitter 9

@Twitter 10

@Twitter 11 What is Finagle?

the JVM

@Twitter 17 What does Finagle do?

@Twitter 18 Standardizes the edges in a “boxes and arrows”
network diagram

@Twitter 19 [1] http://monkey.org/~marius/funsrv.pdf

@Twitter 20 type Service[Req, Rep] = Req => Future[Rep]

@Twitter 21 type Service[Req, Rep] = Req => Future[Rep] Server
Client Req Future[Rep]

@Twitter 22 A contrived example

@Twitter 23 val server = new Service[HttpReq, HttpRep] { def
apply(req: HttpReq): Future[HttpRep] = Future.value(HttpRep(Status.OK, req.body)) } ! Http.serve(":80", server)

@Twitter 24 val client: Service[HttpReq, HttpRep] = Http.newService(“twitter.com:80") ! val
futureResponse: Future[HttpRep] = client(HttpReq(“/")) ! futureResponse map { response => println(response) }

@Twitter 25 Now let’s say you need to authenticate requests

@Twitter 26 type Service[Req, Rep] = Req => Future[Rep] !
type Filter[Req, Rep] = (Req, Service[Req, Rep]) => Future[Rep]

@Twitter 27 type Service[Req, Rep] = Req => Future[Rep] !
type Filter[Req, Rep] = (Req, Service[Req, Rep]) => Future[Rep] Filter Filter Server Client

@Twitter 28 def isAuthed(req: Req): Boolean val authFilter: Filter[HttpReq, HttpRes]
= { (req, svc) => if (isAuthed(req)) svc(req) else Future.exception(new AccessDenied) } ! val authedServer: Service[HttpReq, HttpRes] = authFilter andThen server

@Twitter 29 val instrumentedServer = authFilter andThen traceRequest andThen recordStats
andThen server

@Twitter 30 What are we working on now?

@Twitter 31 Service discovery See the “Names” page on the
Finagle user guide: http://twitter.github.io/ﬁnagle/guide/Names.html ! val client = Http.newService( “zk!myzkhost.mycompany.com:2181!/my/zk/path” )

@Twitter 32 Load balancing

@Twitter 33 Request multiplexing See the “Protocols” page on the
Finagle user guide: http://twitter.github.io/ﬁnagle/guide/Protocols.html

@Twitter 34 Tail-latency optimization

@TwitterAds | Confidential Thanks! github.com/twitter/finagle @finagle @evanm

Netty at Twitter with Finagle

Netty at Twitter with Finagle

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