High Performance RPC with Finagle

@samklr #devoxx #finagle #scala High Performance RPC with Sam BESSALAH
@samklr

@samklr #devoxx #finagle #scala RPC Redux • Control of clients
and servers • Need for predictable performance • Communication between different languages • Isolated computations • Fan out, Fan In distributed systems • ...

@samklr #devoxx #finagle #scala

@samklr #devoxx #finagle #scala Open sourced by Twitter in 2011
to solve this :

@samklr #devoxx #finagle #scala

@samklr #devoxx #finagle #scala Asynchronous Non-Blocking Protocol Agnostic Full Stack
RPC built on top of

@samklr #devoxx #finagle #scala http://monkey.org/~marius/funsrv.pdf

@samklr #devoxx #finagle #scala Load Balancing : Heap Balancer Client
Backoff Strategy BackPressure Failure Detection Failover/Retry Connection Pooling Tracing (via ZipKin) ... Production ready distributed toolbox

@samklr #devoxx #finagle #scala • Box • Foursquare • Nest
• Uber • Pinterest • NY Times • Rdio • PagerDuty • Soundcloud • Strava • StumbleUpon • ... Known Users ...

@samklr #devoxx #finagle #scala @nivdul

@samklr #devoxx #finagle #scala Networking Layer @nivdul

@samklr #devoxx #finagle #scala Building Blocks Futures Services Filters

@samklr #devoxx #finagle #scala Futures • Concurrency primitive in Finagle
• Different from scala.concurrent.Future and java.util.concurrent. Future • Less context-switching, easier cancelability • From com.twitter.util.Future • Composables • Error and Exception Handling

@samklr #devoxx #finagle #scala Futures Combinators • Can be composed
with map, flatMap, handle and rescue • Exception handling via:

@samklr #devoxx #finagle #scala Service

@samklr #devoxx #finagle #scala Services class DummyService extends Service[httpx.Request, httpx.Response]
{ def apply(req: httpx.Request): Future[httpx.Response] = { val response = req.response response.setStatusCode(200) response.setContentTypeJson() response.write(requestHandler(req.getContentString())) Future.value(response) }

@samklr #devoxx #finagle #scala Filters class Filter[-ReqIn, +RepOut, +ReqOut, -RepIn]
extends ((ReqIn, Service[ReqOut, RepIn]) => Future[RepOut]) or type Filter[Req, Rep] = (Req, Service[Req, Rep]) => Future[Rep]

@samklr #devoxx #finagle #scala Filters • Wrap services to modify
inputs or outputs (or both) … • Protocol and Network agnostic • Composable

@samklr #devoxx #finagle #scala Filters val myTimeoutFilter = new TimeoutFilter[String,Int](1.second,DefaultTimer.twitter)

@samklr #devoxx #finagle #scala Filters val myTimeoutFilter = new TimeoutFilter[String,
Int](1.second,DefaultTimer.twitter) val myService = new DummyService

@samklr #devoxx #finagle #scala Filters val myTimeoutFilter = new TimeoutFilter[String,
Int](1.second,DefaultTimer.twitter) val myService = new DummyService val server = myTimeOutFilter andThen myService

@samklr #devoxx #finagle #scala Filters val myTimeoutFilter = new TimeoutFilter[String,Int](
1.second, DefaultTimer.twitter) val myService = new DummyService val service = myService andThen myTimeOutFilter val server = Httpx.serve( “:8080”, service) Await.ready(server)

@samklr #devoxx #finagle #scala Filters Can be used for: •
Retries • Logging • Serialization • Authentication • Retries • Timeouts • ...

@samklr #devoxx #finagle #scala Clients

@samklr #devoxx #finagle #scala Clients Finagle client are just full
stack services val myClient: Service[Request, Response] = Httpx.newService("rtb-bidder.com:8081") val bidder = Httpx.serve(":8080", myClient)

@samklr #devoxx #finagle #scala Finagle in a nutshell

@samklr #devoxx #finagle #scala Protocols • Thrift • Memcache •
Redis • HTTP • SMTP • MySQL • Zookeeper • Mux Protocol.newService( … )

@samklr #devoxx #finagle #scala Finagle Mux • RPC Protocol Multiplexing
• One network connection per client-server session • Maximization of available bandwidth without incurring the cost of opening additional sockets • Elimination of head-of-line blocking • Explicit queue management • Pure session layer (OSI )

@samklr #devoxx #finagle #scala Finagle Serial

@samklr #devoxx #finagle #scala Finagle Serial Use binary format. Scodec,
Protobuf, Thrift, Avro, etc.

@samklr #devoxx #finagle #scala Service discovery • Finagle ServerSets via
”Names” • Uses Zookeeper as Name server val client = Http.newService( “zk!myzkhost.home.com:2181!/my/zk/path” )

@samklr #devoxx #finagle #scala Twitter-Server • Template for servers at
Twitter built on top of Finagle • Flags for configuration • Logging and Metrics • Admin HTTP UI • Lifecycle management endpoints, handy for Docker and/or Mesos • Tracing via ZipKin

@samklr #devoxx #finagle #scala Finagle Java Service<Request, Response> service =
new Service<Request, Response>() { public Future<Response> apply(Request request) { Response response = Response.apply(); response.setContent(ChannelBuffers.wrappedBuffer("yo".getBytes())); Future<Response> future = Future.value(response); return future; }}; ServerBuilder.safeBuild( service, ServerBuilder.get() .codec(Http.get()) .bindTo(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0)) .name("HttpServer")); }

@samklr #devoxx #finagle #scala Finatra • Library to easily build
API Services on top of the Twitter Stack (Finagle, Twitter-Server, Twitter-util, etc.) • Supports Http and Thrift services • Brings Sinatra like Style to Finagle for Rest Services

@samklr #devoxx #finagle #scala Finatra class HelloWorldController extends Controller {
get("/hi") { request: Request => "Hello " + request.params.getOrElse("name", "unnamed") } post("/hi") { hiRequest: HiRequest => "Hello " + hiRequest.name + " with id " + hiRequest.id } }

@samklr #devoxx #finagle #scala Finatra object HelloWorldServerMain extends HelloWorldServer class
HelloWorldServer extends HttpServer { override def modules = Seq(Slf4jBridgeModule) override def configureHttp(router: HttpRouter) { router .filter[LoggingMDCFilter[Request, Response]] .filter[TraceIdMDCFilter[Request, Response]] .filter[CommonFilters] .add[HelloWorldController] } }

@samklr #devoxx #finagle #scala • Thin layer of purely functional
basic blocks, to build composable REST APIs. • Built on top of Finagle • Functional wrapper of Finagle-http • Performance close to Bare Metal Finagle http://github.com/finagle/finch

@samklr #devoxx #finagle #scala Zipkin • Zipkin is a distributed
tracing system that helps us gather timing data for all the disparate services at Twitter. It manages both the collection and lookup of this data through a Collector and a Query service. • Implementation of Google’s Dapper paper • Moved to OpenZipkin

@samklr #devoxx #finagle #scala ZipKin - Open ZipKin

@samklr #devoxx #finagle #scala Finagle : Cons • Stuck to
old versions of Netty. Currently Netty 3 and now moving to 4 • API Changes since 6.x. No more Netty API Leaking through Finagle’s • Mismatch between scala.concurrent.Future and com.twitter.util.Future • Slow to update • Documentation not exhaustive. Thanks for gitter.im and the Mailing List • Can be painful to plug to other Metrics and Monitoring systems. Hopefully it’s changing

@samklr #devoxx #finagle #scala Quick Demo

@samklr #devoxx #finagle #scala Conclusion

High Performance RPC with Finagle

High Performance RPC with Finagle

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