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High Performance RPC with Finagle

Sam Bessalah
November 10, 2015

High Performance RPC with Finagle

Devoxx Belgium Antwerp 2015

Sam Bessalah

November 10, 2015

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  1. @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 • ...
  2. @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
  3. @samklr #devoxx #finagle #scala • Box • Foursquare • Nest

    • Uber • Pinterest • NY Times • Rdio • PagerDuty • Soundcloud • Strava • StumbleUpon • ... Known Users ...
  4. @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
  5. @samklr #devoxx #finagle #scala Futures Combinators • Can be composed

    with map, flatMap, handle and rescue • Exception handling via:
  6. @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) }
  7. @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]
  8. @samklr #devoxx #finagle #scala Filters • Wrap services to modify

    inputs or outputs (or both) … • Protocol and Network agnostic • Composable
  9. @samklr #devoxx #finagle #scala Filters val myTimeoutFilter = new TimeoutFilter[String,

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

    Int](1.second,DefaultTimer.twitter) val myService = new DummyService val server = myTimeOutFilter andThen myService
  11. @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)
  12. @samklr #devoxx #finagle #scala Filters Can be used for: •

    Retries • Logging • Serialization • Authentication • Retries • Timeouts • ...
  13. @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)
  14. @samklr #devoxx #finagle #scala Protocols • Thrift • Memcache •

    Redis • HTTP • SMTP • MySQL • Zookeeper • Mux Protocol.newService( … )
  15. @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 )
  16. @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” )
  17. @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
  18. @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")); }
  19. @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
  20. @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 } }
  21. @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] } }
  22. @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
  23. @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
  24. @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