Packages

•  package root

  Definition Classes

  root

•  package com

  Definition Classes

  root

•  package twitter

  Start with com.twitter.finagle.

  Start with com.twitter.finagle.

  Definition Classes

  com

•  package finagle

  Finagle is an extensible RPC system.

  Finagle is an extensible RPC system.

  Services are represented by class com.twitter.finagle.Service. Clients make use of com.twitter.finagle.Service objects while servers implement them.

  Finagle contains a number of protocol implementations; each of these implement Client and/or com.twitter.finagle.Server. For example, Finagle's HTTP implementation, com.twitter.finagle.Http (in package finagle-http), exposes both.

  Thus a simple HTTP server is built like this:

  import com.twitter.finagle.{Http, Service}
  import com.twitter.finagle.http.{Request, Response}
  import com.twitter.util.{Await, Future}
  
  val service = new Service[Request, Response] {
    def apply(req: Request): Future[Response] =
      Future.value(Response())
  }
  val server = Http.server.serve(":8080", service)
  Await.ready(server)

  We first define a service to which requests are dispatched. In this case, the service returns immediately with a HTTP 200 OK response, and with no content.

  This service is then served via the Http protocol on TCP port 8080. Finally we wait for the server to stop serving.

  We can now query our web server:

  % curl -D - localhost:8080
  HTTP/1.1 200 OK

  Building an HTTP client is also simple. (Note that type annotations are added for illustration.)

  import com.twitter.finagle.{Http, Service}
  import com.twitter.finagle.http.{Request, Response}
  import com.twitter.util.{Future, Return, Throw}
  
  val client: Service[Request, Response] = Http.client.newService("localhost:8080")
  val f: Future[Response] = client(Request()).respond {
    case Return(rep) =>
      printf("Got HTTP response %s\n", rep)
    case Throw(exc) =>
      printf("Got error %s\n", exc)
  }

  Http.client.newService("localhost:8080") constructs a new com.twitter.finagle.Service instance connected to localhost TCP port 8080. We then issue a HTTP/1.1 GET request to URI "/". The service returns a com.twitter.util.Future representing the result of the operation. We listen to this future, printing an appropriate message when the response arrives.

  The Finagle homepage contains useful documentation and resources for using Finagle.

  Definition Classes

  twitter

•  package tracing

  Definition Classes

  finagle

•  package opencensus

  Definition Classes

  tracing

•  object TracingOps

  Scala syntax extensions for OpenCensus tracing.

  Scala syntax extensions for OpenCensus tracing.

  Definition Classes

  opencensus

  Example:

  1. import com.twitter.finagle.tracing.opencensus.TracingOps._
     import io.opencensus.trace._
     
     // run with this Span in the current context and ends
     // it when the returned Future is satisfied
     val span: Span = ???
     span.scopedToFuture {
       // code that returns a com.twitter.util.Future
     }
     
     // run with this Span in the current context and ends
     // it when the block of code completes
     val span: Span = ???
     span.scopedAndEnd {
       // code
     }
     
     // run the given code in a newly scoped Span
     val spanBuilder: SpanBuilder = ???
     spanBuilder.runInScope {
       // code
     }

• RichSpan
• RichSpanBuilder

com.twitter.finagle.tracing.opencensus.TracingOps

RichSpan