twitter

Value Members

1. 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 org.jboss.netty.handler.codec.http.{
     HttpRequest, HttpResponse, DefaultHttpResponse}
   import org.jboss.netty.handler.codec.http.HttpVersion._
   import org.jboss.netty.handler.codec.http.HttpResponseStatus._
   import com.twitter.util.{Future, Await}
   
   val service = new Service[HttpRequest, HttpResponse] {
     def apply(req: HttpRequest) =
       Future.value(new DefaultHttpResponse(HTTP_1_1, OK))
   }
   val server = Http.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 org.jboss.netty.handler.codec.http.{
     HttpRequest, HttpResponse, DefaultHttpRequest}
   import org.jboss.netty.handler.codec.http.HttpVersion._
   import org.jboss.netty.handler.codec.http.HttpMethod._
   import com.twitter.util.{Future, Return, Throw}
   
   val client: Service[HttpRequest, HttpResponse] =
     Http.newService("localhost:8080")
   val f: Future[HttpResponse] =
     client(new DefaultHttpRequest(HTTP_1_1, GET, "/"))
   f respond {
     case Return(res) =>
       printf("Got HTTP response %s\n", res)
     case Throw(exc) =>
       printf("Got error %s\n", exc)
   }

   Http.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.