Start with com.twitter.finagle.
Start with com.twitter.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.
Package exp contains experimental code.
Package exp contains experimental code. This can be removed or stabilized (moved elsewhere) at any time.
This package implements client side load balancing algorithms.
This package implements client side load balancing algorithms.
As an end-user, see the Balancers API to create instances which can be used to configure a Finagle client with various load balancing strategies.
As an implementor, each algorithm gets its own subdirectory and is exposed via the Balancers object. Several convenient traits are provided which factor out common behavior and can be mixed in (i.e. Balancer, DistributorT, NodeT, and Updating).
Defines common com.twitter.finagle.Stack.Param's shared between finagle clients and servers.
Defines common com.twitter.finagle.Stack.Param's shared between finagle clients and servers.
This object contains utility functions for adding and removing weight metadata for com.twitter.finagle.Address.
This object contains utility functions for adding and removing weight metadata for com.twitter.finagle.Address.
These weights are consumed by a com.twitter.finagle.factory.TrafficDistributor.