package exp
Package Members
- package partitioning
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.
Please use the new interface, com.twitter.finagle.Thrift, for constructing Thrift clients and servers.
Please use the new interface, com.twitter.finagle.Thrift, for constructing Thrift clients and servers.
We provide client and server protocol support for the framed protocol. The public implementations are defined on the Thrift object:
The type of the server codec is Service[Array[Byte], Array[Byte]]
and the client codecs are Service[ThriftClientRequest,
Array[Byte]]
. The service provided is that of a "transport" of
thrift messages (requests and replies) according to the protocol
chosen. This is why the client codecs need to have access to a
thrift ProtocolFactory
.
These transports are used by the services produced by the finagle thrift codegenerator.
val service: Service[ThriftClientRequest, Array[Byte]] = ClientBuilder() .hosts("foobar.com:123") .stack(Thrift.client) .build() // Wrap the raw Thrift transport in a Client decorator. The client // provides a convenient procedural interface for accessing the Thrift // server. val client = new Hello.ServiceToClient(service, protocolFactory)
In this example, Hello
is the thrift interface, and the inner
class ServiceToClient
is provided by the finagle thrift code
generator.