quasar.server.control.scala Maven / Gradle / Ivy
/*
* Copyright 2014–2017 SlamData Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package quasar.server
import slamdata.Predef.{ -> => _, _ }
import org.http4s.dsl._
import org.http4s.HttpService
import scalaz._, Scalaz._
import scalaz.concurrent.Task
object control {
/** A service that exposes the ability to change the port the server is listens on.
* @param defaultPort The default port for this server. Will restart the server on this port
* if the `DELETE` http method is used.
* @param restart A function that will restart the server on the specified port
*/
def service(defaultPort: Int, restart: Int => Task[String \/ Unit]): HttpService = {
def safeRestart(port: Int, default: Boolean, currentPort: Int) =
if (currentPort ≟ port)
Ok(s"Server is already running on port $port")
else
Http4sUtils.unavailableReason(port).run.flatMap { possibleReason =>
possibleReason map { reason =>
PreconditionFailed(s"Could not restart on new port because $reason")
} getOrElse {
val defaultString = if(default) " default " else ""
restart(port).flatMap {
case -\/(reason) => BadRequest(s"Cannot restart server on port $port because $reason")
case _ => Accepted(s"Restarting on $defaultString port $port")
} handleWith {
case e: Exception => InternalServerError(s"Failed to restart on port $port because ${e.getMessage}")
case _ => InternalServerError(s"Failed to restart on port $port for unknown reason")
}
}
}
HttpService {
case req @ PUT -> Root =>
req.as[String].flatMap(body =>
body.parseInt.fold(
e => BadRequest(e.getMessage),
portNum => safeRestart(portNum, default = false, req.serverPort)))
case req @ DELETE -> Root =>
safeRestart(defaultPort, default = true, req.serverPort)
}
}
}