Add ability for bot to stop outdated jobs

Author: felixmulder

bot/src/dotty/tools/bot/PullRequestService.scala

@@ -19,6 +19,7 @@ import org.http4s.dsl._
 import org.http4s.util._
 
 import model.Github._
+import model.Drone
 import bot.util.TaskIsApplicative._
 import bot.util.HttpClientAux._
 
@@ -279,6 +280,19 @@ trait PullRequestService {
   private def extractCommitSha(status: StatusResponse): Task[String] =
     Task.delay(status.sha)
 
+  def cancelBuilds(commits: List[Commit])(implicit client: Client): Task[Boolean] =
+    Task.gatherUnordered {
+      val droneContext = "continuous-integration/drone/pr"
+      commits.map { commit =>
+        for {
+          statuses    <- getStatus(commit, client)
+          cancellable =  statuses.filter(status => status.state == "pending" && status.context == droneContext)
+          runningJobs =  cancellable.map(_.target_url.split('/').last.toInt)
+          cancelled   <- Task.gatherUnordered(runningJobs.map(Drone.stopBuild(_, droneToken)))
+        } yield cancelled.foldLeft(true)(_ == _)
+      }
+    }
+    .map(xs => xs.foldLeft(true)(_ == _))
 
   def checkSynchronize(issue: Issue): Task[Response] = {
     val httpClient = PooledHttp1Client()
@@ -288,7 +302,7 @@ trait PullRequestService {
       statuses <- checkCLA(commits, httpClient)
       invalid  =  statuses.filterNot(_.isValid)
       _        <- sendStatuses(invalid, httpClient)
-      _        <- cancelBuilds(commits.dropRight(1), httpClient)
+      _        <- cancelBuilds(commits.dropRight(1))(httpClient)
 
       // Set final commit status based on `invalid`:
       _ <- {

bot/src/dotty/tools/bot/model/Drone.scala

@@ -0,0 +1,49 @@
+package dotty.tools
+package bot
+package model
+
+import io.circe._
+import io.circe.generic.auto._
+import io.circe.syntax._
+
+import org.http4s._
+import org.http4s.circe._
+import org.http4s.client.Client
+
+import scalaz.concurrent.Task
+import bot.util.HttpClientAux
+
+object Drone {
+  import HttpClientAux._
+
+  case class Build(
+    number: Int,
+    event: String,
+    status: String,
+    commit: String,
+    author: String
+  )
+
+  private[this] val baseUrl = "http://dotty-ci.epfl.ch/api"
+
+  private def job(id: Int) =
+    s"$baseUrl/repos/lampepfl/dotty/builds/$id"
+
+  private def job(id: Int, subId: Int) =
+    s"$baseUrl/repos/lampepfl/dotty/builds/$id/$subId"
+
+  def stopBuild(id: Int, token: String)(implicit client: Client): Task[Boolean] = {
+    def resToBoolean(res: Response): Task[Boolean] = Task.now {
+      res.status.code >= 200 && res.status.code < 400
+    }
+
+    val responses = List(1, 2, 3, 4).map { subId =>
+      client.fetch(delete(job(id, subId)).withOauth2(token))(resToBoolean)
+    }
+
+    Task.gatherUnordered(responses).map(xs => xs.exists(_ == true))
+  }
+
+  def startBuild(id: Int, token: String)(implicit client: Client): Task[Build] =
+    client.expect(post(job(id)).withOauth2(token))(jsonOf[Build])
+}

bot/src/dotty/tools/bot/model/Github.scala

@@ -30,7 +30,13 @@ object Github {
     context: String = "CLA"
   )
 
-  case class StatusResponse(url: String, id: Long, state: String) {
+  case class StatusResponse(
+    url: String,
+    id: Long,
+    state: String,
+    context: String,
+    target_url: String
+  ) {
     def sha: String = url.split('/').last
   }
 

bot/test/PRServiceTests.scala

@@ -9,6 +9,7 @@ import io.circe.syntax._
 import io.circe.parser.decode
 
 import model.Github._
+import model.Drone
 import org.http4s.client.blaze._
 import org.http4s.client.Client
 import scalaz.concurrent.Task
@@ -116,4 +117,11 @@ class PRServiceTests extends PullRequestService {
       s"Body of review was not as expected:\n${res.body}"
     )
   }
+
+  @Test def canStartAndStopBuild = {
+    val build = withClient(implicit client => Drone.startBuild(1921, droneToken))
+    assert(build.status == "pending" || build.status == "building")
+    val killed = withClient(implicit client => Drone.stopBuild(1921, droneToken))
+    assert(killed, "Couldn't kill build")
+  }
 }