Allow to start a user task once

modules/backend/src/main/scala/docspell/backend/BackendApp.scala

@@ -54,7 +54,7 @@ object BackendApp {
       jobImpl      <- OJob(store, joexImpl)
       itemImpl     <- OItem(store)
       mailImpl     <- OMail(store, JavaMailEmil(blocker))
-      userTaskImpl <- OUserTask(utStore, joexImpl)
+      userTaskImpl <- OUserTask(utStore, queue, joexImpl)
     } yield new BackendApp[F] {
       val login: Login[F]            = loginImpl
       val signup: OSignup[F]         = signupImpl

modules/backend/src/main/scala/docspell/backend/ops/OUserTask.scala

@@ -2,26 +2,54 @@ package docspell.backend.ops
 
 import cats.implicits._
 import cats.effect._
+import com.github.eikek.calev.CalEvent
+import io.circe.Encoder
+import docspell.store.queue.JobQueue
 import docspell.store.usertask._
 import docspell.common._
-import com.github.eikek.calev.CalEvent
 
 trait OUserTask[F[_]] {
 
+  /** Return the settings for the notify-due-items task of the current
+    * user. There is at most one such task per user.
+    */
   def getNotifyDueItems(account: AccountId): F[UserTask[NotifyDueItemsArgs]]
 
+  /** Updates the notify-due-items tasks and notifies the joex nodes.
+    */
   def submitNotifyDueItems(
       account: AccountId,
       task: UserTask[NotifyDueItemsArgs]
   ): F[Unit]
 
+  /** Discards the schedule and immediately submits the task to the job
+    * executor's queue. It will not update the corresponding periodic
+    * task.
+    */
+  def executeNow[A](account: AccountId, task: UserTask[A])(
+      implicit E: Encoder[A]
+  ): F[Unit]
 }
 
 object OUserTask {
 
-  def apply[F[_]: Effect](store: UserTaskStore[F], joex: OJoex[F]): Resource[F, OUserTask[F]] =
+  def apply[F[_]: Effect](
+      store: UserTaskStore[F],
+      queue: JobQueue[F],
+      joex: OJoex[F]
+  ): Resource[F, OUserTask[F]] =
     Resource.pure[F, OUserTask[F]](new OUserTask[F] {
 
+      def executeNow[A](account: AccountId, task: UserTask[A])(
+          implicit E: Encoder[A]
+      ): F[Unit] =
+        for {
+          ptask <- task.encode.toPeriodicTask(account)
+          job <- ptask.toJob
+          _ <- queue.insert(job)
+          _ <- joex.notifyAllNodes
+        } yield ()
+
       def getNotifyDueItems(account: AccountId): F[UserTask[NotifyDueItemsArgs]] =
         store
           .getOneByName[NotifyDueItemsArgs](account, NotifyDueItemsArgs.taskName)