[core] time shift and control #789

fwbrasil · 2024-10-29T02:22:35Z

This PR uses the new Schedule in kyo-data to reimplement timers in kyo-core. The new design provides two mechanisms to control time: Clock.withTimeShift speeds up or slows down the time for a computation based on a factor and Clock.withTimeControl provides an API for users to manually set the time. Both methods not only affect Clock.now but also scheduled operations in Timer and Async.sleep calls.

fwbrasil · 2024-10-29T02:24:15Z

kyo-core/shared/src/main/scala/kyo/Clock.scala

-                def now()(using AllowUnsafe): Instant = Instant.fromJava(java.time.Instant.now())
+                val executor                 = Executors.newScheduledThreadPool(2, Threads("kyo-core-clock-executor"))
+                def now()(using AllowUnsafe) = Instant.fromJava(java.time.Instant.now())
+                def sleep(duration: Duration) =


I had to move the management of timed tasks to Clock so it's possible to customize the behavior for time shifting and control

fwbrasil · 2024-10-29T02:27:30Z

kyo-core/shared/src/main/scala/kyo/Clock.scala

+                            deadline.toJava.compareTo(other.asInstanceOf[Task].deadline.toJava)
+                    end Task
+
+                    val queue = new DelayQueue[Task]


As simple timer implementation using DelayQueue. The queue is synchronized so sleep can be called concurrently by multiple fibers

I had to change it to a manually-synchronized PriorityQueue because DelayQueue isn't available in js

fwbrasil · 2024-10-29T02:29:27Z

kyo-core/shared/src/main/scala/kyo/Clock.scala

+                            tick()
+                        }
+
+                    def tick(): Unit =


When the user changes the time, this method is called to execute the delayed tasks if it's time=

fwbrasil · 2024-10-29T02:30:53Z

kyo-core/shared/src/main/scala/kyo/Fiber.scala

-            def interrupt(error: Panic)(using AllowUnsafe): Boolean                                      = self.interrupt(error)
-            def interruptDiscard(error: Panic)(using AllowUnsafe): Unit                                  = discard(self.interrupt(error))
-            def mask()(using AllowUnsafe): Unsafe[E, A]                                                  = self.mask()
+            def interrupt()(using frame: Frame, allow: AllowUnsafe): Boolean = self.interrupt(Panic(Interrupted(frame)))


A new overloaded interrupt without params. The following methods were changed only because of formatting

This will be useful! I think kyo-zio can use it.

fwbrasil · 2024-10-29T02:33:51Z

kyo-core/shared/src/main/scala/kyo/Timer.scala

+    def repeatWithDelay[E, S](delaySchedule: Schedule)(f: => Unit < (Async & Abort[E]))(using Frame): Fiber[E, Unit] < IO =
+        repeatWithDelay(delaySchedule, ())(_ => f)
+
+    def repeatWithDelay[E, A: Flat, S](


Instead of relying on the underlying java timer to manage repeated tasks, this new Timer implementation spins up new fibers that use the provided Schedule to repeat and Clock to sleep when necessary. This approach also allows scheduled tasks to maintain internal state between iterations and return a value at the end (see the A type).

I think this is much more useful!

fwbrasil · 2024-10-29T02:37:13Z

kyo-data/shared/src/main/scala/kyo/Duration.scala

@@ -58,7 +59,7 @@ object Duration:
      * @return
      *   A Duration instance
      */
-    inline def fromNanos(value: Long): Duration =


Something that was quite annoying while working on this change were assertion errors reporting inlined trees from Duration operations. It becomes a large and confusing error message. Since these methods don't take functions, the benefit of inlining them is low so I've decided to remove the modifier

Sounds good, I think this is the right move. I've noticed this issue with loop as well. If you incorrectly return a non-loop (Done/Continue) value the expanded tree is massive.

fwbrasil · 2024-10-29T02:37:37Z

kyo-data/shared/src/main/scala/kyo/Duration.scala

-        inline def toWeeks: Long   = self.to(Weeks)
-        inline def toMonths: Long  = self.to(Months)
-        inline def toYears: Long   = self.to(Years)
+        def to(timeUnit: TimeUnit): Long =


new methods to integrate with TimeUnit and ChronoUnit

kyo-core/shared/src/main/scala/kyo/Async.scala

kyo-core/shared/src/main/scala/kyo/Clock.scala

hearnadam · 2024-10-29T14:24:51Z

kyo-core/shared/src/main/scala/kyo/Timer.scala

+    def repeatWithDelay[E, S](delaySchedule: Schedule)(f: => Unit < (Async & Abort[E]))(using Frame): Fiber[E, Unit] < IO =
+        repeatWithDelay(delaySchedule, ())(_ => f)
+
+    def repeatWithDelay[E, A: Flat, S](


I think this is much more useful!

Co-authored-by: Adam Hearn <22334119+hearnadam@users.noreply.github.com>

hearnadam · 2024-10-30T01:07:13Z

kyo-core/shared/src/main/scala/kyo/Timer.scala

+  *   - `repeatWithDelay`: Executes tasks with a fixed delay between task completions
+  *   - `repeatAtInterval`: Executes tasks at fixed time intervals, regardless of task duration
+  */
+object Timer:


Do we need a distinct object for Timer? I generally prefer extension methods (or at least avoiding too many distinct objects) for discoverability.

I think most other effect systems don't have a concept of 'Timer'

Yeah, it doesn't feel necessary. Perhaps the methods could be in Clock since sleep is already there?

I've made the change, it seems ok

hearnadam · 2024-10-30T01:08:57Z

kyo-data/shared/src/main/scala/kyo/Duration.scala

@@ -58,7 +59,7 @@ object Duration:
      * @return
      *   A Duration instance
      */
-    inline def fromNanos(value: Long): Duration =


Sounds good, I think this is the right move. I've noticed this issue with loop as well. If you incorrectly return a non-loop (Done/Continue) value the expanded tree is massive.

hearnadam · 2024-10-30T01:10:16Z

kyo-data/shared/src/main/scala/kyo/Duration.scala

@@ -116,46 +117,72 @@ object Duration:
        val factor: Double = chronoUnit.getDuration.toNanos.toDouble
    end Units

+    object Units:
+        def fromJava(chronoUnit: ChronoUnit): Units =
+            Units.values.find(_.chronoUnit.equals(chronoUnit)) match


Should this be a Map?

hearnadam · 2024-10-30T01:13:55Z

kyo-core/shared/src/main/scala/kyo/Fiber.scala

-            def interrupt(error: Panic)(using AllowUnsafe): Boolean                                      = self.interrupt(error)
-            def interruptDiscard(error: Panic)(using AllowUnsafe): Unit                                  = discard(self.interrupt(error))
-            def mask()(using AllowUnsafe): Unsafe[E, A]                                                  = self.mask()
+            def interrupt()(using frame: Frame, allow: AllowUnsafe): Boolean = self.interrupt(Panic(Interrupted(frame)))


This will be useful! I think kyo-zio can use it.

hearnadam · 2024-10-30T01:14:35Z

kyo-core/shared/src/main/scala/kyo/Clock.scala

+                def now()(using AllowUnsafe) = Instant.fromJava(java.time.Instant.now())
+                def sleep(duration: Duration) =
+                    Promise.Unsafe.fromIOPromise {
+                        new IOPromise[Nothing, Unit] with Callable[Unit]:


Any reason to use Callable[Unit] vs Runnable?

I had changed it to Runnable but then I remembered why I used Callable. It's what's supported by the ScalaJS stubs:

[info] compiling 27 Scala sources to /home/runner/work/kyo/kyo/kyo-prelude/js/target/scala-3.5.2/test-classes ... [error] -- [E007] Type Mismatch Error: /home/runner/work/kyo/kyo/kyo-core/shared/src/main/scala/kyo/Clock.scala:516:57 [error] 516 | val task = executor.schedule(this, duration.toNanos, TimeUnit.NANOSECONDS) [error] | ^^^^ [error] |Found: ($anon.this : kyo.scheduler.IOPromise[Nothing, Unit] with Runnable {...}) [error] |Required: java.util.concurrent.Callable[A] [error] | [error] |where: A is a type variable [error] | [error] | longer explanation available when compiling with `-explain` [error] one error found

This reverts commit aef86c4.

[core] time shift and control

b5cdf1b

fwbrasil commented Oct 29, 2024

View reviewed changes

fwbrasil added 7 commits October 28, 2024 20:15

timer scaladocs + cleanup

afaf42b

fix scalajs build for kyo-data

dbf3e74

fixing js build for kyo-core

23d3891

fixing js build for kyo-core

5f84998

fix flaky tests

4125880

fix flaky tests

a237ad0

simplify clock executor customization

e5e1948

hearnadam reviewed Oct 29, 2024

View reviewed changes

fwbrasil and others added 4 commits October 29, 2024 08:42

Update kyo-core/shared/src/main/scala/kyo/Clock.scala

0d39616

Co-authored-by: Adam Hearn <22334119+hearnadam@users.noreply.github.com>

fix build

e4f1ac2

fix flaky tests

52b45a2

Merge branch 'main' into new-timer3

f9a5ed7

hearnadam reviewed Oct 30, 2024

View reviewed changes

fwbrasil added 4 commits October 29, 2024 20:05

address review feedback

aef86c4

remove Timer and move its methods to Clock

bb585da

cache ChronoUnit to Units lookup

99f540e

Revert "address review feedback"

e07a39b

This reverts commit aef86c4.

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[core] time shift and control #789

[core] time shift and control #789

fwbrasil commented Oct 29, 2024

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[core] time shift and control #789

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[core] time shift and control #789

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