GeneratingTimeline fully functional

This commit is contained in:
Alexander Nozik 2024-12-08 10:37:47 +03:00
parent b4b534df1d
commit bb09a74710
9 changed files with 176 additions and 248 deletions

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@ -1,5 +1,5 @@
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip
distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists

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@ -21,6 +21,10 @@ pluginManagement {
}
}
plugins {
id("org.gradle.toolchains.foojay-resolver-convention") version "0.8.0"
}
dependencyResolutionManagement {
val toolsVersion: String by extra

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@ -28,5 +28,5 @@ kscience {
readme{
maturity = Maturity.EXPERIMENTAL
maturity = Maturity.PROTOTYPE
}

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@ -0,0 +1,70 @@
package space.kscience.simulation
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.channels.BufferOverflow
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.coroutineScope
import kotlinx.coroutines.currentCoroutineContext
import kotlinx.coroutines.flow.*
import kotlinx.coroutines.launch
import kotlinx.datetime.Instant
public abstract class AbstractTimeline<E : TimelineEvent>(
protected val timelineScope: CoroutineScope,
protected var startTime: Instant,
) : Timeline<E> {
private val observers: MutableSet<TimelineObserver> = mutableSetOf()
private val feedbackChannel = Channel<Unit>(onBufferOverflow = BufferOverflow.DROP_OLDEST)
override val time: StateFlow<Instant> = feedbackChannel.consumeAsFlow().map {
maxOf(startTime,observers.maxOfOrNull { it.time.value } ?: startTime)
}.stateIn(timelineScope, SharingStarted.Lazily, startTime)
override suspend fun advance(toTime: Instant) {
observers.forEach {
it.collect(toTime)
}
}
/**
* Flow unobserved events starting at [time]. The flow could be interrupted if timeline changes
*/
protected abstract fun events(): Flow<E>
override suspend fun observe(collector: suspend Flow<E>.() -> Unit): TimelineObserver {
val context = currentCoroutineContext()
val observer = object : TimelineObserver {
// observed time
override val time = MutableStateFlow(startTime)
private val channel = Channel<E>()
private val collectJob = timelineScope.launch(context) {
channel.consumeAsFlow().onEach {
time.emit(it.time)
feedbackChannel.send(Unit)
}.collector()
}
override suspend fun collect(upTo: Instant) = coroutineScope {
require(upTo >= time.value) { "Requested time $upTo is lower than observed ${time.value}" }
events().takeWhile {
it.time <= upTo
}.collect {
channel.send(it)
}
}
override fun close() {
collectJob.cancel()
observers.remove(this)
}
}
observers.add(observer)
return observer
}
}

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@ -1,132 +1,65 @@
package space.kscience.simulation
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Job
import kotlinx.coroutines.channels.BufferOverflow
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.coroutineScope
import kotlinx.coroutines.flow.*
import kotlinx.coroutines.launch
import kotlinx.coroutines.sync.Mutex
import kotlinx.coroutines.sync.withLock
import kotlinx.datetime.Instant
import kotlin.time.Duration
/**
* Suspend the collection of this [Flow] until event time is lower that threshold
*/
public fun <E : TimelineEvent> Flow<E>.withTimeThreshold(
threshold: Flow<Instant>
): Flow<E> = transform { event ->
threshold.first { it > event.time }
emit(event)
}
/**
* @param lookaheadInterval an interval for generated events ahead of the last observed event.
*/
public class GeneratingTimeline<E : TimelineEvent>(
private val generationScope: CoroutineScope,
private val initialEvent: E,
private val origin: E,
private val lookaheadInterval: Duration,
private val generatorChain: suspend (E) -> E
) : Timeline<E>, AutoCloseable {
private val generator: suspend FlowCollector<E>.(E) -> Unit
) : AbstractTimeline<E>(generationScope, origin.time) {
// push to this channel to trigger event generation
private val wakeupChannel = Channel<Unit>(onBufferOverflow = BufferOverflow.DROP_OLDEST)
private val startEventFlow = MutableStateFlow(origin)
private suspend fun kickGenerator() {
wakeupChannel.send(Unit)
private data class EventWithOrigin<E : TimelineEvent>(val origin: E, val event: E) : TimelineEvent {
override val time: Instant get() = event.time
}
private val mutex = Mutex()
private val history = ArrayDeque<E>()
private val lastEvent = MutableSharedFlow<E>(replay = Int.MAX_VALUE)
private val updateHistoryJob = generationScope.launch {
lastEvent.onEach {
mutex.withLock {
history.add(it)
//cleanup old events
val threshold = observedTime ?: return@withLock
while (history.isNotEmpty() && history.last().time > threshold) {
history.removeFirst()
}
private val events: SharedFlow<E> = flow {
coroutineScope {
startEventFlow.collect { startEvent ->
emitAll(
flow { generator(startEvent) }.takeWhile { startEvent == startEventFlow.value }.map {
EventWithOrigin(startEvent, it)
}
)
}
}
}
private val observers: MutableSet<TimelineObserver> = mutableSetOf()
override val time: Instant
get() = history.lastOrNull()?.time ?: initialEvent.time
override val observedTime: Instant?
get() = observers.minOfNotNullOrNull { it.time }
override fun flowUnobservedEvents(): Flow<E> = flow {
history.forEach { e ->
emit(e)
}
emitAll(lastEvent)
}
override suspend fun advance(toTime: Instant) {
observers.forEach {
it.collect(toTime)
}
}
private var generatorJob: Job = launchGenerator(initialEvent)
private fun launchGenerator(event: E): Job = generationScope.launch {
kickGenerator()
var currentEvent = event
// for each wakeup generate all events in lookaheadInterval
for (u in wakeupChannel) {
while (currentEvent.time < (observedTime ?: event.time) + lookaheadInterval) {
val nextEvent = generatorChain(currentEvent)
lastEvent.emit(nextEvent)
currentEvent = nextEvent
}
}
}
}.withTimeThreshold(
threshold = time.map { it + lookaheadInterval }
).buffer(Channel.UNLIMITED).mapNotNull {
//it.event
it.takeIf { it.origin == startEventFlow.value }?.event
}.shareIn(
scope = generationScope,
started = SharingStarted.Eagerly,
)
override fun events(): Flow<E> = events
public suspend fun interrupt(newStart: E) {
check(newStart.time > (observedTime ?: Instant.DISTANT_FUTURE)) {
check(newStart.time >= time.value) {
"Can't interrupt generating timeline after observed event"
}
mutex.withLock {
while (history.isNotEmpty() && history.last().time > newStart.time) {
history.removeLast()
}
generatorJob.cancel()
generatorJob = launchGenerator(newStart)
}
kickGenerator()
}
override fun close() {
updateHistoryJob.cancel()
generatorJob.cancel()
}
override suspend fun observe(collector: suspend Flow<E>.() -> Unit): TimelineObserver {
val observer = object : TimelineObserver {
override var time: Instant = this@GeneratingTimeline.time
override suspend fun collect(upTo: Instant) {
flowUnobservedEvents().takeWhile {
it.time <= upTo
}.onEach {
time = it.time
kickGenerator()
}.collector()
}
override fun close() {
observers.remove(this)
if(observers.isEmpty()){
this@GeneratingTimeline.close()
}
}
}
observers.add(observer)
return observer
startTime = newStart.time
startEventFlow.emit(newStart)
}
}

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@ -1,51 +1,25 @@
package space.kscience.simulation
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.merge
import kotlinx.coroutines.flow.onEach
import kotlinx.coroutines.flow.takeWhile
import kotlinx.datetime.Instant
import kotlinx.coroutines.flow.flow
public class MergedTimeline<E : TimelineEvent>(
timelineScope: CoroutineScope,
private val timelines: List<Timeline<E>>
) : Timeline<E> {
override val time: Instant
get() = timelines.minOfNotNullOrNull { it.time } ?: Instant.DISTANT_PAST
) : AbstractTimeline<E>(timelineScope, timelines.minOf { it.time.value }) {
override val observedTime: Instant?
get() = timelines.maxOfNotNullOrNull { it.observedTime }
override fun flowUnobservedEvents(): Flow<E> = timelines.map { flowUnobservedEvents() }.merge()
override suspend fun advance(toTime: Instant) {
timelines.forEach { it.advance(toTime) }
override fun events(): Flow<E> = flow {
val buffer = TODO()
//
// timelines.forEach { timeline ->
// timeline.observe {
// collect{
// buffer.add(it)
// }
// }
// }
}
// override suspend fun interrupt(atTime: Instant) {
// timelines.forEach { it.interrupt(atTime) }
// }
private val observers: MutableSet<TimelineObserver> = mutableSetOf()
override suspend fun observe(collector: suspend Flow<E>.() -> Unit): TimelineObserver {
val observer = object : TimelineObserver {
override var time: Instant = this@MergedTimeline.time
override suspend fun collect(upTo: Instant) = timelines
.map { flowUnobservedEvents() }
.merge()
.takeWhile { it.time <= upTo }.onEach {
time = it.time
}.collector()
override fun close() {
observers.remove(this)
}
}
observers.add(observer)
return observer
}
}

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@ -1,88 +1,30 @@
package space.kscience.simulation
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.asFlow
import kotlinx.coroutines.flow.onEach
import kotlinx.coroutines.flow.takeWhile
import kotlinx.coroutines.sync.Mutex
import kotlinx.coroutines.sync.withLock
import kotlinx.coroutines.flow.MutableSharedFlow
import kotlinx.datetime.Instant
/**
* A manually mutable [Timeline] that could be modified via [emit] method by multiple
*/
public class SharedTimeline<E : TimelineEvent> : Timeline<E> {
public class SharedTimeline<E : TimelineEvent>(
timelineScope: CoroutineScope,
startTime: Instant
) : AbstractTimeline<E>(timelineScope, startTime) {
private val mutex = Mutex()
private val events = MutableSharedFlow<E>(replay = Channel.UNLIMITED)
private val events = ArrayDeque<E>()
private val observers: MutableSet<TimelineObserver> = mutableSetOf()
override val time: Instant
get() = events.lastOrNull()?.time ?: Instant.DISTANT_PAST
override val observedTime: Instant?
get() = observers.minOfNotNullOrNull { it.time }
override fun flowUnobservedEvents(): Flow<E> = events.asFlow()
override fun events(): Flow<E> = events
/**
* Emit new event to the timeline
*/
public suspend fun emit(event: E): Boolean = mutex.withLock {
if (event.time < (observedTime ?: Instant.DISTANT_PAST)) {
error("Can't emit event $event because there are observed events after $observedTime")
public suspend fun emit(event: E) {
if (event.time < (events.replayCache.lastOrNull()?.time ?: time.value)) {
error("Can't emit event $event because timeline monotony is broken")
}
events.add(event)
}
override suspend fun advance(toTime: Instant) {
observers.forEach {
it.collect(toTime)
}
}
/**
* Discard all events before [observedTime]
*/
private suspend fun cleanup(): Unit = mutex.withLock {
val threshold = observedTime ?: return@withLock
while (events.isNotEmpty() && events.last().time > threshold) {
events.removeFirst()
}
}
// /**
// * Discard unconsumed events after [atTime].
// */
// override suspend fun interrupt(atTime: Instant): Unit = mutex.withLock {
// val threshold = observedTime
// if (atTime < threshold)
// error("Timeline interrupt at time $atTime is not possible because there are observed events before $threshold")
// while (events.isNotEmpty() && events.last().time > atTime) {
// events.removeLast()
// }
// }
override suspend fun observe(collector: suspend Flow<E>.() -> Unit): TimelineObserver {
val observer = object : TimelineObserver {
val observerMutex = Mutex()
override var time: Instant = this@SharedTimeline.time
override suspend fun collect(upTo: Instant) = observerMutex.withLock {
flowUnobservedEvents().takeWhile { it.time <= upTo }.onEach {
time = it.time
}.collector()
cleanup()
}
override fun close() {
observers.remove(this)
}
}
observers.add(observer)
return observer
events.emit(event)
}
}

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@ -1,6 +1,7 @@
package space.kscience.simulation
import kotlinx.coroutines.flow.Flow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.datetime.Instant
import kotlin.time.Duration
@ -21,9 +22,9 @@ public data class SimpleTimelineEvent<T>(override val time: Instant, val value:
public interface TimelineObserver : AutoCloseable {
/**
* The subjective time of this observer
* The subjective time of this observer (last observed time)
*/
public val time: Instant
public val time: StateFlow<Instant>
/**
* Collect all uncollected events from [time] to [upTo].
@ -33,6 +34,8 @@ public interface TimelineObserver : AutoCloseable {
public suspend fun collect(upTo: Instant = Instant.DISTANT_FUTURE)
}
public suspend fun TimelineObserver.collect(duration: Duration) = collect(time.value + duration)
/**
* A time-ordered sequence of events of type [E]. There time of events is strictly monotonic, meaning that the time of
* the next event is greater than the previous event time.
@ -43,29 +46,15 @@ public interface TimelineObserver : AutoCloseable {
*/
public interface Timeline<E : TimelineEvent> {
/**
* A subjective time of this timeline. The time could advance without events being produced.
* A subjective time of this timeline. The subjective time is the last observed time.
*/
public val time: Instant
public val time: StateFlow<Instant>
/**
* The time of the last event that was observed by all observers
*/
public val observedTime: Instant?
/**
* Flow events from [observedTime] to [time].
*
* The resulting flow is finite and should not suspend.
*
* This method does not affect [observedTime].
*/
public fun flowUnobservedEvents(): Flow<E>
/**
* Attach observer to this [Timeline]. The observer collection is not triggered right away, but only on demand.
*
* Each collection shifts [TimelineObserver.time] for this observer.
* The value of [observedTime] is the least of all observers [TimelineObserver.time].
*/
public suspend fun observe(
collector: suspend Flow<E>.() -> Unit
@ -84,4 +73,4 @@ public interface Timeline<E : TimelineEvent> {
// * Throw exception if at least one observer advanced
// */
// public suspend fun interrupt(atTime: Instant): Unit
}
}

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@ -1,34 +1,50 @@
package space.kscience.simulation
import kotlinx.coroutines.isActive
import kotlinx.coroutines.test.runTest
import kotlinx.datetime.Instant
import kotlin.test.Test
import kotlin.time.Duration
import kotlin.time.Duration.Companion.seconds
class TimelineTests {
@Test
fun testGeneration() = runTest(timeout = 5.seconds) {
fun testGeneration() = runTest{
val startTime = Instant.parse("2020-01-01T00:00:00.000Z")
val generation = GeneratingTimeline<SimpleTimelineEvent<DoubleArray>>(
this,
initialEvent = SimpleTimelineEvent(startTime, List(10) { it.toDouble() }.toDoubleArray()),
origin = SimpleTimelineEvent(startTime, List(10) { it.toDouble() }.toDoubleArray()),
lookaheadInterval = 1.seconds
) { event ->
val time = event.time + 0.1.seconds
println("Emit: $time")
SimpleTimelineEvent(time, event.value.map { it + 1.0 }.toDoubleArray())
}
val collector = generation.observe {
collect {
println("Consume: ${it.time}")
var time = event.time
while (isActive) {
time += 0.1.seconds
println("Emit: ${time - startTime}")
emit(SimpleTimelineEvent(time, event.value.map { it + 1.0 }.toDoubleArray()))
}
}
collector.collect(startTime + 2.seconds)
val result = mutableListOf<Duration>()
val collector = generation.observe {
collect {
println("Consume: ${it.time - startTime}")
result.add(it.time - startTime)
}
}
collector.collect(2.seconds)
println("First collection complete")
collector.collect(2.seconds)
println("Second collection complete")
println("Interrupt")
generation.interrupt(SimpleTimelineEvent(startTime + 6.seconds, List(10) { it.toDouble() }.toDoubleArray()))
println("Collecting second")
collector.collect(startTime + 6.seconds + 2.5.seconds)
println(result)
collector.close()
}
}