merge: Increase minimum Java version to 17 (#115)

This pull request increases the minimum version of Java required by OpenDC to 17.
This new version of Java introduces several new features compared to our old minimum 
version (11), which we attempt to apply in this conversion.

## Implementation Notes :hammer_and_pick:

* Increase minimum Java version to Java 17 
* Use RandomGenerator as randomness source 
* Add common dispatcher interface 
* Add compatibility with Kotlin coroutines
* Use InstantSource as time source
* Re-implement SimulationScheduler as Dispatcher 
* Replace use of CoroutineContext by Dispatcher 

## External Dependencies :four_leaf_clover:

* Java 17

## Breaking API Changes :warning:

* The use of `CoroutineContext` and `Clock` as parameters of classes has been replaced 
  by the `Dispatcher` interface.
* The use of `Clock` has been replaced by `InstantSource` which does not carry time
   zone info.
* The use of `Random` and `SplittableRandom` as parameter type has been replaced 
   by `RandomGenerator`

13 files changed, 35 insertions, 43 deletions

diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeSchedulers.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeSchedulers.kt
index bbc70489..125ba6ef 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeSchedulers.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeSchedulers.kt
@@ -34,12 +34,13 @@ import org.opendc.compute.service.scheduler.weights.CoreRamWeigher
 import org.opendc.compute.service.scheduler.weights.InstanceCountWeigher
 import org.opendc.compute.service.scheduler.weights.RamWeigher
 import org.opendc.compute.service.scheduler.weights.VCpuWeigher
-import java.util.Random
+import java.util.SplittableRandom
+import java.util.random.RandomGenerator
 
 /**
  * Create a [ComputeScheduler] for the experiment.
  */
-public fun createComputeScheduler(name: String, seeder: Random, placements: Map<String, String> = emptyMap()): ComputeScheduler {
+public fun createComputeScheduler(name: String, seeder: RandomGenerator, placements: Map<String, String> = emptyMap()): ComputeScheduler {
     val cpuAllocationRatio = 16.0
     val ramAllocationRatio = 1.5
     return when (name) {
@@ -79,7 +80,7 @@ public fun createComputeScheduler(name: String, seeder: Random, placements: Map<
             filters = listOf(ComputeFilter(), VCpuFilter(cpuAllocationRatio), RamFilter(ramAllocationRatio)),
             weighers = emptyList(),
             subsetSize = Int.MAX_VALUE,
-            random = Random(seeder.nextLong())
+            random = SplittableRandom(seeder.nextLong())
         )
         "replay" -> ReplayScheduler(placements)
         else -> throw IllegalArgumentException("Unknown policy $name")
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeServiceProvisioningStep.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeServiceProvisioningStep.kt
index 38cbf2dc..d7347327 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeServiceProvisioningStep.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeServiceProvisioningStep.kt
@@ -41,7 +41,7 @@ public class ComputeServiceProvisioningStep internal constructor(
     private val schedulingQuantum: Duration
 ) : ProvisioningStep {
     override fun apply(ctx: ProvisioningContext): AutoCloseable {
-        val service = ComputeService(ctx.coroutineContext, ctx.clock, scheduler(ctx), schedulingQuantum)
+        val service = ComputeService(ctx.dispatcher, scheduler(ctx), schedulingQuantum)
         ctx.registry.register(serviceDomain, ComputeService::class.java, service)
 
         return AutoCloseable { service.close() }
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeWorkload.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeWorkload.kt
index 2200880d..b7884293 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeWorkload.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/ComputeWorkload.kt
@@ -22,7 +22,7 @@
 
 package org.opendc.experiments.compute
 
-import java.util.Random
+import java.util.random.RandomGenerator
 
 /**
  * An interface that describes how a workload is resolved.
@@ -31,5 +31,5 @@ public interface ComputeWorkload {
     /**
      * Resolve the workload into a list of [VirtualMachine]s to simulate.
      */
-    public fun resolve(loader: ComputeWorkloadLoader, random: Random): List<VirtualMachine>
+    public fun resolve(loader: ComputeWorkloadLoader, random: RandomGenerator): List<VirtualMachine>
 }
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModel.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModel.kt
index 81a5cf33..eb85dbb8 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModel.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModel.kt
@@ -24,8 +24,8 @@ package org.opendc.experiments.compute
 
 import org.opendc.compute.service.ComputeService
 import org.opendc.compute.simulator.failure.HostFaultInjector
-import java.time.Clock
-import java.util.Random
+import java.time.InstantSource
+import java.util.random.RandomGenerator
 import kotlin.coroutines.CoroutineContext
 
 /**
@@ -37,8 +37,8 @@ public interface FailureModel {
      */
     public fun createInjector(
         context: CoroutineContext,
-        clock: Clock,
+        clock: InstantSource,
         service: ComputeService,
-        random: Random
+        random: RandomGenerator
     ): HostFaultInjector
 }
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModels.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModels.kt
index ff747066..679e370a 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModels.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/FailureModels.kt
@@ -31,9 +31,9 @@ import org.opendc.compute.simulator.SimHost
 import org.opendc.compute.simulator.failure.HostFaultInjector
 import org.opendc.compute.simulator.failure.StartStopHostFault
 import org.opendc.compute.simulator.failure.StochasticVictimSelector
-import java.time.Clock
 import java.time.Duration
-import java.util.Random
+import java.time.InstantSource
+import java.util.random.RandomGenerator
 import kotlin.coroutines.CoroutineContext
 import kotlin.math.ln
 
@@ -47,9 +47,9 @@ public fun grid5000(failureInterval: Duration): FailureModel {
     return object : FailureModel {
         override fun createInjector(
             context: CoroutineContext,
-            clock: Clock,
+            clock: InstantSource,
             service: ComputeService,
-            random: Random
+            random: RandomGenerator
         ): HostFaultInjector {
             val rng = Well19937c(random.nextLong())
             val hosts = service.hosts.map { it as SimHost }.toSet()
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/HostsProvisioningStep.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/HostsProvisioningStep.kt
index e224fb84..310aa54c 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/HostsProvisioningStep.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/HostsProvisioningStep.kt
@@ -46,7 +46,7 @@ public class HostsProvisioningStep internal constructor(
 ) : ProvisioningStep {
     override fun apply(ctx: ProvisioningContext): AutoCloseable {
         val service = requireNotNull(ctx.registry.resolve(serviceDomain, ComputeService::class.java)) { "Compute service $serviceDomain does not exist" }
-        val engine = FlowEngine.create(ctx.coroutineContext, ctx.clock)
+        val engine = FlowEngine.create(ctx.dispatcher)
         val graph = engine.newGraph()
         val hosts = mutableSetOf<SimHost>()
 
@@ -58,7 +58,7 @@ public class HostsProvisioningStep internal constructor(
                 spec.uid,
                 spec.name,
                 spec.meta,
-                ctx.clock,
+                ctx.dispatcher.timeSource,
                 machine,
                 hypervisor,
                 optimize = optimize
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/TraceHelpers.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/TraceHelpers.kt
index f0e31932..16d28edb 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/TraceHelpers.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/TraceHelpers.kt
@@ -29,7 +29,7 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.yield
 import org.opendc.compute.service.ComputeService
-import java.time.Clock
+import java.time.InstantSource
 import java.util.Random
 import kotlin.coroutines.coroutineContext
 import kotlin.math.max
@@ -45,7 +45,7 @@ import kotlin.math.max
  * @param interference A flag to indicate that VM interference needs to be enabled.
  */
 public suspend fun ComputeService.replay(
-    clock: Clock,
+    clock: InstantSource,
     trace: List<VirtualMachine>,
     seed: Long,
     submitImmediately: Boolean = false,
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/CompositeComputeWorkload.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/CompositeComputeWorkload.kt
index 3a7a51f2..ca23a7c5 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/CompositeComputeWorkload.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/CompositeComputeWorkload.kt
@@ -26,7 +26,7 @@ import mu.KotlinLogging
 import org.opendc.experiments.compute.ComputeWorkload
 import org.opendc.experiments.compute.ComputeWorkloadLoader
 import org.opendc.experiments.compute.VirtualMachine
-import java.util.Random
+import java.util.random.RandomGenerator
 
 /**
  * A [ComputeWorkload] that samples multiple workloads based on the total load of all workloads.
@@ -37,7 +37,7 @@ internal class CompositeComputeWorkload(val sources: Map<ComputeWorkload, Double
      */
     private val logger = KotlinLogging.logger {}
 
-    override fun resolve(loader: ComputeWorkloadLoader, random: Random): List<VirtualMachine> {
+    override fun resolve(loader: ComputeWorkloadLoader, random: RandomGenerator): List<VirtualMachine> {
         val traces = sources.map { (source, fraction) -> fraction to source.resolve(loader, random) }
 
         val totalLoad = traces.sumOf { (_, vms) -> vms.sumOf { it.totalLoad } }
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/HpcSampledComputeWorkload.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/HpcSampledComputeWorkload.kt
index a6055762..583405da 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/HpcSampledComputeWorkload.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/HpcSampledComputeWorkload.kt
@@ -26,8 +26,8 @@ import mu.KotlinLogging
 import org.opendc.experiments.compute.ComputeWorkload
 import org.opendc.experiments.compute.ComputeWorkloadLoader
 import org.opendc.experiments.compute.VirtualMachine
-import java.util.Random
 import java.util.UUID
+import java.util.random.RandomGenerator
 
 /**
  * A [ComputeWorkload] that samples HPC VMs in the workload.
@@ -46,7 +46,7 @@ internal class HpcSampledComputeWorkload(val source: ComputeWorkload, val fracti
      */
     private val pattern = Regex("^(ComputeNode|cn).*")
 
-    override fun resolve(loader: ComputeWorkloadLoader, random: Random): List<VirtualMachine> {
+    override fun resolve(loader: ComputeWorkloadLoader, random: RandomGenerator): List<VirtualMachine> {
         val vms = source.resolve(loader, random)
 
         val (hpc, nonHpc) = vms.partition { entry ->
@@ -58,7 +58,6 @@ internal class HpcSampledComputeWorkload(val source: ComputeWorkload, val fracti
             .map { index ->
                 val res = mutableListOf<VirtualMachine>()
                 hpc.mapTo(res) { sample(it, index) }
-                res.shuffle(random)
                 res
             }
             .flatten()
@@ -67,7 +66,6 @@ internal class HpcSampledComputeWorkload(val source: ComputeWorkload, val fracti
             .map { index ->
                 val res = mutableListOf<VirtualMachine>()
                 nonHpc.mapTo(res) { sample(it, index) }
-                res.shuffle(random)
                 res
             }
             .flatten()
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/LoadSampledComputeWorkload.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/LoadSampledComputeWorkload.kt
index 793f1de9..ffb7e0c6 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/LoadSampledComputeWorkload.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/LoadSampledComputeWorkload.kt
@@ -26,7 +26,7 @@ import mu.KotlinLogging
 import org.opendc.experiments.compute.ComputeWorkload
 import org.opendc.experiments.compute.ComputeWorkloadLoader
 import org.opendc.experiments.compute.VirtualMachine
-import java.util.Random
+import java.util.random.RandomGenerator
 
 /**
  * A [ComputeWorkload] that is sampled based on total load.
@@ -37,7 +37,7 @@ internal class LoadSampledComputeWorkload(val source: ComputeWorkload, val fract
      */
     private val logger = KotlinLogging.logger {}
 
-    override fun resolve(loader: ComputeWorkloadLoader, random: Random): List<VirtualMachine> {
+    override fun resolve(loader: ComputeWorkloadLoader, random: RandomGenerator): List<VirtualMachine> {
         val vms = source.resolve(loader, random)
         val res = mutableListOf<VirtualMachine>()
 
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/TraceComputeWorkload.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/TraceComputeWorkload.kt
index b4e9005f..d9e311cd 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/TraceComputeWorkload.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/internal/TraceComputeWorkload.kt
@@ -25,13 +25,13 @@ package org.opendc.experiments.compute.internal
 import org.opendc.experiments.compute.ComputeWorkload
 import org.opendc.experiments.compute.ComputeWorkloadLoader
 import org.opendc.experiments.compute.VirtualMachine
-import java.util.Random
+import java.util.random.RandomGenerator
 
 /**
  * A [ComputeWorkload] from a trace.
  */
 internal class TraceComputeWorkload(val name: String, val format: String) : ComputeWorkload {
-    override fun resolve(loader: ComputeWorkloadLoader, random: Random): List<VirtualMachine> {
+    override fun resolve(loader: ComputeWorkloadLoader, random: RandomGenerator): List<VirtualMachine> {
         return loader.get(name, format)
     }
 }
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMetricReader.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMetricReader.kt
index ac058171..efd38a3c 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMetricReader.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMetricReader.kt
@@ -27,6 +27,8 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import mu.KotlinLogging
+import org.opendc.common.Dispatcher
+import org.opendc.common.asCoroutineDispatcher
 import org.opendc.compute.api.Server
 import org.opendc.compute.service.ComputeService
 import org.opendc.compute.service.driver.Host
@@ -35,7 +37,6 @@ import org.opendc.experiments.compute.telemetry.table.HostTableReader
 import org.opendc.experiments.compute.telemetry.table.ServerInfo
 import org.opendc.experiments.compute.telemetry.table.ServerTableReader
 import org.opendc.experiments.compute.telemetry.table.ServiceTableReader
-import java.time.Clock
 import java.time.Duration
 import java.time.Instant
 
@@ -43,20 +44,20 @@ import java.time.Instant
  * A helper class to collect metrics from a [ComputeService] instance and automatically export the metrics every
  * export interval.
  *
- * @param scope The [CoroutineScope] to run the reader in.
- * @param clock The virtual clock.
+ * @param dispatcher A [Dispatcher] for scheduling the future events.
  * @param service The [ComputeService] to monitor.
  * @param monitor The monitor to export the metrics to.
  * @param exportInterval The export interval.
  */
 public class ComputeMetricReader(
-    scope: CoroutineScope,
-    clock: Clock,
+    dispatcher: Dispatcher,
     private val service: ComputeService,
     private val monitor: ComputeMonitor,
     private val exportInterval: Duration = Duration.ofMinutes(5)
 ) : AutoCloseable {
     private val logger = KotlinLogging.logger {}
+    private val scope = CoroutineScope(dispatcher.asCoroutineDispatcher())
+    private val clock = dispatcher.timeSource
 
     /**
      * Aggregator for service metrics.
diff --git a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMonitorProvisioningStep.kt b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMonitorProvisioningStep.kt
index 68ca5ae8..665611dd 100644
--- a/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMonitorProvisioningStep.kt
+++ b/opendc-experiments/opendc-experiments-compute/src/main/kotlin/org/opendc/experiments/compute/telemetry/ComputeMonitorProvisioningStep.kt
@@ -22,9 +22,6 @@
 
 package org.opendc.experiments.compute.telemetry
 
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Job
-import kotlinx.coroutines.cancel
 import org.opendc.compute.service.ComputeService
 import org.opendc.experiments.provisioner.ProvisioningContext
 import org.opendc.experiments.provisioner.ProvisioningStep
@@ -40,13 +37,8 @@ public class ComputeMonitorProvisioningStep internal constructor(
     private val exportInterval: Duration
 ) : ProvisioningStep {
     override fun apply(ctx: ProvisioningContext): AutoCloseable {
-        val scope = CoroutineScope(ctx.coroutineContext + Job())
         val service = requireNotNull(ctx.registry.resolve(serviceDomain, ComputeService::class.java)) { "Compute service $serviceDomain does not exist" }
-        val metricReader = ComputeMetricReader(scope, ctx.clock, service, monitor, exportInterval)
-
-        return AutoCloseable {
-            metricReader.close()
-            scope.cancel()
-        }
+        val metricReader = ComputeMetricReader(ctx.dispatcher, service, monitor, exportInterval)
+        return AutoCloseable { metricReader.close() }
     }
 }