bug(#3): Add timeout for experiments

This change adds a timeout for experiments, which allows the user to set
an upper bound on the duration of an experiment.

Closes #3

3 files changed, 31 insertions, 3 deletions

diff --git a/opendc-core/src/main/kotlin/nl/atlarge/opendc/platform/Experiment.kt b/opendc-core/src/main/kotlin/nl/atlarge/opendc/platform/Experiment.kt
index 225b2813..6aed5364 100644
--- a/opendc-core/src/main/kotlin/nl/atlarge/opendc/platform/Experiment.kt
+++ b/opendc-core/src/main/kotlin/nl/atlarge/opendc/platform/Experiment.kt
@@ -25,6 +25,7 @@
 package nl.atlarge.opendc.platform
 
 import nl.atlarge.opendc.kernel.Kernel
+import nl.atlarge.opendc.kernel.time.Duration
 
 /**
  * A blueprint for a reproducible simulation in a pre-defined setting.
@@ -36,6 +37,16 @@ interface Experiment<out T> {
 	 * Run the experiment on the specified simulation [Kernel].
 	 *
 	 * @param kernel The simulation kernel to run the experiment.
+	 * @return The result of the experiment.
 	 */
 	fun run(kernel: Kernel): T
+
+	/**
+	 * Run the experiment on the specified simulation [Kernel].
+	 *
+	 * @param kernel The simulation kernel to run the experiment.
+	 * @param timeout The maximum duration of the experiment before returning to the caller.
+	 * @return The result of the experiment or `null`.
+	 */
+	fun run(kernel: Kernel, timeout: Duration): T?
 }
diff --git a/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaExperiment.kt b/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaExperiment.kt
index 59b28d0b..9e0e0565 100644
--- a/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaExperiment.kt
+++ b/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaExperiment.kt
@@ -33,6 +33,7 @@ import nl.atlarge.opendc.integration.jpa.schema.TaskState as InternalTaskState
 import nl.atlarge.opendc.integration.jpa.schema.Experiment as InternalExperiment
 import nl.atlarge.opendc.integration.jpa.schema.Task as InternalTask
 import nl.atlarge.opendc.kernel.Kernel
+import nl.atlarge.opendc.kernel.time.Duration
 import nl.atlarge.opendc.platform.workload.TaskState
 import nl.atlarge.opendc.topology.JpaTopologyFactory
 import nl.atlarge.opendc.topology.container.Rack
@@ -60,9 +61,10 @@ class JpaExperiment(private val manager: EntityManager,
 	 * Run the experiment on the specified simulation [Kernel].
 	 *
 	 * @param kernel The simulation kernel to run the experiment.
-	 * @throws IllegalStateException if the simulation is already running or finished.
+	 * @param timeout The maximum duration of the experiment before returning to the caller.
+	 * @return The result of the experiment or `null`.
 	 */
-	override fun run(kernel: Kernel) {
+	override fun run(kernel: Kernel, timeout: Duration): Unit? {
 		if (experiment.state != ExperimentState.CLAIMED) {
 			throw IllegalStateException("The experiment is in illegal state ${experiment.state}")
 		}
@@ -103,6 +105,10 @@ class JpaExperiment(private val manager: EntityManager,
 		logger.info { "Starting simulation" }
 
 		while (trace.jobs.any { !it.finished }) {
+			// If we have reached a timeout, return
+			if (simulation.clock.now >= timeout)
+				return null
+
 			// Collect data of simulation cycle
 			manager.transaction {
 				experiment.last = simulation.clock.now
@@ -163,9 +169,19 @@ class JpaExperiment(private val manager: EntityManager,
 		logger.info { "Average waiting time: $waiting seconds" }
 		logger.info { "Average execution time: $execution seconds" }
 		logger.info { "Average turnaround time: $turnaround seconds" }
+
+		return Unit
 	}
 
 	/**
+	 * Run the experiment on the specified simulation [Kernel].
+	 *
+	 * @param kernel The simulation kernel to run the experiment.
+	 * @throws IllegalStateException if the simulation is already running or finished.
+	 */
+	override fun run(kernel: Kernel) = run(kernel, -1)!!
+
+	/**
 	 * Closes this resource, relinquishing any underlying resources.
 	 * This method is invoked automatically on objects managed by the
 	 * `try`-with-resources statement.
diff --git a/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaPlatformRunner.kt b/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaPlatformRunner.kt
index 794ca44e..104f1aec 100644
--- a/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaPlatformRunner.kt
+++ b/opendc-integration-jpa/core/src/main/kotlin/nl/atlarge/opendc/platform/JpaPlatformRunner.kt
@@ -45,6 +45,7 @@ fun main(args: Array<String>) {
 	properties["javax.persistence.jdbc.password"] = env["PERSISTENCE_PASSWORD"] ?: ""
 	val factory = Persistence.createEntityManagerFactory("opendc-simulator", properties)
 
+	val timeout = 10000L
 	val threads = 4
 	val executorService = Executors.newFixedThreadPool(threads)
 	val experiments = JpaExperimentManager(factory)
@@ -55,7 +56,7 @@ fun main(args: Array<String>) {
 		experiments.poll()?.let { experiment ->
 			logger.info { "Found experiment. Submitting for simulation now..." }
 			executorService.submit {
-				experiment.use { it.run(kernel) }
+				experiment.use { it.run(kernel, timeout) }
 			}
 		}