harness: Extend Harness CLI with classpath options

This change adds support for appending libraries to the classpath when
searching for experiments to run using the OpenDC Harness command line
interface.

8 files changed, 68 insertions, 14 deletions

diff --git a/opendc-harness/opendc-harness-cli/build.gradle.kts b/opendc-harness/opendc-harness-cli/build.gradle.kts
index 26f02f55..3e169e2a 100644
--- a/opendc-harness/opendc-harness-cli/build.gradle.kts
+++ b/opendc-harness/opendc-harness-cli/build.gradle.kts
@@ -25,6 +25,12 @@ description = "Command line interface of OpenDC Harness"
 /* Build configuration */
 plugins {
     `kotlin-library-conventions`
+    application
+}
+
+application {
+    applicationName = "opendc-harness"
+    mainClass.set("org.opendc.harness.runner.cli.ConsoleRunnerKt")
 }
 
 dependencies {
diff --git a/opendc-harness/opendc-harness-cli/src/main/kotlin/org/opendc/harness/runner/cli/ConsoleRunner.kt b/opendc-harness/opendc-harness-cli/src/main/kotlin/org/opendc/harness/runner/cli/ConsoleRunner.kt
index c59e623c..82adb2fd 100644
--- a/opendc-harness/opendc-harness-cli/src/main/kotlin/org/opendc/harness/runner/cli/ConsoleRunner.kt
+++ b/opendc-harness/opendc-harness-cli/src/main/kotlin/org/opendc/harness/runner/cli/ConsoleRunner.kt
@@ -23,16 +23,23 @@
 package org.opendc.harness.runner.cli
 
 import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.parameters.arguments.argument
+import com.github.ajalt.clikt.parameters.arguments.multiple
+import com.github.ajalt.clikt.parameters.arguments.unique
 import com.github.ajalt.clikt.parameters.options.default
 import com.github.ajalt.clikt.parameters.options.multiple
 import com.github.ajalt.clikt.parameters.options.option
+import com.github.ajalt.clikt.parameters.options.unique
+import com.github.ajalt.clikt.parameters.types.file
 import com.github.ajalt.clikt.parameters.types.int
 import mu.KotlinLogging
+import org.junit.platform.commons.util.ClassLoaderUtils
 import org.opendc.harness.engine.ExperimentEngineLauncher
 import org.opendc.harness.engine.discovery.DiscoveryProvider
 import org.opendc.harness.engine.discovery.DiscoveryRequest
 import org.opendc.harness.engine.discovery.DiscoverySelector
 import org.opendc.harness.engine.scheduler.ThreadPoolExperimentScheduler
+import java.net.URLClassLoader
 
 /**
  * The logger for this experiment runner.
@@ -53,23 +60,38 @@ public class ConsoleRunner : CliktCommand(name = "opendc-harness") {
     /**
      * The selected experiments to run by name.
      */
-    private val experiments by option("-e", "--experiments", help = "Names of experiments to explore")
-        .multiple(emptyList())
+    private val experiments by argument(help = "Experiments to explore")
+        .multiple()
+        .unique()
 
     /**
      * The maximum number of worker threads to use.
      */
     private val parallelism by option("-p", "--parallelism", help = "Maximum number of concurrent simulation runs")
         .int()
-        .default(Runtime.getRuntime().availableProcessors())
+        .default(Runtime.getRuntime().availableProcessors() - 1)
+
+    /**
+     * Additional classpath entries to load.
+     */
+    private val additionalClasspathEntries by option("--class-path", help = "Additional classpath entries to load")
+        .file(mustExist = true)
+        .multiple()
+        .unique()
 
     override fun run() {
         logger.info { "Starting OpenDC Console Experiment Runner" }
 
-        val discovery = DiscoveryProvider.createComposite()
+        val classLoader = createClassLoader()
+        // TODO: Add way to specify class loader for scheduler
+        Thread.currentThread().contextClassLoader = classLoader
+
+        val discovery = DiscoveryProvider.createComposite(classLoader)
         val experiments = discovery.discover(
             DiscoveryRequest(
-                selectors = experiments.map { DiscoverySelector.Name(it) }
+                selectors = experiments.flatMap {
+                    listOf(DiscoverySelector.Name(it), DiscoverySelector.Meta("class.name", it))
+                }
             )
         )
 
@@ -91,6 +113,30 @@ public class ConsoleRunner : CliktCommand(name = "opendc-harness") {
 
         logger.info { "Finished all experiments. Exiting." }
     }
+
+    /**
+     * Create a [ClassLoader] that is used to load the
+     */
+    private fun createClassLoader(): ClassLoader {
+        val parent = ClassLoaderUtils.getDefaultClassLoader()
+
+        if (additionalClasspathEntries.isNotEmpty()) {
+            val urls = additionalClasspathEntries.flatMap { file ->
+                if (file.isDirectory) {
+                    file.walk()
+                        .filter { it.extension == "jar" }
+                        .map { it.toURI().toURL() }
+                        .toList()
+                } else {
+                    listOf(file.toURI().toURL())
+                }
+            }
+
+            return URLClassLoader.newInstance(urls.toTypedArray(), parent)
+        }
+
+        return parent
+    }
 }
 
 /**
diff --git a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/discovery/DiscoveryProvider.kt b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/discovery/DiscoveryProvider.kt
index 204de3fc..c4b420c5 100644
--- a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/discovery/DiscoveryProvider.kt
+++ b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/discovery/DiscoveryProvider.kt
@@ -40,7 +40,7 @@ public interface DiscoveryProvider {
     /**
      * Factory method for creating a new [Discovery] instance.
      */
-    public fun create(): Discovery
+    public fun create(classLoader: ClassLoader): Discovery
 
     public companion object {
         /**
@@ -58,8 +58,8 @@ public interface DiscoveryProvider {
         /**
          * Obtain a composite [Discovery] that combines the results of all available providers.
          */
-        public fun createComposite(): Discovery {
-            return CompositeDiscovery(providers)
+        public fun createComposite(classLoader: ClassLoader): Discovery {
+            return CompositeDiscovery(classLoader, providers)
         }
     }
 }
diff --git a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/CompositeDiscovery.kt b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/CompositeDiscovery.kt
index 8ebc485a..726125a8 100644
--- a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/CompositeDiscovery.kt
+++ b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/CompositeDiscovery.kt
@@ -32,11 +32,11 @@ import org.opendc.harness.engine.discovery.DiscoveryRequest
 /**
  * A composite [Discovery] instance that combines the results of multiple delegate instances.
  */
-internal class CompositeDiscovery(providers: Iterable<DiscoveryProvider>) : Discovery {
+internal class CompositeDiscovery(classLoader: ClassLoader, providers: Iterable<DiscoveryProvider>) : Discovery {
     /**
      * The [Discovery] instances to delegate to.
      */
-    private val delegates = providers.map { it.create() }
+    private val delegates = providers.map { it.create(classLoader) }
 
     @OptIn(FlowPreview::class)
     override fun discover(request: DiscoveryRequest): Flow<ExperimentDefinition> {
diff --git a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscovery.kt b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscovery.kt
index 20708230..3fa3fe35 100644
--- a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscovery.kt
+++ b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscovery.kt
@@ -36,7 +36,7 @@ import org.opendc.harness.engine.discovery.DiscoverySelector
 /**
  * A [Discovery] implementation that discovers [Experiment] instances on the classpath.
  */
-internal class DslDiscovery : Discovery {
+internal class DslDiscovery(private val classLoader: ClassLoader) : Discovery {
     /*
      * Lazily memoize the results of the classpath scan.
      */
@@ -84,6 +84,7 @@ internal class DslDiscovery : Discovery {
      */
     private fun scan(): ScanResult {
         return ClassGraph()
+            .addClassLoader(classLoader)
             .enableClassInfo()
             .enableExternalClasses()
             .ignoreClassVisibility()
diff --git a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscoveryProvider.kt b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscoveryProvider.kt
index 987bc889..6a9bd599 100644
--- a/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscoveryProvider.kt
+++ b/opendc-harness/opendc-harness-engine/src/main/kotlin/org/opendc/harness/engine/internal/DslDiscoveryProvider.kt
@@ -32,5 +32,5 @@ import org.opendc.harness.engine.discovery.DiscoveryProvider
 public class DslDiscoveryProvider : DiscoveryProvider {
     override val id: String = "dsl"
 
-    override fun create(): Discovery = DslDiscovery()
+    override fun create(classLoader: ClassLoader): Discovery = DslDiscovery(classLoader)
 }
diff --git a/opendc-harness/opendc-harness-engine/src/test/kotlin/org/opendc/harness/EngineTest.kt b/opendc-harness/opendc-harness-engine/src/test/kotlin/org/opendc/harness/EngineTest.kt
index 6f2989db..6955f7c5 100644
--- a/opendc-harness/opendc-harness-engine/src/test/kotlin/org/opendc/harness/EngineTest.kt
+++ b/opendc-harness/opendc-harness-engine/src/test/kotlin/org/opendc/harness/EngineTest.kt
@@ -50,7 +50,7 @@ internal class EngineTest {
     @Test
     fun discovery() {
         runBlocking {
-            val discovery = DiscoveryProvider.findById("dsl")?.create()
+            val discovery = DiscoveryProvider.findById("dsl")?.create(Thread.currentThread().contextClassLoader)
             assertNotNull(discovery)
             val res = mutableListOf<ExperimentDefinition>()
             discovery?.discover(DiscoveryRequest())?.toList(res)
diff --git a/opendc-harness/opendc-harness-junit5/src/main/kotlin/org/opendc/harness/runner/junit5/OpenDCTestEngine.kt b/opendc-harness/opendc-harness-junit5/src/main/kotlin/org/opendc/harness/runner/junit5/OpenDCTestEngine.kt
index ab7367b8..7fc97f6d 100644
--- a/opendc-harness/opendc-harness-junit5/src/main/kotlin/org/opendc/harness/runner/junit5/OpenDCTestEngine.kt
+++ b/opendc-harness/opendc-harness-junit5/src/main/kotlin/org/opendc/harness/runner/junit5/OpenDCTestEngine.kt
@@ -25,6 +25,7 @@ package org.opendc.harness.runner.junit5
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.emptyFlow
 import mu.KotlinLogging
+import org.junit.platform.commons.util.ClassLoaderUtils
 import org.junit.platform.engine.*
 import org.junit.platform.engine.discovery.ClassNameFilter
 import org.junit.platform.engine.discovery.ClassSelector
@@ -63,7 +64,7 @@ public class OpenDCTestEngine : TestEngine {
         val classNames = request.getSelectorsByType(ClassSelector::class.java).map { DiscoverySelector.Meta("class.name", it.className) }
         val classNameFilters = request.getFiltersByType(ClassNameFilter::class.java).map { DiscoveryFilter.Name(it.toPredicate()) }
 
-        val discovery = DiscoveryProvider.createComposite()
+        val discovery = DiscoveryProvider.createComposite(ClassLoaderUtils.getDefaultClassLoader())
         val definitions = discovery.discover(DiscoveryRequest(classNames, classNameFilters))
 
         return ExperimentEngineDescriptor(uniqueId, definitions)