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.

5 files changed, 9 insertions, 8 deletions

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)