compute: Migrate compute service simulator to OpenTelemetry

This change updates the compute service simulator to use OpenTelemetry
for reporting metrics of the (simulated) hosts as opposed to using
custom event flows.

This approach is more generic, flexible and possibly offers better
performance as we can collect metrics of all services in a single sweep,
as opposed to listening to several services and each invoking the
handlers.

1 files changed, 84 insertions, 58 deletions

diff --git a/simulator/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt b/simulator/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
index e311cd21..830fc868 100644
--- a/simulator/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
+++ b/simulator/opendc-compute/opendc-compute-simulator/src/test/kotlin/org/opendc/compute/simulator/SimHostTest.kt
@@ -22,12 +22,14 @@
 
 package org.opendc.compute.simulator
 
-import kotlinx.coroutines.ExperimentalCoroutinesApi
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.flow.launchIn
-import kotlinx.coroutines.flow.onEach
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.test.TestCoroutineScope
+import io.opentelemetry.api.metrics.MeterProvider
+import io.opentelemetry.sdk.common.CompletableResultCode
+import io.opentelemetry.sdk.metrics.SdkMeterProvider
+import io.opentelemetry.sdk.metrics.data.MetricData
+import io.opentelemetry.sdk.metrics.export.MetricExporter
+import io.opentelemetry.sdk.metrics.export.MetricProducer
+import kotlinx.coroutines.*
+import kotlinx.coroutines.test.runBlockingTest
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
@@ -37,7 +39,8 @@ import org.opendc.compute.api.Image
 import org.opendc.compute.api.Server
 import org.opendc.compute.api.ServerState
 import org.opendc.compute.api.ServerWatcher
-import org.opendc.compute.service.driver.HostEvent
+import org.opendc.compute.service.driver.Host
+import org.opendc.compute.service.driver.HostListener
 import org.opendc.simulator.compute.SimFairShareHypervisorProvider
 import org.opendc.simulator.compute.SimMachineModel
 import org.opendc.simulator.compute.model.MemoryUnit
@@ -45,23 +48,20 @@ import org.opendc.simulator.compute.model.ProcessingNode
 import org.opendc.simulator.compute.model.ProcessingUnit
 import org.opendc.simulator.compute.workload.SimTraceWorkload
 import org.opendc.simulator.utils.DelayControllerClockAdapter
-import java.time.Clock
+import org.opendc.telemetry.sdk.metrics.export.CoroutineMetricReader
+import org.opendc.telemetry.sdk.toOtelClock
 import java.util.UUID
+import kotlin.coroutines.resume
 
 /**
  * Basic test-suite for the hypervisor.
  */
 @OptIn(ExperimentalCoroutinesApi::class)
 internal class SimHostTest {
-    private lateinit var scope: TestCoroutineScope
-    private lateinit var clock: Clock
     private lateinit var machineModel: SimMachineModel
 
     @BeforeEach
     fun setUp() {
-        scope = TestCoroutineScope()
-        clock = DelayControllerClockAdapter(scope)
-
         val cpuNode = ProcessingNode("Intel", "Xeon", "amd64", 2)
 
         machineModel = SimMachineModel(
@@ -74,72 +74,98 @@ internal class SimHostTest {
      * Test overcommitting of resources by the hypervisor.
      */
     @Test
-    fun testOvercommitted() {
+    fun testOvercommitted() = runBlockingTest {
+        val clock = DelayControllerClockAdapter(this)
         var requestedWork = 0L
         var grantedWork = 0L
         var overcommittedWork = 0L
 
-        scope.launch {
-            val virtDriver = SimHost(UUID.randomUUID(), "test", machineModel, emptyMap(), coroutineContext, clock, SimFairShareHypervisorProvider())
-            val duration = 5 * 60L
-            val vmImageA = MockImage(
-                UUID.randomUUID(),
-                "<unnamed>",
-                emptyMap(),
-                mapOf(
-                    "workload" to SimTraceWorkload(
-                        sequenceOf(
-                            SimTraceWorkload.Fragment(duration * 1000, 28.0, 2),
-                            SimTraceWorkload.Fragment(duration * 1000, 3500.0, 2),
-                            SimTraceWorkload.Fragment(duration * 1000, 0.0, 2),
-                            SimTraceWorkload.Fragment(duration * 1000, 183.0, 2)
-                        ),
-                    )
+        val meterProvider: MeterProvider = SdkMeterProvider
+            .builder()
+            .setClock(clock.toOtelClock())
+            .build()
+
+        val virtDriver = SimHost(UUID.randomUUID(), "test", machineModel, emptyMap(), coroutineContext, clock, meterProvider.get("opendc-compute-simulator"), SimFairShareHypervisorProvider())
+        val duration = 5 * 60L
+        val vmImageA = MockImage(
+            UUID.randomUUID(),
+            "<unnamed>",
+            emptyMap(),
+            mapOf(
+                "workload" to SimTraceWorkload(
+                    sequenceOf(
+                        SimTraceWorkload.Fragment(duration * 1000, 28.0, 2),
+                        SimTraceWorkload.Fragment(duration * 1000, 3500.0, 2),
+                        SimTraceWorkload.Fragment(duration * 1000, 0.0, 2),
+                        SimTraceWorkload.Fragment(duration * 1000, 183.0, 2)
+                    ),
                 )
             )
-            val vmImageB = MockImage(
-                UUID.randomUUID(),
-                "<unnamed>",
-                emptyMap(),
-                mapOf(
-                    "workload" to SimTraceWorkload(
-                        sequenceOf(
-                            SimTraceWorkload.Fragment(duration * 1000, 28.0, 2),
-                            SimTraceWorkload.Fragment(duration * 1000, 3100.0, 2),
-                            SimTraceWorkload.Fragment(duration * 1000, 0.0, 2),
-                            SimTraceWorkload.Fragment(duration * 1000, 73.0, 2)
-                        )
+        )
+        val vmImageB = MockImage(
+            UUID.randomUUID(),
+            "<unnamed>",
+            emptyMap(),
+            mapOf(
+                "workload" to SimTraceWorkload(
+                    sequenceOf(
+                        SimTraceWorkload.Fragment(duration * 1000, 28.0, 2),
+                        SimTraceWorkload.Fragment(duration * 1000, 3100.0, 2),
+                        SimTraceWorkload.Fragment(duration * 1000, 0.0, 2),
+                        SimTraceWorkload.Fragment(duration * 1000, 73.0, 2)
                     )
                 )
             )
+        )
 
-            delay(5)
-
-            val flavor = MockFlavor(2, 0)
-            virtDriver.events
-                .onEach { event ->
-                    when (event) {
-                        is HostEvent.SliceFinished -> {
-                            requestedWork += event.requestedBurst
-                            grantedWork += event.grantedBurst
-                            overcommittedWork += event.overcommissionedBurst
-                        }
-                    }
+        val flavor = MockFlavor(2, 0)
+
+        // Setup metric reader
+        val reader = CoroutineMetricReader(
+            this, listOf(meterProvider as MetricProducer),
+            object : MetricExporter {
+                override fun export(metrics: Collection<MetricData>): CompletableResultCode {
+                    val metricsByName = metrics.associateBy { it.name }
+                    requestedWork += metricsByName.getValue("cpu.work.total").doubleSummaryData.points.first().sum.toLong()
+                    grantedWork += metricsByName.getValue("cpu.work.granted").doubleSummaryData.points.first().sum.toLong()
+                    overcommittedWork += metricsByName.getValue("cpu.work.overcommit").doubleSummaryData.points.first().sum.toLong()
+                    return CompletableResultCode.ofSuccess()
                 }
-                .launchIn(this)
 
+                override fun flush(): CompletableResultCode = CompletableResultCode.ofSuccess()
+
+                override fun shutdown(): CompletableResultCode = CompletableResultCode.ofSuccess()
+            },
+            exportInterval = duration * 1000
+        )
+
+        coroutineScope {
             launch { virtDriver.spawn(MockServer(UUID.randomUUID(), "a", flavor, vmImageA)) }
             launch { virtDriver.spawn(MockServer(UUID.randomUUID(), "b", flavor, vmImageB)) }
+
+            suspendCancellableCoroutine<Unit> { cont ->
+                virtDriver.addListener(object : HostListener {
+                    private var finished = 0
+
+                    override fun onStateChanged(host: Host, server: Server, newState: ServerState) {
+                        if (newState == ServerState.TERMINATED && ++finished == 2) {
+                            cont.resume(Unit)
+                        }
+                    }
+                })
+            }
         }
 
-        scope.advanceUntilIdle()
+        // Ensure last cycle is collected
+        delay(1000 * duration)
+        virtDriver.close()
+        reader.close()
 
         assertAll(
-            { assertEquals(emptyList<Throwable>(), scope.uncaughtExceptions, "No errors") },
             { assertEquals(4197600, requestedWork, "Requested work does not match") },
             { assertEquals(2157600, grantedWork, "Granted work does not match") },
             { assertEquals(2040000, overcommittedWork, "Overcommitted work does not match") },
-            { assertEquals(1200006, scope.currentTime) }
+            { assertEquals(1500001, currentTime) }
         )
     }