merge: Expose metrics directly to user (#80)

This pull request adds the ability to access the metrics of resources modeled
by the OpenDC Compute, Workflow, FaaS, and TensorFlow services directly from
their corresponding interfaces. Previously, users would have to interact with
OpenTelemetry to obtain these values, which is complex and provides
significant overhead.

With this pull request, users can access the metrics of all cloud resources
modeled by OpenDC via methods such as `getSchedulerStats()`, etc.

** Breaking Changes **

- `ComputeService.hostCount` removed in favour of `ComputeService.hosts.size`

3 files changed, 16 insertions, 18 deletions

diff --git a/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/OpenDCRunner.kt b/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/OpenDCRunner.kt
index a150de4e..7c0c43ed 100644
--- a/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/OpenDCRunner.kt
+++ b/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/OpenDCRunner.kt
@@ -23,8 +23,9 @@
 package org.opendc.web.runner
 
 import mu.KotlinLogging
+import org.opendc.compute.api.Server
 import org.opendc.compute.workload.*
-import org.opendc.compute.workload.telemetry.SdkTelemetryManager
+import org.opendc.compute.workload.telemetry.NoopTelemetryManager
 import org.opendc.compute.workload.topology.HostSpec
 import org.opendc.compute.workload.topology.Topology
 import org.opendc.compute.workload.topology.apply
@@ -35,13 +36,12 @@ import org.opendc.simulator.compute.model.ProcessingUnit
 import org.opendc.simulator.compute.power.LinearPowerModel
 import org.opendc.simulator.compute.power.SimplePowerDriver
 import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.telemetry.compute.collectServiceMetrics
-import org.opendc.telemetry.sdk.metrics.export.CoroutineMetricReader
+import org.opendc.telemetry.compute.ComputeMetricReader
 import org.opendc.web.client.runner.OpenDCRunnerClient
 import org.opendc.web.proto.runner.Job
 import org.opendc.web.proto.runner.Scenario
 import org.opendc.web.runner.internal.JobManager
-import org.opendc.web.runner.internal.WebComputeMetricExporter
+import org.opendc.web.runner.internal.WebComputeMonitor
 import java.io.File
 import java.time.Duration
 import java.util.*
@@ -180,9 +180,9 @@ public class OpenDCRunner(
         private val scenario: Scenario,
         private val repeat: Int,
         private val topology: Topology,
-    ) : RecursiveTask<WebComputeMetricExporter.Results>() {
-        override fun compute(): WebComputeMetricExporter.Results {
-            val exporter = WebComputeMetricExporter()
+    ) : RecursiveTask<WebComputeMonitor.Results>() {
+        override fun compute(): WebComputeMonitor.Results {
+            val monitor = WebComputeMonitor()
 
             // Schedule task that interrupts the simulation if it runs for too long.
             val currentThread = Thread.currentThread()
@@ -206,25 +206,24 @@ public class OpenDCRunner(
                         else
                             null
 
-                    val telemetry = SdkTelemetryManager(clock)
                     val simulator = ComputeServiceHelper(
                         coroutineContext,
                         clock,
-                        telemetry,
+                        NoopTelemetryManager(),
                         computeScheduler,
                         failureModel,
                         interferenceModel.takeIf { phenomena.interference }
                     )
-
-                    telemetry.registerMetricReader(CoroutineMetricReader(this, exporter, exportInterval = Duration.ofHours(1)))
+                    val servers = mutableListOf<Server>()
+                    val reader = ComputeMetricReader(this, clock, simulator.service, servers, monitor)
 
                     try {
                         // Instantiate the topology onto the simulator
                         simulator.apply(topology)
                         // Run workload trace
-                        simulator.run(vms, seeder.nextLong())
+                        simulator.run(vms, seeder.nextLong(), servers)
 
-                        val serviceMetrics = collectServiceMetrics(telemetry.metricProducer)
+                        val serviceMetrics = simulator.service.getSchedulerStats()
                         logger.debug {
                             "Scheduler " +
                                 "Success=${serviceMetrics.attemptsSuccess} " +
@@ -235,14 +234,14 @@ public class OpenDCRunner(
                         }
                     } finally {
                         simulator.close()
-                        telemetry.close()
+                        reader.close()
                     }
                 }
             } finally {
                 interruptTask.cancel(false)
             }
 
-            return exporter.collectResults()
+            return monitor.collectResults()
         }
     }
 
diff --git a/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/JobManager.kt b/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/JobManager.kt
index 8de0cee4..99b8aaf1 100644
--- a/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/JobManager.kt
+++ b/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/JobManager.kt
@@ -62,7 +62,7 @@ internal class JobManager(private val client: OpenDCRunnerClient) {
     /**
      * Persist the specified results.
      */
-    fun finish(id: Long, results: List<WebComputeMetricExporter.Results>) {
+    fun finish(id: Long, results: List<WebComputeMonitor.Results>) {
         client.jobs.update(
             id,
             Job.Update(
diff --git a/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/WebComputeMetricExporter.kt b/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/WebComputeMonitor.kt
index 04437a5f..69350d8c 100644
--- a/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/WebComputeMetricExporter.kt
+++ b/opendc-web/opendc-web-runner/src/main/kotlin/org/opendc/web/runner/internal/WebComputeMonitor.kt
@@ -22,7 +22,6 @@
 
 package org.opendc.web.runner.internal
 
-import org.opendc.telemetry.compute.ComputeMetricExporter
 import org.opendc.telemetry.compute.ComputeMonitor
 import org.opendc.telemetry.compute.table.HostTableReader
 import org.opendc.telemetry.compute.table.ServiceTableReader
@@ -32,7 +31,7 @@ import kotlin.math.roundToLong
 /**
  * A [ComputeMonitor] that tracks the aggregate metrics for each repeat.
  */
-internal class WebComputeMetricExporter : ComputeMetricExporter() {
+internal class WebComputeMonitor : ComputeMonitor {
     override fun record(reader: HostTableReader) {
         val slices = reader.downtime / SLICE_LENGTH