merge: Improve workflow service (#43)

This pull request is the first in a series of changes to the workflow service. 
This pull request aims to help users setup workflow simulations. 
The next pull requests will focus on improving the design of the workflow service.

* Remove WorkflowSchedulerMode 
* Add helper tools for workflow simulations (e.g. `WorkflowServiceHelper`)

**Breaking API Changes**

* Removal of `WorkflowSchedulerMode`
* Rename from `ComputeWorkloadRunner` to `ComputeServiceHelper`

2 files changed, 42 insertions, 181 deletions

diff --git a/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/TraceReplayer.kt b/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/TraceReplayer.kt
deleted file mode 100644
index 9ee3736e..00000000
--- a/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/TraceReplayer.kt
+++ /dev/null
@@ -1,127 +0,0 @@
-/*
- * Copyright (c) 2021 AtLarge Research
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-package org.opendc.workflow.service
-
-import kotlinx.coroutines.coroutineScope
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.launch
-import org.opendc.simulator.compute.workload.SimFlopsWorkload
-import org.opendc.trace.*
-import org.opendc.workflow.api.Job
-import org.opendc.workflow.api.Task
-import org.opendc.workflow.api.WORKFLOW_TASK_CORES
-import org.opendc.workflow.api.WORKFLOW_TASK_DEADLINE
-import java.time.Clock
-import java.util.*
-import kotlin.collections.HashMap
-import kotlin.collections.HashSet
-import kotlin.math.max
-import kotlin.math.min
-
-/**
- * Helper tool to replay workflow trace.
- */
-internal class TraceReplayer(private val trace: Trace) {
-    /**
-     * Replay the workload.
-     */
-    public suspend fun replay(clock: Clock, service: WorkflowService) {
-        val jobs = parseTrace(trace)
-
-        // Sort jobs by their arrival time
-        (jobs as MutableList<Job>).sortBy { it.metadata["WORKFLOW_SUBMIT_TIME"] as Long }
-
-        // Wait until the trace is started
-        val startTime = jobs[0].metadata["WORKFLOW_SUBMIT_TIME"] as Long
-        delay(min(0L, startTime - clock.millis()))
-
-        val offset = startTime - clock.millis()
-
-        coroutineScope {
-            for (job in jobs) {
-                val submitTime = job.metadata["WORKFLOW_SUBMIT_TIME"] as Long
-                delay(max(0, (submitTime - offset) - clock.millis()))
-
-                launch { service.run(job) }
-            }
-        }
-    }
-
-    /**
-     * Convert [trace] into a list of [Job]s that can be submitted to the workflow service.
-     */
-    public fun parseTrace(trace: Trace): List<Job> {
-        val table = checkNotNull(trace.getTable(TABLE_TASKS))
-        val reader = table.newReader()
-
-        val jobs = mutableMapOf<Long, Job>()
-        val tasks = mutableMapOf<Long, Task>()
-        val taskDependencies = mutableMapOf<Task, Set<Long>>()
-
-        try {
-            while (reader.nextRow()) {
-                // Bag of tasks without workflow ID all share the same workflow
-                val workflowId = if (reader.hasColumn(TASK_WORKFLOW_ID)) reader.get(TASK_WORKFLOW_ID).toLong() else 0L
-                val workflow = jobs.computeIfAbsent(workflowId) { id -> Job(UUID(0L, id), "<unnamed>", HashSet(), HashMap()) }
-
-                val id = reader.get(TASK_ID).toLong()
-                val grantedCpus = if (reader.hasColumn(TASK_ALLOC_NCPUS))
-                    reader.getInt(TASK_ALLOC_NCPUS)
-                else
-                    reader.getInt(TASK_REQ_NCPUS)
-                val submitTime = reader.get(TASK_SUBMIT_TIME)
-                val runtime = reader.get(TASK_RUNTIME)
-                val flops: Long = 4000 * runtime.seconds * grantedCpus
-                val workload = SimFlopsWorkload(flops)
-                val task = Task(
-                    UUID(0L, id),
-                    "<unnamed>",
-                    HashSet(),
-                    mapOf(
-                        "workload" to workload,
-                        WORKFLOW_TASK_CORES to grantedCpus,
-                        WORKFLOW_TASK_DEADLINE to runtime.toMillis()
-                    ),
-                )
-
-                tasks[id] = task
-                taskDependencies[task] = reader.get(TASK_PARENTS).map { it.toLong() }.toSet()
-
-                (workflow.metadata as MutableMap<String, Any>).merge("WORKFLOW_SUBMIT_TIME", submitTime.toEpochMilli()) { a, b -> min(a as Long, b as Long) }
-                (workflow.tasks as MutableSet<Task>).add(task)
-            }
-
-            // Resolve dependencies for all tasks
-            for ((task, deps) in taskDependencies) {
-                for (dep in deps) {
-                    val parent = requireNotNull(tasks[dep]) { "Dependency task with id $dep not found" }
-                    (task.dependencies as MutableSet<Task>).add(parent)
-                }
-            }
-        } finally {
-            reader.close()
-        }
-
-        return jobs.values.toList()
-    }
-}
diff --git a/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/WorkflowServiceTest.kt b/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/WorkflowServiceTest.kt
index 04f54e58..066e9685 100644
--- a/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/WorkflowServiceTest.kt
+++ b/opendc-workflow/opendc-workflow-service/src/test/kotlin/org/opendc/workflow/service/WorkflowServiceTest.kt
@@ -22,41 +22,40 @@
 
 package org.opendc.workflow.service
 
-import io.opentelemetry.api.metrics.MeterProvider
-import io.opentelemetry.sdk.metrics.SdkMeterProvider
 import io.opentelemetry.sdk.metrics.export.MetricProducer
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.DisplayName
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertAll
-import org.opendc.compute.service.ComputeService
 import org.opendc.compute.service.scheduler.FilterScheduler
 import org.opendc.compute.service.scheduler.filters.ComputeFilter
 import org.opendc.compute.service.scheduler.filters.RamFilter
 import org.opendc.compute.service.scheduler.filters.VCpuFilter
 import org.opendc.compute.service.scheduler.weights.VCpuWeigher
-import org.opendc.compute.simulator.SimHost
+import org.opendc.compute.workload.ComputeServiceHelper
+import org.opendc.compute.workload.topology.HostSpec
 import org.opendc.simulator.compute.kernel.SimSpaceSharedHypervisorProvider
 import org.opendc.simulator.compute.model.MachineModel
 import org.opendc.simulator.compute.model.MemoryUnit
 import org.opendc.simulator.compute.model.ProcessingNode
 import org.opendc.simulator.compute.model.ProcessingUnit
+import org.opendc.simulator.compute.power.ConstantPowerModel
+import org.opendc.simulator.compute.power.SimplePowerDriver
 import org.opendc.simulator.core.runBlockingSimulation
-import org.opendc.simulator.flow.FlowEngine
-import org.opendc.telemetry.sdk.toOtelClock
 import org.opendc.trace.Trace
-import org.opendc.workflow.service.internal.WorkflowServiceImpl
-import org.opendc.workflow.service.scheduler.WorkflowSchedulerMode
 import org.opendc.workflow.service.scheduler.job.NullJobAdmissionPolicy
 import org.opendc.workflow.service.scheduler.job.SubmissionTimeJobOrderPolicy
 import org.opendc.workflow.service.scheduler.task.NullTaskEligibilityPolicy
 import org.opendc.workflow.service.scheduler.task.SubmissionTimeTaskOrderPolicy
+import org.opendc.workflow.workload.WorkflowSchedulerSpec
+import org.opendc.workflow.workload.WorkflowServiceHelper
+import org.opendc.workflow.workload.toJobs
 import java.nio.file.Paths
 import java.time.Duration
 import java.util.*
 
 /**
- * Integration test suite for the [WorkflowServiceImpl].
+ * Integration test suite for the [WorkflowService].
  */
 @DisplayName("WorkflowService")
 internal class WorkflowServiceTest {
@@ -65,60 +64,39 @@ internal class WorkflowServiceTest {
      */
     @Test
     fun testTrace() = runBlockingSimulation {
-        val meterProvider: MeterProvider = SdkMeterProvider
-            .builder()
-            .setClock(clock.toOtelClock())
-            .build()
-
-        val interpreter = FlowEngine(coroutineContext, clock)
-        val machineModel = createMachineModel()
-        val hvProvider = SimSpaceSharedHypervisorProvider()
-        val hosts = List(4) { id ->
-            SimHost(
-                UUID(0, id.toLong()),
-                "node-$id",
-                machineModel,
-                emptyMap(),
-                coroutineContext,
-                interpreter,
-                MeterProvider.noop(),
-                hvProvider,
-            )
-        }
-
+        // Configure the ComputeService that is responsible for mapping virtual machines onto physical hosts
+        val HOST_COUNT = 4
         val computeScheduler = FilterScheduler(
             filters = listOf(ComputeFilter(), VCpuFilter(1.0), RamFilter(1.0)),
             weighers = listOf(VCpuWeigher(1.0, multiplier = 1.0))
         )
-        val compute = ComputeService(coroutineContext, clock, MeterProvider.noop(), computeScheduler, schedulingQuantum = Duration.ofSeconds(1))
+        val computeHelper = ComputeServiceHelper(coroutineContext, clock, computeScheduler, schedulingQuantum = Duration.ofSeconds(1))
 
-        hosts.forEach { compute.addHost(it) }
+        repeat(HOST_COUNT) { computeHelper.registerHost(createHostSpec(it)) }
 
-        val scheduler = WorkflowService(
-            coroutineContext,
-            clock,
-            meterProvider,
-            compute.newClient(),
-            mode = WorkflowSchedulerMode.Batch(100),
+        // Configure the WorkflowService that is responsible for scheduling the workflow tasks onto machines
+        val workflowScheduler = WorkflowSchedulerSpec(
+            schedulingQuantum = Duration.ofMillis(100),
             jobAdmissionPolicy = NullJobAdmissionPolicy,
             jobOrderPolicy = SubmissionTimeJobOrderPolicy(),
             taskEligibilityPolicy = NullTaskEligibilityPolicy,
             taskOrderPolicy = SubmissionTimeTaskOrderPolicy(),
         )
+        val workflowHelper = WorkflowServiceHelper(coroutineContext, clock, computeHelper.service.newClient(), workflowScheduler)
 
-        val trace = Trace.open(
-            Paths.get(checkNotNull(WorkflowServiceTest::class.java.getResource("/trace.gwf")).toURI()),
-            format = "gwf"
-        )
-        val replayer = TraceReplayer(trace)
-
-        replayer.replay(clock, scheduler)
+        try {
+            val trace = Trace.open(
+                Paths.get(checkNotNull(WorkflowServiceTest::class.java.getResource("/trace.gwf")).toURI()),
+                format = "gwf"
+            )
 
-        hosts.forEach(SimHost::close)
-        scheduler.close()
-        compute.close()
+            workflowHelper.replay(trace.toJobs())
+        } finally {
+            workflowHelper.close()
+            computeHelper.close()
+        }
 
-        val metrics = collectMetrics(meterProvider as MetricProducer)
+        val metrics = collectMetrics(workflowHelper.metricProducer)
 
         assertAll(
             { assertEquals(758, metrics.jobsSubmitted, "No jobs submitted") },
@@ -126,19 +104,29 @@ internal class WorkflowServiceTest {
             { assertEquals(metrics.jobsSubmitted, metrics.jobsFinished, "Not all started jobs finished") },
             { assertEquals(0, metrics.tasksActive, "Not all started tasks finished") },
             { assertEquals(metrics.tasksSubmitted, metrics.tasksFinished, "Not all started tasks finished") },
-            { assertEquals(33213236L, clock.millis()) }
+            { assertEquals(33214236L, clock.millis()) { "Total duration incorrect" } }
         )
     }
 
     /**
-     * The machine model based on: https://www.spec.org/power_ssj2008/results/res2020q1/power_ssj2008-20191125-01012.html
+     * Construct a [HostSpec] for a simulated host.
      */
-    private fun createMachineModel(): MachineModel {
+    private fun createHostSpec(uid: Int): HostSpec {
+        // Machine model based on: https://www.spec.org/power_ssj2008/results/res2020q1/power_ssj2008-20191125-01012.html
         val node = ProcessingNode("AMD", "am64", "EPYC 7742", 32)
-        val cpus = List(node.coreCount) { id -> ProcessingUnit(node, id, 3400.0) }
+        val cpus = List(node.coreCount) { ProcessingUnit(node, it, 3400.0) }
         val memory = List(8) { MemoryUnit("Samsung", "Unknown", 2933.0, 16_000) }
 
-        return MachineModel(cpus, memory)
+        val machineModel = MachineModel(cpus, memory)
+
+        return HostSpec(
+            UUID(0, uid.toLong()),
+            "host-$uid",
+            emptyMap(),
+            machineModel,
+            SimplePowerDriver(ConstantPowerModel(0.0)),
+            SimSpaceSharedHypervisorProvider()
+        )
     }
 
     class WorkflowMetrics {