predefined machine type

supportedBackends/google/pipelines/common/src/main/scala/cromwell/backend/google/pipelines/common/MachineConstraints.scala

@@ -15,11 +15,21 @@ object MachineConstraints {
                  ): String = {
     if (googleLegacyMachineSelection) {
       s"predefined-$cpu-${memory.to(MemoryUnit.MB).amount.intValue()}"
+    }
+    else if (cpuPlatformOption.contains(PipelinesApiRuntimeAttributes.CpuPlatformIntelSapphireRapidsValue)) {
+      // As of 11/2023, C3 machine types (the general purpose platform for the Intel Sapphire Rapids CPU)
+      // cannot be customized like other general purpose platforms can. Select one of a few legal options.
+      PredefinedMachineType.getClosestC3Machine(memory, cpu, jobLogger)
     } else {
-      // If someone requests Intel Cascade Lake as their CPU platform then switch the machine type to n2.
-      // Similarly, CPU platform of AMD Rome corresponds to the machine type n2d.  
+      // Users specify a CPU platform in their WDL, but GCP also needs to know which machine type to use.
+      // The below logic infers the machine type from the requested CPU. We're assuming that users want  the newest
+      // "General Purpose" machine type that is compatible with the requested CPU. For example, if someone requests
+      // Intel Cascade Lake as their CPU platform, then infer the n2 machine type. AMD Rome -> n2d.
+      // The heuristic we're using is "find the newest 'General Purpose' type that supports the given CPU.
+      // https://cloud.google.com/compute/docs/machine-resource
       val customMachineType =
         cpuPlatformOption match {
+          case Some(PipelinesApiRuntimeAttributes.CpuPlatformIntelIceLakeValue) => N2CustomMachineType
           case Some(PipelinesApiRuntimeAttributes.CpuPlatformIntelCascadeLakeValue) => N2CustomMachineType
           case Some(PipelinesApiRuntimeAttributes.CpuPlatformAMDRomeValue)          => N2DCustomMachineType 
           case _ => N1CustomMachineType

supportedBackends/google/pipelines/common/src/main/scala/cromwell/backend/google/pipelines/common/PipelinesApiRuntimeAttributes.scala

@@ -78,6 +78,8 @@ object PipelinesApiRuntimeAttributes {
   // via `gcloud compute zones describe us-central1-a`
   val CpuPlatformIntelCascadeLakeValue = "Intel Cascade Lake"
   val CpuPlatformAMDRomeValue = "AMD Rome"
+  val CpuPlatformIntelIceLakeValue = "Intel Ice Lake"
+  val CpuPlatformIntelSapphireRapidsValue = "Intel Sapphire Rapids"
 
   val UseDockerImageCacheKey = "useDockerImageCache"
   private val useDockerImageCacheValidationInstance = new BooleanRuntimeAttributesValidation(UseDockerImageCacheKey).optional

supportedBackends/google/pipelines/common/src/main/scala/cromwell/backend/google/pipelines/common/PredefinedMachineType.scala

@@ -0,0 +1,41 @@
+package cromwell.backend.google.pipelines.common
+
+import cromwell.backend.google.pipelines.common.CustomMachineType._
+import eu.timepit.refined.api.Refined
+import eu.timepit.refined.numeric.Positive
+import eu.timepit.refined.refineV
+import mouse.all._
+import org.slf4j.Logger
+import wdl4s.parser.MemoryUnit
+import wom.format.MemorySize
+import math.{log, pow}
+
+case class PredefinedMachineType(cpuCount: Int, gcpString: String)
+object PredefinedMachineType {
+  val c3Standard_4 = PredefinedMachineType(4, "c3-standard-4")
+  val c3Standard_8 = PredefinedMachineType(8, "c3-standard-8")
+  val c3Standard_22 = PredefinedMachineType(22, "c3-standard-22")
+  val c3Standard_44 = PredefinedMachineType(44, "c3-standard-44")
+  val c3Standard_88 = PredefinedMachineType(88, "c3-standard-88")
+  val c3Standard_176 = PredefinedMachineType(176, "c3-standard-176")
+
+  def getClosestC3Machine(requestedMemory: MemorySize, requestedCpu: Refined[Int, Positive],  jobLogger: Logger): String = {
+    val adjustedMemory: MemorySize = MemorySize(requestedCpu.value * 4.0, MemoryUnit.GB)
+    if (adjustedMemory != requestedMemory) {
+      jobLogger.info(s"Adjusting memory from ${requestedMemory.amount} to ${adjustedMemory.amount} in order to match GCP requirements for the requested CPU.")
+    }
+    val machine = requestedCpu.value match {
+      case cpu if cpu <= 4 => c3Standard_4
+      case cpu if cpu > 4 && cpu <= 8 => c3Standard_8
+      case cpu if cpu > 8 && cpu <= 22 => c3Standard_22
+      case cpu if cpu > 22 && cpu <= 44 => c3Standard_44
+      case cpu if cpu > 44 && cpu <= 88 => c3Standard_88
+      case cpu if cpu > 88 => c3Standard_176
+    }
+
+    if(machine.cpuCount != requestedCpu.value) {
+      jobLogger.info(s"Rounding up CPU count from ${requestedCpu} to ${machine.cpuCount} in order to match GCP requirements for the requested CPU.")
+    }
+    machine.gcpString
+  }
+}