Fail fast for impossible fsl (#216)

cmd/metal-api/internal/service/machine-service.go

@@ -1003,6 +1003,16 @@ func allocateMachine(logger *zap.SugaredLogger, ds *datastore.RethinkStore, ipam
 		return nil, err
 	}
 
+	// Allocation of a specific machine is requested, therefor size and partition are not given, fetch them
+	if allocationSpec.UUID != "" {
+		m, err := ds.FindMachineByID(allocationSpec.UUID)
+		if err != nil {
+			return nil, err
+		}
+		allocationSpec.SizeID = m.SizeID
+		allocationSpec.PartitionID = m.PartitionID
+	}
+
 	// Check if more machine would be allocated than project quota permits
 	if p.GetProject() != nil && p.GetProject().GetQuotas() != nil && p.GetProject().GetQuotas().GetMachine() != nil {
 		mq := p.GetProject().GetQuotas().GetMachine()
@@ -1017,6 +1027,24 @@ func allocateMachine(logger *zap.SugaredLogger, ds *datastore.RethinkStore, ipam
 		}
 	}
 
+	var fsl *metal.FilesystemLayout
+	if allocationSpec.FilesystemLayoutID == nil {
+		fsls, err := ds.ListFilesystemLayouts()
+		if err != nil {
+			return nil, err
+		}
+
+		fsl, err = fsls.From(allocationSpec.SizeID, allocationSpec.Image.ID)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		fsl, err = ds.FindFilesystemLayout(*allocationSpec.FilesystemLayoutID)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	var machineCandidate *metal.Machine
 	err = retry.Do(
 		func() error {
@@ -1036,8 +1064,6 @@ func allocateMachine(logger *zap.SugaredLogger, ds *datastore.RethinkStore, ipam
 	}
 	// as some fields in the allocation spec are optional, they will now be clearly defined by the machine candidate
 	allocationSpec.UUID = machineCandidate.ID
-	allocationSpec.PartitionID = machineCandidate.PartitionID
-	allocationSpec.SizeID = machineCandidate.SizeID
 
 	alloc := &metal.MachineAllocation{
 		Creator:         allocationSpec.Creator,
@@ -1077,24 +1103,6 @@ func allocateMachine(logger *zap.SugaredLogger, ds *datastore.RethinkStore, ipam
 		return err
 	}
 
-	var fsl *metal.FilesystemLayout
-	if allocationSpec.FilesystemLayoutID == nil {
-		fsls, err := ds.ListFilesystemLayouts()
-		if err != nil {
-			return nil, rollbackOnError(err)
-		}
-
-		fsl, err = fsls.From(allocationSpec.SizeID, allocationSpec.Image.ID)
-		if err != nil {
-			return nil, rollbackOnError(err)
-		}
-	} else {
-		fsl, err = ds.FindFilesystemLayout(*allocationSpec.FilesystemLayoutID)
-		if err != nil {
-			return nil, rollbackOnError(err)
-		}
-	}
-
 	err = fsl.Matches(machineCandidate.Hardware)
 	if err != nil {
 		return nil, rollbackOnError(err)