DRA resource claim controller: add statistics

This is primarily for testing. Proper metrics might be useful, but can still be
added later.

staging/src/k8s.io/dynamic-resource-allocation/resourceslice/resourceslicecontroller.go

@@ -21,6 +21,7 @@ import (
 	"errors"
 	"fmt"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/google/go-cmp/cmp"
@@ -66,6 +67,11 @@ type Controller struct {
 	queue      workqueue.TypedRateLimitingInterface[string]
 	sliceStore cache.Indexer
 
+	// Must use atomic access...
+	numCreates int64
+	numUpdates int64
+	numDeletes int64
+
 	mutex sync.RWMutex
 
 	// When receiving updates from the driver, the entire pointer replaced,
@@ -209,6 +215,25 @@ func (c *Controller) Update(resources *DriverResources) {
 	}
 }
 
+// GetStats provides some insights into operations of the controller.
+func (c *Controller) GetStats() Stats {
+	s := Stats{
+		NumCreates: atomic.LoadInt64(&c.numCreates),
+		NumUpdates: atomic.LoadInt64(&c.numUpdates),
+		NumDeletes: atomic.LoadInt64(&c.numDeletes),
+	}
+	return s
+}
+
+type Stats struct {
+	// NumCreates counts the number of ResourceSlices that got created.
+	NumCreates int64
+	// NumUpdates counts the number of ResourceSlices that got update.
+	NumUpdates int64
+	// NumDeletes counts the number of ResourceSlices that got deleted.
+	NumDeletes int64
+}
+
 // newController creates a new controller.
 func newController(ctx context.Context, options Options) (*Controller, error) {
 	if options.KubeClient == nil {
@@ -540,6 +565,7 @@ func (c *Controller) syncPool(ctx context.Context, poolName string) error {
 			if _, err := c.kubeClient.ResourceV1alpha3().ResourceSlices().Update(ctx, slice, metav1.UpdateOptions{}); err != nil {
 				return fmt.Errorf("update resource slice: %w", err)
 			}
+			atomic.AddInt64(&c.numUpdates, 1)
 		}
 
 		// Create new slices.
@@ -596,6 +622,7 @@ func (c *Controller) syncPool(ctx context.Context, poolName string) error {
 			if _, err := c.kubeClient.ResourceV1alpha3().ResourceSlices().Create(ctx, slice, metav1.CreateOptions{}); err != nil {
 				return fmt.Errorf("create resource slice: %w", err)
 			}
+			atomic.AddInt64(&c.numCreates, 1)
 		}
 	} else if len(slices) > 0 {
 		// All are obsolete, pool does not exist anymore.
@@ -620,7 +647,13 @@ func (c *Controller) syncPool(ctx context.Context, poolName string) error {
 		// changes on the server. The only downside is the extra API
 		// call. This isn't as bad as extra creates.
 		logger.V(5).Info("Deleting obsolete resource slice", "slice", klog.KObj(slice), "deleteOptions", options)
-		if err := c.kubeClient.ResourceV1alpha3().ResourceSlices().Delete(ctx, slice.Name, options); err != nil && !apierrors.IsNotFound(err) {
+		err := c.kubeClient.ResourceV1alpha3().ResourceSlices().Delete(ctx, slice.Name, options)
+		switch {
+		case err == nil:
+			atomic.AddInt64(&c.numDeletes, 1)
+		case apierrors.IsNotFound(err):
+			// okay
+		default:
 			return fmt.Errorf("delete resource slice: %w", err)
 		}
 	}

staging/src/k8s.io/dynamic-resource-allocation/resourceslice/resourceslicecontroller_test.go

@@ -96,6 +96,7 @@ func TestControllerSyncPool(t *testing.T) {
 		initialOtherObjects    []runtime.Object
 		inputDriverResources   *DriverResources
 		expectedResourceSlices []resourceapi.ResourceSlice
+		expectedStats          Stats
 	}{
 		"create-slice": {
 			nodeUID:        nodeUID,
@@ -107,6 +108,9 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
+			expectedStats: Stats{
+				NumCreates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(generatedName1).GenerateName(generateName).
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -145,7 +149,10 @@ func TestControllerSyncPool(t *testing.T) {
 					Driver(driverName).Devices([]resourceapi.Device{}).
 					Pool(resourceapi.ResourcePool{Name: poolName, Generation: 1, ResourceSliceCount: 1}).Obj(),
 			},
-			inputDriverResources:   &DriverResources{},
+			inputDriverResources: &DriverResources{},
+			expectedStats: Stats{
+				NumDeletes: 1,
+			},
 			expectedResourceSlices: nil,
 		},
 		"delete-and-add-slice": {
@@ -163,6 +170,10 @@ func TestControllerSyncPool(t *testing.T) {
 						Slices: []Slice{{Devices: []resourceapi.Device{{Name: deviceName}}}}},
 				},
 			},
+			expectedStats: Stats{
+				NumDeletes: 1,
+				NumCreates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(generatedName1).GenerateName(generateName).
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -188,6 +199,9 @@ func TestControllerSyncPool(t *testing.T) {
 						Slices: []Slice{{Devices: []resourceapi.Device{{Name: deviceName}}}}},
 				},
 			},
+			expectedStats: Stats{
+				NumDeletes: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -215,6 +229,9 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
+			expectedStats: Stats{
+				NumUpdates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).ResourceVersion("1").
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -248,6 +265,9 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
+			expectedStats: Stats{
+				NumUpdates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).ResourceVersion("1").
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -334,6 +354,9 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
+			expectedStats: Stats{
+				NumDeletes: 2,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice2).UID(resourceSlice2).
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -369,6 +392,9 @@ func TestControllerSyncPool(t *testing.T) {
 				},
 			},
 			// Generation not bumped, only one update.
+			expectedStats: Stats{
+				NumUpdates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -412,6 +438,9 @@ func TestControllerSyncPool(t *testing.T) {
 				},
 			},
 			// Generation bumped, all updated.
+			expectedStats: Stats{
+				NumUpdates: 3,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).ResourceVersion("1").
@@ -454,6 +483,10 @@ func TestControllerSyncPool(t *testing.T) {
 				},
 			},
 			// Generation bumped, two updated, one removed.
+			expectedStats: Stats{
+				NumUpdates: 2,
+				NumDeletes: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).ResourceVersion("1").
@@ -493,7 +526,10 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
-			// Three updated, one generated.
+			expectedStats: Stats{
+				NumUpdates: 3,
+				NumCreates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).ResourceVersion("1").
 					NodeOwnerReferences(ownerName, string(nodeUID)).NodeName(ownerName).
@@ -523,6 +559,9 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
+			expectedStats: Stats{
+				NumCreates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(driverName + "-0").GenerateName(driverName + "-").
 					AllNodes(true).
@@ -540,6 +579,9 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
+			expectedStats: Stats{
+				NumCreates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(generatedName1).GenerateName(generateName).
 					AppOwnerReferences(ownerName).NodeSelector(nodeSelector).
@@ -562,6 +604,9 @@ func TestControllerSyncPool(t *testing.T) {
 					},
 				},
 			},
+			expectedStats: Stats{
+				NumUpdates: 1,
+			},
 			expectedResourceSlices: []resourceapi.ResourceSlice{
 				*MakeResourceSlice().Name(resourceSlice1).UID(resourceSlice1).ResourceVersion("1").
 					AppOwnerReferences(ownerName).NodeSelector(otherNodeSelector).
@@ -626,6 +671,8 @@ func TestControllerSyncPool(t *testing.T) {
 			sortResourceSlices(resourceSlices.Items)
 			assert.Equal(t, test.expectedResourceSlices, resourceSlices.Items)
 
+			assert.Equal(t, test.expectedStats, ctrl.GetStats())
+
 			// The informer might have added a work item after ctrl.run returned.
 			state := queue.State()
 			state.Ready = nil