nfd-worker: add core.featureSources config option

Add a configuration option for controlling the enabled "raw" feature
sources. This is useful e.g. in testing and development, plus it also
allows fully shutting down discovery of features that are not needed in
a deployment. Supplements core.labelSources which controls the
enablement of label sources.

deployment/components/worker-config/nfd-worker.conf.example

@@ -2,6 +2,7 @@
 #  labelWhiteList:
 #  noPublish: false
 #  sleepInterval: 60s
+#  featureSources: [all]
 #  labelSources: [all]
 #  klog:
 #    addDirHeader: false

deployment/helm/node-feature-discovery/values.yaml

@@ -91,6 +91,7 @@ worker:
     #  labelWhiteList:
     #  noPublish: false
     #  sleepInterval: 60s
+    #  featureSources: [all]
     #  labelSources: [all]
     #  klog:
     #    addDirHeader: false

docs/advanced/worker-configuration-reference.md

@@ -43,12 +43,44 @@ core:
   sleepInterval: 60s
 ```
 
+### core.featureSources
+
+`core.featureSources` specifies the list of enabled feature sources. A special
+value `all` enables all sources. Prefixing a source name with `-` indicates
+that the source will be disabled instead - this is only meaningful when used in
+conjunction with `all`. This option allows completely disabling the feature
+detection so that neither standard feature labels are generated nor the raw
+feature data is available for custom rule processing.
+
+Default: `[all]`
+
+Example:
+
+```yaml
+core:
+  # Enable all but cpu and local sources
+  featureSources:
+    - "all"
+    - "-cpu"
+    - "-local"
+```
+
+```yaml
+core:
+  # Enable only cpu and local sources
+  featureSources:
+    - "cpu"
+    - "local"
+```
+
 ### core.labelSources
 
 `core.labelSources` specifies the list of enabled label sources. A special
 value `all` enables all sources. Prefixing a source name with `-` indicates
 that the source will be disabled instead - this is only meaningful when used in
-conjunction with `all`.
+conjunction with `all`. This configuration option affects the generation of
+node labels but not the actual discovery of the underlying feature data that is
+used e.g. in custom/`NodeFeatureRule` rules.
 
 Note: Overridden by the `-label-sources` and `-sources` command line flags and
 the `core.sources` configurations option (if any of them is specified).

pkg/nfd-client/worker/nfd-worker-internal_test.go

@@ -308,6 +308,7 @@ func TestNewNfdWorker(t *testing.T) {
 			worker := w.(*nfdWorker)
 			So(worker.configure("", ""), ShouldBeNil)
 			Convey("all sources should be enabled and the whitelist regexp should be empty", func() {
+				So(len(worker.featureSources), ShouldEqual, len(source.GetAllFeatureSources()))
 				So(len(worker.labelSources), ShouldEqual, len(source.GetAllLabelSources())-1)
 				So(worker.config.Core.LabelWhiteList, ShouldResemble, emptyRegexp)
 			})
@@ -376,12 +377,18 @@ func TestCreateFeatureLabels(t *testing.T) {
 
 func TestAdvertiseFeatureLabels(t *testing.T) {
 	Convey("When advertising labels", t, func() {
+		w, err := NewNfdWorker(&Args{})
+		So(err, ShouldBeNil)
+		worker := w.(*nfdWorker)
+
 		mockClient := &labeler.MockLabelerClient{}
+		worker.client = mockClient
+
 		labels := map[string]string{"feature-1": "value-1"}
 
 		Convey("Correct labeling request is sent", func() {
 			mockClient.On("SetLabels", mock.AnythingOfType("*context.timerCtx"), mock.AnythingOfType("*labeler.SetLabelsRequest")).Return(&labeler.SetLabelsReply{}, nil)
-			err := advertiseFeatureLabels(mockClient, labels)
+			err := worker.advertiseFeatureLabels(labels)
 			Convey("There should be no error", func() {
 				So(err, ShouldBeNil)
 			})
@@ -389,7 +396,7 @@ func TestAdvertiseFeatureLabels(t *testing.T) {
 		Convey("Labeling request fails", func() {
 			mockErr := errors.New("mock-error")
 			mockClient.On("SetLabels", mock.AnythingOfType("*context.timerCtx"), mock.AnythingOfType("*labeler.SetLabelsRequest")).Return(&labeler.SetLabelsReply{}, mockErr)
-			err := advertiseFeatureLabels(mockClient, labels)
+			err := worker.advertiseFeatureLabels(labels)
 			Convey("An error should be returned", func() {
 				So(err, ShouldEqual, mockErr)
 			})

pkg/nfd-client/worker/nfd-worker.go

@@ -64,6 +64,7 @@ type coreConfig struct {
 	Klog           map[string]string
 	LabelWhiteList utils.RegexpVal
 	NoPublish      bool
+	FeatureSources []string
 	Sources        *[]string
 	LabelSources   []string
 	SleepInterval  duration
@@ -105,6 +106,7 @@ type nfdWorker struct {
 	configFilePath string
 	config         *NFDConfig
 	stop           chan struct{} // channel for signaling stop
+	featureSources []source.FeatureSource
 	labelSources   []source.LabelSource
 }
 
@@ -139,6 +141,7 @@ func newDefaultConfig() *NFDConfig {
 		Core: coreConfig{
 			LabelWhiteList: utils.RegexpVal{Regexp: *regexp.MustCompile("")},
 			SleepInterval:  duration{60 * time.Second},
+			FeatureSources: []string{"all"},
 			LabelSources:   []string{"all"},
 			Klog:           make(map[string]string),
 		},
@@ -178,10 +181,10 @@ func (w *nfdWorker) Run() error {
 		select {
 		case <-labelTrigger:
 			// Run feature discovery
-			for n, s := range source.GetAllFeatureSources() {
-				klog.V(2).Infof("running discovery for %q source", n)
+			for _, s := range w.featureSources {
+				klog.V(2).Infof("running discovery for %q source", s.Name())
 				if err := s.Discover(); err != nil {
-					klog.Errorf("feature discovery of %q source failed: %v", n, err)
+					klog.Errorf("feature discovery of %q source failed: %v", s.Name(), err)
 				}
 			}
 
@@ -190,7 +193,7 @@ func (w *nfdWorker) Run() error {
 
 			// Update the node with the feature labels.
 			if w.client != nil {
-				err := advertiseFeatureLabels(w.client, labels)
+				err := w.advertiseFeatureLabels(labels)
 				if err != nil {
 					return fmt.Errorf("failed to advertise labels: %s", err.Error())
 				}
@@ -293,6 +296,41 @@ func (w *nfdWorker) configureCore(c coreConfig) error {
 		}
 	}
 
+	// Determine enabled feature sources
+	featureSources := make(map[string]source.FeatureSource)
+	for _, name := range c.FeatureSources {
+		if name == "all" {
+			for n, s := range source.GetAllFeatureSources() {
+				if ts, ok := s.(source.TestSource); !ok || !ts.IsTestSource() {
+					featureSources[n] = s
+				}
+			}
+		} else {
+			disable := false
+			strippedName := name
+			if strings.HasPrefix(name, "-") {
+				strippedName = name[1:]
+				disable = true
+			}
+			if s := source.GetFeatureSource(strippedName); s != nil {
+				if !disable {
+					featureSources[name] = s
+				} else {
+					delete(featureSources, strippedName)
+				}
+			} else {
+				klog.Warningf("skipping unknown feature source %q specified in core.featureSources", name)
+			}
+		}
+	}
+
+	w.featureSources = make([]source.FeatureSource, 0, len(featureSources))
+	for _, s := range featureSources {
+		w.featureSources = append(w.featureSources, s)
+	}
+
+	sort.Slice(w.featureSources, func(i, j int) bool { return w.featureSources[i].Name() < w.featureSources[j].Name() })
+
 	// Determine enabled label sources
 	labelSources := make(map[string]source.LabelSource)
 	for _, name := range c.LabelSources {
@@ -335,7 +373,13 @@ func (w *nfdWorker) configureCore(c coreConfig) error {
 	})
 
 	if klog.V(1).Enabled() {
-		n := make([]string, len(w.labelSources))
+		n := make([]string, len(w.featureSources))
+		for i, s := range w.featureSources {
+			n[i] = s.Name()
+		}
+		klog.Infof("enabled feature sources: %s", strings.Join(n, ", "))
+
+		n = make([]string, len(w.labelSources))
 		for i, s := range w.labelSources {
 			n[i] = s.Name()
 		}
@@ -510,7 +554,7 @@ func getFeatures() map[string]*feature.DomainFeatures {
 
 // advertiseFeatureLabels advertises the feature labels to a Kubernetes node
 // via the NFD server.
-func advertiseFeatureLabels(client pb.LabelerClient, labels Labels) error {
+func (w *nfdWorker) advertiseFeatureLabels(labels Labels) error {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
@@ -520,7 +564,7 @@ func advertiseFeatureLabels(client pb.LabelerClient, labels Labels) error {
 		Features:   getFeatures(),
 		NfdVersion: version.Get(),
 		NodeName:   nfdclient.NodeName()}
-	_, err := client.SetLabels(ctx, &labelReq)
+	_, err := w.client.SetLabels(ctx, &labelReq)
 	if err != nil {
 		klog.Errorf("failed to set node labels: %v", err)
 		return err