add minimumKubeletVersionObserver

Signed-off-by: Peter Hunt <[email protected]>

pkg/operator/configobserver/node/observe_minimum_kubelet_version.go

@@ -0,0 +1,46 @@
+package node
+
+import (
+	"github.com/openshift/library-go/pkg/operator/configobserver"
+	"github.com/openshift/library-go/pkg/operator/events"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/klog/v2"
+)
+
+var minimumKubeletVersionConfigPath = "minimumKubeletVersion"
+
+// ObserveKubeletMinimumVersion watches the node configuration and generates the minimumKubeletVersion
+func ObserveMinimumKubeletVersion(genericListers configobserver.Listers, _ events.Recorder, existingConfig map[string]interface{}) (ret map[string]interface{}, errs []error) {
+	defer func() {
+		// Prune the observed config so that it only contains minimumKubeletVersion field.
+		ret = configobserver.Pruned(ret, []string{minimumKubeletVersionConfigPath})
+	}()
+	ret = map[string]interface{}{}
+	listers := genericListers.(NodeLister)
+	configNode, err := listers.NodeLister().Get("cluster")
+	// we got an error so without the node object we are not able to determine minimumKubeletVersion
+	if err != nil {
+		// if config/v1/node/cluster object is not found, that can be treated as a non-error case
+		if !apierrors.IsNotFound(err) {
+			errs = append(errs, err)
+		} else { // but raise a warning
+			klog.Warningf("nodes.config.openshift.io/cluster object could not be found")
+		}
+		return existingConfig, errs
+	}
+
+	if configNode.Spec.MinimumKubeletVersion == "" {
+		// in case minimum kubelet version is not set on cluster
+		// return empty set of configs, this helps to unset the config
+		// values related to the minimumKubeletVersion.
+		// Also, ensures that this observer doesn't break cluster upgrades/downgrades
+		return map[string]interface{}{}, errs
+	}
+
+	if err := unstructured.SetNestedField(ret, configNode.Spec.MinimumKubeletVersion, minimumKubeletVersionConfigPath); err != nil {
+		errs = append(errs, err)
+	}
+
+	return ret, errs
+}

pkg/operator/configobserver/node/observe_minimum_kubelet_version_test.go

@@ -0,0 +1,78 @@
+package node
+
+import (
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	configv1 "github.com/openshift/api/config/v1"
+	configlistersv1 "github.com/openshift/client-go/config/listers/config/v1"
+	"github.com/openshift/library-go/pkg/operator/events"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/tools/cache"
+)
+
+func TestObserveKubeletMinimumVersion(t *testing.T) {
+	type Test struct {
+		name                   string
+		existingConfig         map[string]interface{}
+		expectedObservedConfig map[string]interface{}
+		minimumKubeletVersion  string
+	}
+	tests := []Test{
+		{
+			name:                   "empty minimumKubeletVersion",
+			expectedObservedConfig: map[string]interface{}{},
+			minimumKubeletVersion:  "",
+		},
+		{
+			name: "set minimumKubeletVersion",
+			expectedObservedConfig: map[string]interface{}{
+				"minimumKubeletVersion": string("1.30.0"),
+			},
+			minimumKubeletVersion: "1.30.0",
+		},
+		{
+			name: "existing minimumKubeletVersion",
+			expectedObservedConfig: map[string]interface{}{
+				"minimumKubeletVersion": string("1.30.0"),
+			},
+			existingConfig: map[string]interface{}{
+				"minimumKubeletVersion": string("1.29.0"),
+			},
+			minimumKubeletVersion: "1.30.0",
+		},
+		{
+			name:                   "existing minimumKubeletVersion unset",
+			expectedObservedConfig: map[string]interface{}{},
+			existingConfig: map[string]interface{}{
+				"minimumKubeletVersion": string("1.29.0"),
+			},
+			minimumKubeletVersion: "",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			// test data
+			eventRecorder := events.NewInMemoryRecorder("")
+			configNodeIndexer := cache.NewIndexer(cache.MetaNamespaceKeyFunc, cache.Indexers{})
+			configNodeIndexer.Add(&configv1.Node{
+				ObjectMeta: metav1.ObjectMeta{Name: "cluster"},
+				Spec:       configv1.NodeSpec{MinimumKubeletVersion: test.minimumKubeletVersion},
+			})
+			listers := testLister{
+				nodeLister: configlistersv1.NewNodeLister(configNodeIndexer),
+			}
+
+			// act
+			actualObservedConfig, err := ObserveMinimumKubeletVersion(listers, eventRecorder, test.existingConfig)
+
+			// validate
+			if len(err) > 0 {
+				t.Fatal(err)
+			}
+			if !cmp.Equal(test.expectedObservedConfig, actualObservedConfig) {
+				t.Fatalf("unexpected configuration, diff = %v", cmp.Diff(test.expectedObservedConfig, actualObservedConfig))
+			}
+		})
+	}
+}