feat: add cluster uid derived from kube-system ns

pkg/agent/run.go

@@ -32,6 +32,7 @@ import (
 
 	"github.com/jetstack/preflight/api"
 	"github.com/jetstack/preflight/pkg/client"
+	"github.com/jetstack/preflight/pkg/clusteruid"
 	"github.com/jetstack/preflight/pkg/datagatherer"
 	"github.com/jetstack/preflight/pkg/datagatherer/k8s"
 	"github.com/jetstack/preflight/pkg/kubeconfig"
@@ -78,6 +79,28 @@ func Run(cmd *cobra.Command, args []string) (returnErr error) {
 		return fmt.Errorf("While evaluating configuration: %v", err)
 	}
 
+	// We need the cluster UID before we progress further so it can be sent along with other data readings
+
+	{
+		restCfg, err := kubeconfig.LoadRESTConfig("")
+		if err != nil {
+			return err
+		}
+
+		clientset, err := kubernetes.NewForConfig(restCfg)
+		if err != nil {
+			return err
+		}
+
+		ctx, err = clusteruid.GetClusterUID(ctx, clientset)
+		if err != nil {
+			return fmt.Errorf("failed to get cluster UID: %v", err)
+		}
+
+		clusterUID := clusteruid.ClusterUIDFromContext(ctx)
+		log.V(logs.Debug).Info("Retrieved cluster UID", "clusterUID", clusterUID)
+	}
+
 	group, gctx := errgroup.WithContext(ctx)
 	defer func() {
 		cancel()

pkg/clusteruid/clusteruid.go

@@ -0,0 +1,45 @@
+package clusteruid
+
+import (
+	"context"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+)
+
+// clusterUIDKey is the context key for storing the cluster UID
+type clusterUIDKey struct{}
+
+// GetClusterUID retrieves the UID of the kube-system namespace using the given Kubernetes clientset.
+// This UID can be used as a unique identifier for the Kubernetes cluster.
+// The UID is stored in the given context for later retrieval; use ClusterUIDFromContext to get it.
+func GetClusterUID(ctx context.Context, clientset kubernetes.Interface) (context.Context, error) {
+	namespace, err := clientset.CoreV1().Namespaces().Get(ctx, "kube-system", metav1.GetOptions{})
+	if err != nil {
+		return ctx, err
+	}
+
+	ctx = withClusterUID(ctx, string(namespace.ObjectMeta.UID))
+	return ctx, nil
+}
+
+// ClusterUIDFromContext retrieves the cluster UID from the context.
+// Panics if the value is not found or if the value is not a string.
+func ClusterUIDFromContext(ctx context.Context) string {
+	value := ctx.Value(clusterUIDKey{})
+	if value == nil {
+		panic("cluster UID not found in context")
+	}
+
+	uid, ok := value.(string)
+	if !ok {
+		panic("cluster UID in context is not a string")
+	}
+
+	return uid
+}
+
+// withClusterUID adds the given cluster UID to the context
+func withClusterUID(ctx context.Context, clusterUID string) context.Context {
+	return context.WithValue(ctx, clusterUIDKey{}, clusterUID)
+}

pkg/clusteruid/clusteruid_test.go

@@ -0,0 +1,40 @@
+package clusteruid
+
+import (
+	"testing"
+
+	"k8s.io/client-go/kubernetes/fake"
+
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+)
+
+func TestGetClusterUID(t *testing.T) {
+	client := fake.NewSimpleClientset()
+
+	mockUID := "12345678-1234-5678-1234-567812345678"
+
+	kubeSystemNS := &corev1.Namespace{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "kube-system",
+			UID:  types.UID(mockUID),
+		},
+	}
+
+	_, err := client.CoreV1().Namespaces().Create(t.Context(), kubeSystemNS, metav1.CreateOptions{})
+	if err != nil {
+		t.Fatalf("failed to create kube-system namespace with fake client: %v", err)
+	}
+
+	ctx, err := GetClusterUID(t.Context(), client)
+	if err != nil {
+		t.Fatalf("expected no error, got %v", err)
+	}
+
+	uid := ClusterUIDFromContext(ctx)
+
+	if uid != mockUID {
+		t.Fatalf("expected to get uid=%v, but got uid=%v", mockUID, uid)
+	}
+}