fix(preflight): Loosen up the regex for checking vm image name

relax the image name kubernetes version regexp.

Author: thunderboltsid

pkg/webhook/preflight/nutanix/imagekubernetesversioncheck.go

@@ -16,7 +16,8 @@ import (
 )
 
 // Examples: nkp-ubuntu-22.04-vgpu-1.32.3-20250604180644, nkp-rocky-9.5-release-cis-1.32.3-20250430150550.
-var kubernetesVersionRegex = regexp.MustCompile(`-(\d+\.\d+\.\d+)-\d{14}$`)
+// The regex captures the Kubernetes version in the format of 1.x.y, where x and y are digits.
+var kubernetesVersionRegex = regexp.MustCompile(`(?i)\b[vV]?(1\.\d+(?:\.\d+)?)\b`)
 
 type imageKubernetesVersionCheck struct {
 	machineDetails    *carenv1.NutanixMachineDetails
@@ -89,8 +90,8 @@ func (c *imageKubernetesVersionCheck) checkKubernetesVersion(image *vmmv4.Image)
 	imageK8sVersion, err := extractKubernetesVersionFromImageName(imageName)
 	if err != nil {
 		return fmt.Errorf("failed to extract Kubernetes version from image name '%s': %s. "+
-			"This check assumes NKP image naming convention. "+
-			"You can opt out of this check if using custom image naming", imageName, err)
+			"This check assumes a naming convention that includes kubernetes version in the name. "+
+			"You can opt out of this check if using non-compliant naming", imageName, err)
 	}
 
 	if imageK8sVersion != c.clusterK8sVersion {
@@ -105,12 +106,14 @@ func (c *imageKubernetesVersionCheck) checkKubernetesVersion(image *vmmv4.Image)
 	return nil
 }
 
+// extractKubernetesVersionFromImageName extracts the Kubernetes version from the given image name.
+// It expects something that looks like a kubernetes version in the image name i.e. 1.x.y?,
 // Examples: nkp-ubuntu-22.04-vgpu-1.32.3-20250604180644 -> 1.32.3.
 func extractKubernetesVersionFromImageName(imageName string) (string, error) {
 	matches := kubernetesVersionRegex.FindStringSubmatch(imageName)
 	if len(matches) < 2 {
 		return "", fmt.Errorf(
-			"image name does not match expected NKP naming convention (expected pattern: *-<k8s-version>-<timestamp>)",
+			"image name does not match expected naming convention (expected pattern: .*<k8s-version>.*)",
 		)
 	}
 	return matches[1], nil

pkg/webhook/preflight/nutanix/imagekubernetesversioncheck_test.go

@@ -57,20 +57,26 @@ func TestExtractKubernetesVersionFromImageName(t *testing.T) {
 			wantErr:   false,
 		},
 		{
-			name:      "custom image name - no match", // e.g., not following NKP naming convention
-			imageName: "my-custom-image-name",
-			want:      "",
-			wantErr:   true,
+			name:      "custom image name with kubernetes-version at end", // e.g., not following NKP naming convention
+			imageName: "custom-image-v1.23",
+			want:      "1.23",
+			wantErr:   false,
 		},
 		{
-			name:      "missing timestamp",
-			imageName: "nkp-ubuntu-22.04-1.32.3",
-			want:      "",
-			wantErr:   true,
+			name:      "custom image name with kubernetes version in middle", // e.g., not following NKP naming convention
+			imageName: "custom-v1.23.1-image",
+			want:      "1.23.1",
+			wantErr:   false,
+		},
+		{
+			name:      "custom image name with kubernetes version in start", // e.g., not following NKP naming convention
+			imageName: "v1.23.1-alpha-custom-image",
+			want:      "1.23.1",
+			wantErr:   false,
 		},
 		{
-			name:      "invalid version format", // e.g., missing patch version
-			imageName: "nkp-ubuntu-22.04-1.32-20250604180644",
+			name:      "custom image name - no match", // e.g., not following NKP naming convention
+			imageName: "my-custom-image-name",
 			want:      "",
 			wantErr:   true,
 		},
@@ -88,7 +94,7 @@ func TestExtractKubernetesVersionFromImageName(t *testing.T) {
 
 			if tc.wantErr {
 				require.Error(t, err)
-				assert.Contains(t, err.Error(), "image name does not match expected NKP naming convention")
+				assert.Contains(t, err.Error(), "image name does not match expected naming convention")
 			} else {
 				require.NoError(t, err)
 				assert.Equal(t, tc.want, got)
@@ -188,7 +194,7 @@ func TestVMImageCheckWithKubernetesVersion(t *testing.T) {
 				Error:   true,
 				Causes: []preflight.Cause{
 					{
-						Message: "failed to extract Kubernetes version from image name 'my-custom-image-name': image name does not match expected NKP naming convention (expected pattern: *-<k8s-version>-<timestamp>). This check assumes NKP image naming convention. You can opt out of this check if using custom image naming", //nolint:lll // cause is long
+						Message: "failed to extract Kubernetes version from image name 'my-custom-image-name': image name does not match expected naming convention (expected pattern: .*<k8s-version>.*). This check assumes a naming convention that includes kubernetes version in the name. You can opt out of this check if using non-compliant naming", //nolint:lll // cause is long
 						Field:   "test-field",
 					},
 				},