add tests

controller/konnect/ops/objects_metadata.go

@@ -47,31 +47,33 @@ type ObjectWithMetadata interface {
 // It returns a slice of unique, sorted strings for deterministic output.
 func GenerateTagsForObject(obj ObjectWithMetadata, additionalTags ...string) []string {
 	const (
+		// The maximum length of a tag in Konnect.
 		maxAllowedTagLength = 128
-		maxAllowedTagCount  = 20
+		// The maximum number of tags that can be attached to a Konnect entity.
+		maxAllowedTagsCount = 20
 	)
 
-	// truncate the tags from annotations.
+	// Truncate the tags from annotations as we do not validate their length in CEL validations rules.
 	var annotationTags []string
 	for _, tag := range metadata.ExtractTags(obj) {
 		annotationTags = append(annotationTags, truncate(tag, maxAllowedTagLength))
 	}
 
-	// tags from k8s metadata must be kept.
 	k8sMetaTags := generateKubernetesMetadataTags(obj)
 
-	// If numbers "custom" tags from spec and annotations exceeds allowed count of tags, truncate them.
-	customTagCountLimit := maxAllowedTagCount - len(k8sMetaTags)
-	customTags := lo.Uniq(slices.Concat(annotationTags, additionalTags))
-	// TODO: Since the order of tags is not deterministic, when truncate happens, the preserved tags are also non deterministic.
-	// Should we provide some order like alphabetical order?
-	if len(customTags) > customTagCountLimit {
-		customTags = customTags[:customTagCountLimit]
+	// We concatenate the tags in this order to ensure that the k8sMetaTags and additionalTags (from spec) are never
+	// truncated below. CEL rules ensure that the total length of k8sMetaTags and additionalTags never exceeds
+	// the maximum allowed tags count. That means we will only discard tags from annotations.
+	allTags := lo.Uniq(slices.Concat(k8sMetaTags, additionalTags, annotationTags))
+
+	// If the total number of tags exceeds the maximum allowed tags counts, we limit the number of tags to the maximum
+	// allowed tags count, discarding the tags from annotations.
+	if len(allTags) > maxAllowedTagsCount {
+		allTags = allTags[:maxAllowedTagsCount]
 	}
 
-	res := lo.Uniq(slices.Concat(k8sMetaTags, customTags))
-	sort.Strings(res)
-	return res
+	sort.Strings(allTags)
+	return allTags
 }
 
 // generateKubernetesMetadataTags generates a list of tags from a Kubernetes object's metadata. The tags are formatted as

controller/konnect/ops/objects_metadata_test.go

@@ -283,6 +283,71 @@ func TestGenerateTagsForObject(t *testing.T) {
 				"tag2",
 			},
 		},
+		{
+			name: "when too many tags in total, last from annotations are discarded",
+			obj: func() testObjectKind {
+				obj := namespacedObject()
+				obj.ObjectMeta.Annotations = map[string]string{
+					"konghq.com/tags": "a,b,c,d,e,f,g,h,i,j,k,l,m,iwillbediscarded",
+				}
+				return obj
+			}(),
+			expectedTags: []string{
+				"a",
+				"b",
+				"c",
+				"d",
+				"e",
+				"f",
+				"g",
+				"h",
+				"i",
+				"j",
+				"k",
+				"k8s-generation:2",
+				"k8s-group:test.objects.io",
+				"k8s-kind:TestObjectKind",
+				"k8s-name:test-object",
+				"k8s-namespace:test-namespace",
+				"k8s-uid:test-uid",
+				"k8s-version:v1",
+				"l",
+				"m",
+			},
+		},
+		{
+			name: "when too many tags in total and additional tags are passed, last from annotations are discarded",
+			obj: func() testObjectKind {
+				obj := namespacedObject()
+				obj.ObjectMeta.Annotations = map[string]string{
+					"konghq.com/tags": "a,c,e,gwillbediscarded,iwillbediscarded,kwillbediscarded,mwillbediscarded",
+				}
+				return obj
+			}(),
+			additionalTags: []string{"b", "d", "f", "h", "j", "l", "n", "o", "p", "r"},
+			expectedTags: []string{
+				"a",
+				"b",
+				"c",
+				"d",
+				"e",
+				"f",
+				"h",
+				"j",
+				"k8s-generation:2",
+				"k8s-group:test.objects.io",
+				"k8s-kind:TestObjectKind",
+				"k8s-name:test-object",
+				"k8s-namespace:test-namespace",
+				"k8s-uid:test-uid",
+				"k8s-version:v1",
+				"l",
+				"n",
+				"o",
+				"p",
+				"r",
+			},
+		},
 	}
 
 	for _, tc := range testCases {

controller/konnect/ops/ops_kongpluginbinding.go

@@ -7,6 +7,7 @@ import (
 
 	sdkkonnectcomp "github.com/Kong/sdk-konnect-go/models/components"
 	sdkkonnectops "github.com/Kong/sdk-konnect-go/models/operations"
+	"github.com/kong/kubernetes-configuration/pkg/metadata"
 	"github.com/samber/lo"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
@@ -16,7 +17,6 @@ import (
 	configurationv1 "github.com/kong/kubernetes-configuration/api/configuration/v1"
 	configurationv1alpha1 "github.com/kong/kubernetes-configuration/api/configuration/v1alpha1"
 	configurationv1beta1 "github.com/kong/kubernetes-configuration/api/configuration/v1beta1"
-	"github.com/kong/kubernetes-configuration/pkg/metadata"
 )
 
 // -----------------------------------------------------------------------------