Fix : Enable system tag support prefix match (#8151)

pkg/provider/azure.go

@@ -167,6 +167,7 @@ type Config struct {
 	// SystemTags determines the tag keys managed by cloud provider. If it is not set, no tags would be deleted if
 	// the `Tags` is changed. However, the old tags would be deleted if they are neither included in `Tags` nor
 	// in `SystemTags` after the update of `Tags`.
+	// SystemTags now support prefix match, which means that if a key in `SystemTags` is a prefix of a key in `Tags`, that tag will not be deleted
 	SystemTags string `json:"systemTags,omitempty" yaml:"systemTags,omitempty"`
 	// Sku of Load Balancer and Public IP. Candidate values are: basic and standard.
 	// If not set, it will be default to basic.

pkg/provider/azure_utils.go

@@ -157,6 +157,23 @@ func findKeyInMapCaseInsensitive(targetMap map[string]*string, key string) (bool
 	return false, ""
 }
 
+// This function extends the functionality of findKeyInMapCaseInsensitive by supporting both
+// exact case-insensitive key matching and prefix-based key matching in the given map.
+// 1. If the key is found in the map (case-insensitively), the function returns true and the matching key in the map.
+// 2. If the key's prefix is found in the map (case-insensitively), the function also returns true and the matching key in the map.
+// This function is designed to enable systemTags to support prefix-based tag keys,
+// allowing more flexible and efficient tag key matching.
+func findKeyInMapWithPrefix(targetMap map[string]*string, key string) (bool, string) {
+	for k := range targetMap {
+		// use prefix-based key matching
+		// use case-insensitive comparison
+		if strings.HasPrefix(strings.ToLower(key), strings.ToLower(k)) {
+			return true, k
+		}
+	}
+	return false, ""
+}
+
 func (az *Cloud) reconcileTags(currentTagsOnResource, newTags map[string]*string) (reconciledTags map[string]*string, changed bool) {
 	var systemTags []string
 	systemTagsMap := make(map[string]*string)
@@ -189,7 +206,7 @@ func (az *Cloud) reconcileTags(currentTagsOnResource, newTags map[string]*string
 	if len(systemTagsMap) > 0 {
 		for k := range currentTagsOnResource {
 			if _, ok := newTags[k]; !ok {
-				if found, _ := findKeyInMapCaseInsensitive(systemTagsMap, k); !found {
+				if found, _ := findKeyInMapWithPrefix(systemTagsMap, k); !found {
 					klog.V(2).Infof("reconcileTags: delete tag %s: %s", k, pointer.StringDeref(currentTagsOnResource[k], ""))
 					delete(currentTagsOnResource, k)
 					changed = true

pkg/provider/azure_utils_test.go

@@ -177,6 +177,69 @@ func TestReconcileTags(t *testing.T) {
 			},
 			expectedChanged: true,
 		},
+		{
+			description: "reconcileTags should support prefix matching in systemTags",
+			currentTagsOnResource: map[string]*string{
+				"prefix-a": pointer.String("b"),
+				"c":        pointer.String("d"),
+			},
+			systemTags: "prefix",
+			expectedTags: map[string]*string{
+				"prefix-a": pointer.String("b"),
+			},
+			expectedChanged: true,
+		},
+		{
+			description: "reconcileTags should support prefix matching in systemTags case insensitive",
+			currentTagsOnResource: map[string]*string{
+				"prefix-a": pointer.String("b"),
+				"c":        pointer.String("d"),
+			},
+			systemTags: "PrEFiX",
+			expectedTags: map[string]*string{
+				"prefix-a": pointer.String("b"),
+			},
+			expectedChanged: true,
+		},
+		{
+			description: "reconcileTags should support prefix matching in systemTags with multiple prefixes",
+			currentTagsOnResource: map[string]*string{
+				"prefix-a": pointer.String("b"),
+				"sys-b":    pointer.String("c"),
+			},
+			systemTags: "prefix, sys",
+			expectedTags: map[string]*string{
+				"prefix-a": pointer.String("b"),
+				"sys-b":    pointer.String("c"),
+			},
+			expectedChanged: false,
+		},
+		{
+			description: "reconcileTags should work with full length aks managed cluster tags",
+			currentTagsOnResource: map[string]*string{
+				"aks-managed-cluster-name": pointer.String("test-name"),
+				"aks-managed-cluster-rg":   pointer.String("test-rg"),
+			},
+			systemTags: "aks-managed-cluster-name, aks-managed-cluster-rg",
+			expectedTags: map[string]*string{
+				"aks-managed-cluster-name": pointer.String("test-name"),
+				"aks-managed-cluster-rg":   pointer.String("test-rg"),
+			},
+			expectedChanged: false,
+		},
+		{
+			description: "real case test for systemTags",
+			currentTagsOnResource: map[string]*string{
+				"aks-managed-cluster-name": pointer.String("test-name"),
+				"aks-managed-cluster-rg":   pointer.String("test-rg"),
+			},
+			systemTags: "aks-managed",
+			expectedTags: map[string]*string{
+				"aks-managed-cluster-name": pointer.String("test-name"),
+				"aks-managed-cluster-rg":   pointer.String("test-rg"),
+			},
+			expectedChanged: false,
+		},
 	} {
 		t.Run(testCase.description, func(t *testing.T) {
 			cloud := &Cloud{}