RBAC: Add function to generate wildcards from prefix (#54275)

* RBAC: Move metadata to own file

* RBAC: Rename test files

* RBAC: Add wildcard structure and helper function to generate wildcards
from prefix

* RBAC: Refactor filter to use WildcardsFromPrefix

* RBAC: Refactor GetResourceMetadata to use WildcardsFromPrefix

pkg/services/accesscontrol/metadata.go

@@ -0,0 +1,63 @@
+package accesscontrol
+
+import (
+	"context"
+	"strings"
+)
+
+// Metadata contains user accesses for a given resource
+// Ex: map[string]bool{"create":true, "delete": true}
+type Metadata map[string]bool
+
+// GetResourcesMetadata returns a map of accesscontrol metadata, listing for each resource, users available actions
+func GetResourcesMetadata(ctx context.Context, permissions map[string][]string, prefix string, resourceIDs map[string]bool) map[string]Metadata {
+	wildcards := WildcardsFromPrefix(prefix)
+
+	// index of the prefix in the scope
+	prefixIndex := len(prefix)
+
+	// Loop through permissions once
+	result := map[string]Metadata{}
+
+	for action, scopes := range permissions {
+		for _, scope := range scopes {
+			if wildcards.Contains(scope) {
+				for id := range resourceIDs {
+					result = addActionToMetadata(result, action, id)
+				}
+				break
+			}
+			if len(scope) > prefixIndex && strings.HasPrefix(scope, prefix) && resourceIDs[scope[prefixIndex:]] {
+				// Add action to a specific resource
+				result = addActionToMetadata(result, action, scope[prefixIndex:])
+			}
+		}
+	}
+
+	return result
+}
+
+func addActionToMetadata(allMetadata map[string]Metadata, action, id string) map[string]Metadata {
+	metadata, initialized := allMetadata[id]
+	if !initialized {
+		metadata = Metadata{action: true}
+	} else {
+		metadata[action] = true
+	}
+	allMetadata[id] = metadata
+	return allMetadata
+}
+
+// MergeMeta will merge actions matching prefix of second metadata into first
+func MergeMeta(prefix string, first Metadata, second Metadata) Metadata {
+	if first == nil {
+		first = Metadata{}
+	}
+
+	for key := range second {
+		if strings.HasPrefix(key, prefix) {
+			first[key] = true
+		}
+	}
+	return first
+}