add valid entities

cmd/gateway_validate.go

@@ -214,19 +214,19 @@ this command unless --online flag is used.
 
 			// Iterate over the input values and validate them against the keys in entityMap
 			for _, value := range validateCmdOnlineEntitiesFilter {
-				// Check if the value is valid by comparing it with keys in entityMap
-				isValid := false
-				for key := range validate.EntityMap {
-					if value == key {
-						isValid = true
-						break
+				// Check if the value is valid by comparing it with keys in EntityMap
+				if _, exists := validate.EntityMap[value]; !exists {
+					// Generate an error message with the list of valid keys
+					listOfKeys := make([]string, 0, len(validate.EntityMap))
+					for key := range validate.EntityMap {
+						listOfKeys = append(listOfKeys, key)
 					}
-				}
 
-				if !isValid {
-					// Generate an error message stating that the value should be part of Kong entities
-					return fmt.Errorf("invalid value '%s' for --check-online-plugins-only; it should be a valid Kong entity",
-						value)
+					return fmt.Errorf(
+						"invalid value '%s' for --check-online-plugins-only; it should be a valid Kong entity. "+
+							"Valid entities: %v",
+						value, listOfKeys,
+					)
 				}
 			}
 			return preRunSilenceEventsFlag()