fix: add default Operation in Azure Service Bus scaler (#6731)

Signed-off-by: Rick Brouwer <[email protected]>

Author: rickbrouwer

CHANGELOG.md

@@ -74,6 +74,7 @@ To learn more about active deprecations, we recommend checking [GitHub Discussio
 
 - **General**: Admission Webhook blocks ScaledObject without metricType with fallback ([#6696](https://github.com/kedacore/keda/issues/6696))
 - **AWS SQS Queue Scaler**: Fix AWS SQS Queue queueURLFromEnv not working ([#6712](https://github.com/kedacore/keda/issues/6712))
+- **Azure Service Bus scaler**: Fix Azure Service Bus scaler add default Operation ([#6730](https://github.com/kedacore/keda/issues/6730))
 - **Temporal Scaler**: Fix Temporal Scaler does not work properly with API Key authentication against Temporal Cloud as TLS is not enabled on the client ([#6703](https://github.com/kedacore/keda/issues/6703))
 
 ### Deprecations

pkg/scalers/azure_servicebus_scaler.go

@@ -67,7 +67,7 @@ type azureServiceBusMetadata struct {
 	FullyQualifiedNamespace string
 	UseRegex                bool `keda:"name=useRegex,          order=triggerMetadata, optional"`
 	EntityNameRegex         *regexp.Regexp
-	Operation               string `keda:"name=operation,          order=triggerMetadata, enum=sum;max;avg, optional"`
+	Operation               string `keda:"name=operation,          order=triggerMetadata, enum=sum;max;avg, default=sum"`
 	triggerIndex            int
 	timeout                 time.Duration
 }

pkg/scalers/azure_servicebus_scaler_test.go

@@ -108,6 +108,7 @@ var parseServiceBusMetadataDataset = []parseServiceBusMetadataTestData{
 	{map[string]string{"queueName": queueName, "connectionFromEnv": connectionSetting, "useRegex": "true", "operation": avgOperation}, false, queue, defaultSuffix, map[string]string{}, ""},
 	{map[string]string{"queueName": queueName, "connectionFromEnv": connectionSetting, "useRegex": "true", "operation": sumOperation}, false, queue, defaultSuffix, map[string]string{}, ""},
 	{map[string]string{"queueName": queueName, "connectionFromEnv": connectionSetting, "useRegex": "true", "operation": maxOperation}, false, queue, defaultSuffix, map[string]string{}, ""},
+	{map[string]string{"queueName": queueName, "connectionFromEnv": connectionSetting, "useRegex": "true"}, false, queue, defaultSuffix, map[string]string{}, ""},
 	{map[string]string{"queueName": queueName, "connectionFromEnv": connectionSetting, "useRegex": "true", "operation": "random"}, true, queue, defaultSuffix, map[string]string{}, ""},
 	// queue with invalid regex string
 	{map[string]string{"queueName": "*", "connectionFromEnv": connectionSetting, "useRegex": "true", "operation": "avg"}, true, queue, defaultSuffix, map[string]string{}, ""},