Deprecate explicitly setting metricName for all scalers

CHANGELOG.md

@@ -94,6 +94,7 @@ You can find all deprecations in [this overview](https://github.com/kedacore/ked
 
 New deprecation(s):
 
+- **General**: Deprecate explicitly setting `metricName` field from `ScaledObject.triggers[*].metadata` ([#4220])(https://github.com/kedacore/keda/issues/4220)
 - **Prometheus Scaler**: `cortexOrgId` metadata deprecated in favor of custom headers ([#4208](https://github.com/kedacore/keda/issues/4208))
 
 ### Other

controllers/keda/scaledobject_controller.go

@@ -351,6 +351,13 @@ func (r *ScaledObjectReconciler) checkTriggers(scaledObject *kedav1alpha1.Scaled
 				}
 			}
 
+			// FIXME: DEPRECATED to be removed in v2.12
+			_, hasMetricName := trigger.Metadata["metricName"]
+			// aws-cloudwatch and huawei-cloudeye have a meaningful use of metricName
+			if hasMetricName && trigger.Type != "aws-cloudwatch" && trigger.Type != "huawei-cloudeye" {
+				log.Log.Info("metricName is deprecated and will be removed in v2.12, please do not set it anymore (used in %q)", trigger.Type)
+			}
+
 			name := trigger.Name
 			if name != "" {
 				if _, found := triggerNames[name]; found {

pkg/scalers/azure_blob_scaler.go

@@ -143,6 +143,7 @@ func parseAzureBlobMetadata(config *ScalerConfig, logger logr.Logger) (*azure.Bl
 		config.PodIdentity = kedav1alpha1.AuthPodIdentity{Provider: kedav1alpha1.PodIdentityProviderAzure}
 	}
 
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		meta.MetricName = kedautil.NormalizeString(fmt.Sprintf("azure-blob-%s", val))
 	} else {

pkg/scalers/azure_log_analytics_scaler.go

@@ -203,6 +203,8 @@ func parseAzureLogAnalyticsMetadata(config *ScalerConfig) (*azureLogAnalyticsMet
 	}
 
 	// Resolve metricName
+
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("%s-%s", "azure-log-analytics", val))
 	} else {

pkg/scalers/cassandra_scaler.go

@@ -148,6 +148,7 @@ func parseCassandraMetadata(config *ScalerConfig) (*CassandraMetadata, error) {
 		return nil, fmt.Errorf("no keyspace given")
 	}
 
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("cassandra-%s", val))
 	} else {

pkg/scalers/couchdb_scaler.go

@@ -176,9 +176,8 @@ func parseCouchDBMetadata(config *ScalerConfig) (*couchDBMetadata, string, error
 		// nosemgrep: db-connection-string
 		connStr = "http://" + addr
 	}
-	if val, ok := config.TriggerMetadata["metricName"]; ok {
-		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("couchdb-%s", val))
-	}
+
+	// FIXME: DEPRECATED to be removed in v2.12
 	meta.metricName = GenerateMetricNameWithIndex(config.ScalerIndex, kedautil.NormalizeString(fmt.Sprintf("coucdb-%s", meta.dbName)))
 	meta.scalerIndex = config.ScalerIndex
 	return &meta, connStr, nil

pkg/scalers/graphite_scaler.go

@@ -17,8 +17,11 @@ import (
 )
 
 const (
-	graphiteServerAddress              = "serverAddress"
-	graphiteMetricName                 = "metricName"
+	graphiteServerAddress = "serverAddress"
+
+	// FIXME: DEPRECATED to be removed in v2.12
+	graphiteMetricName = "metricName"
+
 	graphiteQuery                      = "query"
 	graphiteThreshold                  = "threshold"
 	graphiteActivationThreshold        = "activationThreshold"
@@ -92,10 +95,11 @@ func parseGraphiteMetadata(config *ScalerConfig) (*graphiteMetadata, error) {
 		return nil, fmt.Errorf("no %s given", graphiteQuery)
 	}
 
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata[graphiteMetricName]; ok && val != "" {
 		meta.metricName = val
 	} else {
-		return nil, fmt.Errorf("no %s given", graphiteMetricName)
+		meta.metricName = "graphite"
 	}
 
 	if val, ok := config.TriggerMetadata[graphiteQueryTime]; ok && val != "" {

pkg/scalers/graphite_scaler_test.go

@@ -27,8 +27,6 @@ var testGrapMetadata = []parseGraphiteMetadataTestData{
 	{map[string]string{"serverAddress": "http://localhost:81", "metricName": "request-count", "threshold": "100", "activationThreshold": "23", "query": "stats.counters.http.hello-world.request.count.count", "queryTime": "-30Seconds"}, false},
 	// missing serverAddress
 	{map[string]string{"serverAddress": "", "metricName": "request-count", "threshold": "100", "query": "stats.counters.http.hello-world.request.count.count", "queryTime": "-30Seconds"}, true},
-	// missing metricName
-	{map[string]string{"serverAddress": "http://localhost:81", "metricName": "", "threshold": "100", "query": "stats.counters.http.hello-world.request.count.count", "queryTime": "-30Seconds"}, true},
 	// malformed threshold
 	{map[string]string{"serverAddress": "http://localhost:81", "metricName": "request-count", "threshold": "one", "query": "stats.counters.http.hello-world.request.count.count", "queryTime": "-30Seconds"}, true},
 	// malformed activationThreshold

pkg/scalers/influxdb_scaler.go

@@ -118,6 +118,7 @@ func parseInfluxDBMetadata(config *ScalerConfig) (*influxDBMetadata, error) {
 		return nil, fmt.Errorf("no server url given")
 	}
 
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		metricName = util.NormalizeString(fmt.Sprintf("influxdb-%s", val))
 	} else {

pkg/scalers/mongo_scaler.go

@@ -198,6 +198,7 @@ func parseMongoDBMetadata(config *ScalerConfig) (*mongoDBMetadata, string, error
 		connStr = fmt.Sprintf("mongodb://%s:%s@%s/%s", url.QueryEscape(meta.username), url.QueryEscape(meta.password), addr, meta.dbName)
 	}
 
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("mongodb-%s", val))
 	} else {

pkg/scalers/mssql_scaler.go

@@ -170,6 +170,8 @@ func parseMSSQLMetadata(config *ScalerConfig) (*mssqlMetadata, error) {
 	}
 
 	// get the metricName, which can be explicit or from the (masked) connection string
+
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("mssql-%s", val))
 	} else {

pkg/scalers/postgresql_scaler.go

@@ -135,6 +135,7 @@ func parsePostgreSQLMetadata(config *ScalerConfig) (*postgreSQLMetadata, error)
 		meta.connection = strings.Join(params, " ")
 	}
 
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("postgresql-%s", val))
 	} else {

pkg/scalers/prometheus_scaler.go

@@ -20,8 +20,11 @@ import (
 )
 
 const (
-	promServerAddress       = "serverAddress"
-	promMetricName          = "metricName"
+	promServerAddress = "serverAddress"
+
+	// FIXME: DEPRECATED to be removed in v2.12
+	promMetricName = "metricName"
+
 	promQuery               = "query"
 	promThreshold           = "threshold"
 	promActivationThreshold = "activationThreshold"
@@ -125,10 +128,11 @@ func parsePrometheusMetadata(config *ScalerConfig) (meta *prometheusMetadata, er
 		return nil, fmt.Errorf("no %s given", promQuery)
 	}
 
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata[promMetricName]; ok && val != "" {
 		meta.metricName = val
 	} else {
-		return nil, fmt.Errorf("no %s given", promMetricName)
+		meta.metricName = "prometheus"
 	}
 
 	if val, ok := config.TriggerMetadata[promThreshold]; ok && val != "" {

pkg/scalers/prometheus_scaler_test.go

@@ -34,8 +34,6 @@ var testPromMetadata = []parsePrometheusMetadataTestData{
 	{map[string]string{"serverAddress": "http://localhost:9090", "metricName": "http_requests_total", "threshold": "100", "query": "up", "activationThreshold": "50"}, false},
 	// missing serverAddress
 	{map[string]string{"serverAddress": "", "metricName": "http_requests_total", "threshold": "100", "query": "up"}, true},
-	// missing metricName
-	{map[string]string{"serverAddress": "http://localhost:9090", "metricName": "", "threshold": "100", "query": "up"}, true},
 	// missing threshold
 	{map[string]string{"serverAddress": "http://localhost:9090", "metricName": "http_requests_total", "query": "up"}, true},
 	// malformed threshold

pkg/scalers/rabbitmq_scaler.go

@@ -245,6 +245,8 @@ func parseRabbitMQMetadata(config *ScalerConfig) (*rabbitMQMetadata, error) {
 	}
 
 	// Resolve metricName
+
+	// FIXME: DEPRECATED to be removed in v2.12
 	if val, ok := config.TriggerMetadata["metricName"]; ok {
 		meta.metricName = kedautil.NormalizeString(fmt.Sprintf("rabbitmq-%s", url.QueryEscape(val)))
 	} else {