Cloudwatch: Refactor dimension keys resource request (#57148)

* use new layered architecture in get dimension keys request

* go lint fixes

* pr feedback

* more pr feedback

* remove not used code

* refactor route middleware

* change signature

* add integration tests for the dimension keys route

* use request suffix instead of query

* use typed args also in frontend

* remove unused import

* harmonize naming

* fix merge conflict

pkg/tsdb/cloudwatch/resource_handler.go

@@ -9,6 +9,7 @@ import (
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/resource/httpadapter"
 	"github.com/grafana/grafana/pkg/tsdb/cloudwatch/cwlog"
+	"github.com/grafana/grafana/pkg/tsdb/cloudwatch/routes"
 )
 
 func (e *cloudWatchExecutor) newResourceMux() *http.ServeMux {
@@ -17,13 +18,13 @@ func (e *cloudWatchExecutor) newResourceMux() *http.ServeMux {
 	mux.HandleFunc("/namespaces", handleResourceReq(e.handleGetNamespaces))
 	mux.HandleFunc("/metrics", handleResourceReq(e.handleGetMetrics))
 	mux.HandleFunc("/all-metrics", handleResourceReq(e.handleGetAllMetrics))
-	mux.HandleFunc("/dimension-keys", handleResourceReq(e.handleGetDimensionKeys))
 	mux.HandleFunc("/dimension-values", handleResourceReq(e.handleGetDimensionValues))
 	mux.HandleFunc("/ebs-volume-ids", handleResourceReq(e.handleGetEbsVolumeIds))
 	mux.HandleFunc("/ec2-instance-attribute", handleResourceReq(e.handleGetEc2InstanceAttribute))
 	mux.HandleFunc("/resource-arns", handleResourceReq(e.handleGetResourceArns))
 	mux.HandleFunc("/log-groups", handleResourceReq(e.handleGetLogGroups))
 	mux.HandleFunc("/all-log-groups", handleResourceReq(e.handleGetAllLogGroups))
+	mux.HandleFunc("/dimension-keys", routes.ResourceRequestMiddleware(routes.DimensionKeysHandler, e.getClients))
 	return mux
 }