Ajay tripathy pvc error fix (#644)

* add csv fallback

* log class match

* filter empty volumenames out

pkg/costmodel/costmodel.go

@@ -177,10 +177,10 @@ const (
 		)
 	) by (namespace,container_name,pod_name,node,cluster_id)
 	* on (pod_name, namespace, cluster_id) group_left(container) label_replace(avg(avg_over_time(kube_pod_status_phase{phase="Running"}[%s] %s)) by (pod,namespace,cluster_id), "pod_name","$1","pod","(.+)")`
-	queryPVRequestsStr = `avg(avg(kube_persistentvolumeclaim_info) by (persistentvolumeclaim, storageclass, namespace, volumename, cluster_id)
+	queryPVRequestsStr = `avg(avg(kube_persistentvolumeclaim_info{volumename != ""}) by (persistentvolumeclaim, storageclass, namespace, volumename, cluster_id)
 	*
 	on (persistentvolumeclaim, namespace, cluster_id) group_right(storageclass, volumename)
-	sum(kube_persistentvolumeclaim_resource_requests_storage_bytes) by (persistentvolumeclaim, namespace, cluster_id, kubernetes_name)) by (persistentvolumeclaim, storageclass, namespace, volumename, cluster_id)`
+	sum(kube_persistentvolumeclaim_resource_requests_storage_bytes{volumename != ""}) by (persistentvolumeclaim, namespace, cluster_id, kubernetes_name)) by (persistentvolumeclaim, storageclass, namespace, volumename, cluster_id)`
 	// queryRAMAllocationByteHours yields the total byte-hour RAM allocation over the given
 	// window, aggregated by container.
 	//  [line 3]  sum_over_time(each byte) = [byte*scrape] by metric