Prometheus: Read feature toggles once when creating plugin instance (#102131)

* initialize an instance with feature toggles

* read grafana config only once

* use feature toggles directly

pkg/promlib/library.go

@@ -67,8 +67,10 @@ func newInstanceSettings(httpClientProvider *sdkhttpclient.Provider, log log.Log
 			return nil, fmt.Errorf("error creating http client: %v", err)
 		}
 
+		featureToggles := backend.GrafanaConfigFromContext(ctx).FeatureToggles()
+
 		// New version using custom client and better response parsing
-		qd, err := querydata.New(httpClient, settings, log)
+		qd, err := querydata.New(httpClient, settings, log, featureToggles)
 		if err != nil {
 			return nil, err
 		}

pkg/promlib/querydata/request.go

@@ -46,12 +46,14 @@ type QueryData struct {
 	URL                string
 	TimeInterval       string
 	exemplarSampler    func() exemplar.Sampler
+	featureToggles     backend.FeatureToggles
 }
 
 func New(
 	httpClient *http.Client,
 	settings backend.DataSourceInstanceSettings,
 	plog log.Logger,
+	featureToggles backend.FeatureToggles,
 ) (*QueryData, error) {
 	jsonData, err := utils.GetJsonData(settings)
 	if err != nil {
@@ -86,6 +88,7 @@ func New(
 		ID:                 settings.ID,
 		URL:                settings.URL,
 		exemplarSampler:    exemplarSampler,
+		featureToggles:     featureToggles,
 	}, nil
 }
 
@@ -98,9 +101,8 @@ func (s *QueryData) Execute(ctx context.Context, req *backend.QueryDataRequest)
 	}
 
 	var (
-		cfg                               = backend.GrafanaConfigFromContext(ctx)
-		hasPromQLScopeFeatureFlag         = cfg.FeatureToggles().IsEnabled("promQLScope")
-		hasPrometheusRunQueriesInParallel = cfg.FeatureToggles().IsEnabled("prometheusRunQueriesInParallel")
+		hasPromQLScopeFeatureFlag         = s.featureToggles.IsEnabled("promQLScope")
+		hasPrometheusRunQueriesInParallel = s.featureToggles.IsEnabled("prometheusRunQueriesInParallel")
 	)
 
 	if hasPrometheusRunQueriesInParallel {

pkg/promlib/querydata/request_test.go

@@ -472,7 +472,7 @@ func setup() (*testContext, error) {
 		return nil, err
 	}
 
-	queryData, _ := querydata.New(httpClient, settings, log.New())
+	queryData, _ := querydata.New(httpClient, settings, log.New(), backend.FeatureToggles{})
 
 	return &testContext{
 		httpProvider: httpProvider,