loki: add feature-toggle check to live-mode (#49012)

packages/grafana-data/src/types/featureToggles.gen.ts

@@ -36,6 +36,7 @@ export interface FeatureToggles {
   showFeatureFlagsInUI?: boolean;
   publicDashboards?: boolean;
   lokiLive?: boolean;
+  lokiDataframeApi?: boolean;
   swaggerUi?: boolean;
   featureHighlights?: boolean;
   dashboardComments?: boolean;

pkg/plugins/manager/manager_integration_test.go

@@ -79,7 +79,7 @@ func TestPluginManager_int_init(t *testing.T) {
 	es := elasticsearch.ProvideService(hcp)
 	grap := graphite.ProvideService(hcp, tracer)
 	idb := influxdb.ProvideService(hcp)
-	lk := loki.ProvideService(hcp, tracer)
+	lk := loki.ProvideService(hcp, features, tracer)
 	otsdb := opentsdb.ProvideService(hcp)
 	pr := prometheus.ProvideService(hcp, cfg, features, tracer)
 	tmpo := tempo.ProvideService(hcp)

pkg/services/featuremgmt/registry.go

@@ -117,6 +117,11 @@ var (
 			Description: "support websocket streaming for loki (early prototype)",
 			State:       FeatureStateAlpha,
 		},
+		{
+			Name:        "lokiDataframeApi",
+			Description: "use experimental loki api for websocket streaming (early prototype)",
+			State:       FeatureStateAlpha,
+		},
 		{
 			Name:        "swaggerUi",
 			Description: "Serves swagger UI",

pkg/services/featuremgmt/toggles_gen.go

@@ -87,6 +87,10 @@ const (
 	// support websocket streaming for loki (early prototype)
 	FlagLokiLive = "lokiLive"
 
+	// FlagLokiDataframeApi
+	// use experimental loki api for websocket streaming (early prototype)
+	FlagLokiDataframeApi = "lokiDataframeApi"
+
 	// FlagSwaggerUi
 	// Serves swagger UI
 	FlagSwaggerUi = "swaggerUi"

pkg/tsdb/loki/loki.go

@@ -16,11 +16,13 @@ import (
 	"github.com/grafana/grafana/pkg/infra/httpclient"
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/infra/tracing"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"go.opentelemetry.io/otel/attribute"
 )
 
 type Service struct {
 	im       instancemgmt.InstanceManager
+	features featuremgmt.FeatureToggles
 	plog     log.Logger
 	tracer   tracing.Tracer
 }
@@ -31,9 +33,10 @@ var (
 	_ backend.CallResourceHandler = (*Service)(nil)
 )
 
-func ProvideService(httpClientProvider httpclient.Provider, tracer tracing.Tracer) *Service {
+func ProvideService(httpClientProvider httpclient.Provider, features featuremgmt.FeatureToggles, tracer tracing.Tracer) *Service {
 	return &Service{
 		im:       datasource.NewInstanceManager(newInstanceSettings(httpClientProvider)),
+		features: features,
 		plog:     log.New("tsdb.loki"),
 		tracer:   tracer,
 	}

pkg/tsdb/loki/streaming.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"net/http"
 	"net/url"
 	"os"
 	"os/signal"
@@ -14,6 +13,7 @@ import (
 	"github.com/gorilla/websocket"
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/data"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
 )
 
 func (s *Service) SubscribeStream(_ context.Context, req *backend.SubscribeStreamRequest) (*backend.SubscribeStreamResponse, error) {
@@ -82,13 +82,13 @@ func (s *Service) RunStream(ctx context.Context, req *backend.RunStreamRequest,
 	params := url.Values{}
 	params.Add("query", query.Expr)
 
-	isV1 := false
+	lokiDataframeApi := s.features.IsEnabled(featuremgmt.FlagLokiDataframeApi)
+
 	wsurl, _ := url.Parse(dsInfo.URL)
 
-	// Check if the v2alpha endpoint exists
+	if lokiDataframeApi {
 		wsurl.Path = "/loki/api/v2alpha/tail"
-	if !is400(dsInfo.HTTPClient, wsurl) {
+	} else {
-		isV1 = true
 		wsurl.Path = "/loki/api/v1/tail"
 	}
 
@@ -131,7 +131,7 @@ func (s *Service) RunStream(ctx context.Context, req *backend.RunStreamRequest,
 			}
 
 			frame := &data.Frame{}
-			if isV1 {
+			if !lokiDataframeApi {
 				frame, err = lokiBytesToLabeledFrame(message)
 			} else {
 				err = json.Unmarshal(message, &frame)
@@ -182,19 +182,3 @@ func (s *Service) PublishStream(_ context.Context, _ *backend.PublishStreamReque
 		Status: backend.PublishStreamStatusPermissionDenied,
 	}, nil
 }
-
-// if the v2 endpoint exists it will give a 400 rather than 404/500
-func is400(client *http.Client, url *url.URL) bool {
-	req, err := http.NewRequest("GET", url.String(), nil)
-	if err != nil {
-		return false
-	}
-	rsp, err := client.Do(req)
-	if err != nil {
-		return false
-	}
-	defer func() {
-		_ = rsp.Body.Close()
-	}()
-	return rsp.StatusCode == 400 // will be true
-}