Prometheus: Browser resource caching (#60711)

Add cache control headers and range snapping to Prometheus resource API calls.

pkg/services/featuremgmt/registry.go

@@ -438,6 +438,13 @@ var (
 			FrontendOnly: true,
 			Owner:        appO11ySquad,
 		},
+		{
+			Name:         "prometheusResourceBrowserCache",
+			Description:  "Displays browser caching options in Prometheus data source configuration",
+			State:        FeatureStateAlpha,
+			FrontendOnly: true,
+			Owner:        grafanaObservabilityMetricsSquad,
+		},
 		{
 			Name:         "influxdbBackendMigration",
 			Description:  "Query InfluxDB InfluxQL without the proxy",

pkg/services/featuremgmt/toggles_gen.csv

@@ -64,6 +64,7 @@ drawerDataSourcePicker,alpha,@grafana/grafana-bi-squad,false,false,false,true
 traceqlSearch,alpha,@grafana/observability-traces-and-profiling,false,false,false,true
 prometheusMetricEncyclopedia,alpha,@grafana/observability-metrics,false,false,false,true
 timeSeriesTable,alpha,@grafana/app-o11y,false,false,false,true
+prometheusResourceBrowserCache,alpha,@grafana/observability-metrics,false,false,false,true
 influxdbBackendMigration,alpha,@grafana/observability-metrics,false,false,false,true
 clientTokenRotation,alpha,@grafana/grafana-authnz-team,false,false,false,false
 disableElasticsearchBackendExploreQuery,beta,@grafana/observability-logs,false,false,false,false

pkg/services/featuremgmt/toggles_gen.go

@@ -267,6 +267,10 @@ const (
 	// Enable time series table transformer & sparkline cell type
 	FlagTimeSeriesTable = "timeSeriesTable"
 
+	// FlagPrometheusResourceBrowserCache
+	// Displays browser caching options in Prometheus data source configuration
+	FlagPrometheusResourceBrowserCache = "prometheusResourceBrowserCache"
+
 	// FlagInfluxdbBackendMigration
 	// Query InfluxDB InfluxQL without the proxy
 	FlagInfluxdbBackendMigration = "influxdbBackendMigration"

pkg/tsdb/prometheus/resource/resource.go

@@ -7,7 +7,6 @@ import (
 	"net/http"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
-
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/tsdb/prometheus/client"
 	"github.com/grafana/grafana/pkg/tsdb/prometheus/utils"
@@ -47,6 +46,12 @@ func (r *Resource) Execute(ctx context.Context, req *backend.CallResourceRequest
 		return nil, fmt.Errorf("error querying resource: %v", err)
 	}
 
+	// frontend sets the X-Grafana-Cache with the desired response cache control value
+	if len(req.GetHTTPHeaders().Get("X-Grafana-Cache")) > 0 {
+		resp.Header.Set("X-Grafana-Cache", "y")
+		resp.Header.Set("Cache-Control", req.GetHTTPHeaders().Get("X-Grafana-Cache"))
+	}
+
 	defer func() {
 		tmpErr := resp.Body.Close()
 		if tmpErr != nil && err == nil {