Live: expose HTTP push endpoint that will read influx line protocol and publish to websocket (#32311)

Co-authored-by: Ryan McKinley <ryantxu@gmail.com>

pkg/services/live/push/push.go

@@ -0,0 +1,104 @@
+package push
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/grafana/grafana-live-sdk/telemetry/telegraf"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/registry"
+	"github.com/grafana/grafana/pkg/services/live"
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+var (
+	logger = log.New("live_push")
+)
+
+func init() {
+	registry.RegisterServiceWithPriority(&Gateway{}, registry.Low)
+}
+
+// Gateway receives data and translates it to Grafana Live publications.
+type Gateway struct {
+	Cfg         *setting.Cfg      `inject:""`
+	GrafanaLive *live.GrafanaLive `inject:""`
+
+	telegrafConverterWide         *telegraf.Converter
+	telegrafConverterLabelsColumn *telegraf.Converter
+}
+
+// Init Gateway.
+func (g *Gateway) Init() error {
+	logger.Info("Telemetry Gateway initialization")
+
+	if !g.IsEnabled() {
+		logger.Debug("Telemetry Gateway not enabled, skipping initialization")
+		return nil
+	}
+
+	// For now only Telegraf converter (influx format) is supported.
+	g.telegrafConverterWide = telegraf.NewConverter()
+	g.telegrafConverterLabelsColumn = telegraf.NewConverter(telegraf.WithUseLabelsColumn(true))
+	return nil
+}
+
+// Run Gateway.
+func (g *Gateway) Run(ctx context.Context) error {
+	if !g.IsEnabled() {
+		logger.Debug("GrafanaLive feature not enabled, skipping initialization of Telemetry Gateway")
+		return nil
+	}
+	<-ctx.Done()
+	return ctx.Err()
+}
+
+// IsEnabled returns true if the Grafana Live feature is enabled.
+func (g *Gateway) IsEnabled() bool {
+	return g.Cfg.IsLiveEnabled() // turn on when Live on for now.
+}
+
+func (g *Gateway) Handle(ctx *models.ReqContext) {
+	streamID := ctx.Params(":streamId")
+
+	stream, err := g.GrafanaLive.ManagedStreamRunner.GetOrCreateStream(streamID)
+	if err != nil {
+		logger.Error("Error getting stream", "error", err)
+		ctx.Resp.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	// TODO Grafana 8: decide which format to use or keep both.
+	converter := g.telegrafConverterWide
+	if ctx.Req.URL.Query().Get("format") == "labels_column" {
+		converter = g.telegrafConverterLabelsColumn
+	}
+
+	body, err := ctx.Req.Body().Bytes()
+	if err != nil {
+		logger.Error("Error reading body", "error", err)
+		ctx.Resp.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	logger.Debug("Live Push request body", "streamId", streamID, "bodyLength", len(body))
+
+	metricFrames, err := converter.Convert(body)
+	if err != nil {
+		logger.Error("Error converting metrics", "error", err)
+		ctx.Resp.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	// TODO -- make sure all packets are combined together!
+	// interval = "1s" vs flush_interval = "5s"
+
+	for _, mf := range metricFrames {
+		err := stream.Push(mf.Key(), mf.Frame())
+		if err != nil {
+			ctx.Resp.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+	}
+}