Plugins: Transform plugin support (#20036)

currently temporary separate http api

pkg/api/api.go

@@ -328,6 +328,7 @@ func (hs *HTTPServer) registerRoutes() {
 		// metrics
 		apiRoute.Post("/tsdb/query", bind(dtos.MetricRequest{}), Wrap(hs.QueryMetrics))
 		apiRoute.Post("/tsdb/query/v2", bind(dtos.MetricRequest{}), Wrap(hs.QueryMetricsV2))
+		apiRoute.Post("/tsdb/transform", bind(dtos.MetricRequest{}), Wrap(hs.Transform))
 		apiRoute.Get("/tsdb/testdata/scenarios", Wrap(GetTestDataScenarios))
 		apiRoute.Get("/tsdb/testdata/gensql", reqGrafanaAdmin, Wrap(GenerateSQLTestData))
 		apiRoute.Get("/tsdb/testdata/random-walk", Wrap(GetTestDataRandomWalk))

pkg/api/transform.go

@@ -0,0 +1,79 @@
+package api
+
+import (
+	"net/http"
+
+	"github.com/grafana/grafana/pkg/api/dtos"
+	m "github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/setting"
+	"github.com/grafana/grafana/pkg/tsdb"
+)
+
+// POST /api/tsdb/transform
+// This enpoint is tempory, will be part of v2 query endpoint.
+func (hs *HTTPServer) Transform(c *m.ReqContext, reqDto dtos.MetricRequest) Response {
+	if !setting.IsExpressionsEnabled() {
+		return Error(404, "Expressions feature toggle is not enabled", nil)
+	}
+	if plugins.Transform == nil {
+		return Error(http.StatusServiceUnavailable, "transform plugin is not loaded", nil)
+	}
+
+	timeRange := tsdb.NewTimeRange(reqDto.From, reqDto.To)
+
+	if len(reqDto.Queries) == 0 {
+		return Error(400, "No queries found in query", nil)
+	}
+
+	var datasourceID int64
+	for _, query := range reqDto.Queries {
+		name, err := query.Get("datasource").String()
+		if err != nil {
+			return Error(500, "datasource missing name", err)
+		}
+		datasourceID, err = query.Get("datasourceId").Int64()
+		if err != nil {
+			return Error(400, "GEL datasource missing ID", nil)
+		}
+		if name == "-- GEL --" {
+			break
+		}
+	}
+
+	ds, err := hs.DatasourceCache.GetDatasource(datasourceID, c.SignedInUser, c.SkipCache)
+	if err != nil {
+		if err == m.ErrDataSourceAccessDenied {
+			return Error(403, "Access denied to datasource", err)
+		}
+		return Error(500, "Unable to load datasource meta data", err)
+	}
+
+	request := &tsdb.TsdbQuery{TimeRange: timeRange, Debug: reqDto.Debug}
+
+	for _, query := range reqDto.Queries {
+		request.Queries = append(request.Queries, &tsdb.Query{
+			RefId:         query.Get("refId").MustString("A"),
+			MaxDataPoints: query.Get("maxDataPoints").MustInt64(100),
+			IntervalMs:    query.Get("intervalMs").MustInt64(1000),
+			Model:         query,
+			DataSource:    ds,
+		})
+	}
+
+	resp, err := plugins.Transform.Transform(c.Req.Context(), ds, request)
+	if err != nil {
+		return Error(500, "Transform request error", err)
+	}
+
+	statusCode := 200
+	for _, res := range resp.Results {
+		if res.Error != nil {
+			res.ErrorString = res.Error.Error()
+			resp.Message = res.ErrorString
+			statusCode = 400
+		}
+	}
+
+	return JSON(statusCode, &resp)
+}