From 4d1b969a5c640287c25e6d0f602278f5a4da7aac Mon Sep 17 00:00:00 2001
From: Ryan McKinley <ryantxu@gmail.com>
Date: Thu, 31 Oct 2019 16:22:00 -0700
Subject: [PATCH] GEL: include the expression count in the request (#20114)

---
 pkg/api/api.go                                    |  4 +++-
 pkg/api/metrics.go                                |  2 +-
 public/app/features/dashboard/state/runRequest.ts |  2 --
 .../features/expressions/ExpressionDatasource.ts  | 15 +++++++++++----
 4 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/pkg/api/api.go b/pkg/api/api.go
index 9308403b276..3f10f3565fe 100644
--- a/pkg/api/api.go
+++ b/pkg/api/api.go
@@ -327,11 +327,13 @@ 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.Get("/tsdb/testdata/scenarios", Wrap(GetTestDataScenarios))
 		apiRoute.Get("/tsdb/testdata/gensql", reqGrafanaAdmin, Wrap(GenerateSQLTestData))
 		apiRoute.Get("/tsdb/testdata/random-walk", Wrap(GetTestDataRandomWalk))
 
+		// DataSource w/ expressions
+		apiRoute.Post("/ds/query", bind(dtos.MetricRequest{}), Wrap(hs.QueryMetricsV2))
+
 		apiRoute.Group("/alerts", func(alertsRoute routing.RouteRegister) {
 			alertsRoute.Post("/test", bind(dtos.AlertTestCommand{}), Wrap(AlertTest))
 			alertsRoute.Post("/:alertId/pause", reqEditorRole, bind(dtos.PauseAlertCommand{}), Wrap(PauseAlert))
diff --git a/pkg/api/metrics.go b/pkg/api/metrics.go
index 7889fb9ec94..a0ca62cfc23 100644
--- a/pkg/api/metrics.go
+++ b/pkg/api/metrics.go
@@ -16,7 +16,7 @@ import (
 	"github.com/grafana/grafana/pkg/util"
 )
 
-// POST /api/tsdb/query/v2
+// POST /api/ds/query   DataSource query w/ expressions
 func (hs *HTTPServer) QueryMetricsV2(c *m.ReqContext, reqDto dtos.MetricRequest) Response {
 	if !setting.IsExpressionsEnabled() {
 		return Error(404, "Expressions feature toggle is not enabled", nil)
diff --git a/public/app/features/dashboard/state/runRequest.ts b/public/app/features/dashboard/state/runRequest.ts
index 9b07e07a363..85f8f54f67f 100644
--- a/public/app/features/dashboard/state/runRequest.ts
+++ b/public/app/features/dashboard/state/runRequest.ts
@@ -137,8 +137,6 @@ function cancelNetworkRequestsOnUnsubscribe(req: DataQueryRequest) {
 }
 
 export function callQueryMethod(datasource: DataSourceApi, request: DataQueryRequest) {
-  console.log('CALL', request.targets);
-
   // If any query has an expression, use the expression endpoint
   for (const target of request.targets) {
     if (target.datasource === ExpressionDatasourceID) {
diff --git a/public/app/features/expressions/ExpressionDatasource.ts b/public/app/features/expressions/ExpressionDatasource.ts
index d9c900f0c9a..d876227a81a 100644
--- a/public/app/features/expressions/ExpressionDatasource.ts
+++ b/public/app/features/expressions/ExpressionDatasource.ts
@@ -12,7 +12,7 @@ import { config } from '@grafana/runtime';
 import { getBackendSrv } from 'app/core/services/backend_srv';
 
 /**
- * This is a singleton that is not actually instantiated
+ * This is a singleton instance that just pretends to be a DataSource
  */
 export class ExpressionDatasourceApi extends DataSourceApi<ExpressionQuery> {
   constructor(instanceSettings: DataSourceInstanceSettings) {
@@ -26,30 +26,37 @@ export class ExpressionDatasourceApi extends DataSourceApi<ExpressionQuery> {
   query(request: DataQueryRequest): Observable<DataQueryResponse> {
     const { targets, intervalMs, maxDataPoints, range } = request;
 
+    let expressionCount = 0;
     const orgId = (window as any).grafanaBootData.user.orgId;
     const queries = targets.map(q => {
       if (q.datasource === ExpressionDatasourceID) {
+        expressionCount++;
         return {
           ...q,
           datasourceId: this.id,
           orgId,
         };
       }
-      const ds = config.datasources[q.datasource || config.defaultDatasource];
+      const dsName = q.datasource && q.datasource !== 'default' ? q.datasource : config.defaultDatasource;
+      const ds = config.datasources[dsName];
+      if (!ds) {
+        throw new Error('Unknown Datasource: ' + q.datasource);
+      }
       return {
         ...q,
         datasourceId: ds.id,
         intervalMs,
         maxDataPoints,
         orgId,
-        // ?? alias: templateSrv.replace(q.alias || ''),
       };
     });
     const req: Promise<DataQueryResponse> = getBackendSrv()
-      .post('/api/tsdb/query/v2', {
+      .post('/api/ds/query', {
         from: range.from.valueOf().toString(),
         to: range.to.valueOf().toString(),
         queries: queries,
+        range,
+        expressionCount,
       })
       .then((rsp: any) => {
         return this.toDataQueryResponse(rsp);