tag alert queries that return no_data

pkg/cmd/grafana-server/main.go

@@ -25,6 +25,7 @@ import (
 	_ "github.com/grafana/grafana/pkg/tsdb/mqe"
 	_ "github.com/grafana/grafana/pkg/tsdb/mysql"
 	_ "github.com/grafana/grafana/pkg/tsdb/opentsdb"
+
 	_ "github.com/grafana/grafana/pkg/tsdb/prometheus"
 	_ "github.com/grafana/grafana/pkg/tsdb/testdata"
 )

pkg/services/alerting/engine.go

@@ -132,6 +132,15 @@ func (e *Engine) processJob(grafanaCtx context.Context, job *Job) error {
 		span.SetTag("alertId", evalContext.Rule.Id)
 		span.SetTag("dashboardId", evalContext.Rule.DashboardId)
 		span.SetTag("firing", evalContext.Firing)
+		span.SetTag("no_data", evalContext.NoDataFound)
+		if evalContext.Error != nil {
+			ext.Error.Set(span, true)
+			span.LogFields(
+				tlog.Error(evalContext.Error),
+				tlog.String("message", "alerting execution failed"),
+			)
+		}
+
 		span.Finish()
 		close(done)
 	}()