Loki: alerting: handle variables like __interval and __range (#42126)

pkg/tsdb/loki/parse_query_test.go

@@ -0,0 +1,54 @@
+package loki
+
+import (
+	"testing"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/stretchr/testify/require"
+)
+
+func TestParseQuery(t *testing.T) {
+	t.Run("parsing query model", func(t *testing.T) {
+		queryContext := &backend.QueryDataRequest{
+			Queries: []backend.DataQuery{
+				{
+					JSON: []byte(`
+					{
+						"expr": "go_goroutines $__interval $__interval_ms $__range $__range_s $__range_ms",
+						"format": "time_series",
+						"refId": "A"
+					}`,
+					),
+					TimeRange: backend.TimeRange{
+						From: time.Now().Add(-3000 * time.Second),
+						To:   time.Now(),
+					},
+					Interval:      time.Second * 15,
+					MaxDataPoints: 200,
+				},
+			},
+		}
+		dsInfo := &datasourceInfo{}
+		models, err := parseQuery(dsInfo, queryContext)
+		require.NoError(t, err)
+		require.Equal(t, time.Second*15, models[0].Step)
+		require.Equal(t, "go_goroutines 15s 15000 3000s 3000 3000000", models[0].Expr)
+	})
+	t.Run("interpolate variables, range between 1s and 0.5s", func(t *testing.T) {
+		expr := "go_goroutines $__interval $__interval_ms $__range $__range_s $__range_ms"
+
+		interval := time.Millisecond * 50
+		timeRange := time.Millisecond * 750
+
+		require.Equal(t, "go_goroutines 50ms 50 1s 1 750", interpolateVariables(expr, interval, timeRange))
+	})
+	t.Run("parsing query model, range below 0.5s", func(t *testing.T) {
+		expr := "go_goroutines $__interval $__interval_ms $__range $__range_s $__range_ms"
+
+		interval := time.Millisecond * 50
+		timeRange := time.Millisecond * 250
+
+		require.Equal(t, "go_goroutines 50ms 50 0s 0 250", interpolateVariables(expr, interval, timeRange))
+	})
+}