Prometheus: Add support for streaming scalar parsing (#48725)

pkg/util/converter/prom.go

@@ -111,6 +111,8 @@ func readPrometheusData(iter *jsoniter.Iterator) *backend.DataResponse {
 				rsp = readMatrixOrVector(iter)
 			case "streams":
 				rsp = readStream(iter)
+			case "scalar":
+				rsp = readScalar(iter)
 			default:
 				iter.Skip()
 				rsp = &backend.DataResponse{
@@ -288,6 +290,29 @@ func readLabelsOrExemplars(iter *jsoniter.Iterator) (*data.Frame, [][2]string) {
 	return frame, pairs
 }
 
+func readScalar(iter *jsoniter.Iterator) *backend.DataResponse {
+	timeField := data.NewFieldFromFieldType(data.FieldTypeTime, 0)
+	timeField.Name = data.TimeSeriesTimeFieldName
+	valueField := data.NewFieldFromFieldType(data.FieldTypeFloat64, 0)
+	valueField.Name = data.TimeSeriesValueFieldName
+	valueField.Labels = data.Labels{}
+
+	t, v, err := readTimeValuePair(iter)
+	if err == nil {
+		timeField.Append(t)
+		valueField.Append(v)
+	}
+
+	frame := data.NewFrame("", timeField, valueField)
+	frame.Meta = &data.FrameMeta{
+		Type: data.FrameTypeTimeSeriesMany,
+	}
+
+	return &backend.DataResponse{
+		Frames: []*data.Frame{frame},
+	}
+}
+
 func readMatrixOrVector(iter *jsoniter.Iterator) *backend.DataResponse {
 	rsp := &backend.DataResponse{}
 

pkg/util/converter/prom_test.go

@@ -19,6 +19,7 @@ func TestReadPromFrames(t *testing.T) {
 		"prom-matrix",
 		"prom-matrix-with-nans",
 		"prom-vector",
+		"prom-scalar",
 		"prom-series",
 		"prom-warnings",
 		"prom-error",

pkg/util/converter/testdata/prom-scalar-frame.json

@@ -0,0 +1,40 @@
+{
+  "frames": [
+    {
+      "schema": {
+        "meta": {
+          "type": "timeseries-many"
+        },
+        "fields": [
+          {
+            "name": "Time",
+            "type": "time",
+            "typeInfo": {
+              "frame": "time.Time"
+            }
+          },
+          {
+            "name": "Value",
+            "type": "number",
+            "typeInfo": {
+              "frame": "float64"
+            },
+            "labels": {
+              
+            }
+          }
+        ]
+      },
+      "data": {
+        "values": [
+          [
+            1651680139104
+          ],
+          [
+            0.00002482
+          ]
+        ]
+      }
+    }
+  ]
+}

pkg/util/converter/testdata/prom-scalar-golden.txt

@@ -0,0 +1,18 @@
+🌟 This was machine generated.  Do not edit. 🌟
+
+Frame[0] {
+    "type": "timeseries-many"
+}
+Name: 
+Dimensions: 2 Fields by 1 Rows
++-----------------------------------+-----------------+
+| Name: Time                        | Name: Value     |
+| Labels:                           | Labels:         |
+| Type: []time.Time                 | Type: []float64 |
++-----------------------------------+-----------------+
+| 2022-05-04 16:02:19.104 +0000 UTC | 2.482e-05       |
++-----------------------------------+-----------------+
+
+
+====== TEST DATA RESPONSE (arrow base64) ======
+FRAME=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

pkg/util/converter/testdata/prom-scalar.json

@@ -0,0 +1,10 @@
+{
+	"status": "success",
+	"data": {
+		"resultType": "scalar",
+		"result": [
+			1651680139.104,
+			"0.00002482"
+		]
+	}
+}