Prometheus: fix parsing of infinite sample values (#28287) (#28288)

* Prometheus: fix parsing of infinite sample values (#28287)

* Prometheus: Use common function to parse both sample values and histogram "le" label

public/app/plugins/datasource/prometheus/result_transformer.test.ts

@@ -379,4 +379,47 @@ describe('Prometheus Result Transformer', () => {
       expect(result[0].fields[1].values.toArray()).toEqual([null, null, 10, null, 10]);
     });
   });
+
+  describe('When infinity values are returned', () => {
+    describe('When resultType is scalar', () => {
+      const response = {
+        status: 'success',
+        data: {
+          resultType: 'scalar',
+          result: [1443454528, '+Inf'],
+        },
+      };
+
+      it('should correctly parse values', () => {
+        const result: DataFrame[] = transform({ data: response } as any, { ...options, target: { format: 'table' } });
+        expect(result[0].fields[1].values.toArray()).toEqual([Number.POSITIVE_INFINITY]);
+      });
+    });
+
+    describe('When resultType is vector', () => {
+      const response = {
+        status: 'success',
+        data: {
+          resultType: 'vector',
+          result: [
+            {
+              metric: { __name__: 'test', job: 'testjob' },
+              value: [1443454528, '+Inf'],
+            },
+            {
+              metric: { __name__: 'test', job: 'testjob' },
+              value: [1443454528, '-Inf'],
+            },
+          ],
+        },
+      };
+
+      describe('When format is table', () => {
+        it('should correctly parse values', () => {
+          const result: DataFrame[] = transform({ data: response } as any, { ...options, target: { format: 'table' } });
+          expect(result[0].fields[3].values.toArray()).toEqual([Number.POSITIVE_INFINITY, Number.NEGATIVE_INFINITY]);
+        });
+      });
+    });
+  });
 });

public/app/plugins/datasource/prometheus/result_transformer.ts

@@ -22,6 +22,9 @@ import {
   TransformOptions,
 } from './types';
 
+const POSITIVE_INFINITY_SAMPLE_VALUE = '+Inf';
+const NEGATIVE_INFINITY_SAMPLE_VALUE = '-Inf';
+
 export function transform(
   response: FetchResponse<PromDataSuccessResponse>,
   transformOptions: {
@@ -116,7 +119,7 @@ function transformToDataFrame(data: MatrixOrVectorResult, options: TransformOpti
     const dps: PromValue[] = [];
 
     for (const value of data.values) {
-      let dpValue: number | null = parseFloat(value[1]);
+      let dpValue: number | null = parseSampleValue(value[1]);
 
       if (isNaN(dpValue)) {
         dpValue = null;
@@ -180,12 +183,12 @@ function transformMetricDataToTable(md: MatrixOrVectorResult[], options: Transfo
       d.values.forEach(val => {
         timeField.values.add(val[0] * 1000);
         metricFields.forEach(metricField => metricField.values.add(getLabelValue(d.metric, metricField.name)));
-        valueField.values.add(parseFloat(val[1]));
+        valueField.values.add(parseSampleValue(val[1]));
       });
     } else {
       timeField.values.add(d.value[0] * 1000);
       metricFields.forEach(metricField => metricField.values.add(getLabelValue(d.metric, metricField.name)));
-      valueField.values.add(parseFloat(d.value[1]));
+      valueField.values.add(parseSampleValue(d.value[1]));
     }
   });
 
@@ -200,7 +203,7 @@ function transformMetricDataToTable(md: MatrixOrVectorResult[], options: Transfo
 function getLabelValue(metric: PromMetric, label: string): string | number {
   if (metric.hasOwnProperty(label)) {
     if (label === 'le') {
-      return parseHistogramLabel(metric[label]);
+      return parseSampleValue(metric[label]);
     }
     return metric[label];
   }
@@ -225,7 +228,7 @@ function getValueField(
     name: valueName,
     type: FieldType.number,
     config: {},
-    values: new ArrayVector<number | null>(data.map(val => (parseValue ? parseFloat(val[1]) : val[1]))),
+    values: new ArrayVector<number | null>(data.map(val => (parseValue ? parseSampleValue(val[1]) : val[1]))),
   };
 }
 
@@ -289,8 +292,8 @@ function sortSeriesByLabel(s1: DataFrame, s2: DataFrame): number {
 
   try {
     // fail if not integer. might happen with bad queries
-    le1 = parseHistogramLabel(s1.name ?? '');
+    le1 = parseSampleValue(s1.name ?? '');
-    le2 = parseHistogramLabel(s2.name ?? '');
+    le2 = parseSampleValue(s2.name ?? '');
   } catch (err) {
     console.error(err);
     return 0;
@@ -307,9 +310,13 @@ function sortSeriesByLabel(s1: DataFrame, s2: DataFrame): number {
   return 0;
 }
 
-function parseHistogramLabel(le: string): number {
+function parseSampleValue(value: string): number {
-  if (le === '+Inf') {
+  switch (value) {
-    return +Infinity;
+    case POSITIVE_INFINITY_SAMPLE_VALUE:
+      return Number.POSITIVE_INFINITY;
+    case NEGATIVE_INFINITY_SAMPLE_VALUE:
+      return Number.NEGATIVE_INFINITY;
+    default:
+      return parseFloat(value);
   }
-  return Number(le);
 }