Prometheus: parse value as number when label is le (#26375)

* Prometheus: parse value as number when label is le

* Convert prometheus table value back to string for modify query

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

@@ -24,6 +24,12 @@ describe('addLabelToQuery()', () => {
     expect(addLabelToQuery('sum by (xx) (foo)', 'bar', 'baz')).toBe('sum by (xx) (foo{bar="baz"})');
   });
 
+  it('should convert number Infinity to +Inf', () => {
+    expect(
+      addLabelToQuery('sum(rate(prometheus_tsdb_compaction_chunk_size_bytes_bucket[5m])) by (le)', 'le', Infinity)
+    ).toBe('sum(rate(prometheus_tsdb_compaction_chunk_size_bytes_bucket{le="+Inf"}[5m])) by (le)');
+  });
+
   it('should handle selectors with punctuation', () => {
     expect(addLabelToQuery('foo{instance="my-host.com:9100"}', 'bar', 'baz')).toBe(
       'foo{bar="baz",instance="my-host.com:9100"}'

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

@@ -21,7 +21,7 @@ const selectorRegexp = /{([^{]*)}/g;
 export function addLabelToQuery(
   query: string,
   key: string,
-  value: string,
+  value: string | number,
   operator?: string,
   hasNoMetrics?: boolean
 ): string {
@@ -29,6 +29,9 @@ export function addLabelToQuery(
     throw new Error('Need label to add to query.');
   }
 
+  // We need to make sure that we convert the value back to string because it may be a number
+  const transformedValue = value === Infinity ? '+Inf' : value.toString();
+
   // Add empty selectors to bare metric names
   let previousWord: string;
   query = query.replace(metricNameRegexp, (match, word, offset) => {
@@ -65,7 +68,7 @@ export function addLabelToQuery(
   while (match) {
     const prefix = query.slice(lastIndex, match.index);
     const selector = match[1];
-    const selectorWithLabel = addLabelToSelector(selector, key, value, operator);
+    const selectorWithLabel = addLabelToSelector(selector, key, transformedValue, operator);
     lastIndex = match.index + match[1].length + 2;
     suffix = query.slice(match.index + match[0].length);
     parts.push(prefix, selectorWithLabel);

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

@@ -114,6 +114,17 @@ describe('Prometheus Result Transformer', () => {
         { text: 'Value' },
       ]);
     });
+
+    it('should return table model with le label values parsed as numbers', () => {
+      const table = ctx.resultTransformer.transformMetricDataToTable([
+        {
+          metric: { le: '102' },
+          value: [1594908838, '0'],
+        },
+      ]);
+      expect(table.type).toBe('table');
+      expect(table.rows).toEqual([[1594908838000, 102, 0]]);
+    });
   });
 
   describe('When resultFormat is time series and instant = true', () => {

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

@@ -132,7 +132,11 @@ export class ResultTransformer {
             for (j = 0; j < sortedLabels.length; j++) {
               const label = sortedLabels[j];
               if (series.metric.hasOwnProperty(label)) {
+                if (label === 'le') {
+                  reordered.push(parseHistogramLabel(series.metric[label]));
+                } else {
                   reordered.push(series.metric[label]);
+                }
               } else {
                 reordered.push('');
               }