Merge branch '223790-nan-or-null-values-should-not-be-removed' into 'master'

Keep NaN values in data series

Closes #223790

See merge request gitlab-org/gitlab!35086

app/assets/javascripts/helpers/monitor_helper.js

@@ -65,18 +65,10 @@ const getSeriesLabel = (queryLabel, metricAttributes) => {
  */
 // eslint-disable-next-line import/prefer-default-export
 export const makeDataSeries = (queryResults, defaultConfig) =>
-  queryResults
-    .map(result => {
-      // NaN values may disrupt avg., max. & min. calculations in the legend, filter them out
-      const data = result.values.filter(([, value]) => !Number.isNaN(value));
-      if (!data.length) {
-        return null;
-      }
-      const series = { data };
+  queryResults.map(result => {
     return {
       ...defaultConfig,
-        ...series,
+      data: result.values,
       name: getSeriesLabel(defaultConfig.name, result.metric),
     };
-    })
-    .filter(series => series !== null);
+  });

changelogs/unreleased/223790-nan-or-null-values-should-not-be-removed.yml

+---
+title: Stop removing NaN values from monitoring data series
+merge_request: 35086
+author:
+type: changed

spec/frontend/helpers/monitor_helper_spec.js

@@ -33,15 +33,6 @@ describe('monitor helper', () => {
       ]);
     });
 
-    it('excludes NaN values', () => {
-      expect(
-        monitorHelper.makeDataSeries(
-          data({ metric: {}, values: [[1, 1], [2, NaN]] }),
-          defaultConfig,
-        ),
-      ).toEqual([{ ...expectedDataSeries[0], data: [[1, 1]] }]);
-    });
-
     it('updates series name from templates', () => {
       const config = {
         ...defaultConfig,

spec/frontend/monitoring/store/utils_spec.js

@@ -815,6 +815,50 @@ describe('normalizeQueryResponseData', () => {
       },
     ]);
   });
+
+  it('processes a scalar result with a NaN result', () => {
+    // Queries may return "NaN" string values.
+    // e.g. when Prometheus cannot find a metric the query
+    // `scalar(does_not_exist)` will return a "NaN" value.
+
+    const mockScalar = {
+      resultType: 'scalar',
+      result: [1435781451.781, 'NaN'],
+    };
+
+    expect(normalizeQueryResponseData(mockScalar)).toEqual([
+      {
+        metric: {},
+        value: ['2015-07-01T20:10:51.781Z', NaN],
+        values: [['2015-07-01T20:10:51.781Z', NaN]],
+      },
+    ]);
+  });
+
+  it('processes a matrix result with a "NaN" value', () => {
+    // Queries may return "NaN" string values.
+    const mockMatrix = {
+      resultType: 'matrix',
+      result: [
+        {
+          metric: {
+            __name__: 'up',
+            job: 'prometheus',
+            instance: 'localhost:9090',
+          },
+          values: [[1435781430.781, '1'], [1435781460.781, 'NaN']],
+        },
+      ],
+    };
+
+    expect(normalizeQueryResponseData(mockMatrix)).toEqual([
+      {
+        metric: { __name__: 'up', instance: 'localhost:9090', job: 'prometheus' },
+        value: ['2015-07-01T20:11:00.781Z', NaN],
+        values: [['2015-07-01T20:10:30.781Z', 1], ['2015-07-01T20:11:00.781Z', NaN]],
+      },
+    ]);
+  });
 });
 
 describe('normalizeCustomDashboardPath', () => {