prometheus: metadata: simplify the metrics-metadata format (#39411)

* prometheus: metadata: simplify the metrics-metadata format

* fixed unit test

* fixed tests

public/app/plugins/datasource/prometheus/components/PrometheusMetricsBrowser.tsx

@@ -404,7 +404,7 @@ export class UnthemedPrometheusMetricsBrowser extends React.Component<BrowserPro
         const value: FacettableValue = { name: labelValue };
         // Adding type/help text to metrics
         if (name === METRIC_LABEL && metricsMetadata) {
-          const meta = metricsMetadata[labelValue]?.[0];
+          const meta = metricsMetadata[labelValue];
           if (meta) {
             value.details = `(${meta.type}) ${meta.help}`;
           }

public/app/plugins/datasource/prometheus/components/monaco-query-field/MonacoQueryField.tsx

@@ -86,7 +86,7 @@ const MonacoQueryField = (props: Props) => {
           const getAllMetricNames = () => {
             const { metrics, metricsMetadata } = lpRef.current;
             const result = metrics.map((m) => {
-              const metaItem = metricsMetadata?.[m]?.[0];
+              const metaItem = metricsMetadata?.[m];
               return {
                 name: m,
                 help: metaItem?.help ?? '',

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

@@ -53,7 +53,7 @@ export function addHistoryMetadata(item: CompletionItem, history: any[]): Comple
 function addMetricsMetadata(metric: string, metadata?: PromMetricsMetadata): CompletionItem {
   const item: CompletionItem = { label: metric };
   if (metadata && metadata[metric]) {
-    const { type, help } = metadata[metric][0];
+    const { type, help } = metadata[metric];
     item.documentation = `${type.toUpperCase()}: ${help}`;
   }
   return item;

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

@@ -73,23 +73,25 @@ describe('parseSelector()', () => {
 
 describe('fixSummariesMetadata', () => {
   const synthetics = {
-    ALERTS: [
+    ALERTS: {
-      {
       type: 'counter',
       help:
         'Time series showing pending and firing alerts. The sample value is set to 1 as long as the alert is in the indicated active (pending or firing) state.',
     },
-    ],
   };
   it('returns only synthetics on empty metadata', () => {
     expect(fixSummariesMetadata({})).toEqual({ ...synthetics });
   });
 
   it('returns unchanged metadata if no summary is present', () => {
-    const metadata = {
+    const metadataRaw = {
       foo: [{ type: 'not_a_summary', help: 'foo help' }],
     };
-    expect(fixSummariesMetadata(metadata)).toEqual({ ...metadata, ...synthetics });
+
+    const metadata = {
+      foo: { type: 'not_a_summary', help: 'foo help' },
+    };
+    expect(fixSummariesMetadata(metadataRaw)).toEqual({ ...metadata, ...synthetics });
   });
 
   it('returns metadata with added count and sum for a summary', () => {
@@ -98,10 +100,10 @@ describe('fixSummariesMetadata', () => {
       bar: [{ type: 'summary', help: 'bar help' }],
     };
     const expected = {
-      foo: [{ type: 'not_a_summary', help: 'foo help' }],
+      foo: { type: 'not_a_summary', help: 'foo help' },
-      bar: [{ type: 'summary', help: 'bar help' }],
+      bar: { type: 'summary', help: 'bar help' },
-      bar_count: [{ type: 'counter', help: 'Count of events that have been observed for the base metric (bar help)' }],
+      bar_count: { type: 'counter', help: 'Count of events that have been observed for the base metric (bar help)' },
-      bar_sum: [{ type: 'counter', help: 'Total sum of all observed values for the base metric (bar help)' }],
+      bar_sum: { type: 'counter', help: 'Total sum of all observed values for the base metric (bar help)' },
     };
     expect(fixSummariesMetadata(metadata)).toEqual({ ...expected, ...synthetics });
   });
@@ -112,13 +114,14 @@ describe('fixSummariesMetadata', () => {
       bar: [{ type: 'histogram', help: 'bar help' }],
     };
     const expected = {
-      foo: [{ type: 'not_a_histogram', help: 'foo help' }],
+      foo: { type: 'not_a_histogram', help: 'foo help' },
-      bar: [{ type: 'histogram', help: 'bar help' }],
+      bar: { type: 'histogram', help: 'bar help' },
-      bar_bucket: [{ type: 'counter', help: 'Cumulative counters for the observation buckets (bar help)' }],
+      bar_bucket: { type: 'counter', help: 'Cumulative counters for the observation buckets (bar help)' },
-      bar_count: [
+      bar_count: {
-        { type: 'counter', help: 'Count of events that have been observed for the histogram metric (bar help)' },
+        type: 'counter',
-      ],
+        help: 'Count of events that have been observed for the histogram metric (bar help)',
-      bar_sum: [{ type: 'counter', help: 'Total sum of all observed values for the histogram metric (bar help)' }],
+      },
+      bar_sum: { type: 'counter', help: 'Total sum of all observed values for the histogram metric (bar help)' },
     };
     expect(fixSummariesMetadata(metadata)).toEqual({ ...expected, ...synthetics });
   });

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

@@ -1,4 +1,4 @@
-import { PromMetricsMetadata } from './types';
+import { PromMetricsMetadata, PromMetricsMetadataItem } from './types';
 import { addLabelToQuery } from './add_label_to_query';
 import { SUGGESTIONS_LIMIT } from './language_provider';
 
@@ -169,59 +169,56 @@ function addLabelsToExpression(expr: string, invalidLabelsRegexp: RegExp) {
  *
  * @param metadata HELP and TYPE metadata from /api/v1/metadata
  */
-export function fixSummariesMetadata(metadata: PromMetricsMetadata): PromMetricsMetadata {
+export function fixSummariesMetadata(metadata: { [metric: string]: PromMetricsMetadataItem[] }): PromMetricsMetadata {
   if (!metadata) {
     return metadata;
   }
+  const baseMetadata: PromMetricsMetadata = {};
   const summaryMetadata: PromMetricsMetadata = {};
   for (const metric in metadata) {
+    // NOTE: based on prometheus-documentation, we can receive
+    // multiple metadata-entries for the given metric, it seems
+    // it happens when the same metric is on multiple targets
+    // and their help-text differs
+    // (https://prometheus.io/docs/prometheus/latest/querying/api/#querying-metric-metadata)
+    // for now we just use the first entry.
     const item = metadata[metric][0];
+    baseMetadata[metric] = item;
+
     if (item.type === 'histogram') {
-      summaryMetadata[`${metric}_bucket`] = [
+      summaryMetadata[`${metric}_bucket`] = {
-        {
         type: 'counter',
         help: `Cumulative counters for the observation buckets (${item.help})`,
-        },
+      };
-      ];
+      summaryMetadata[`${metric}_count`] = {
-      summaryMetadata[`${metric}_count`] = [
-        {
         type: 'counter',
         help: `Count of events that have been observed for the histogram metric (${item.help})`,
-        },
+      };
-      ];
+      summaryMetadata[`${metric}_sum`] = {
-      summaryMetadata[`${metric}_sum`] = [
-        {
         type: 'counter',
         help: `Total sum of all observed values for the histogram metric (${item.help})`,
-        },
+      };
-      ];
     }
     if (item.type === 'summary') {
-      summaryMetadata[`${metric}_count`] = [
+      summaryMetadata[`${metric}_count`] = {
-        {
         type: 'counter',
         help: `Count of events that have been observed for the base metric (${item.help})`,
-        },
+      };
-      ];
+      summaryMetadata[`${metric}_sum`] = {
-      summaryMetadata[`${metric}_sum`] = [
-        {
         type: 'counter',
         help: `Total sum of all observed values for the base metric (${item.help})`,
-        },
+      };
-      ];
     }
   }
   // Synthetic series
   const syntheticMetadata: PromMetricsMetadata = {};
-  syntheticMetadata['ALERTS'] = [
+  syntheticMetadata['ALERTS'] = {
-    {
     type: 'counter',
     help:
       'Time series showing pending and firing alerts. The sample value is set to 1 as long as the alert is in the indicated active (pending or firing) state.',
-    },
+  };
-  ];
 
-  return { ...metadata, ...summaryMetadata, ...syntheticMetadata };
+  return { ...baseMetadata, ...summaryMetadata, ...syntheticMetadata };
 }
 
 export function roundMsToMin(milliseconds: number): number {

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

@@ -42,7 +42,7 @@ describe('getQueryHints()', () => {
         ],
       },
     ];
-    const mock: unknown = { languageProvider: { metricsMetadata: { foo: [{ type: 'counter' }] } } };
+    const mock: unknown = { languageProvider: { metricsMetadata: { foo: { type: 'counter' } } } };
     const datasource = mock as PrometheusDatasource;
 
     let hints = getQueryHints('foo', series, datasource);

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

@@ -40,7 +40,7 @@ export function getQueryHints(query: string, series?: any[], datasource?: Promet
       counterNameMetric =
         metricMetadataKeys.find((metricName) => {
           // Only considering first type information, could be non-deterministic
-          const metadata = metricsMetadata[metricName][0];
+          const metadata = metricsMetadata[metricName];
           if (metadata.type.toLowerCase() === 'counter') {
             const metricRegex = new RegExp(`\\b${metricName}\\b`);
             if (query.match(metricRegex)) {

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

@@ -50,7 +50,7 @@ export interface PromMetricsMetadataItem {
 }
 
 export interface PromMetricsMetadata {
-  [metric: string]: PromMetricsMetadataItem[];
+  [metric: string]: PromMetricsMetadataItem;
 }
 
 export interface PromDataSuccessResponse<T = PromData> {