Revert "Revert "Prometheus: Provide label values match parameter API when supported prometheus instance is configured (#56510)" (#57551)" (#57553)

This reverts commit e7671bf909.

docs/sources/whatsnew/whats-new-in-v9-2.md

@@ -219,3 +219,10 @@ For more information, see the [SAML configuration documentation](https://grafana
 You can now map OAuth groups and roles to Server Admin for the GitLab, GitHub, AzureAD, Okta, and Generic OAuth integrations.
 To enable this functionality, set the `allow_assign_grafana_admin` configuration option to `true` in the desired OAuth integration section.
 For more information, see the [authentication configuration documentation](https://grafana.com/docs/grafana/latest/setup-grafana/configure-security/configure-authentication/) for each OAuth client.
+
+## Match parameter support in prometheus labels API
+
+Prometheus users running Prometheus v2.24 and higher can use the [labels endpoint](https://prometheus.io/docs/prometheus/latest/querying/api/#querying-label-values) instead of the [series endpoint](https://prometheus.io/docs/prometheus/latest/querying/api/#finding-series-by-label-matchers) for the [`label_values` function]({{< relref "../datasources/prometheus/#query-variable" >}}).
+This decreases load times for templated high-cardinality Prometheus instances.
+
+If you want to benefit from this endpoint you must first configure the Prometheus type and version in any Prometheus data sources' [configuration]({{< relref "../datasources/prometheus/" >}}).

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

@@ -3,6 +3,7 @@ import LRU from 'lru-cache';
 import React from 'react';
 import { forkJoin, lastValueFrom, merge, Observable, of, OperatorFunction, pipe, throwError } from 'rxjs';
 import { catchError, filter, map, tap } from 'rxjs/operators';
+import semver from 'semver/preload';
 
 import {
   AnnotationEvent,
@@ -146,6 +147,33 @@ export class PrometheusDatasource
     return query.expr;
   }
 
+  hasLabelsMatchAPISupport(): boolean {
+    return (
+      // https://github.com/prometheus/prometheus/releases/tag/v2.24.0
+      this._isDatasourceVersionGreaterOrEqualTo('2.24.0', PromApplication.Prometheus) ||
+      // All versions of Mimir support matchers for labels API
+      this._isDatasourceVersionGreaterOrEqualTo('2.0.0', PromApplication.Mimir) ||
+      // https://github.com/cortexproject/cortex/discussions/4542
+      this._isDatasourceVersionGreaterOrEqualTo('1.11.0', PromApplication.Cortex) ||
+      // https://github.com/thanos-io/thanos/pull/3566
+      //https://github.com/thanos-io/thanos/releases/tag/v0.18.0
+      this._isDatasourceVersionGreaterOrEqualTo('0.18', PromApplication.Thanos)
+    );
+  }
+
+  _isDatasourceVersionGreaterOrEqualTo(targetVersion: string, targetFlavor: PromApplication): boolean {
+    // User hasn't configured flavor/version yet, default behavior is to not support features that require version configuration when not provided
+    if (!this.datasourceConfigurationPrometheusVersion || !this.datasourceConfigurationPrometheusFlavor) {
+      return false;
+    }
+
+    if (targetFlavor !== this.datasourceConfigurationPrometheusFlavor) {
+      return false;
+    }
+
+    return semver.gte(this.datasourceConfigurationPrometheusVersion, targetVersion);
+  }
+
   _addTracingHeaders(httpOptions: PromQueryRequest, options: DataQueryRequest<PromQuery>) {
     httpOptions.headers = {};
     if (this.access === 'proxy') {

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

@@ -70,16 +70,10 @@ export default class PrometheusMetricFindQuery {
   labelValuesQuery(label: string, metric?: string) {
     const start = this.datasource.getPrometheusTime(this.range.from, false);
     const end = this.datasource.getPrometheusTime(this.range.to, true);
+    const params = { ...(metric && { 'match[]': metric }), start: start.toString(), end: end.toString() };
 
-    let url: string;
-
-    if (!metric) {
-      const params = {
-        start: start.toString(),
-        end: end.toString(),
-      };
-      // return label values globally
-      url = `/api/v1/label/${label}/values`;
+    if (!metric || this.datasource.hasLabelsMatchAPISupport()) {
+      const url = `/api/v1/label/${label}/values`;
 
       return this.datasource.metadataRequest(url, params).then((result: any) => {
         return _map(result.data.data, (value) => {
@@ -87,12 +81,7 @@ export default class PrometheusMetricFindQuery {
         });
       });
     } else {
-      const params = {
-        'match[]': metric,
-        start: start.toString(),
-        end: end.toString(),
-      };
-      url = `/api/v1/series`;
+      const url = `/api/v1/series`;
 
       return this.datasource.metadataRequest(url, params).then((result: any) => {
         const _labels = _map(result.data.data, (metric) => {