Prometheus: Refactoring in datasource.ts (#107208)

* start cleanup

* update vars

* prettier

packages/grafana-prometheus/src/constants.ts

@@ -6,28 +6,43 @@ export const PROMETHEUS_QUERY_BUILDER_MAX_RESULTS = 1000;
 export const PROM_CONFIG_LABEL_WIDTH = 30;
 
 export const LIST_ITEM_SIZE = 25;
+
 export const LAST_USED_LABELS_KEY = 'grafana.datasources.prometheus.browser.labels';
 
-// single duration input
 export const DURATION_REGEX = /^$|^\d+(ms|[Mwdhmsy])$/;
 
-// multiple duration input
 export const MULTIPLE_DURATION_REGEX = /(\d+)(.+)/;
 
 export const NON_NEGATIVE_INTEGER_REGEX = /^(0|[1-9]\d*)(\.\d+)?(e\+?\d+)?$/; // non-negative integers, including scientific notation
 
 export const EMPTY_SELECTOR = '{}';
+
 export const DEFAULT_SERIES_LIMIT = 40000;
+
 export const MATCH_ALL_LABELS_STR = '__name__!=""';
+
 export const MATCH_ALL_LABELS = '{__name__!=""}';
+
 export const METRIC_LABEL = '__name__';
 
+export const durationError = 'Value is not valid, you can use number with time unit specifier: y, M, w, d, h, m, s';
+
+export const countError = 'Value is not valid, you can use non-negative integers, including scientific notation';
+
+export const seriesLimitError =
+  'Value is not valid, you can use only numbers or leave it empty to use default limit or set 0 to have no limit.';
+
+export const InstantQueryRefIdIndex = '-Instant';
+
+export const GET_AND_POST_METADATA_ENDPOINTS = [
+  'api/v1/query',
+  'api/v1/query_range',
+  'api/v1/series',
+  'api/v1/labels',
+  'suggestions',
+];
+
 /**
  * @deprecated
  */
 export const REMOVE_SERIES_LIMIT = 'none';
-
-export const durationError = 'Value is not valid, you can use number with time unit specifier: y, M, w, d, h, m, s';
-export const countError = 'Value is not valid, you can use non-negative integers, including scientific notation';
-export const seriesLimitError =
-  'Value is not valid, you can use only numbers or leave it empty to use default limit or set 0 to have no limit.';

packages/grafana-prometheus/src/datasource.ts

@@ -1,4 +1,3 @@
-// Core Grafana history https://github.com/grafana/grafana/blob/v11.0.0-preview/public/app/plugins/datasource/prometheus/datasource.ts
 import { defaults } from 'lodash';
 import { tz } from 'moment-timezone';
 import { lastValueFrom, Observable, throwError } from 'rxjs';
@@ -42,7 +41,12 @@ import {
 
 import { addLabelToQuery } from './add_label_to_query';
 import { PrometheusAnnotationSupport } from './annotations';
-import { DEFAULT_SERIES_LIMIT, SUGGESTIONS_LIMIT } from './constants';
+import {
+  DEFAULT_SERIES_LIMIT,
+  GET_AND_POST_METADATA_ENDPOINTS,
+  InstantQueryRefIdIndex,
+  SUGGESTIONS_LIMIT,
+} from './constants';
 import { prometheusRegularEscape, prometheusSpecialRegexEscape } from './escaping';
 import {
   exportToAbstractQuery,
@@ -72,44 +76,34 @@ import {
 import { utf8Support, wrapUtf8Filters } from './utf8_support';
 import { PrometheusVariableSupport } from './variables';
 
-const GET_AND_POST_METADATA_ENDPOINTS = [
-  'api/v1/query',
-  'api/v1/query_range',
-  'api/v1/series',
-  'api/v1/labels',
-  'suggestions',
-];
-
-export const InstantQueryRefIdIndex = '-Instant';
-
 export class PrometheusDatasource
   extends DataSourceWithBackend<PromQuery, PromOptions>
   implements DataSourceWithQueryImportSupport<PromQuery>, DataSourceWithQueryExportSupport<PromQuery>
 {
-  type: string;
-  ruleMappings: RuleQueryMapping;
-  hasIncrementalQuery: boolean;
-  url: string;
-  id: number;
   access: 'direct' | 'proxy';
   basicAuth: any;
-  withCredentials: boolean;
-  interval: string;
-  httpMethod: string;
-  languageProvider: PrometheusLanguageProviderInterface;
-  exemplarTraceIdDestinations: ExemplarTraceIdDestination[] | undefined;
-  lookupsDisabled: boolean;
+  cache: QueryCache<PromQuery>;
+  cacheLevel: PrometheusCacheLevel;
   customQueryParameters: URLSearchParams;
   datasourceConfigurationPrometheusFlavor?: PromApplication;
   datasourceConfigurationPrometheusVersion?: string;
   disableRecordingRules: boolean;
-  defaultEditor?: QueryEditorMode;
+  exemplarTraceIdDestinations: ExemplarTraceIdDestination[] | undefined;
   exemplarsAvailable: boolean;
-  cacheLevel: PrometheusCacheLevel;
-  cache: QueryCache<PromQuery>;
+  hasIncrementalQuery: boolean;
+  httpMethod: string;
+  id: number;
+  interval: string;
+  languageProvider: PrometheusLanguageProviderInterface;
+  lookupsDisabled: boolean;
   metricNamesAutocompleteSuggestionLimit: number;
+  ruleMappings: RuleQueryMapping;
   seriesEndpoint: boolean;
   seriesLimit: number;
+  type: string;
+  url: string;
+  withCredentials: boolean;
+  defaultEditor?: QueryEditorMode;
 
   constructor(
     instanceSettings: DataSourceInstanceSettings<PromOptions>,
@@ -118,48 +112,106 @@ export class PrometheusDatasource
   ) {
     super(instanceSettings);
 
-    this.type = 'prometheus';
-    this.id = instanceSettings.id;
-    this.url = instanceSettings.url!;
+    // DATASOURCE CONFIGURATION PROPERTIES
     this.access = instanceSettings.access;
     this.basicAuth = instanceSettings.basicAuth;
-    this.withCredentials = Boolean(instanceSettings.withCredentials);
-    this.interval = instanceSettings.jsonData.timeInterval || '15s';
-    this.httpMethod = instanceSettings.jsonData.httpMethod || 'GET';
-    this.exemplarTraceIdDestinations = instanceSettings.jsonData.exemplarTraceIdDestinations;
-    this.hasIncrementalQuery = instanceSettings.jsonData.incrementalQuerying ?? false;
-    this.ruleMappings = {};
-    this.lookupsDisabled = instanceSettings.jsonData.disableMetricsLookup ?? false;
-    this.customQueryParameters = new URLSearchParams(instanceSettings.jsonData.customQueryParameters);
-    this.datasourceConfigurationPrometheusFlavor = instanceSettings.jsonData.prometheusType;
-    this.datasourceConfigurationPrometheusVersion = instanceSettings.jsonData.prometheusVersion;
-    this.seriesLimit = instanceSettings.jsonData.seriesLimit ?? DEFAULT_SERIES_LIMIT;
-    this.seriesEndpoint = instanceSettings.jsonData.seriesEndpoint ?? false;
-    this.defaultEditor = instanceSettings.jsonData.defaultEditor;
-    this.disableRecordingRules = instanceSettings.jsonData.disableRecordingRules ?? false;
-    this.variables = new PrometheusVariableSupport(this, this.templateSrv);
-    this.exemplarsAvailable = true;
-    this.cacheLevel = instanceSettings.jsonData.cacheLevel ?? PrometheusCacheLevel.Low;
-    this.metricNamesAutocompleteSuggestionLimit =
-      instanceSettings.jsonData.codeModeMetricNamesSuggestionLimit ?? SUGGESTIONS_LIMIT;
-
     this.cache = new QueryCache({
       getTargetSignature: this.getPrometheusTargetSignature.bind(this),
       overlapString: instanceSettings.jsonData.incrementalQueryOverlapWindow ?? defaultPrometheusQueryOverlapWindow,
       applyInterpolation: this.interpolateString.bind(this),
     });
+    this.cacheLevel = instanceSettings.jsonData.cacheLevel ?? PrometheusCacheLevel.Low;
+    this.customQueryParameters = new URLSearchParams(instanceSettings.jsonData.customQueryParameters);
+    this.datasourceConfigurationPrometheusFlavor = instanceSettings.jsonData.prometheusType;
+    this.datasourceConfigurationPrometheusVersion = instanceSettings.jsonData.prometheusVersion;
+    this.disableRecordingRules = instanceSettings.jsonData.disableRecordingRules ?? false;
+    this.exemplarTraceIdDestinations = instanceSettings.jsonData.exemplarTraceIdDestinations;
+    this.exemplarsAvailable = true;
+    this.hasIncrementalQuery = instanceSettings.jsonData.incrementalQuerying ?? false;
+    this.httpMethod = instanceSettings.jsonData.httpMethod || 'GET';
+    this.id = instanceSettings.id;
+    this.interval = instanceSettings.jsonData.timeInterval || '15s';
+    this.lookupsDisabled = instanceSettings.jsonData.disableMetricsLookup ?? false;
+    this.metricNamesAutocompleteSuggestionLimit =
+      instanceSettings.jsonData.codeModeMetricNamesSuggestionLimit ?? SUGGESTIONS_LIMIT;
+    this.ruleMappings = {};
+    this.seriesEndpoint = instanceSettings.jsonData.seriesEndpoint ?? false;
+    this.seriesLimit = instanceSettings.jsonData.seriesLimit ?? DEFAULT_SERIES_LIMIT;
+    this.type = 'prometheus';
+    this.url = instanceSettings.url!;
+    this.withCredentials = Boolean(instanceSettings.withCredentials);
+    this.defaultEditor = instanceSettings.jsonData.defaultEditor;
 
+    // INHERITED PROPERTIES
     this.annotations = PrometheusAnnotationSupport(this);
+    this.variables = new PrometheusVariableSupport(this, this.templateSrv);
+
+    // LANGUAGE PROVIDER
+    // This needs to be the last thing we initialize.
     this.languageProvider = languageProvider ?? new PrometheusLanguageProvider(this);
   }
 
-  init = async () => {
+  /**
+   * Initializes the Prometheus datasource by loading recording rules and checking exemplar availability.
+   *
+   * This method performs two key initialization tasks: Loads recording rules from the
+   * Prometheus API and checks if exemplars are available by testing the exemplars API endpoint.
+   */
+  init = async (): Promise<void> => {
     if (!this.disableRecordingRules) {
       this.loadRules();
     }
     this.exemplarsAvailable = await this.areExemplarsAvailable();
   };
 
+  /**
+   * Loads recording rules from the Prometheus API and extracts rule mappings.
+   *
+   * This method fetches rules from the `/api/v1/rules` endpoint and processes
+   * them to create a mapping of rule names to their corresponding queries and labels.
+   * The rules API is experimental, so errors are logged but not thrown.
+   */
+  private async loadRules(): Promise<void> {
+    try {
+      const params = {};
+      const options = { showErrorAlert: false };
+      const res = await this.metadataRequest('/api/v1/rules', params, options);
+      const ruleGroups = res.data?.data?.groups;
+
+      if (ruleGroups) {
+        this.ruleMappings = extractRuleMappingFromGroups(ruleGroups);
+      }
+    } catch (err) {
+      console.log('Rules API is experimental. Ignore next error.');
+      console.error(err);
+    }
+  }
+
+  /**
+   * Checks if exemplars are available by testing the exemplars API endpoint.
+   *
+   * This method makes a test request to the `/api/v1/query_exemplars` endpoint to determine
+   * if the Prometheus instance supports exemplars. The test uses a simple query with a
+   * 30-minute time range. If the request succeeds with a 'success' status, exemplars
+   * are considered available. Errors are caught and return false to avoid breaking
+   * the datasource initialization.
+   */
+  private async areExemplarsAvailable(): Promise<boolean> {
+    try {
+      const params = {
+        query: 'test',
+        start: dateTime().subtract(30, 'minutes').valueOf().toString(),
+        end: dateTime().valueOf().toString(),
+      };
+      const options = { showErrorAlert: false };
+      const res = await this.metadataRequest('/api/v1/query_exemplars', params, options);
+
+      return res.data.status === 'success';
+    } catch (err) {
+      return false;
+    }
+  }
+
   getQueryDisplayText(query: PromQuery) {
     return query.expr;
   }
@@ -604,43 +656,6 @@ export class PrometheusDatasource
     return getQueryHints(query.expr ?? '', result, this);
   }
 
-  async loadRules() {
-    try {
-      const res = await this.metadataRequest('/api/v1/rules', {}, { showErrorAlert: false });
-      const groups = res.data?.data?.groups;
-
-      if (groups) {
-        this.ruleMappings = extractRuleMappingFromGroups(groups);
-      }
-    } catch (e) {
-      console.log('Rules API is experimental. Ignore next error.');
-      console.error(e);
-    }
-  }
-
-  async areExemplarsAvailable() {
-    try {
-      const res = await this.metadataRequest(
-        '/api/v1/query_exemplars',
-        {
-          query: 'test',
-          start: dateTime().subtract(30, 'minutes').valueOf().toString(),
-          end: dateTime().valueOf().toString(),
-        },
-        {
-          // Avoid alerting the user if this test fails
-          showErrorAlert: false,
-        }
-      );
-      if (res.data.status === 'success') {
-        return true;
-      }
-      return false;
-    } catch (err) {
-      return false;
-    }
-  }
-
   modifyQuery(query: PromQuery, action: QueryFixAction): PromQuery {
     let expression = query.expr ?? '';
     switch (action.type) {

packages/grafana-prometheus/src/index.ts

@@ -20,7 +20,7 @@ export { PromVariableQueryEditor } from './components/VariableQueryEditor';
 // Main export
 export { ConfigEditor } from './configuration/ConfigEditor';
 export { overhaulStyles, validateInput, docsTip } from './configuration/shared/utils';
-export { PROM_CONFIG_LABEL_WIDTH } from './constants';
+export { PROM_CONFIG_LABEL_WIDTH, InstantQueryRefIdIndex } from './constants';
 // The parts
 export { AlertingSettingsOverhaul } from './configuration/AlertingSettingsOverhaul';
 export { DataSourceHttpSettingsOverhaul } from './configuration/DataSourceHttpSettingsOverhaul';
@@ -54,7 +54,7 @@ export { MetricsModal } from './querybuilder/components/metrics-modal/MetricsMod
 
 // SRC/
 // Main export
-export { PrometheusDatasource, InstantQueryRefIdIndex } from './datasource';
+export { PrometheusDatasource } from './datasource';
 // The parts
 export { addLabelToQuery } from './add_label_to_query';
 export { type QueryEditorMode, type PromQueryFormat, type Prometheus } from './dataquery';