* prometheus fix variables fetching when customQueryParameters used #28907 (#28949)

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

@@ -90,7 +90,7 @@ export const PromSettings = (props: Props) => {
             <FormField
               label="Custom query parameters"
               labelWidth={14}
-              tooltip="Add Custom parameters to Prometheus or Thanos queries."
+              tooltip="Add Custom parameters to all Prometheus or Thanos queries."
               inputEl={
                 <Input
                   className="width-25"

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

@@ -59,7 +59,9 @@ describe('PrometheusDatasource', () => {
     directUrl: 'direct',
     user: 'test',
     password: 'mupp',
-    jsonData: {} as any,
+    jsonData: {
+      customQueryParameters: '',
+    } as any,
   } as unknown) as DataSourceInstanceSettings<PromOptions>;
 
   beforeEach(() => {
@@ -141,6 +143,30 @@ describe('PrometheusDatasource', () => {
     });
   });
 
+  describe('When using customQueryParams', () => {
+    const promDs = new PrometheusDatasource(
+      { ...instanceSettings, jsonData: { customQueryParameters: 'customQuery=123' } as any },
+      templateSrvStub as any,
+      timeSrvStub as any
+    );
+    it('added to metadata request', () => {
+      promDs.metadataRequest('/foo');
+      expect(fetchMock.mock.calls.length).toBe(1);
+      expect(fetchMock.mock.calls[0][0].url).toBe('proxied/foo?customQuery=123');
+    });
+    it('added to query', () => {
+      promDs.query({
+        range: { from: time({ seconds: 63 }), to: time({ seconds: 183 }) },
+        targets: [{ expr: 'test{job="testjob"}', format: 'time_series' }],
+        interval: '60s',
+      } as any);
+      expect(fetchMock.mock.calls.length).toBe(1);
+      expect(fetchMock.mock.calls[0][0].url).toBe(
+        'proxied/api/v1/query_range?query=test%7Bjob%3D%22testjob%22%7D&start=60&end=180&step=60&customQuery=123'
+      );
+    });
+  });
+
   describe('When using adhoc filters', () => {
     const DEFAULT_QUERY_EXPRESSION = 'metric{job="foo"} - metric';
     const target = { expr: DEFAULT_QUERY_EXPRESSION };

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

@@ -111,7 +111,7 @@ export class PrometheusDatasource extends DataSourceApi<PromQuery, PromOptions>
       if (data && Object.keys(data).length) {
         options.url =
           options.url +
-          '?' +
+          (options.url.search(/\?/) >= 0 ? '&' : '?') +
           Object.entries(data)
             .map(([k, v]) => `${encodeURIComponent(k)}=${encodeURIComponent(v)}`)
             .join('&');
@@ -134,7 +134,13 @@ export class PrometheusDatasource extends DataSourceApi<PromQuery, PromOptions>
 
   // Use this for tab completion features, wont publish response to other components
   metadataRequest<T = any>(url: string) {
-    return this._request<T>(url, null, { method: 'GET', hideFromInspector: true }).toPromise(); // toPromise until we change getTagValues, getTagKeys to Observable
+    const data: any = {};
+    for (const [key, value] of this.customQueryParameters) {
+      if (data[key] == null) {
+        data[key] = value;
+      }
+    }
+    return this._request<T>(url, data, { method: 'GET', hideFromInspector: true }).toPromise(); // toPromise until we change getTagValues, getTagKeys to Observable
   }
 
   interpolateQueryExpr(value: string | string[] = [], variable: any) {