Prometheus: fix proxy check (#54823)

The original check has been added ~3 years ago and since then a new
variable has been added that says whether the mode is browser or
proxied.

Start using the new variable in this function so that proxy mode could
be properly detected. It's important to us to get these headers and this
check is currently broken for HTTP/HTTPS URLs.

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>

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

@@ -12,6 +12,8 @@ import {
   LoadingState,
   toDataFrame,
 } from '@grafana/data';
+import { TimeSrv } from 'app/features/dashboard/services/TimeSrv';
+import { TemplateSrv } from 'app/features/templating/template_srv';
 import { QueryOptions } from 'app/types';
 
 import { VariableHide } from '../../../features/variables/types';
@@ -1846,6 +1848,23 @@ describe('PrometheusDatasource for POST', () => {
     const httpOptions = {
       headers: {} as { [key: string]: number | undefined },
     };
+    const instanceSettings = {
+      url: 'proxied',
+      directUrl: 'direct',
+      user: 'test',
+      password: 'mupp',
+      access: 'proxy',
+      jsonData: { httpMethod: 'POST' },
+    } as unknown as DataSourceInstanceSettings<PromOptions>;
+
+    let ds: PrometheusDatasource;
+    beforeEach(() => {
+      ds = new PrometheusDatasource(
+        instanceSettings,
+        templateSrvStub as unknown as TemplateSrv,
+        timeSrvStub as unknown as TimeSrv
+      );
+    });
 
     it('with proxy access tracing headers should be added', () => {
       ds._addTracingHeaders(httpOptions as any, options as any);
@@ -1855,6 +1874,14 @@ describe('PrometheusDatasource for POST', () => {
     });
 
     it('with direct access tracing headers should not be added', () => {
+      const instanceSettings = {
+        url: 'proxied',
+        directUrl: 'direct',
+        user: 'test',
+        password: 'mupp',
+        jsonData: { httpMethod: 'POST' },
+      } as unknown as DataSourceInstanceSettings<PromOptions>;
+
       const mockDs = new PrometheusDatasource(
         { ...instanceSettings, url: 'http://127.0.0.1:8000' },
         templateSrvStub as any,
@@ -1882,6 +1909,7 @@ function getPrepareTargetsContext({
   const instanceSettings = {
     url: 'proxied',
     directUrl: 'direct',
+    access: 'proxy',
     user: 'test',
     password: 'mupp',
     jsonData: { httpMethod: 'POST' },

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

@@ -144,8 +144,7 @@ export class PrometheusDatasource
 
   _addTracingHeaders(httpOptions: PromQueryRequest, options: DataQueryRequest<PromQuery>) {
     httpOptions.headers = {};
-    const proxyMode = !this.url.match(/^http/);
-    if (proxyMode) {
+    if (this.access === 'proxy') {
       httpOptions.headers['X-Dashboard-Id'] = options.dashboardId;
       httpOptions.headers['X-Dashboard-UID'] = options.dashboardUID;
       httpOptions.headers['X-Panel-Id'] = options.panelId;