plugins/rollbar: switch RollbarClient to use DiscoveryApi

packages/app/src/apis.ts

@@ -201,13 +201,7 @@ export const apis = (config: ConfigApi) => {
     ]),
   );
 
-  builder.add(
-    rollbarApiRef,
-    new RollbarClient({
-      apiOrigin: backendUrl,
-      basePath: '/rollbar',
-    }),
-  );
+  builder.add(rollbarApiRef, new RollbarClient({ discoveryApi }));
 
   builder.add(
     techdocsStorageApiRef,

plugins/rollbar/src/api/RollbarClient.ts

@@ -20,20 +20,13 @@ import {
   RollbarProject,
   RollbarTopActiveItem,
 } from './types';
+import { DiscoveryApi } from '@backstage/core';
 
 export class RollbarClient implements RollbarApi {
-  private apiOrigin: string;
-  private basePath: string;
+  private readonly discoveryApi: DiscoveryApi;
 
-  constructor({
-    apiOrigin,
-    basePath,
-  }: {
-    apiOrigin: string;
-    basePath: string;
-  }) {
-    this.apiOrigin = apiOrigin;
-    this.basePath = basePath;
+  constructor(options: { discoveryApi: DiscoveryApi }) {
+    this.discoveryApi = options.discoveryApi;
   }
 
   async getAllProjects(): Promise<RollbarProject[]> {
@@ -59,7 +52,7 @@ export class RollbarClient implements RollbarApi {
   }
 
   private async get(path: string): Promise<any> {
-    const url = `${this.apiOrigin}${this.basePath}${path}`;
+    const url = `${await this.discoveryApi.getBaseUrl('rollbar')}${path}`;
     const response = await fetch(url);
 
     if (!response.ok) {