Merge pull request #13510 from backstage/mob/factories

backend-next: incorporate options into createServiceFactory

packages/backend-app-api/api-report.md

@@ -28,10 +28,12 @@ export interface Backend {
 }
 
 // @public (undocumented)
-export const cacheFactory: ServiceFactory<PluginCacheManager>;
+export const cacheFactory: (
+  options?: undefined,
+) => ServiceFactory<PluginCacheManager>;
 
 // @public (undocumented)
-export const configFactory: ServiceFactory<Config>;
+export const configFactory: (options?: undefined) => ServiceFactory<Config>;
 
 // @public (undocumented)
 export function createSpecializedBackend(
@@ -41,28 +43,36 @@ export function createSpecializedBackend(
 // @public (undocumented)
 export interface CreateSpecializedBackendOptions {
   // (undocumented)
-  services: ServiceFactory[];
+  services: (ServiceFactory | (() => ServiceFactory))[];
 }
 
 // @public (undocumented)
-export const databaseFactory: ServiceFactory<PluginDatabaseManager>;
+export const databaseFactory: (
+  options?: undefined,
+) => ServiceFactory<PluginDatabaseManager>;
 
 // @public (undocumented)
-export const discoveryFactory: ServiceFactory<PluginEndpointDiscovery>;
+export const discoveryFactory: (
+  options?: undefined,
+) => ServiceFactory<PluginEndpointDiscovery>;
 
 // @public (undocumented)
-export const httpRouterFactory: ServiceFactory<HttpRouterService>;
+export const httpRouterFactory: (
+  options?: undefined,
+) => ServiceFactory<HttpRouterService>;
 
 // @public (undocumented)
-export const loggerFactory: ServiceFactory<Logger>;
+export const loggerFactory: (options?: undefined) => ServiceFactory<Logger>;
 
 // @public (undocumented)
-export const permissionsFactory: ServiceFactory<
-  PermissionAuthorizer | PermissionEvaluator
->;
+export const permissionsFactory: (
+  options?: undefined,
+) => ServiceFactory<PermissionAuthorizer | PermissionEvaluator>;
 
 // @public (undocumented)
-export const schedulerFactory: ServiceFactory<PluginTaskScheduler>;
+export const schedulerFactory: (
+  options?: undefined,
+) => ServiceFactory<PluginTaskScheduler>;
 
 // @public (undocumented)
 export type ServiceOrExtensionPoint<T = unknown> =
@@ -70,8 +80,12 @@ export type ServiceOrExtensionPoint<T = unknown> =
   | ServiceRef<T>;
 
 // @public (undocumented)
-export const tokenManagerFactory: ServiceFactory<TokenManager>;
+export const tokenManagerFactory: (
+  options?: undefined,
+) => ServiceFactory<TokenManager>;
 
 // @public (undocumented)
-export const urlReaderFactory: ServiceFactory<UrlReader>;
+export const urlReaderFactory: (
+  options?: undefined,
+) => ServiceFactory<UrlReader>;
 ```

packages/backend-app-api/src/wiring/ServiceRegistry.ts

@@ -26,7 +26,9 @@ import { stringifyError } from '@backstage/errors';
  * @internal
  */
 export type InternalServiceRef<T> = ServiceRef<T> & {
-  __defaultFactory?: (service: ServiceRef<T>) => Promise<ServiceFactory<T>>;
+  __defaultFactory?: (
+    service: ServiceRef<T>,
+  ) => Promise<ServiceFactory<T> | (() => ServiceFactory<T>)>;
 };
 
 export class ServiceRegistry {
@@ -40,8 +42,18 @@ export class ServiceRegistry {
     }
   >;
 
-  constructor(factories: ServiceFactory<any>[]) {
-    this.#providedFactories = new Map(factories.map(f => [f.service.id, f]));
+  constructor(
+    factories: Array<ServiceFactory<unknown> | (() => ServiceFactory<unknown>)>,
+  ) {
+    this.#providedFactories = new Map(
+      factories.map(f => {
+        if (typeof f === 'function') {
+          const cf = f();
+          return [cf.service.id, cf];
+        }
+        return [f.service.id, f];
+      }),
+    );
     this.#loadedDefaultFactories = new Map();
     this.#implementations = new Map();
   }
@@ -57,9 +69,11 @@ export class ServiceRegistry {
       if (!factory) {
         let loadedFactory = this.#loadedDefaultFactories.get(defaultFactory!);
         if (!loadedFactory) {
-          loadedFactory = Promise.resolve().then(
-            () => defaultFactory!(ref) as Promise<ServiceFactory>,
-          );
+          loadedFactory = Promise.resolve()
+            .then(() => defaultFactory!(ref))
+            .then(f =>
+              typeof f === 'function' ? f() : f,
+            ) as Promise<ServiceFactory>;
           this.#loadedDefaultFactories.set(defaultFactory!, loadedFactory);
         }
         // NOTE: This await is safe as long as #providedFactories is not mutated.

packages/backend-app-api/src/wiring/types.ts

@@ -43,7 +43,7 @@ export interface BackendRegisterInit {
  * @public
  */
 export interface CreateSpecializedBackendOptions {
-  services: ServiceFactory[];
+  services: (ServiceFactory | (() => ServiceFactory))[];
 }
 
 export type ServiceHolder = {
@@ -56,7 +56,9 @@ export type ServiceHolder = {
 export function createSpecializedBackend(
   options: CreateSpecializedBackendOptions,
 ): Backend {
-  return new BackstageBackend(options.services);
+  return new BackstageBackend(
+    options.services.map(s => (typeof s === 'function' ? s() : s)),
+  );
 }
 
 /**