Merge pull request #25585 from backstage/rugvip/nopts

backend-defaults: deprecate config service options

.changeset/wet-rivers-travel.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-defaults': patch
+---
+
+Refactor of `rootConfigServiceFactory` to allow it to be constructed with options, but without declaring options via `createServiceFactory`.

docs/backend-system/core-services/root-config.md

@@ -60,3 +60,34 @@ backend.add(
   }),
 );
 ```
+
+For more advanced customization, there are several APIs from the `@backstage/config-loader` package that allow you to customize the implementation of the config service. The default implementation uses the `ConfigSources.default` method, which has the same options as the `rootConfigServiceFactory` function. You can use these to create your own config service implementation:
+
+```ts
+import { ConfigSources } from '@backstage/config-loader';
+import { createServiceFactory } from '@backstage/backend-plugin-api';
+
+const backend = createBackend();
+
+backend.add(
+  createServiceFactory({
+    service: coreServices.rootConfig,
+    deps: {},
+    async factory() {
+      const source = ConfigSources.default({
+        argv: [
+          '--config',
+          '/backstage/app-config.development.yaml',
+          '--config',
+          '/backstage/app-config.yaml',
+        ],
+        remote: { reloadIntervalSeconds: 60 },
+      });
+      console.log(`Loading config from ${source}`);
+      return await ConfigSources.toConfig(source);
+    },
+  }),
+);
+```
+
+You can also use other config source such as `StaticConfigSource` and combine them with other sources using `ConfigSources.merge(...)`. You can also create your own config source by implementing the `ConfigSource` interface.

packages/backend-defaults/api-report-rootConfig.md

@@ -8,7 +8,7 @@ import { ConfigSchema } from '@backstage/config-loader';
 import { LoggerService } from '@backstage/backend-plugin-api';
 import { RemoteConfigSourceOptions } from '@backstage/config-loader';
 import { RootConfigService } from '@backstage/backend-plugin-api';
-import { ServiceFactoryCompat } from '@backstage/backend-plugin-api';
+import { ServiceFactory } from '@backstage/backend-plugin-api';
 
 // @public (undocumented)
 export function createConfigSecretEnumerator(options: {
@@ -26,11 +26,10 @@ export interface RootConfigFactoryOptions {
 }
 
 // @public (undocumented)
-export const rootConfigServiceFactory: ServiceFactoryCompat<
-  RootConfigService,
-  'root',
-  RootConfigFactoryOptions
->;
+export const rootConfigServiceFactory: ((
+  options?: RootConfigFactoryOptions,
+) => ServiceFactory<RootConfigService, 'root'>) &
+  ServiceFactory<RootConfigService, 'root'>;
 
 // (No @packageDocumentation comment for this package)
 ```

packages/backend-defaults/src/entrypoints/rootConfig/rootConfigServiceFactory.ts

@@ -45,11 +45,10 @@ export interface RootConfigFactoryOptions {
   watch?: boolean;
 }
 
-/**
- * @public
- */
-export const rootConfigServiceFactory = createServiceFactory(
-  (options?: RootConfigFactoryOptions) => ({
+export const rootConfigServiceFactoryWithOptions = (
+  options?: RootConfigFactoryOptions,
+) =>
+  createServiceFactory({
     service: coreServices.rootConfig,
     deps: {},
     async factory() {
@@ -61,5 +60,12 @@ export const rootConfigServiceFactory = createServiceFactory(
       console.log(`Loading config from ${source}`);
       return await ConfigSources.toConfig(source);
     },
-  }),
+  })();
+
+/**
+ * @public
+ */
+export const rootConfigServiceFactory = Object.assign(
+  rootConfigServiceFactoryWithOptions,
+  rootConfigServiceFactoryWithOptions(),
 );