feat(backend-app-api): add ability to configure node server in root http router

Signed-off-by: Alec Jacobs <cajacobs5401@gmail.com>

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

@@ -37,6 +37,7 @@ import { RootHttpRouterService } from '@backstage/backend-plugin-api';
 import { RootLifecycleService } from '@backstage/backend-plugin-api';
 import { RootLoggerService } from '@backstage/backend-plugin-api';
 import { SchedulerService } from '@backstage/backend-plugin-api';
+import type { Server } from 'node:http';
 import { ServiceFactory } from '@backstage/backend-plugin-api';
 import { ServiceFactoryOrFunction } from '@backstage/backend-plugin-api';
 import { TokenManagerService } from '@backstage/backend-plugin-api';
@@ -287,6 +288,8 @@ export interface RootHttpRouterConfigureContext {
   // (undocumented)
   app: Express_2;
   // (undocumented)
+  applyDefaults: () => void;
+  // (undocumented)
   config: RootConfigService;
   // (undocumented)
   lifecycle: LifecycleService;
@@ -296,6 +299,8 @@ export interface RootHttpRouterConfigureContext {
   middleware: MiddlewareFactory;
   // (undocumented)
   routes: RequestHandler;
+  // (undocumented)
+  server: Server;
 }
 
 // @public (undocumented)

packages/backend-app-api/src/services/implementations/rootHttpRouter/rootHttpRouterServiceFactory.ts

@@ -22,6 +22,7 @@ import {
   LoggerService,
 } from '@backstage/backend-plugin-api';
 import express, { RequestHandler, Express } from 'express';
+import type { Server } from 'node:http';
 import {
   createHttpServer,
   MiddlewareFactory,
@@ -34,11 +35,13 @@ import { DefaultRootHttpRouter } from './DefaultRootHttpRouter';
  */
 export interface RootHttpRouterConfigureContext {
   app: Express;
+  server: Server;
   middleware: MiddlewareFactory;
   routes: RequestHandler;
   config: RootConfigService;
   logger: LoggerService;
   lifecycle: LifecycleService;
+  applyDefaults: () => void;
 }
 
 /**
@@ -54,15 +57,8 @@ export type RootHttpRouterFactoryOptions = {
   configure?(context: RootHttpRouterConfigureContext): void;
 };
 
-function defaultConfigure(context: RootHttpRouterConfigureContext) {
-  const { app, routes, middleware } = context;
-  app.use(middleware.helmet());
-  app.use(middleware.cors());
-  app.use(middleware.compression());
-  app.use(middleware.logging());
-  app.use(routes);
-  app.use(middleware.notFound());
-  app.use(middleware.error());
+function defaultConfigure({ applyDefaults }: RootHttpRouterConfigureContext) {
+  applyDefaults();
 }
 
 /** @public */
@@ -81,22 +77,32 @@ export const rootHttpRouterServiceFactory = createServiceFactory(
 
       const router = DefaultRootHttpRouter.create({ indexPath });
       const middleware = MiddlewareFactory.create({ config, logger });
-
-      configure({
-        app,
-        routes: router.handler(),
-        middleware,
-        config,
-        logger,
-        lifecycle,
-      });
-
+      const routes = router.handler();
       const server = await createHttpServer(
         app,
         readHttpServerOptions(config.getOptionalConfig('backend')),
         { logger },
       );
 
+      configure({
+        app,
+        server,
+        routes,
+        middleware,
+        config,
+        logger,
+        lifecycle,
+        applyDefaults() {
+          app.use(middleware.helmet());
+          app.use(middleware.cors());
+          app.use(middleware.compression());
+          app.use(middleware.logging());
+          app.use(routes);
+          app.use(middleware.notFound());
+          app.use(middleware.error());
+        },
+      });
+
       lifecycle.addShutdownHook(() => server.stop());
 
       await server.start();