Merge branch 'main' into RHIDP-2919

packages/backend/package.json

@@ -47,7 +47,6 @@
     "@janus-idp/backstage-scaffolder-backend-module-annotator": "1.3.1",
     "@manypkg/get-packages": "1.1.3",
     "app": "*",
-    "express": "4.21.0",
     "express-prom-bundle": "6.6.0",
     "global-agent": "3.0.0",
     "prom-client": "15.1.3",

packages/backend/src/index.ts

@@ -1,52 +1,27 @@
-import { statusCheckHandler } from '@backstage/backend-common';
 import { createBackend } from '@backstage/backend-defaults';
-import { rootHttpRouterServiceFactory } from '@backstage/backend-defaults/rootHttpRouter';
 import {
   dynamicPluginsFeatureDiscoveryServiceFactory,
   dynamicPluginsFrontendSchemas,
   dynamicPluginsSchemasServiceFactory,
   dynamicPluginsServiceFactory,
 } from '@backstage/backend-dynamic-feature-service';
 import { PackageRoles } from '@backstage/cli-node';
-import { RequestHandler } from 'express';
 import * as path from 'path';
 import { configureCorporateProxyAgent } from './corporate-proxy';
 import { CommonJSModuleLoader } from './loader';
 import { customLogger } from './logger';
-import { metricsHandler } from './metrics';
 import {
+  metricsPlugin,
+  healthCheckPlugin,
   pluginIDProviderService,
   rbacDynamicPluginsProvider,
-} from './modules/rbacDynamicPluginsModule';
+} from './modules';
 
 // RHIDP-2217: adds support for corporate proxy
 configureCorporateProxyAgent();
 
 const backend = createBackend();
 
-backend.add(
-  rootHttpRouterServiceFactory({
-    configure(context) {
-      let healthCheckHandler: RequestHandler | undefined;
-
-      const { app, routes, middleware } = context;
-      app.use(middleware.helmet());
-      app.use(middleware.cors());
-      app.use(middleware.compression());
-      app.use(middleware.logging());
-      app.use('/healthcheck', async (_, response, next) => {
-        if (!healthCheckHandler) {
-          healthCheckHandler = await statusCheckHandler();
-        }
-        healthCheckHandler(_, response, next);
-      });
-      app.use('/metrics', metricsHandler());
-      app.use(routes);
-      app.use(middleware.notFound());
-      app.use(middleware.error());
-    },
-  }),
-);
 backend.add(dynamicPluginsFeatureDiscoveryServiceFactory); // overridden version of the FeatureDiscoveryService which provides features loaded by dynamic plugins
 backend.add(
   dynamicPluginsServiceFactory({
@@ -70,6 +45,9 @@ backend.add(
 backend.add(dynamicPluginsFrontendSchemas);
 backend.add(customLogger);
 
+backend.add(metricsPlugin);
+backend.add(healthCheckPlugin);
+
 backend.add(import('@backstage/plugin-app-backend/alpha'));
 backend.add(
   import('@backstage/plugin-catalog-backend-module-scaffolder-entity-model'),

packages/backend/src/modules/healthcheck.ts

@@ -0,0 +1,22 @@
+import {
+  coreServices,
+  createBackendPlugin,
+} from '@backstage/backend-plugin-api';
+
+export const healthCheckPlugin = createBackendPlugin({
+  pluginId: 'healthcheck',
+  register(reg) {
+    reg.registerInit({
+      deps: {
+        rootHttpRouter: coreServices.rootHttpRouter,
+        rootHealth: coreServices.rootHealth,
+      },
+      async init({ rootHttpRouter, rootHealth }) {
+        rootHttpRouter.use('/healthcheck', async (_, res) => {
+          const { status, payload } = await rootHealth.getLiveness();
+          res.status(status).json(payload);
+        });
+      },
+    });
+  },
+});

packages/backend/src/modules/index.ts

@@ -0,0 +1,4 @@
+export * from './authProvidersModule';
+export * from './rbacDynamicPluginsModule';
+export * from './healthcheck';
+export * from './metrics';

packages/backend/src/modules/metrics.ts

@@ -0,0 +1,47 @@
+import {
+  coreServices,
+  createBackendPlugin,
+} from '@backstage/backend-plugin-api';
+import promBundle from 'express-prom-bundle';
+import * as url from 'url';
+
+const rootRegEx = new RegExp('^/([^/]*)/.*');
+const apiRegEx = new RegExp('^/api/([^/]*)/.*');
+
+function normalizePath(req: any): string {
+  const path = url.parse(req.originalUrl || req.url).pathname || '/';
+
+  // Capture /api/ and the plugin name
+  if (apiRegEx.test(path)) {
+    return path.replace(apiRegEx, '/api/$1');
+  }
+
+  // Only the first path segment at root level
+  return path.replace(rootRegEx, '/$1');
+}
+
+export const metricsPlugin = createBackendPlugin({
+  pluginId: 'metrics',
+  register(reg) {
+    reg.registerInit({
+      deps: {
+        rootHttpRouter: coreServices.rootHttpRouter,
+      },
+      async init({ rootHttpRouter }) {
+        rootHttpRouter.use(
+          '/metrics',
+          promBundle({
+            includeMethod: true,
+            includePath: true,
+            // Using includePath alone is problematic, as it will include path labels with high
+            // cardinality (e.g. path params). Instead we would have to template them. However, this
+            // is difficult, as every backend plugin might use different routes. Instead we only take
+            // the first directory of the path, to have at least an idea how each plugin performs:
+            normalizePath,
+            promClient: { collectDefaultMetrics: {} },
+          }),
+        );
+      },
+    });
+  },
+});