Add proxyEndpointsExtensionPoint

Signed-off-by: Matt Benson <gudnabrsam@gmail.com>

plugins/proxy-backend/dev/index.ts

@@ -15,7 +15,35 @@
  */
 
 import { createBackend } from '@backstage/backend-defaults';
+import { createBackendModule } from '@backstage/backend-plugin-api';
+import { proxyEndpointsExtensionPoint } from '@backstage/plugin-proxy-node/alpha';
 
 const backend = createBackend();
 backend.add(import('../src/alpha'));
+
+backend.add(
+  createBackendModule({
+    pluginId: 'proxy',
+    moduleId: 'demo-additional-endpoints',
+    register: reg => {
+      reg.registerInit({
+        deps: {
+          proxyEndpoints: proxyEndpointsExtensionPoint,
+        },
+        init: async ({ proxyEndpoints }) => {
+          proxyEndpoints.addProxyEndpoints({
+            ...Object.fromEntries(
+              ['foo', 'bar', 'baz'].map(msv => [
+                `/${msv}`,
+                { target: `http://${msv}.org` },
+              ]),
+            ),
+            '/gocd': 'http://cannot-override-config.no',
+          });
+        },
+      });
+    },
+  }),
+);
+
 backend.start();

plugins/proxy-backend/package.json

@@ -56,6 +56,7 @@
     "@backstage/backend-common": "^0.25.0",
     "@backstage/backend-plugin-api": "workspace:^",
     "@backstage/config": "workspace:^",
+    "@backstage/plugin-proxy-node": "workspace:^",
     "@backstage/types": "workspace:^",
     "@types/express": "^4.17.6",
     "express": "^4.17.1",

plugins/proxy-backend/report.api.md

@@ -6,6 +6,7 @@
 import { BackendFeature } from '@backstage/backend-plugin-api';
 import { DiscoveryService } from '@backstage/backend-plugin-api';
 import express from 'express';
+import { JsonObject } from '@backstage/types';
 import { Logger } from 'winston';
 import { RootConfigService } from '@backstage/backend-plugin-api';
 
@@ -18,6 +19,8 @@ export default proxyPlugin;
 
 // @public @deprecated (undocumented)
 export interface RouterOptions {
+  // (undocumented)
+  additionalEndpoints?: JsonObject;
   // (undocumented)
   config: RootConfigService;
   // (undocumented)

plugins/proxy-backend/src/plugin.ts

@@ -20,6 +20,8 @@ import {
   coreServices,
 } from '@backstage/backend-plugin-api';
 import { createRouterInternal } from './service/router';
+import { proxyEndpointsExtensionPoint } from '@backstage/plugin-proxy-node/alpha';
+import { JsonObject } from '@backstage/types';
 
 /**
  * The proxy backend plugin.
@@ -29,6 +31,13 @@ import { createRouterInternal } from './service/router';
 export const proxyPlugin = createBackendPlugin({
   pluginId: 'proxy',
   register(env) {
+    const additionalEndpoints = {};
+
+    env.registerExtensionPoint(proxyEndpointsExtensionPoint, {
+      addProxyEndpoints(endpoints: JsonObject) {
+        Object.assign(additionalEndpoints, endpoints);
+      },
+    });
     env.registerInit({
       deps: {
         config: coreServices.rootConfig,
@@ -42,6 +51,7 @@ export const proxyPlugin = createBackendPlugin({
           discovery,
           logger: loggerToWinstonLogger(logger),
           httpRouterService: httpRouter,
+          additionalEndpoints,
         });
       },
     });

plugins/proxy-backend/src/service/router.ts

@@ -63,6 +63,7 @@ export interface RouterOptions {
   discovery: DiscoveryService;
   skipInvalidProxies?: boolean;
   reviveConsumedRequestBodies?: boolean;
+  additionalEndpoints?: JsonObject;
 }
 
 export interface ProxyConfig extends Options {
@@ -315,7 +316,10 @@ export async function createRouterInternal(
   const externalUrl = await options.discovery.getExternalBaseUrl('proxy');
   const { pathname: pathPrefix } = new URL(externalUrl);
 
-  const proxyConfig = readProxyConfig(options.config, options.logger);
+  const proxyConfig = {
+    ...(options.additionalEndpoints ?? {}),
+    ...readProxyConfig(options.config, options.logger),
+  };
   configureMiddlewares(
     proxyOptions,
     currentRouter,