feat(app): dynamic authentication provider support

This change adds support for loading authentication providers or modules
from dynamic plugins.  An environment variable
ENABLE_AUTH_PROVIDER_MODULE_OVERRIDE controls whether or not the backend
installs the default authentication provider module.  When this override
is enabled dynamic plugins can be used to supply custom authentication
providers.  This change also adds a "components" configuration for
frontend dynamic plugins, which can be used to supply overrides for the
AppComponents option.  This is required for dynamic plugins to be able to
provide a custom SignInPage component, for example:

```
frontend:
  my-plugin-package:
    components:
      - name: SignInPage
        module: PluginRoot
        importName: SignInPage
```

Where the named export SignInPage will be mapped to
`components.SignInPage` when the frontend is initialized.

Signed-off-by: Stan Lewis <gashcrumb@gmail.com>

packages/app/src/components/DynamicRoot/DynamicRoot.tsx

@@ -3,7 +3,11 @@ import React, { useCallback, useEffect, useRef, useState } from 'react';
 
 import { createApp } from '@backstage/app-defaults';
 import { BackstageApp } from '@backstage/core-app-api';
-import { AnyApiFactory, BackstagePlugin } from '@backstage/core-plugin-api';
+import {
+  AnyApiFactory,
+  AppComponents,
+  BackstagePlugin,
+} from '@backstage/core-plugin-api';
 
 import { useThemes } from '@redhat-developer/red-hat-developer-hub-theme';
 import { AppsConfig } from '@scalprum/core';
@@ -61,7 +65,9 @@ export const DynamicRoot = ({
     React.ComponentType | undefined
   >(undefined);
   // registry of remote components loaded at bootstrap
-  const [components, setComponents] = useState<ComponentRegistry | undefined>();
+  const [componentRegistry, setComponentRegistry] = useState<
+    ComponentRegistry | undefined
+  >();
   const { initialized, pluginStore, api: scalprumApi } = useScalprum();
 
   const themes = useThemes();
@@ -72,6 +78,7 @@ export const DynamicRoot = ({
       pluginModules,
       apiFactories,
       appIcons,
+      components,
       dynamicRoutes,
       menuItems,
       entityTabs,
@@ -86,6 +93,10 @@ export const DynamicRoot = ({
         scope,
         module,
       })),
+      ...components.map(({ scope, module }) => ({
+        scope,
+        module,
+      })),
       ...routeBindingTargets.map(({ scope, module }) => ({
         scope,
         module,
@@ -172,6 +183,23 @@ export const DynamicRoot = ({
       ),
     );
 
+    const appComponents = components.reduce<Partial<AppComponents>>(
+      (componentMap, { scope, module, importName, name }) => {
+        if (typeof allPlugins[scope]?.[module]?.[importName] !== 'undefined') {
+          componentMap[name] = allPlugins[scope]?.[module]?.[
+            importName
+          ] as React.ComponentType<any>;
+        } else {
+          // eslint-disable-next-line no-console
+          console.warn(
+            `Plugin ${scope} is not configured properly: ${module}.${importName} not found, ignoring AppComponent: ${name}`,
+          );
+        }
+        return componentMap;
+      },
+      {},
+    );
+
     let icons = Object.fromEntries(
       appIcons.reduce<[string, React.ComponentType<{}>][]>(
         (acc, { scope, module, importName, name }) => {
@@ -408,7 +436,10 @@ export const DynamicRoot = ({
           ...remoteBackstagePlugins,
         ],
         themes: [...filteredStaticThemes, ...dynamicThemeProviders],
-        components: defaultAppComponents,
+        components: {
+          ...defaultAppComponents,
+          ...appComponents,
+        } as Partial<AppComponents>,
       });
     }
 
@@ -424,7 +455,7 @@ export const DynamicRoot = ({
       scaffolderFieldExtensionComponents;
 
     // make the dynamic UI configuration available to DynamicRootContext consumers
-    setComponents({
+    setComponentRegistry({
       AppProvider: app.current.getProvider(),
       AppRouter: app.current.getRouter(),
       dynamicRoutes: dynamicRoutesComponents,
@@ -449,17 +480,17 @@ export const DynamicRoot = ({
   ]);
 
   useEffect(() => {
-    if (initialized && !components) {
+    if (initialized && !componentRegistry) {
       initializeRemoteModules();
     }
-  }, [initialized, components, initializeRemoteModules]);
+  }, [initialized, componentRegistry, initializeRemoteModules]);
 
-  if (!initialized || !components) {
+  if (!initialized || !componentRegistry) {
     return <Loader />;
   }
 
   return (
-    <DynamicRootContext.Provider value={components}>
+    <DynamicRootContext.Provider value={componentRegistry}>
       {ChildComponent ? <ChildComponent /> : <Loader />}
     </DynamicRootContext.Provider>
   );

packages/app/src/utils/dynamicUI/extractDynamicConfig.test.ts

@@ -148,6 +148,7 @@ describe('extractDynamicConfig', () => {
     const config = extractDynamicConfig(source as DynamicPluginConfig);
     expect(config).toEqual({
       pluginModules: [],
+      components: [],
       routeBindings: [],
       dynamicRoutes: [],
       entityTabs: [],
@@ -162,6 +163,20 @@ describe('extractDynamicConfig', () => {
   });
 
   it.each([
+    [
+      'a component',
+      { components: [{ name: 'foo', importName: 'blah' }] },
+      {
+        components: [
+          {
+            importName: 'blah',
+            module: 'PluginRoot',
+            name: 'foo',
+            scope: 'janus-idp.plugin-foo',
+          },
+        ],
+      },
+    ],
     [
       'a dynamicRoute',
       { dynamicRoutes: [{ path: '/foo' }] },
@@ -506,6 +521,7 @@ describe('extractDynamicConfig', () => {
           scope: 'janus-idp.plugin-foo',
         },
       ],
+      components: [],
       routeBindings: [],
       routeBindingTargets: [],
       dynamicRoutes: [],

packages/app/src/utils/dynamicUI/extractDynamicConfig.ts

@@ -1,5 +1,5 @@
 import { Entity } from '@backstage/catalog-model';
-import { ApiHolder } from '@backstage/core-plugin-api';
+import { ApiHolder, AppComponents } from '@backstage/core-plugin-api';
 import { isKind } from '@backstage/plugin-catalog';
 
 import { hasAnnotation, isType } from '../../components/catalog/utils';
@@ -116,8 +116,17 @@ type ThemeEntry = {
   importName: string;
 };
 
+type ComponentEntry = {
+  scope: string;
+  module: string;
+  id: string;
+  importName: string;
+  name: keyof AppComponents;
+};
+
 type CustomProperties = {
   pluginModule?: string;
+  components: ComponentEntry[];
   dynamicRoutes?: (DynamicModuleEntry & {
     importName?: string;
     module?: string;
@@ -149,6 +158,7 @@ type DynamicConfig = {
   pluginModules: PluginModule[];
   apiFactories: ApiFactory[];
   appIcons: AppIcon[];
+  components: ComponentEntry[];
   dynamicRoutes: DynamicRoute[];
   menuItems: MenuItem[];
   entityTabs: EntityTabEntry[];
@@ -171,6 +181,7 @@ function extractDynamicConfig(
     pluginModules: [],
     apiFactories: [],
     appIcons: [],
+    components: [],
     dynamicRoutes: [],
     menuItems: [],
     entityTabs: [],
@@ -190,6 +201,20 @@ function extractDynamicConfig(
     },
     [],
   );
+  config.components = Object.entries(frontend).reduce<ComponentEntry[]>(
+    (pluginSet, [scope, customProperties]) => {
+      pluginSet.push(
+        ...(customProperties.components ?? []).map(component => ({
+          ...component,
+          module: component.module ?? 'PluginRoot',
+          importName: component.importName ?? 'default',
+          scope,
+        })),
+      );
+      return pluginSet;
+    },
+    [],
+  );
   config.dynamicRoutes = Object.entries(frontend).reduce<DynamicRoute[]>(
     (pluginSet, [scope, customProperties]) => {
       pluginSet.push(

packages/backend/src/index.ts

@@ -91,7 +91,11 @@ backend.add(rbacDynamicPluginsProvider);
 
 backend.add(import('@backstage/plugin-auth-backend'));
 backend.add(import('@backstage/plugin-auth-backend-module-guest-provider'));
-backend.add(import('./modules/authProvidersModule'));
+if (process.env.ENABLE_AUTH_PROVIDER_MODULE_OVERRIDE !== 'true') {
+  backend.add(import('./modules/authProvidersModule'));
+} else {
+  staticLogger.info(`Default authentication provider module disabled`);
+}
 
 backend.add(import('@internal/plugin-dynamic-plugins-info-backend'));
 backend.add(import('@internal/plugin-scalprum-backend'));