frontend/core: added plugin route registration api + moved home page to plugin

frontend/packages/app/package.json

@@ -5,6 +5,7 @@
   "dependencies": {
     "@backstage/core": "0.0.0",
     "@backstage/plugin-hello-world": "0.0.0",
+    "@backstage/plugin-home-page": "0.0.0",
     "@backstage/plugin-login": "0.0.0",
     "@react-workspaces/react-scripts": "^3.3.0-alpha-08",
     "@testing-library/jest-dom": "^4.2.4",

frontend/packages/app/src/App.test.tsx

@@ -6,6 +6,5 @@ describe('App', () => {
   it('renders learn react link', () => {
     const rendered = render(<App />);
     rendered.getByText('This is Backstage!');
-    rendered.getByText('…with plugin hello-world:');
   });
 });

frontend/packages/app/src/App.tsx

@@ -1,17 +1,15 @@
 import {
   BackstageTheme,
   createApp,
-  EntityLink,
   Header,
   InfoCard,
   Page,
   theme,
 } from '@backstage/core';
-import helloWorld, { MyComponent } from '@backstage/plugin-hello-world';
 //import PageHeader from './components/PageHeader';
 import { LoginComponent } from '@backstage/plugin-login';
+import HomePagePlugin from '@backstage/plugin-home-page';
 import { CssBaseline, makeStyles, ThemeProvider } from '@material-ui/core';
-import Typography from '@material-ui/core/Typography';
 import React, { FC } from 'react';
 import {
   BrowserRouter as Router,
@@ -58,27 +56,6 @@ const useStyles = makeStyles(theme => ({
   },
 }));
 
-const Home: FC<{}> = () => {
-  return (
-    <InfoCard title="Home Page">
-      <Typography variant="body1">
-        {' '}
-        …with plugin {helloWorld?.id ?? 'wat'}:
-      </Typography>
-      <MyComponent />
-      <div>
-        <RouterLink to="/login">Go to Login</RouterLink>
-        <EntityLink kind="service" id="backstage-backend">
-          Backstage Backend
-        </EntityLink>
-        <EntityLink uri="entity:service:backstage-lb" subPath="ci-cd">
-          Backstage LB CI/CD
-        </EntityLink>
-      </div>
-    </InfoCard>
-  );
-};
-
 const Login: FC<{}> = () => {
   return (
     <InfoCard title="Login Page">
@@ -111,7 +88,8 @@ const AppShell: FC<{}> = ({ children }) => {
 const app = createApp();
 
 app.registerEntityKind(...entities);
-app.setHomePage(Home);
+app.registerPlugin(HomePagePlugin);
+
 const AppComponent = app.build();
 
 const App: FC<{}> = () => {

frontend/packages/core/package.json

@@ -15,7 +15,7 @@
     "@types/react-router-dom": "^5.1.3",
     "react": "^16.12.0",
     "react-dom": "^16.12.0",
-    "react-helmet":"5.2.1",
+    "react-helmet": "5.2.1",
     "react-addons-text-content": "0.0.4",
     "react-router-dom": "^5.1.2",
     "recompose": "0.30.0"

frontend/packages/core/src/appApi/AppBuilder.tsx

@@ -1,13 +1,10 @@
 import React, { ComponentType, FC } from 'react';
 import { AppContextProvider } from './AppContext';
 import { App, EntityConfig, AppComponentBuilder } from './types';
-import { Route, Switch, useParams } from 'react-router-dom';
+import { Route, Switch, useParams, Redirect } from 'react-router-dom';
 import EntityKind from './EntityKind';
 import { EntityContextProvider } from './EntityContext';
-
-const DefaultHomePage: FC<{}> = () => {
-  return <span>Hello! I am default home page</span>;
-};
+import { BackstagePlugin } from './types';
 
 class AppImpl implements App {
   constructor(private readonly entities: Map<string, EntityKind>) {}
@@ -33,7 +30,7 @@ function builtComponent(
 
 export default class AppBuilder {
   private readonly entities = new Map<string, EntityKind>();
-  private homePage: ComponentType = DefaultHomePage;
+  private readonly plugins = new Map<string, BackstagePlugin>();
 
   registerEntityKind(...entity: EntityKind[]) {
     for (const e of entity) {
@@ -45,14 +42,20 @@ export default class AppBuilder {
     }
   }
 
-  setHomePage(page: ComponentType<{}>) {
-    this.homePage = page;
+  registerPlugin(...plugin: BackstagePlugin[]) {
+    for (const p of plugin) {
+      const { id } = p;
+      if (this.plugins.has(id)) {
+        throw new Error(`Plugin '${id}' is already registered`);
+      }
+      this.plugins.set(id, p);
+    }
   }
 
   build(): ComponentType<{}> {
     const app = new AppImpl(this.entities);
 
-    const entityRoutes = [];
+    const entityRoutes = new Array<JSX.Element>();
 
     for (const { config } of this.entities.values()) {
       const { kind, pages } = config;
@@ -92,13 +95,41 @@ export default class AppBuilder {
       }
     }
 
-    const routes = [...entityRoutes];
+    const pluginRoutes = new Array<JSX.Element>();
+
+    for (const plugin of this.plugins.values()) {
+      plugin.register({
+        router: {
+          registerRoute(path, component, options = {}) {
+            if (path.startsWith('/entity/')) {
+              throw new Error(
+                `Plugin ${plugin.id} tried to register forbidden route ${path}`,
+              );
+            }
+            pluginRoutes.push(
+              <Route path={path} component={component} {...options} />,
+            );
+          },
+          registerRedirect(path, target, options = {}) {
+            if (path.startsWith('/entity/')) {
+              throw new Error(
+                `Plugin ${plugin.id} tried to register forbidden redirect ${path}`,
+              );
+            }
+            pluginRoutes.push(
+              <Redirect path={path} to={target} {...options} />,
+            );
+          },
+        },
+      });
+    }
+
+    const routes = [...pluginRoutes, ...entityRoutes];
 
     return () => (
       <AppContextProvider app={app}>
         <Switch>
           {routes}
-          <Route exact path="/" component={this.homePage} />
           <Route component={() => <span>404 Not Found</span>} />
         </Switch>
       </AppContextProvider>

frontend/packages/core/src/appApi/api.ts

@@ -1,5 +1,5 @@
 import AppBuilder from './AppBuilder';
-import { EntityConfig } from './types';
+import { EntityConfig, PluginConfig, BackstagePlugin } from './types';
 import EntityKind from './EntityKind';
 import OverviewPageBuilder from './OverviewPageBuilder';
 import EntityViewBuilder from './EntityViewPageBuilder';
@@ -19,3 +19,7 @@ export function createOverviewPage() {
 export function createEntityView() {
   return new EntityViewBuilder();
 }
+
+export function createPlugin(config: PluginConfig): BackstagePlugin {
+  return { register() {}, ...config };
+}

frontend/packages/core/src/appApi/createPlugin.ts

@@ -0,0 +1,10 @@
+import { BackstagePlugin, PluginConfig } from './types';
+
+function createPlugin(config: PluginConfig): BackstagePlugin {
+  return {
+    register() {},
+    ...config,
+  };
+}
+
+export default createPlugin;

frontend/packages/core/src/appApi/types.ts

@@ -34,3 +34,40 @@ export type UserApi = {
 
   getUser(): Promise<User>;
 };
+
+export type PluginConfig = {
+  id: string;
+  register?(hooks: PluginHooks): void;
+};
+
+export interface BackstagePlugin {
+  id: string;
+  register(hooks: PluginHooks): void;
+}
+
+export type PluginHooks = {
+  router: Router;
+};
+
+export type RouteOptions = {
+  // Whether the route path must match exactly, defaults to true.
+  exact?: boolean;
+};
+
+export type RedirectOptions = {
+  // Whether the route path must match exactly, defaults to true.
+  exact?: boolean;
+};
+
+export type Router = {
+  registerRoute(
+    path: string,
+    Component: React.ComponentType<any>,
+    options?: RouteOptions,
+  ): void;
+  registerRedirect(
+    path: string,
+    target: string,
+    options?: RedirectOptions,
+  ): void;
+};

frontend/packages/core/src/createPlugin.ts

@@ -1,11 +0,0 @@
-import { BackstagePlugin } from './types';
-
-export type PluginConfig = {
-  id: string;
-};
-
-function createPlugin(config: PluginConfig): BackstagePlugin {
-  return config;
-}
-
-export default createPlugin;

frontend/packages/core/src/index.ts

@@ -1,6 +1,4 @@
 export * from './appApi';
-export * from './types';
-export { default as createPlugin } from './createPlugin';
 export { default as Page } from '../src/layout/Page';
 export { gradients, theme } from '../src/layout/Page';
 export { default as Header } from '../src/layout/Header/Header';

frontend/packages/core/src/types.ts

@@ -1,3 +0,0 @@
-export type BackstagePlugin = {
-  id: string;
-};

frontend/packages/plugins/home-page/README.md

@@ -0,0 +1 @@
+Welcome to your home-page plugin!

frontend/packages/plugins/home-page/jest.config.js

@@ -0,0 +1,4 @@
+module.exports = {
+  ...require('@spotify/web-scripts/config/jest.config.js'),
+  setupFilesAfterEnv: ['../jest.setup.ts'],
+};

frontend/packages/plugins/home-page/jest.setup.ts

@@ -0,0 +1 @@
+import '@testing-library/jest-dom/extend-expect';

frontend/packages/plugins/home-page/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "@backstage/plugin-home-page",
+  "version": "0.0.0",
+  "main": "src/index.ts",
+  "main:src": "src/index.ts",
+  "devDependencies": {
+    "@backstage/core": "0.0.0",
+    "@spotify/web-scripts": "^6.0.0",
+    "@testing-library/jest-dom": "^4.2.4",
+    "@testing-library/react": "^9.3.2",
+    "@testing-library/user-event": "^7.1.2",
+    "@types/jest": "^24.0.0",
+    "@types/node": "^12.0.0",
+    "@types/react": "^16.9.0",
+    "@types/react-dom": "^16.9.0",
+    "react": "^16.12.0",
+    "react-dom": "^16.12.0",
+    "@material-ui/core": "^4.9.1",
+    "@material-ui/icons": "^4.9.1"
+  },
+  "scripts": {
+    "lint": "web-scripts lint",
+    "test": "web-scripts test"
+  },
+  "license": "Apache-2.0"
+}

frontend/packages/plugins/home-page/src/components/HomePage/HomePage.test.tsx

@@ -0,0 +1,10 @@
+import React from 'react';
+import { render } from '@testing-library/react';
+import HomePage from './HomePage';
+
+describe('HomePage', () => {
+  it('should render', () => {
+    const rendered = render(<HomePage />);
+    expect(rendered.baseElement).toBeInTheDocument();
+  });
+});

frontend/packages/plugins/home-page/src/components/HomePage/HomePage.tsx

@@ -0,0 +1,23 @@
+import React, { FC } from 'react';
+import { InfoCard, EntityLink } from '@backstage/core';
+import { Link } from 'react-router-dom';
+import { Typography } from '@material-ui/core';
+
+const HomePage: FC<{}> = () => {
+  return (
+    <InfoCard title="Home Page">
+      <Typography variant="body1">Welcome to Backstage!</Typography>
+      <div>
+        <Link to="/login">Go to Login</Link>
+        <EntityLink kind="service" id="backstage-backend">
+          Backstage Backend
+        </EntityLink>
+        <EntityLink uri="entity:service:backstage-lb" subPath="ci-cd">
+          Backstage LB CI/CD
+        </EntityLink>
+      </div>
+    </InfoCard>
+  );
+};
+
+export default HomePage;

frontend/packages/plugins/home-page/src/components/HomePage/index.ts

@@ -0,0 +1 @@
+export { default } from './HomePage';

frontend/packages/plugins/home-page/src/index.ts

@@ -0,0 +1 @@
+export { default } from './plugin';

frontend/packages/plugins/home-page/src/plugin.test.ts

@@ -0,0 +1,7 @@
+import plugin from './plugin';
+
+describe('home-page', () => {
+  it('should export plugin', () => {
+    expect(plugin.id).toBe('home-page');
+  });
+});

frontend/packages/plugins/home-page/src/plugin.ts

@@ -0,0 +1,9 @@
+import { createPlugin } from '@backstage/core';
+import HomePage from './components/HomePage';
+
+export default createPlugin({
+  id: 'home-page',
+  register({ router }) {
+    router.registerRoute('/', HomePage);
+  },
+});

frontend/yarn.lock

@@ -15388,11 +15388,6 @@ tiny-warning@^1.0.0, tiny-warning@^1.0.2:
   resolved "https://registry.npmjs.org/tiny-warning/-/tiny-warning-1.0.3.tgz#94a30db453df4c643d0fd566060d60a875d84754"
   integrity sha512-lBN9zLN/oAf68o3zNXYrdCt1kP8WsiGW8Oo2ka41b2IM5JL/S1CTyX1rW0mb/zSuJun0ZUrDxx4sqvYS2FWzPA==
 
-tinycolor2@1.4.1:
-  version "1.4.1"
-  resolved "https://registry.npmjs.org/tinycolor2/-/tinycolor2-1.4.1.tgz#f4fad333447bc0b07d4dc8e9209d8f39a8ac77e8"
-  integrity sha1-9PrTM0R7wLB9TcjpIJ2POaisd+g=
-
 tmp@^0.0.33:
   version "0.0.33"
   resolved "https://registry.npmjs.org/tmp/-/tmp-0.0.33.tgz#6d34335889768d21b2bcda0aa277ced3b1bfadf9"