packages/cli: use app.baseUrl to configure dev server

packages/cli/src/lib/bundler/bundle.ts

@@ -23,7 +23,7 @@ import {
   printFileSizesAfterBuild,
 } from 'react-dev-utils/FileSizeReporter';
 import formatWebpackMessages from 'react-dev-utils/formatWebpackMessages';
-import { createConfig } from './config';
+import { createConfig, resolveBaseUrl } from './config';
 import { BuildOptions } from './types';
 import { resolveBundlingPaths } from './paths';
 import chalk from 'chalk';
@@ -40,6 +40,7 @@ export async function buildBundle(options: BuildOptions) {
     ...options,
     checksEnabled: false,
     isDev: false,
+    baseUrl: resolveBaseUrl(options.config),
   });
   const compiler = webpack(config);
 

packages/cli/src/lib/bundler/config.ts

@@ -18,6 +18,7 @@ import webpack from 'webpack';
 import ForkTsCheckerWebpackPlugin from 'fork-ts-checker-webpack-plugin';
 import ModuleScopePlugin from 'react-dev-utils/ModuleScopePlugin';
 import HtmlWebpackPlugin from 'html-webpack-plugin';
+import { Config } from '@backstage/config';
 import { BundlingPaths } from './paths';
 import { transforms } from './transforms';
 import { optimization } from './optimization';
@@ -28,6 +29,18 @@ import { BundlingOptions } from './types';
 // import evalSourceMapMiddleware from 'react-dev-utils/evalSourceMapMiddleware';
 // import WatchMissingNodeModulesPlugin from 'react-dev-utils/WatchMissingNodeModulesPlugin';
 
+export function resolveBaseUrl(config: Config): URL {
+  const baseUrl = config.getString('app.baseUrl');
+  if (!baseUrl) {
+    throw new Error('app.baseUrl must be set in config');
+  }
+  try {
+    return new URL(baseUrl, 'http://localhost:3000');
+  } catch (error) {
+    throw new Error(`Invalid app.baseUrl, ${error}`);
+  }
+}
+
 export function createConfig(
   paths: BundlingPaths,
   options: BundlingOptions,

packages/cli/src/lib/bundler/server.ts

@@ -15,30 +15,22 @@
  */
 
 import fs from 'fs-extra';
-import yn from 'yn';
 import webpack from 'webpack';
 import WebpackDevServer from 'webpack-dev-server';
 import openBrowser from 'react-dev-utils/openBrowser';
-import { choosePort, prepareUrls } from 'react-dev-utils/WebpackDevServerUtils';
-import { createConfig } from './config';
+import { createConfig, resolveBaseUrl } from './config';
 import { ServeOptions } from './types';
 import { resolveBundlingPaths } from './paths';
 
 export async function serveBundle(options: ServeOptions) {
-  const host = process.env.HOST ?? '0.0.0.0';
-  const defaultPort = parseInt(process.env.PORT ?? '', 10) || 3000;
+  const url = resolveBaseUrl(options.config);
 
-  const port = await choosePort(host, defaultPort);
-  if (!port) {
-    throw new Error(`Invalid or no port set: '${port}'`);
-  }
-
-  const protocol = yn(process.env.HTTPS, { default: false }) ? 'https' : 'http';
+  const port = Number(url.port) || (url.protocol === 'https:' ? 443 : 80);
 
   const paths = resolveBundlingPaths(options);
   const pkgPath = paths.targetPackageJson;
   const pkg = await fs.readJson(pkgPath);
-  const config = createConfig(paths, { ...options, isDev: true });
+  const config = createConfig(paths, { ...options, isDev: true, baseUrl: url });
   const compiler = webpack(config);
 
   const server = new WebpackDevServer(compiler, {
@@ -49,33 +41,20 @@ export async function serveBundle(options: ServeOptions) {
     historyApiFallback: true,
     clientLogLevel: 'warning',
     stats: 'errors-warnings',
-    https: protocol === 'https',
-    host,
+    https: url.protocol === 'https:',
+    host: url.hostname,
     port,
     proxy: pkg.proxy,
   });
 
   await new Promise((resolve, reject) => {
-    server.listen(port, host, (err?: Error) => {
+    server.listen(port, url.hostname, (err?: Error) => {
       if (err) {
         reject(err);
         return;
       }
 
-      // TODO: This signature is available in 10.2.1 but doesn't have types published yet
-      const latestPrepareUrls = prepareUrls as (
-        protocol: string,
-        host: string,
-        port: number,
-        path?: string,
-      ) => ReturnType<typeof prepareUrls>;
-      const urls = latestPrepareUrls(
-        protocol,
-        host,
-        port,
-        config.output?.publicPath,
-      );
-      openBrowser(urls.localUrlForBrowser);
+      openBrowser(url.href);
       resolve();
     });
   });

packages/cli/src/lib/bundler/types.ts

@@ -22,6 +22,7 @@ export type BundlingOptions = {
   isDev: boolean;
   config: Config;
   appConfigs: AppConfig[];
+  baseUrl: URL;
 };
 
 export type ServeOptions = BundlingPathsOptions & {