CLI: Add --build-only option

Author: kaelig

docs/api/cli-options.md

@@ -25,6 +25,7 @@ Usage: start-storybook [options]
 | --ssl-cert `<cert>`            | Provide an SSL certificate. (Required with --https)                                                                                            | `start-storybook --ssl-cert my-ssl-certificate` |
 | --ssl-key `<key>`              | Provide an SSL key. (Required with --https)                                                                                                    | `start-storybook --ssl-key my-ssl-key`          |
 | --smoke-test                   | Exit after successful start                                                                                                                    | `start-storybook --smoke-test`                  |
+| --build-only                   | Only build, don’t start the server (useful to warm up the cache)                                                                               | `start-storybook --build-only`                  |
 | --ci                           | CI mode (skip interactive prompts, don't open browser)                                                                                         | `start-storybook --ci`                          |
 | --quiet                        | Suppress verbose build output                                                                                                                  | `start-storybook --quiet`                       |
 | --no-dll                       | Do not use dll reference (no-op)                                                                                                               | `start-storybook --no-dll`                      |

lib/core/docs/standalone.md

@@ -64,6 +64,7 @@ sslCa <ca>              Provide an SSL certificate authority. (Optional with "ht
 sslCert <cert>          Provide an SSL certificate. (Required with "https")
 sslKey <key>            Provide an SSL key. (Required with "https")
 smokeTest               Exit after successful start
+buildOnly               Only build, don’t start the server (useful to warm up the cache)
 ci                      CI mode (skip interactive prompts, don't open browser)
 quiet                   Suppress verbose build output
 ```

lib/core/src/server/build-dev.ts

@@ -254,7 +254,13 @@ export async function buildDevStandalone(
         : Promise.resolve(getReleaseNotesFailedState(version)),
     ]);
 
-    if (!options.ci && !options.smokeTest && options.port != null && port !== options.port) {
+    if (
+      !options.buildOnly &&
+      !options.ci &&
+      !options.smokeTest &&
+      options.port != null &&
+      port !== options.port
+    ) {
       const { shouldChangePort } = await prompts({
         type: 'confirm',
         initial: true,
@@ -283,12 +289,17 @@ export async function buildDevStandalone(
 
     if (options.smokeTest) {
       await outputStats(previewStats, managerStats);
+
       const hasManagerWarnings = managerStats && managerStats.toJson().warnings.length > 0;
       const hasPreviewWarnings = previewStats && previewStats.toJson().warnings.length > 0;
       process.exit(hasManagerWarnings || (hasPreviewWarnings && !options.ignorePreview) ? 1 : 0);
       return;
     }
 
+    if (options.buildOnly) {
+      process.exit(0);
+    }
+
     outputStartupInformation({
       updateInfo,
       version,

lib/core/src/server/cli/dev.ts

@@ -13,6 +13,7 @@ export interface DevCliOptions {
   sslCert?: string;
   sslKey?: string;
   smokeTest?: boolean;
+  buildOnly?: boolean;
   ci?: boolean;
   loglevel?: string;
   quiet?: boolean;
@@ -50,6 +51,7 @@ export async function getDevCli(packageJson: {
     .option('--ssl-cert <cert>', 'Provide an SSL certificate. (Required with --https)')
     .option('--ssl-key <key>', 'Provide an SSL key. (Required with --https)')
     .option('--smoke-test', 'Exit after successful start')
+    .option('--build-only', 'Only build, don’t start the server (useful to warm up the cache)')
     .option('--ci', "CI mode (skip interactive prompts, don't open browser)")
     .option('--loglevel [level]', 'Control level of logging during build')
     .option('--quiet', 'Suppress verbose build output')

lib/core/src/server/dev-server.ts

@@ -365,45 +365,51 @@ export function getServerAddresses(port: number, host: string, proto: string) {
 
 export async function storybookDevServer(options: any) {
   const app = express();
-  const server = await getServer(app, options);
 
   const configDir = path.resolve(options.configDir);
   const outputDir = options.smokeTest
     ? resolvePathInStorybookCache('public')
     : path.resolve(options.outputDir || resolvePathInStorybookCache('public'));
   const configType = 'DEVELOPMENT';
   const startTime = process.hrtime();
+  const prebuiltDir = await getPrebuiltDir({ configDir, options });
+  let address;
+  let networkAddress;
 
-  if (typeof options.extendServer === 'function') {
-    options.extendServer(server);
-  }
+  if (!options.buildOnly) {
+    const server = await getServer(app, options);
 
-  app.use((req, res, next) => {
-    res.header('Access-Control-Allow-Origin', '*');
-    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
-    next();
-  });
+    if (typeof options.extendServer === 'function') {
+      options.extendServer(server);
+    }
 
-  // User's own static files
-  await useStatics(router, options);
+    app.use((req, res, next) => {
+      res.header('Access-Control-Allow-Origin', '*');
+      res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept');
+      next();
+    });
 
-  getMiddleware(configDir)(router);
-  app.use(router);
+    // User's own static files
+    await useStatics(router, options);
 
-  const { port, host } = options;
-  const proto = options.https ? 'https' : 'http';
-  const { address, networkAddress } = getServerAddresses(port, host, proto);
+    getMiddleware(configDir)(router);
+    app.use(router);
 
-  await new Promise((resolve, reject) => {
-    // FIXME: Following line doesn't match TypeScript signature at all 🤔
-    // @ts-ignore
-    server.listen({ port, host }, (error: Error) => (error ? reject(error) : resolve()));
-  });
+    const { port, host } = options;
+    const proto = options.https ? 'https' : 'http';
+    const serverAddresses = getServerAddresses(port, host, proto);
+    networkAddress = serverAddresses.networkAddress;
+    address = serverAddresses.address;
 
-  const prebuiltDir = await getPrebuiltDir({ configDir, options });
+    await new Promise((resolve, reject) => {
+      // FIXME: Following line doesn't match TypeScript signature at all 🤔
+      // @ts-ignore
+      server.listen({ port, host }, (error: Error) => (error ? reject(error) : resolve()));
+    });
 
-  // Manager static files
-  router.use('/', express.static(prebuiltDir || outputDir));
+    // Manager static files
+    router.use('/', express.static(prebuiltDir || outputDir));
+  }
 
   // Build the manager and preview in parallel.
   // Start the server (and open the browser) as soon as the manager is ready.
@@ -413,14 +419,14 @@ export async function storybookDevServer(options: any) {
     startManager({ startTime, options, configType, outputDir, configDir, prebuiltDir })
       // TODO #13083 Restore this when compiling the preview is fast enough
       // .then((result) => {
-      //   if (!options.ci && !options.smokeTest) openInBrowser(address);
+      //   if (!options.ci && !options.smokeTest && !options.buildOnly) openInBrowser(address);
       //   return result;
       // })
       .catch(bailPreview),
   ]);
 
   // TODO #13083 Remove this when compiling the preview is fast enough
-  if (!options.ci && !options.smokeTest) openInBrowser(networkAddress);
+  if (!options.ci && !options.smokeTest && !options.buildOnly) openInBrowser(networkAddress);
 
   return { ...previewResult, ...managerResult, address, networkAddress };
 }