feat(core): Add bundler tracing/profiling

.gitignore

@@ -45,3 +45,6 @@ website/i18n/**/*
 #!website/i18n/fr/**/*
 
 .netlify
+
+website/rspack-tracing.json
+website/bundler-cpu-profile.json

package.json

@@ -15,13 +15,15 @@
   "scripts": {
     "start": "yarn build:packages && yarn start:website",
     "start:website": "yarn workspace website start",
+    "start:website:profile": "DOCUSAURUS_BUNDLER_CPU_PROFILE=true DOCUSAURUS_RSPACK_TRACE=true yarn workspace website start",
     "start:website:baseUrl": "yarn workspace website start:baseUrl",
     "start:website:blogOnly": "yarn workspace website start:blogOnly",
     "start:website:deployPreview": "cross-env NETLIFY=true CONTEXT='deploy-preview' yarn workspace website start",
     "examples:generate": "node admin/scripts/generateExamples.js",
     "build": "yarn build:packages && yarn build:website",
     "build:packages": "lerna run build --no-private",
     "build:website": "yarn workspace website build",
+    "build:website:profile": "DOCUSAURUS_BUNDLER_CPU_PROFILE=true DOCUSAURUS_RSPACK_TRACE=true yarn workspace website build",
     "build:website:baseUrl": "yarn workspace website build:baseUrl",
     "build:website:blogOnly": "yarn workspace website build:blogOnly",
     "build:website:deployPreview:testWrap": "yarn workspace website test:swizzle:wrap:ts",

packages/docusaurus-faster/src/index.ts

@@ -11,6 +11,16 @@ import browserslist from 'browserslist';
 import {minify as swcHtmlMinifier} from '@swc/html';
 import type {JsMinifyOptions, Options as SwcOptions} from '@swc/core';
 
+// See https://rspack.dev/contribute/development/profiling
+// File can be opened with https://ui.perfetto.dev/
+if (process.env.DOCUSAURUS_RSPACK_TRACE) {
+  Rspack.experiments.globalTrace.register(
+    'trace',
+    'chrome',
+    './rspack-tracing.json',
+  );
+}
+
 export const swcLoader = require.resolve('swc-loader');
 
 export const getSwcLoaderOptions = ({

packages/docusaurus/src/commands/start/start.ts

@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import logger from '@docusaurus/logger';
+import logger, {PerfLogger} from '@docusaurus/logger';
 import openBrowser from '../utils/openBrowser/openBrowser';
 import {setupSiteFileWatchers} from './watcher';
 import {createWebpackDevServer} from './webpack';
@@ -21,7 +21,7 @@ export type StartCLIOptions = HostPortOptions &
     minify?: boolean;
   };
 
-export async function start(
+async function doStart(
   siteDirParam: string = '.',
   cliOptions: Partial<StartCLIOptions> = {},
 ): Promise<void> {
@@ -62,3 +62,10 @@ export async function start(
     await openBrowser(reloadableSite.getOpenUrl());
   }
 }
+
+export async function start(
+  siteDirParam: string = '.',
+  cliOptions: Partial<StartCLIOptions> = {},
+): Promise<void> {
+  return PerfLogger.async('CLI start', () => doStart(siteDirParam, cliOptions));
+}

packages/docusaurus/src/webpack/base.ts

@@ -9,13 +9,14 @@ import fs from 'fs-extra';
 import path from 'path';
 import {getCustomBabelConfigFilePath} from '@docusaurus/babel';
 import {
+  createJsLoaderFactory,
   getCSSExtractPlugin,
   getMinimizers,
-  createJsLoaderFactory,
 } from '@docusaurus/bundler';
 
-import {md5Hash, getFileLoaderUtils} from '@docusaurus/utils';
-import {loadThemeAliases, loadDocusaurusAliases} from './aliases';
+import {getFileLoaderUtils, md5Hash} from '@docusaurus/utils';
+import {loadDocusaurusAliases, loadThemeAliases} from './aliases';
+import {BundlerCPUProfilerPlugin} from './plugins/BundlerCPUProfilerPlugin';
 import type {Configuration} from 'webpack';
 import type {
   ConfigureWebpackUtils,
@@ -339,6 +340,8 @@ export async function createBaseConfig({
         // for more reasoning
         ignoreOrder: true,
       }),
-    ],
+      process.env.DOCUSAURUS_BUNDLER_CPU_PROFILE &&
+        new BundlerCPUProfilerPlugin(),
+    ].filter(Boolean),
   };
 }

packages/docusaurus/src/webpack/plugins/BundlerCPUProfilerPlugin.ts

@@ -0,0 +1,49 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import inspector from 'node:inspector';
+import fs from 'fs-extra';
+import type {Compiler} from 'webpack';
+
+// Bundle CPU profiling plugin, contributed by the Rspack team
+// Can be opened in https://www.speedscope.app/
+// See also https://github.com/jerrykingxyz/docusaurus/pull/1
+// See also https://github.com/facebook/docusaurus/pull/10985
+export class BundlerCPUProfilerPlugin {
+  output: string;
+
+  constructor(output?: string) {
+    this.output = output ?? './bundler-cpu-profile.json';
+  }
+
+  apply(compiler: Compiler): void {
+    const session = new inspector.Session();
+    session.connect();
+    session.post('Profiler.enable');
+    session.post('Profiler.start');
+
+    // In dev/watch mode, we restart the profiler before each compilation
+    compiler.hooks.watchRun.tapPromise(
+      BundlerCPUProfilerPlugin.name,
+      async () => {
+        session.post('Profiler.start');
+      },
+    );
+
+    compiler.hooks.done.tapPromise(BundlerCPUProfilerPlugin.name, async () => {
+      session.post('Profiler.stop', (error, param) => {
+        if (error) {
+          console.error('Failed to generate JS CPU profile:', error);
+          return;
+        }
+        fs.writeFile(this.output, JSON.stringify(param.profile)).catch(
+          console.error,
+        );
+      });
+    });
+  }
+}