Add unstable_enableWorkerThreads options to transformer and watcher

Summary: Add two options to use Node worker threads rather than `child_process` for Metro's transformer and watcher. This directly corresponds to `jest-worker`'s `enableWorkerThreads` option. These are largely for internal experimentation - it's likely the options will be removed and worker threads will be enabled by default as non-breaking change in a subsequent release. Changelog: ``` * **[Experimental]:** Add `unstable_workerThreads` options to `transformer` and `watcher` configuration. ``` Reviewed By: motiz88 Differential Revision: D50655866 fbshipit-source-id: 498b6a73b11e00c12d109bf6d00d345939aaba0a
facebook · Oct 26, 2023 · 20df4ec · 20df4ec
1 parent 9732f4a
commit 20df4ec
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diff --git a/packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap b/packages/metro-config/src/__tests__/__snapshots__/loadConfig-test.js.snap
@@ -151,6 +151,7 @@ Object {
     "unstable_dependencyMapReservedName": null,
     "unstable_disableModuleWrapping": false,
     "unstable_disableNormalizePseudoGlobals": false,
+    "unstable_workerThreads": false,
     "workerPath": "metro/src/DeltaBundler/Worker",
   },
   "transformerPath": "",
@@ -169,6 +170,7 @@ Object {
       "interval": 30000,
       "timeout": 5000,
     },
+    "unstable_workerThreads": false,
     "watchman": Object {
       "deferStates": Array [
         "hg.update",
@@ -329,6 +331,7 @@ Object {
     "unstable_dependencyMapReservedName": null,
     "unstable_disableModuleWrapping": false,
     "unstable_disableNormalizePseudoGlobals": false,
+    "unstable_workerThreads": false,
     "workerPath": "metro/src/DeltaBundler/Worker",
   },
   "transformerPath": "",
@@ -347,6 +350,7 @@ Object {
       "interval": 30000,
       "timeout": 5000,
     },
+    "unstable_workerThreads": false,
     "watchman": Object {
       "deferStates": Array [
         "hg.update",
@@ -507,6 +511,7 @@ Object {
     "unstable_dependencyMapReservedName": null,
     "unstable_disableModuleWrapping": false,
     "unstable_disableNormalizePseudoGlobals": false,
+    "unstable_workerThreads": false,
     "workerPath": "metro/src/DeltaBundler/Worker",
   },
   "transformerPath": "",
@@ -525,6 +530,7 @@ Object {
       "interval": 30000,
       "timeout": 5000,
     },
+    "unstable_workerThreads": false,
     "watchman": Object {
       "deferStates": Array [
         "hg.update",
@@ -685,6 +691,7 @@ Object {
     "unstable_dependencyMapReservedName": null,
     "unstable_disableModuleWrapping": false,
     "unstable_disableNormalizePseudoGlobals": false,
+    "unstable_workerThreads": false,
     "workerPath": "metro/src/DeltaBundler/Worker",
   },
   "transformerPath": "",
@@ -703,6 +710,7 @@ Object {
       "interval": 30000,
       "timeout": 5000,
     },
+    "unstable_workerThreads": false,
     "watchman": Object {
       "deferStates": Array [
         "hg.update",

diff --git a/packages/metro-config/src/configTypes.flow.js b/packages/metro-config/src/configTypes.flow.js
@@ -146,6 +146,7 @@ type TransformerConfigT = {
   transformVariants: {+[name: string]: {...}},
   workerPath: string,
   publicPath: string,
+  unstable_workerThreads: boolean,
 };
 
 type MetalConfigT = {
@@ -196,6 +197,7 @@ type WatcherConfigT = {
     timeout: number,
     filePrefix: string,
   },
+  unstable_workerThreads: boolean,
   watchman: {
     deferStates: $ReadOnlyArray<string>,
   },

diff --git a/packages/metro-config/src/defaults/index.js b/packages/metro-config/src/defaults/index.js
@@ -135,6 +135,7 @@ const getDefaultValues = (projectRoot: ?string): ConfigT => ({
     unstable_disableModuleWrapping: false,
     unstable_disableNormalizePseudoGlobals: false,
     unstable_compactOutput: false,
+    unstable_workerThreads: false,
   },
   watcher: {
     additionalExts,
@@ -144,6 +145,7 @@ const getDefaultValues = (projectRoot: ?string): ConfigT => ({
       interval: 30000,
       timeout: 5000,
     },
+    unstable_workerThreads: false,
     watchman: {
       deferStates: ['hg.update'],
     },

diff --git a/packages/metro-file-map/src/index.js b/packages/metro-file-map/src/index.js
@@ -77,6 +77,7 @@ export type InputOptions = $ReadOnly<{
   computeSha1?: ?boolean,
   enableHastePackages?: boolean,
   enableSymlinks?: ?boolean,
+  enableWorkerThreads?: ?boolean,
   extensions: $ReadOnlyArray<string>,
   forceNodeFilesystemAPI?: ?boolean,
   ignorePattern?: ?RegExp,
@@ -112,6 +113,7 @@ type HealthCheckOptions = $ReadOnly<{
 
 type InternalOptions = {
   ...BuildParameters,
+  enableWorkerThreads: boolean,
   healthCheck: HealthCheckOptions,
   perfLoggerFactory: ?PerfLoggerFactory,
   resetCache: ?boolean,
@@ -309,6 +311,7 @@ export default class FileMap extends EventEmitter {
 
     this._options = {
       ...buildParameters,
+      enableWorkerThreads: options.enableWorkerThreads ?? false,
       healthCheck: options.healthCheck,
       maxWorkers: options.maxWorkers,
       perfLoggerFactory: options.perfLoggerFactory,
@@ -808,6 +811,7 @@ export default class FileMap extends EventEmitter {
           exposedMethods: ['worker'],
           maxRetries: 3,
           numWorkers: this._options.maxWorkers,
+          enableWorkerThreads: this._options.enableWorkerThreads,
           forkOptions: {
             // Don't pass Node arguments down to workers. In particular, avoid
             // unnecessarily registering Babel when we're running Metro from

diff --git a/packages/metro/src/DeltaBundler/Transformer.js b/packages/metro/src/DeltaBundler/Transformer.js
@@ -44,6 +44,7 @@ class Transformer {
       getTransformOptions: _getTransformOptions,
       transformVariants: _transformVariants,
       workerPath: _workerPath,
+      unstable_workerThreads: _workerThreads,
       ...transformerConfig
     } = this._config.transformer;
 

diff --git a/packages/metro/src/DeltaBundler/WorkerFarm.js b/packages/metro/src/DeltaBundler/WorkerFarm.js
@@ -125,6 +125,7 @@ class WorkerFarm {
           this._computeWorkerKey
         : undefined,
       exposedMethods,
+      enableWorkerThreads: this._config.transformer.unstable_workerThreads,
       forkOptions: {env},
       numWorkers,
     });

diff --git a/packages/metro/src/node-haste/DependencyGraph/createFileMap.js b/packages/metro/src/node-haste/DependencyGraph/createFileMap.js
@@ -84,6 +84,7 @@ function createFileMap(
     dependencyExtractor: config.resolver.dependencyExtractor,
     enableHastePackages: config?.resolver.enableGlobalPackages,
     enableSymlinks: config.resolver.unstable_enableSymlinks,
+    enableWorkerThreads: config.watcher.unstable_workerThreads,
     extensions: Array.from(
       new Set([
         ...config.resolver.sourceExts,