worker: create per-Environment message port after bootstrap

PR-URL: #26593
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: joyeecheung

lib/internal/bootstrap/node.js

@@ -146,7 +146,7 @@ if (isMainThread) {
   setupProcessStdio(getStdout, getStdin, getStderr);
 } else {
   const { getStdout, getStdin, getStderr } =
-    workerThreadSetup.initializeWorkerStdio();
+    workerThreadSetup.createStdioGetters();
   setupProcessStdio(getStdout, getStdin, getStderr);
 }
 

lib/internal/process/worker_thread_only.js

@@ -2,32 +2,25 @@
 
 // This file contains process bootstrappers that can only be
 // run in the worker thread.
-const {
-  getEnvMessagePort
-} = internalBinding('worker');
 
 const {
-  kWaitingStreams,
-  ReadableWorkerStdio,
-  WritableWorkerStdio
+  createWorkerStdio
 } = require('internal/worker/io');
 
 const {
   codes: { ERR_WORKER_UNSUPPORTED_OPERATION }
 } = require('internal/errors');
-const workerStdio = {};
-
-function initializeWorkerStdio() {
-  const port = getEnvMessagePort();
-  port[kWaitingStreams] = 0;
-  workerStdio.stdin = new ReadableWorkerStdio(port, 'stdin');
-  workerStdio.stdout = new WritableWorkerStdio(port, 'stdout');
-  workerStdio.stderr = new WritableWorkerStdio(port, 'stderr');
 
+let workerStdio;
+function lazyWorkerStdio() {
+  if (!workerStdio) workerStdio = createWorkerStdio();
+  return workerStdio;
+}
+function createStdioGetters() {
   return {
-    getStdout() { return workerStdio.stdout; },
-    getStderr() { return workerStdio.stderr; },
-    getStdin() { return workerStdio.stdin; }
+    getStdout() { return lazyWorkerStdio().stdout; },
+    getStderr() { return lazyWorkerStdio().stderr; },
+    getStdin() { return lazyWorkerStdio().stdin; }
   };
 }
 
@@ -55,7 +48,7 @@ function unavailable(name) {
 }
 
 module.exports = {
-  initializeWorkerStdio,
+  createStdioGetters,
   unavailable,
   wrapProcessMethods
 };

lib/internal/worker/io.js

@@ -11,7 +11,10 @@ const {
   moveMessagePortToContext,
   stopMessagePort
 } = internalBinding('messaging');
-const { threadId } = internalBinding('worker');
+const {
+  threadId,
+  getEnvMessagePort
+} = internalBinding('worker');
 
 const { Readable, Writable } = require('stream');
 const EventEmitter = require('events');
@@ -227,6 +230,16 @@ class WritableWorkerStdio extends Writable {
   }
 }
 
+function createWorkerStdio() {
+  const port = getEnvMessagePort();
+  port[kWaitingStreams] = 0;
+  return {
+    stdin: new ReadableWorkerStdio(port, 'stdin'),
+    stdout: new WritableWorkerStdio(port, 'stdout'),
+    stderr: new WritableWorkerStdio(port, 'stderr')
+  };
+}
+
 module.exports = {
   drainMessagePort,
   messageTypes,
@@ -239,5 +252,6 @@ module.exports = {
   MessageChannel,
   setupPortReferencing,
   ReadableWorkerStdio,
-  WritableWorkerStdio
+  WritableWorkerStdio,
+  createWorkerStdio
 };

src/node_worker.cc

@@ -269,22 +269,6 @@ void Worker::Run() {
       Debug(this, "Created Environment for worker with id %llu", thread_id_);
       if (is_stopped()) return;
       {
-        HandleScope handle_scope(isolate_);
-        Mutex::ScopedLock lock(mutex_);
-        // Set up the message channel for receiving messages in the child.
-        child_port_ = MessagePort::New(env_.get(),
-                                       env_->context(),
-                                       std::move(child_port_data_));
-        // MessagePort::New() may return nullptr if execution is terminated
-        // within it.
-        if (child_port_ != nullptr)
-          env_->set_message_port(child_port_->object(isolate_));
-
-        Debug(this, "Created message port for worker %llu", thread_id_);
-      }
-
-      if (is_stopped()) return;
-      {
 #if NODE_USE_V8_PLATFORM && HAVE_INSPECTOR
         StartWorkerInspector(env_.get(),
                              std::move(inspector_parent_handle_),
@@ -296,6 +280,9 @@ void Worker::Run() {
         Environment::AsyncCallbackScope callback_scope(env_.get());
         env_->async_hooks()->push_async_ids(1, 0);
         if (!RunBootstrapping(env_.get()).IsEmpty()) {
+          CreateEnvMessagePort(env_.get());
+          if (is_stopped()) return;
+          Debug(this, "Created message port for worker %llu", thread_id_);
           USE(StartExecution(env_.get(), "internal/main/worker_thread"));
         }
 
@@ -348,6 +335,19 @@ void Worker::Run() {
   Debug(this, "Worker %llu thread stops", thread_id_);
 }
 
+void Worker::CreateEnvMessagePort(Environment* env) {
+  HandleScope handle_scope(isolate_);
+  Mutex::ScopedLock lock(mutex_);
+  // Set up the message channel for receiving messages in the child.
+  child_port_ = MessagePort::New(env,
+                                 env->context(),
+                                 std::move(child_port_data_));
+  // MessagePort::New() may return nullptr if execution is terminated
+  // within it.
+  if (child_port_ != nullptr)
+    env->set_message_port(child_port_->object(isolate_));
+}
+
 void Worker::JoinThread() {
   if (thread_joined_)
     return;

src/node_worker.h

@@ -50,7 +50,7 @@ class Worker : public AsyncWrap {
 
  private:
   void OnThreadStopped();
-
+  void CreateEnvMessagePort(Environment* env);
   const std::string url_;
 
   std::shared_ptr<PerIsolateOptions> per_isolate_opts_;