worker: set up child Isolate inside Worker thread

Refs: https://github.com/nodejs/node/issues/24016

PR-URL: https://github.com/nodejs/node/pull/26011
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

src/inspector_agent.cc

@@ -885,12 +885,14 @@ bool Agent::IsActive() {
   return io_ != nullptr || client_->IsActive();
 }
 
-void Agent::AddWorkerInspector(int thread_id,
+void Agent::SetParentHandle(
-                               const std::string& url,
+    std::unique_ptr<ParentInspectorHandle> parent_handle) {
-                               Agent* agent) {
+  parent_handle_ = std::move(parent_handle);
-  CHECK_NOT_NULL(client_);
+}
-  agent->parent_handle_ =
+
-      client_->getWorkerManager()->NewParentHandle(thread_id, url);
+std::unique_ptr<ParentInspectorHandle> Agent::GetParentHandle(
+    int thread_id, const std::string& url) {
+  return client_->getWorkerManager()->NewParentHandle(thread_id, url);
 }
 
 void Agent::WaitForConnect() {

src/inspector_agent.h

@@ -85,7 +85,9 @@ class Agent {
   void EnableAsyncHook();
   void DisableAsyncHook();
 
-  void AddWorkerInspector(int thread_id, const std::string& url, Agent* agent);
+  void SetParentHandle(std::unique_ptr<ParentInspectorHandle> parent_handle);
+  std::unique_ptr<ParentInspectorHandle> GetParentHandle(
+      int thread_id, const std::string& url);
 
   // Called to create inspector sessions that can be used from the main thread.
   // The inspector responds by using the delegate to send messages back.

src/node_worker.cc

@@ -8,6 +8,10 @@
 #include "async_wrap.h"
 #include "async_wrap-inl.h"
 
+#if NODE_USE_V8_PLATFORM && HAVE_INSPECTOR
+#include "inspector/worker_inspector.h"  // ParentInspectorHandle
+#endif
+
 #include <string>
 #include <vector>
 
@@ -35,34 +39,21 @@ namespace worker {
 namespace {
 
 #if NODE_USE_V8_PLATFORM && HAVE_INSPECTOR
-void StartWorkerInspector(Environment* child, const std::string& url) {
+void StartWorkerInspector(
+    Environment* child,
+    std::unique_ptr<inspector::ParentInspectorHandle> parent_handle,
+    const std::string& url) {
+  child->inspector_agent()->SetParentHandle(std::move(parent_handle));
   child->inspector_agent()->Start(url,
                                   child->options()->debug_options(),
                                   child->inspector_host_port(),
                                   false);
 }
 
-void AddWorkerInspector(Environment* parent,
-                        Environment* child,
-                        int id,
-                        const std::string& url) {
-  parent->inspector_agent()->AddWorkerInspector(id, url,
-                                                child->inspector_agent());
-}
-
 void WaitForWorkerInspectorToStop(Environment* child) {
   child->inspector_agent()->WaitForDisconnect();
   child->inspector_agent()->Stop();
 }
-
-#else
-// No-ops
-void StartWorkerInspector(Environment* child, const std::string& url) {}
-void AddWorkerInspector(Environment* parent,
-                        Environment* child,
-                        int id,
-                        const std::string& url) {}
-void WaitForWorkerInspectorToStop(Environment* child) {}
 #endif
 
 }  // anonymous namespace
@@ -71,9 +62,13 @@ Worker::Worker(Environment* env,
                Local<Object> wrap,
                const std::string& url,
                std::shared_ptr<PerIsolateOptions> per_isolate_opts)
-    : AsyncWrap(env, wrap, AsyncWrap::PROVIDER_WORKER), url_(url),
+    : AsyncWrap(env, wrap, AsyncWrap::PROVIDER_WORKER),
+      url_(url),
+      per_isolate_opts_(per_isolate_opts),
+      platform_(env->isolate_data()->platform()),
+      profiler_idle_notifier_started_(env->profiler_idle_notifier_started()),
       thread_id_(Environment::AllocateThreadId()) {
-  Debug(this, "Creating new worker instance at %p", static_cast<void*>(this));
+  Debug(this, "Creating new worker instance with thread id %llu", thread_id_);
 
   // Set up everything that needs to be set up in the parent environment.
   parent_port_ = MessagePort::New(env, env->context());
@@ -89,57 +84,17 @@ Worker::Worker(Environment* env,
                 env->message_port_string(),
                 parent_port_->object()).FromJust();
 
-  array_buffer_allocator_.reset(CreateArrayBufferAllocator());
+  object()->Set(env->context(),
-
+                env->thread_id_string(),
-  CHECK_EQ(uv_loop_init(&loop_), 0);
+                Number::New(env->isolate(), static_cast<double>(thread_id_)))
-  isolate_ = NewIsolate(array_buffer_allocator_.get(), &loop_);
-  CHECK_NOT_NULL(isolate_);
-
-  {
-    // Enter an environment capable of executing code in the child Isolate
-    // (and only in it).
-    Locker locker(isolate_);
-    Isolate::Scope isolate_scope(isolate_);
-    HandleScope handle_scope(isolate_);
-
-    isolate_data_.reset(CreateIsolateData(isolate_,
-                                          &loop_,
-                                          env->isolate_data()->platform(),
-                                          array_buffer_allocator_.get()));
-    if (per_isolate_opts != nullptr) {
-      isolate_data_->set_options(per_isolate_opts);
-    }
-    CHECK(isolate_data_);
-
-    Local<Context> context = NewContext(isolate_);
-    Context::Scope context_scope(context);
-
-    // TODO(addaleax): Use CreateEnvironment(), or generally another public API.
-    env_.reset(new Environment(
-        isolate_data_.get(), context, Flags::kNoFlags, thread_id_));
-    CHECK_NOT_NULL(env_);
-    env_->set_abort_on_uncaught_exception(false);
-    env_->set_worker_context(this);
-
-    env_->Start(env->profiler_idle_notifier_started());
-    env_->ProcessCliArgs(std::vector<std::string>{},
-                            std::vector<std::string>{});
-    // Done while on the parent thread
-    AddWorkerInspector(env, env_.get(), thread_id_, url_);
-  }
-
-  // The new isolate won't be bothered on this thread again.
-  isolate_->DiscardThreadSpecificMetadata();
-
-  wrap->Set(env->context(),
-            env->thread_id_string(),
-            Number::New(env->isolate(), static_cast<double>(thread_id_)))
       .FromJust();
 
-  Debug(this,
+#if NODE_USE_V8_PLATFORM && HAVE_INSPECTOR
-        "Set up worker at %p with id %llu",
+  inspector_parent_handle_ =
-        static_cast<void*>(this),
+      env->inspector_agent()->GetParentHandle(thread_id_, url);
-        thread_id_);
+#endif
+
+  Debug(this, "Preparation for worker %llu finished", thread_id_);
 }
 
 bool Worker::is_stopped() const {
@@ -147,14 +102,79 @@ bool Worker::is_stopped() const {
   return stopped_;
 }
 
+// This class contains data that is only relevant to the child thread itself,
+// and only while it is running.
+// (Eventually, the Environment instance should probably also be moved here.)
+class WorkerThreadData {
+ public:
+  explicit WorkerThreadData(Worker* w)
+    : w_(w),
+      array_buffer_allocator_(CreateArrayBufferAllocator()) {
+    CHECK_EQ(uv_loop_init(&loop_), 0);
+
+    Isolate* isolate = NewIsolate(array_buffer_allocator_.get(), &loop_);
+    CHECK_NOT_NULL(isolate);
+
+    {
+      Locker locker(isolate);
+      Isolate::Scope isolate_scope(isolate);
+      HandleScope handle_scope(isolate);
+      isolate_data_.reset(CreateIsolateData(isolate,
+                                            &loop_,
+                                            w_->platform_,
+                                            array_buffer_allocator_.get()));
+      CHECK(isolate_data_);
+      if (w_->per_isolate_opts_)
+        isolate_data_->set_options(std::move(w_->per_isolate_opts_));
+    }
+
+    Mutex::ScopedLock lock(w_->mutex_);
+    w_->isolate_ = isolate;
+  }
+
+  ~WorkerThreadData() {
+    Debug(w_, "Worker %llu dispose isolate", w_->thread_id_);
+    Isolate* isolate;
+    {
+      Mutex::ScopedLock lock(w_->mutex_);
+      isolate = w_->isolate_;
+      w_->isolate_ = nullptr;
+    }
+
+    w_->platform_->CancelPendingDelayedTasks(isolate);
+
+    isolate_data_.reset();
+    w_->platform_->UnregisterIsolate(isolate);
+
+    isolate->Dispose();
+
+    // Need to run the loop one more time to close the platform's uv_async_t
+    uv_run(&loop_, UV_RUN_ONCE);
+
+    CheckedUvLoopClose(&loop_);
+  }
+
+ private:
+  Worker* const w_;
+  uv_loop_t loop_;
+  DeleteFnPtr<ArrayBufferAllocator, FreeArrayBufferAllocator>
+    array_buffer_allocator_;
+  DeleteFnPtr<IsolateData, FreeIsolateData> isolate_data_;
+
+  friend class Worker;
+};
+
 void Worker::Run() {
   std::string name = "WorkerThread ";
   name += std::to_string(thread_id_);
   TRACE_EVENT_METADATA1(
       "__metadata", "thread_name", "name",
       TRACE_STR_COPY(name.c_str()));
-  MultiIsolatePlatform* platform = isolate_data_->platform();
+  CHECK_NOT_NULL(platform_);
-  CHECK_NOT_NULL(platform);
+
+  Debug(this, "Creating isolate for worker with id %llu", thread_id_);
+
+  WorkerThreadData data(this);
 
   Debug(this, "Starting worker with id %llu", thread_id_);
   {
@@ -163,10 +183,73 @@ void Worker::Run() {
     SealHandleScope outer_seal(isolate_);
     bool inspector_started = false;
 
-    {
+    DeleteFnPtr<Environment, FreeEnvironment> env_;
-      Context::Scope context_scope(env_->context());
+    OnScopeLeave cleanup_env([&]() {
-      HandleScope handle_scope(isolate_);
+      if (!env_) return;
+      env_->set_can_call_into_js(false);
+      Isolate::DisallowJavascriptExecutionScope disallow_js(isolate_,
+          Isolate::DisallowJavascriptExecutionScope::THROW_ON_FAILURE);
 
+      // Grab the parent-to-child channel and render is unusable.
+      MessagePort* child_port;
+      {
+        Mutex::ScopedLock lock(mutex_);
+        child_port = child_port_;
+        child_port_ = nullptr;
+      }
+
+      {
+        Context::Scope context_scope(env_->context());
+        if (child_port != nullptr)
+          child_port->Close();
+        env_->stop_sub_worker_contexts();
+        env_->RunCleanup();
+        RunAtExit(env_.get());
+#if NODE_USE_V8_PLATFORM && HAVE_INSPECTOR
+        if (inspector_started)
+          WaitForWorkerInspectorToStop(env_.get());
+#endif
+
+        {
+          Mutex::ScopedLock stopped_lock(stopped_mutex_);
+          stopped_ = true;
+        }
+
+        env_->RunCleanup();
+
+        // This call needs to be made while the `Environment` is still alive
+        // because we assume that it is available for async tracking in the
+        // NodePlatform implementation.
+        platform_->DrainTasks(isolate_);
+      }
+    });
+
+    {
+      HandleScope handle_scope(isolate_);
+      Local<Context> context = NewContext(isolate_);
+      if (is_stopped()) return;
+
+      CHECK(!context.IsEmpty());
+      Context::Scope context_scope(context);
+      {
+        // TODO(addaleax): Use CreateEnvironment(), or generally another
+        // public API.
+        env_.reset(new Environment(data.isolate_data_.get(),
+                                   context,
+                                   Environment::kNoFlags,
+                                   thread_id_));
+        CHECK_NOT_NULL(env_);
+        env_->set_abort_on_uncaught_exception(false);
+        env_->set_worker_context(this);
+
+        env_->Start(profiler_idle_notifier_started_);
+        env_->ProcessCliArgs(std::vector<std::string>{},
+                             std::vector<std::string>{});
+      }
+
+      Debug(this, "Created Environment for worker with id %llu", thread_id_);
+
+      if (is_stopped()) return;
       {
         HandleScope handle_scope(isolate_);
         Mutex::ScopedLock lock(mutex_);
@@ -182,8 +265,13 @@ void Worker::Run() {
         Debug(this, "Created message port for worker %llu", thread_id_);
       }
 
-      if (!is_stopped()) {
+      if (is_stopped()) return;
-        StartWorkerInspector(env_.get(), url_);
+      {
+#if NODE_USE_V8_PLATFORM && HAVE_INSPECTOR
+        StartWorkerInspector(env_.get(),
+                             std::move(inspector_parent_handle_),
+                             url_);
+#endif
         inspector_started = true;
 
         HandleScope handle_scope(isolate_);
@@ -198,6 +286,7 @@ void Worker::Run() {
         Debug(this, "Loaded environment for worker %llu", thread_id_);
       }
 
+      if (is_stopped()) return;
       {
         SealHandleScope seal(isolate_);
         bool more;
@@ -205,12 +294,12 @@ void Worker::Run() {
             node::performance::NODE_PERFORMANCE_MILESTONE_LOOP_START);
         do {
           if (is_stopped()) break;
-          uv_run(&loop_, UV_RUN_DEFAULT);
+          uv_run(&data.loop_, UV_RUN_DEFAULT);
           if (is_stopped()) break;
 
-          platform->DrainTasks(isolate_);
+          platform_->DrainTasks(isolate_);
 
-          more = uv_loop_alive(&loop_);
+          more = uv_loop_alive(&data.loop_);
           if (more && !is_stopped())
             continue;
 
@@ -218,7 +307,7 @@ void Worker::Run() {
 
           // Emit `beforeExit` if the loop became alive either after emitting
           // event, or after running some callbacks.
-          more = uv_loop_alive(&loop_);
+          more = uv_loop_alive(&data.loop_);
         } while (more == true);
         env_->performance_state()->Mark(
             node::performance::NODE_PERFORMANCE_MILESTONE_LOOP_EXIT);
@@ -237,79 +326,11 @@ void Worker::Run() {
       Debug(this, "Exiting thread for worker %llu with exit code %d",
             thread_id_, exit_code_);
     }
-
-    env_->set_can_call_into_js(false);
-    Isolate::DisallowJavascriptExecutionScope disallow_js(isolate_,
-        Isolate::DisallowJavascriptExecutionScope::THROW_ON_FAILURE);
-
-    // Grab the parent-to-child channel and render is unusable.
-    MessagePort* child_port;
-    {
-      Mutex::ScopedLock lock(mutex_);
-      child_port = child_port_;
-      child_port_ = nullptr;
-    }
-
-    {
-      Context::Scope context_scope(env_->context());
-      child_port->Close();
-      env_->stop_sub_worker_contexts();
-      env_->RunCleanup();
-      RunAtExit(env_.get());
-      if (inspector_started)
-        WaitForWorkerInspectorToStop(env_.get());
-
-      {
-        Mutex::ScopedLock stopped_lock(stopped_mutex_);
-        stopped_ = true;
-      }
-
-      env_->RunCleanup();
-
-      // This call needs to be made while the `Environment` is still alive
-      // because we assume that it is available for async tracking in the
-      // NodePlatform implementation.
-      platform->DrainTasks(isolate_);
-    }
-
-    env_.reset();
-  }
-
-  DisposeIsolate();
-
-  {
-    Mutex::ScopedLock lock(mutex_);
-    CHECK(thread_exit_async_);
-    scheduled_on_thread_stopped_ = true;
-    uv_async_send(thread_exit_async_.get());
   }
 
   Debug(this, "Worker %llu thread stops", thread_id_);
 }
 
-void Worker::DisposeIsolate() {
-  if (env_) {
-    CHECK_NOT_NULL(isolate_);
-    Locker locker(isolate_);
-    Isolate::Scope isolate_scope(isolate_);
-    env_.reset();
-  }
-
-  if (isolate_ == nullptr)
-    return;
-
-  Debug(this, "Worker %llu dispose isolate", thread_id_);
-  CHECK(isolate_data_);
-  MultiIsolatePlatform* platform = isolate_data_->platform();
-  platform->CancelPendingDelayedTasks(isolate_);
-
-  isolate_data_.reset();
-  platform->UnregisterIsolate(isolate_);
-
-  isolate_->Dispose();
-  isolate_ = nullptr;
-}
-
 void Worker::JoinThread() {
   if (thread_joined_)
     return;
@@ -340,7 +361,6 @@ void Worker::OnThreadStopped() {
       CHECK(stopped_);
     }
 
-    CHECK_NULL(child_port_);
     parent_port_ = nullptr;
   }
 
@@ -370,16 +390,9 @@ Worker::~Worker() {
 
   CHECK(stopped_);
   CHECK(thread_joined_);
-  CHECK_NULL(child_port_);
 
   // This has most likely already happened within the worker thread -- this
   // is just in case Worker creation failed early.
-  DisposeIsolate();
-
-  // Need to run the loop one more time to close the platform's uv_async_t
-  uv_run(&loop_, UV_RUN_ONCE);
-
-  CheckedUvLoopClose(&loop_);
 
   Debug(this, "Worker %llu destroyed", thread_id_);
 }
@@ -476,7 +489,13 @@ void Worker::StartThread(const FunctionCallbackInfo<Value>& args) {
   }), 0);
 
   CHECK_EQ(uv_thread_create(&w->tid_, [](void* arg) {
-    static_cast<Worker*>(arg)->Run();
+    Worker* w = static_cast<Worker*>(arg);
+    w->Run();
+
+    Mutex::ScopedLock lock(w->mutex_);
+    CHECK(w->thread_exit_async_);
+    w->scheduled_on_thread_stopped_ = true;
+    uv_async_send(w->thread_exit_async_.get());
   }, static_cast<void*>(w)), 0);
 }
 
@@ -510,12 +529,12 @@ void Worker::Exit(int code) {
   Debug(this, "Worker %llu called Exit(%d)", thread_id_, code);
 
   if (!stopped_) {
-    CHECK_NOT_NULL(env_);
     stopped_ = true;
     exit_code_ = code;
     if (child_port_ != nullptr)
       child_port_->StopEventLoop();
-    isolate_->TerminateExecution();
+    if (isolate_ != nullptr)
+      isolate_->TerminateExecution();
   }
 }
 

src/node_worker.h

@@ -9,6 +9,8 @@
 namespace node {
 namespace worker {
 
+class WorkerThreadData;
+
 // A worker thread, as represented in its parent thread.
 class Worker : public AsyncWrap {
  public:
@@ -49,17 +51,19 @@ class Worker : public AsyncWrap {
 
  private:
   void OnThreadStopped();
-  void DisposeIsolate();
 
-  uv_loop_t loop_;
-  DeleteFnPtr<IsolateData, FreeIsolateData> isolate_data_;
-  DeleteFnPtr<Environment, FreeEnvironment> env_;
   const std::string url_;
+
+  std::shared_ptr<PerIsolateOptions> per_isolate_opts_;
+  MultiIsolatePlatform* platform_;
   v8::Isolate* isolate_ = nullptr;
-  DeleteFnPtr<ArrayBufferAllocator, FreeArrayBufferAllocator>
+  bool profiler_idle_notifier_started_;
-      array_buffer_allocator_;
   uv_thread_t tid_;
 
+#if NODE_USE_V8_PLATFORM && HAVE_INSPECTOR
+  std::unique_ptr<inspector::ParentInspectorHandle> inspector_parent_handle_;
+#endif
+
   // This mutex protects access to all variables listed below it.
   mutable Mutex mutex_;
 
@@ -79,12 +83,14 @@ class Worker : public AsyncWrap {
 
   std::unique_ptr<MessagePortData> child_port_data_;
 
-  // The child port is always kept alive by the child Environment's persistent
+  // The child port is kept alive by the child Environment's persistent
-  // handle to it.
+  // handle to it, as long as that child Environment exists.
   MessagePort* child_port_ = nullptr;
   // This is always kept alive because the JS object associated with the Worker
   // instance refers to it via its [kPort] property.
   MessagePort* parent_port_ = nullptr;
+
+  friend class WorkerThreadData;
 };
 
 }  // namespace worker