From 1481e5b5c124e848a12eb730ae269d71787a6c65 Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Tue, 12 Mar 2019 18:34:22 +0800
Subject: [PATCH] process: set the trace category update handler during
 bootstrap

Set the trace category update handler during bootstrap, but delay
the initial invocation of it until pre-execution. In addition, do
not serialize the `node.async_hooks` category state when loading
the trace_event binding during bootstrap, since it depends on
run time states (e.g. CLI flags). Instead, use the
`isTraceCategoryEnabled` v8 intrinsics to query that value during
pre-execution.

PR-URL: https://github.com/nodejs/node/pull/26605
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 lib/internal/bootstrap/node.js          |  7 +++++++
 lib/internal/bootstrap/pre_execution.js | 26 +++----------------------
 lib/internal/process/per_thread.js      | 17 ++++++++++++++++
 src/node_trace_events.cc                | 10 ----------
 4 files changed, 27 insertions(+), 33 deletions(-)

diff --git a/lib/internal/bootstrap/node.js b/lib/internal/bootstrap/node.js
index e0c220d2a8c3fa..6cd480ffe08f3c 100644
--- a/lib/internal/bootstrap/node.js
+++ b/lib/internal/bootstrap/node.js
@@ -250,6 +250,13 @@ if (process.platform === 'win32') {
   }
 }
 
+// Set the per-Environment callback that will be called
+// when the TrackingTraceStateObserver updates trace state.
+// Note that when NODE_USE_V8_PLATFORM is true, the observer is
+// attached to the per-process TracingController.
+const { setTraceCategoryStateUpdateHandler } = internalBinding('trace_events');
+setTraceCategoryStateUpdateHandler(perThreadSetup.toggleTraceCategoryState);
+
 // process.allowedNodeEnvironmentFlags
 Object.defineProperty(process, 'allowedNodeEnvironmentFlags', {
   get() {
diff --git a/lib/internal/bootstrap/pre_execution.js b/lib/internal/bootstrap/pre_execution.js
index 52a6be6dee63c3..607951a0bb4aba 100644
--- a/lib/internal/bootstrap/pre_execution.js
+++ b/lib/internal/bootstrap/pre_execution.js
@@ -1,9 +1,6 @@
 'use strict';
 
 const { getOptionValue } = require('internal/options');
-// Lazy load internal/trace_events_async_hooks only if the async_hooks
-// trace event category is enabled.
-let traceEventsAsyncHook;
 
 function prepareMainThreadExecution() {
   setupTraceCategoryState();
@@ -136,26 +133,9 @@ function initializeReportSignalHandlers() {
 }
 
 function setupTraceCategoryState() {
-  const {
-    asyncHooksEnabledInitial,
-    setTraceCategoryStateUpdateHandler
-  } = internalBinding('trace_events');
-
-  toggleTraceCategoryState(asyncHooksEnabledInitial);
-  setTraceCategoryStateUpdateHandler(toggleTraceCategoryState);
-}
-
-// Dynamically enable/disable the traceEventsAsyncHook
-function toggleTraceCategoryState(asyncHooksEnabled) {
-  if (asyncHooksEnabled) {
-    if (!traceEventsAsyncHook) {
-      traceEventsAsyncHook =
-        require('internal/trace_events_async_hooks').createHook();
-    }
-    traceEventsAsyncHook.enable();
-  } else if (traceEventsAsyncHook) {
-    traceEventsAsyncHook.disable();
-  }
+  const { isTraceCategoryEnabled } = internalBinding('trace_events');
+  const { toggleTraceCategoryState } = require('internal/process/per_thread');
+  toggleTraceCategoryState(isTraceCategoryEnabled('node.async_hooks'));
 }
 
 // In general deprecations are intialized wherever the APIs are implemented,
diff --git a/lib/internal/process/per_thread.js b/lib/internal/process/per_thread.js
index 37b9e31167a336..9e53ac3a1982da 100644
--- a/lib/internal/process/per_thread.js
+++ b/lib/internal/process/per_thread.js
@@ -304,7 +304,24 @@ function buildAllowedFlags() {
   ));
 }
 
+// Lazy load internal/trace_events_async_hooks only if the async_hooks
+// trace event category is enabled.
+let traceEventsAsyncHook;
+// Dynamically enable/disable the traceEventsAsyncHook
+function toggleTraceCategoryState(asyncHooksEnabled) {
+  if (asyncHooksEnabled) {
+    if (!traceEventsAsyncHook) {
+      traceEventsAsyncHook =
+        require('internal/trace_events_async_hooks').createHook();
+    }
+    traceEventsAsyncHook.enable();
+  } else if (traceEventsAsyncHook) {
+    traceEventsAsyncHook.disable();
+  }
+}
+
 module.exports = {
+  toggleTraceCategoryState,
   assert,
   buildAllowedFlags,
   wrapProcessMethods
diff --git a/src/node_trace_events.cc b/src/node_trace_events.cc
index 5e30df41c4f4fa..1fad37743fb418 100644
--- a/src/node_trace_events.cc
+++ b/src/node_trace_events.cc
@@ -11,7 +11,6 @@
 namespace node {
 
 using v8::Array;
-using v8::Boolean;
 using v8::Context;
 using v8::Function;
 using v8::FunctionCallbackInfo;
@@ -149,15 +148,6 @@ void NodeCategorySet::Initialize(Local<Object> target,
                   .FromJust();
   target->Set(context, trace,
               binding->Get(context, trace).ToLocalChecked()).FromJust();
-
-  // Initial value of async hook trace events
-  bool async_hooks_enabled = (*(TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(
-                                 TRACING_CATEGORY_NODE1(async_hooks)))) != 0;
-  target
-      ->Set(context,
-            FIXED_ONE_BYTE_STRING(env->isolate(), "asyncHooksEnabledInitial"),
-            Boolean::New(env->isolate(), async_hooks_enabled))
-      .FromJust();
 }
 
 }  // namespace node