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: #26605 Reviewed-By: James M Snell <[email protected]> Reviewed-By: Anna Henningsen <[email protected]>
nodejs · Mar 18, 2019 · a91d36f · a91d36f
1 parent e2a2f93
commit a91d36f
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Showing 4 changed files with 27 additions and 33 deletions.
diff --git a/lib/internal/bootstrap/node.js b/lib/internal/bootstrap/node.js
@@ -197,6 +197,13 @@ if (!config.noBrowserGlobals) {
   defineOperation(global, 'setImmediate', timers.setImmediate);
 }
 
+// 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
@@ -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() {
   // Patch the process object with legacy properties and normalizations
@@ -162,26 +159,9 @@ 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
@@ -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
@@ -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