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>

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/internal/process/per_thread.js b/lib/internal/process/per_thread.js
index a0d6b32596..7a3bee3098 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