perf: disable js tracing in non-profile mode (#9046)

* perf: disable js tracing in non-profile mode

* chore: fix type

* chore: fix type again

* chore: fix type

* Update packages/rspack-tracing/types/package.json

---------

Co-authored-by: neverland <[email protected]>

Author: hardfist

packages/rspack-tracing/README.md

@@ -0,0 +1,3 @@
+# Tracing Utility for Rspack
+
+> Rspack's internal tracing tools, don't use it directly in your project, it may contain breaking change in minor & patch release right now.

packages/rspack-tracing/package.json

@@ -16,7 +16,7 @@
   },
   "license": "MIT",
   "main": "./index.js",
-  "types": "./index.d.ts",
+  "types": "./types/index.d.ts",
   "scripts": {
     "build": "tsc -b ./tsconfig.build.json"
   },

packages/rspack-tracing/index.d.ts renamed to packages/rspack-tracing/types/index.d.ts

@@ -1,3 +1,4 @@
 export function initOpenTelemetry(): Promise<void>;
 export function shutdownOpenTelemetry(): Promise<void>;
 export { trace, propagation, context } from "@opentelemetry/api";
+export type { Tracer, Context } from "@opentelemetry/api";

packages/rspack-tracing/types/package.json

@@ -0,0 +1,4 @@
+{
+  "//": "This file is for making TypeScript work with moduleResolution node16+.",
+  "version": "0.0.0"
+}

packages/rspack/src/loader-runner/index.ts

@@ -26,6 +26,7 @@ import {
 	SourceMapSource
 } from "webpack-sources";
 
+import type { Context, Tracer } from "@rspack/tracing";
 import type { Compilation } from "../Compilation";
 import type { Compiler } from "../Compiler";
 import { Module } from "../Module";
@@ -339,8 +340,12 @@ function getCurrentLoader(
 	}
 	return null;
 }
-
+let tracingCache!: { tracer?: Tracer; activeContext?: Context };
 async function tryTrace(context: JsLoaderContext) {
+	// disable tracing in non-profile mode
+	if (!process.env.RSPACK_PROFILE) {
+		return {};
+	}
 	try {
 		const {
 			trace,
@@ -352,9 +357,11 @@ async function tryTrace(context: JsLoaderContext) {
 			tracingContext.active(),
 			context.__internal__tracingCarrier
 		);
-		return { tracer, activeContext };
+		tracingCache = { tracer, activeContext };
+		return tracingCache;
 	} catch (error) {
-		return { tracer: null, activeContext: null };
+		tracingCache = {};
+		return tracingCache;
 	}
 }