lib: add diagnostics_channel events to module loading

This commit adds a tracing channel for module loading
through `import()` and `require()`.
Co-Authored-By: Stephen Belanger <admin@stephenbelanger.com>
PR-URL: #44340
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

Author: 2 people

doc/api/diagnostics_channel.md

@@ -1117,6 +1117,58 @@ Emitted when server receives a request.
 
 Emitted when server sends a response.
 
+#### Modules
+
+`module.require.start`
+
+*`event` {Object} containing the following properties
+*`id` - Argument passed to `require()`. Module name.
+*`parentFilename` - Name of the module that attempted to require(id).
+
+Emitted when `require()` is executed. See [`start` event][].
+
+`module.require.end`
+
+*`event` {Object} containing the following properties
+*`id` - Argument passed to `require()`. Module name.
+*`parentFilename` - Name of the module that attempted to require(id).
+
+Emitted when a `require()` call returns. See [`end` event][].
+
+`module.require.error`
+
+*`event` {Object} containing the following properties
+*`id` - Argument passed to `require()`. Module name.
+*`parentFilename` - Name of the module that attempted to require(id).
+*`error` {Error}
+
+Emitted when a `require()` throws an error. See [`error` event][].
+
+`module.import.asyncStart`
+
+*`event` {Object} containing the following properties
+*`id` - Argument passed to `import()`. Module name.
+*`parentURL` - URL object of the module that attempted to import(id).
+
+Emitted when `import()` is invoked. See [`asyncStart` event][].
+
+`module.import.asyncEnd`
+
+*`event` {Object} containing the following properties
+*`id` - Argument passed to `import()`. Module name.
+*`parentURL` - URL object of the module that attempted to import(id).
+
+Emitted when `import()` has completed. See [`asyncEnd` event][].
+
+`module.import.error`
+
+*`event` {Object} containing the following properties
+*`id` - Argument passed to `import()`. Module name.
+*`parentURL` - URL object of the module that attempted to import(id).
+*`error` {Error}
+
+Emitted when a `import()` throws an error. See [`error` event][].
+
 #### NET
 
 `net.client.socket`

lib/diagnostics_channel.js

@@ -269,7 +269,8 @@ function tracingChannelFrom(nameOrChannels, name) {
 
 classTracingChannel{
 constructor(nameOrChannels){
-for(consteventNameoftraceEvents){
+for(leti=0;i<traceEvents.length;++i){
+consteventName=traceEvents[i];
 ObjectDefineProperty(this,eventName,{
 __proto__: null,
 value: tracingChannelFrom(nameOrChannels,eventName),
@@ -278,15 +279,16 @@ class TracingChannel {
 }
 
 gethasSubscribers(){
-returnthis.start.hasSubscribers||
-this.end.hasSubscribers||
-this.asyncStart.hasSubscribers||
-this.asyncEnd.hasSubscribers||
-this.error.hasSubscribers;
+returnthis.start?.hasSubscribers||
+this.end?.hasSubscribers||
+this.asyncStart?.hasSubscribers||
+this.asyncEnd?.hasSubscribers||
+this.error?.hasSubscribers;
 }
 
 subscribe(handlers){
-for(constnameoftraceEvents){
+for(leti=0;i<traceEvents.length;++i){
+constname=traceEvents[i];
 if(!handlers[name])continue;
 
 this[name]?.subscribe(handlers[name]);
@@ -296,7 +298,8 @@ class TracingChannel {
 unsubscribe(handlers){
 letdone=true;
 
-for(constnameoftraceEvents){
+for(leti=0;i<traceEvents.length;++i){
+constname=traceEvents[i];
 if(!handlers[name])continue;
 
 if(!this[name]?.unsubscribe(handlers[name])){

lib/internal/modules/cjs/loader.js

@@ -189,6 +189,9 @@ let { startTimer, endTimer } = debugWithTimer('module_timer', (start, end) => {
 endTimer=end;
 });
 
+const{ tracingChannel }=require('diagnostics_channel');
+constonRequire=getLazy(()=>tracingChannel('module.require'));
+
 constisWindows=process.platform==='win32';
 
 constrelativeResolveCache={__proto__: null};
@@ -209,7 +212,11 @@ function wrapModuleLoad(request, parent, isMain) {
 startTimer(logLabel,traceLabel);
 
 try{
-returnModule._load(request,parent,isMain);
+returnonRequire().traceSync(Module._load,{
+__proto__: null,
+parentFilename: parent?.filename,
+id: request,
+},Module,request,parent,isMain);
 }finally{
 endTimer(logLabel,traceLabel);
 }

lib/internal/modules/esm/loader.js

@@ -42,6 +42,9 @@ const {
 }=require('internal/modules/helpers');
 letdefaultResolve,defaultLoad,defaultLoadSync,importMetaInitializer;
 
+const{ tracingChannel }=require('diagnostics_channel');
+constonImport=tracingChannel('module.import');
+
 /**
  * @typedef {import('url').URL} URL
  */
@@ -210,10 +213,17 @@ class ModuleLoader {
 returncompileSourceTextModule(url,source,this);
 };
 const{ ModuleJob }=require('internal/modules/esm/module_job');
-constjob=newModuleJob(
-this,url,undefined,evalInstance,false,false);
-this.loadCache.set(url,undefined,job);
-const{ module }=awaitjob.run(isEntryPoint);
+constmodule=awaitonImport.tracePromise(async()=>{
+constjob=newModuleJob(
+this,url,undefined,evalInstance,false,false);
+this.loadCache.set(url,undefined,job);
+const{ module }=awaitjob.run(isEntryPoint);
+returnmodule;
+},{
+__proto__: null,
+parentURL: '<eval>',
+ url,
+});
 
 return{
 __proto__: null,
@@ -470,9 +480,15 @@ class ModuleLoader {
  * @returns {Promise<ModuleExports>}
  */
 asyncimport(specifier,parentURL,importAttributes,isEntryPoint=false){
-constmoduleJob=awaitthis.getModuleJob(specifier,parentURL,importAttributes);
-const{ module }=awaitmoduleJob.run(isEntryPoint);
-returnmodule.getNamespace();
+returnonImport.tracePromise(async()=>{
+constmoduleJob=awaitthis.getModuleJob(specifier,parentURL,importAttributes);
+const{ module }=awaitmoduleJob.run(isEntryPoint);
+returnmodule.getNamespace();
+},{
+__proto__: null,
+ parentURL,
+url: specifier,
+});
 }
 
 /**

test/fixtures/console/console.snapshot

@@ -7,3 +7,4 @@ Trace: foo
  at *
  at *
  at *
+ at *

test/fixtures/errors/force_colors.snapshot

@@ -11,5 +11,6 @@ Error: Should include grayed stack trace
  at *
  at *
  at *
+ at *
 
 Node.js *

test/fixtures/errors/promise_unhandled_warn_with_error.snapshot

@@ -7,5 +7,6 @@
  at *
  at *
  at *
+ at *
 (Use `node --trace-warnings ...` to show where the warning was created)
 (node:*) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https:*nodejs.org*api*cli.html#cli_unhandled_rejections_mode). (rejection id: 1)

test/fixtures/errors/unhandled_promise_trace_warnings.snapshot

@@ -11,6 +11,7 @@
  at *
  at *
  at *
+ at *
 (node:*) Error: This was rejected
  at *
  at *
@@ -20,6 +21,7 @@
  at *
  at *
  at *
+ at *
 (node:*) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 1)
  at *
  at *

test/message/assert_throws_stack.out

@@ -16,6 +16,7 @@ AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
  at *
  at *
  at *
+ at *
  at * {
  generatedMessage: true,
  code: 'ERR_ASSERTION',

test/message/internal_assert.out

@@ -13,6 +13,7 @@ Please open an issue with this stack trace at https://github.com/nodejs/node/iss
  at *
  at *
  at *
+ at *
  at * {
  code: 'ERR_INTERNAL_ASSERTION'
 }