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doc: add esm examples to node:trace_events · nodejs/node@233a6a9 · GitHub

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doc: add esm examples to node:trace_events
PR-URL: #56514 Reviewed-By: Ulises Gascón <ulisesgascongonzalez@gmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
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‎doc/api/tracing.md‎

Lines changed: 102 additions & 19 deletions
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@@ -69,9 +69,19 @@ node --trace-event-categories v8,node,node.async_hooks
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Alternatively, trace events may be enabled using the `node:trace_events` module:
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```js
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const trace_events = require('node:trace_events');
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const tracing = trace_events.createTracing({ categories: ['node.perf'] });
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```mjs
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import { createTracing } from 'node:trace_events';
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const tracing = createTracing({ categories: ['node.perf'] });
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tracing.enable(); // Enable trace event capture for the 'node.perf' category
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// do work
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tracing.disable(); // Disable trace event capture for the 'node.perf' category
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```
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```cjs
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const { createTracing } = require('node:trace_events');
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const tracing = createTracing({ categories: ['node.perf'] });
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tracing.enable(); // Enable trace event capture for the 'node.perf' category
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// do work
@@ -153,20 +163,36 @@ Disables this `Tracing` object.
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Only trace event categories _not_ covered by other enabled `Tracing` objects
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and _not_ specified by the `--trace-event-categories` flag will be disabled.
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```js
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const trace_events = require('node:trace_events');
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const t1 = trace_events.createTracing({ categories: ['node', 'v8'] });
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const t2 = trace_events.createTracing({ categories: ['node.perf', 'node'] });
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```mjs
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import { createTracing, getEnabledCategories } from 'node:trace_events';
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const t1 = createTracing({ categories: ['node', 'v8'] });
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const t2 = createTracing({ categories: ['node.perf', 'node'] });
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t1.enable();
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t2.enable();
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// Prints 'node,node.perf,v8'
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console.log(getEnabledCategories());
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t2.disable(); // Will only disable emission of the 'node.perf' category
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// Prints 'node,v8'
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console.log(getEnabledCategories());
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```
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```cjs
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const { createTracing, getEnabledCategories } = require('node:trace_events');
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const t1 = createTracing({ categories: ['node', 'v8'] });
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const t2 = createTracing({ categories: ['node.perf', 'node'] });
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t1.enable();
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t2.enable();
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// Prints 'node,node.perf,v8'
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console.log(trace_events.getEnabledCategories());
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console.log(getEnabledCategories());
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t2.disable(); // Will only disable emission of the 'node.perf' category
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// Prints 'node,v8'
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console.log(trace_events.getEnabledCategories());
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console.log(getEnabledCategories());
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```
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#### `tracing.enable()`
@@ -200,10 +226,19 @@ added: v10.0.0
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Creates and returns a `Tracing` object for the given set of `categories`.
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```js
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const trace_events = require('node:trace_events');
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```mjs
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import { createTracing } from 'node:trace_events';
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const categories = ['node.perf', 'node.async_hooks'];
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const tracing = createTracing({ categories });
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tracing.enable();
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// do stuff
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tracing.disable();
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```
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```cjs
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const { createTracing } = require('node:trace_events');
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const categories = ['node.perf', 'node.async_hooks'];
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const tracing = trace_events.createTracing({ categories });
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const tracing = createTracing({ categories });
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tracing.enable();
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// do stuff
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tracing.disable();
@@ -226,23 +261,71 @@ Given the file `test.js` below, the command
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`node --trace-event-categories node.perf test.js` will print
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`'node.async_hooks,node.perf'` to the console.
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```js
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const trace_events = require('node:trace_events');
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const t1 = trace_events.createTracing({ categories: ['node.async_hooks'] });
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const t2 = trace_events.createTracing({ categories: ['node.perf'] });
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const t3 = trace_events.createTracing({ categories: ['v8'] });
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```mjs
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import { createTracing, getEnabledCategories } from 'node:trace_events';
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const t1 = createTracing({ categories: ['node.async_hooks'] });
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const t2 = createTracing({ categories: ['node.perf'] });
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const t3 = createTracing({ categories: ['v8'] });
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t1.enable();
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t2.enable();
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console.log(getEnabledCategories());
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```
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```cjs
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const { createTracing, getEnabledCategories } = require('node:trace_events');
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const t1 = createTracing({ categories: ['node.async_hooks'] });
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const t2 = createTracing({ categories: ['node.perf'] });
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const t3 = createTracing({ categories: ['v8'] });
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t1.enable();
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t2.enable();
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console.log(trace_events.getEnabledCategories());
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console.log(getEnabledCategories());
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```
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## Examples
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### Collect trace events data by inspector
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```js
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```mjs
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import { Session } from 'node:inspector';
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const session = new Session();
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session.connect();
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function post(message, data) {
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return new Promise((resolve, reject) => {
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session.post(message, data, (err, result) => {
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if (err)
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reject(new Error(JSON.stringify(err)));
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else
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resolve(result);
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});
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});
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}
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async function collect() {
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const data = [];
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session.on('NodeTracing.dataCollected', (chunk) => data.push(chunk));
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session.on('NodeTracing.tracingComplete', () => {
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// done
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});
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const traceConfig = { includedCategories: ['v8'] };
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await post('NodeTracing.start', { traceConfig });
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// do something
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setTimeout(() => {
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post('NodeTracing.stop').then(() => {
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session.disconnect();
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console.log(data);
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});
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}, 1000);
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}
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collect();
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```
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```cjs
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'use strict';
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const { Session } = require('node:inspector');

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