我需要有关Puppeteer page.metrics和queryObjects的更多信息 [英] I need more info about Puppeteer page.metrics and queryObjects

问题描述

我正在使用木偶来查找内存泄漏问题.我正在使用puppeteer的 page.metrics() API，但我在理解每个属性的含义时遇到了麻烦.我在指标中的所有值随着时间的推移而不断增加.这是预期的吗?还是这表明可能存在严重的内存泄漏?

I'm using Puppeteer to find a memory leak issue. I'm using puppeteer's page.metrics() API but I am having trouble understanding each properties meaning. All my values in the metrics keep increasing in value over time. Is this expected? Or is this an indication that there might be a serious memory leak?

随着应用程序的运行，其价值不断增长的属性是: JSEventListeners, Nodes, LayoutCount, RecalcStyleCount, LayoutDuration, RecalcStyleDuration, ScriptDuration, TaskDuration, JSHeapUsedSize, JSHeapTotalSize

The properties which are growing in value as the app runs are: JSEventListeners, Nodes, LayoutCount, RecalcStyleCount, LayoutDuration, RecalcStyleDuration, ScriptDuration, TaskDuration, JSHeapUsedSize, JSHeapTotalSize

关于这些东西的信息非常稀少，而且我一直看到人们引用page.queryObjects作为查找内存泄漏的另一种方法.但是我找不到有关如何使用此API以及要查找的内容的任何信息.

The information about this stuff is very sparse and also I keep seeing people refer to page.queryObjects as another way to find memory leaks. But I cannot find any information about how to use this API and what to look for.

推荐答案

根据

page.metrics()

• 返回:< 承诺 < 对象 >>包含指标的对象作为键/值对.
  • Timestamp< 数字>采集指标样本的时间戳.
  • Documents< 数字>页面中的文档数.
  • Frames< 数字>页面中的帧数.
  • JSEventListeners< 数字>页面中的事件数.
  • Nodes< 数字>页面中的DOM节点数.
  • LayoutCount< 数字>全部或部分页面布局的总数.
  • RecalcStyleCount< 数字>页面样式重新计算的总数.
  • LayoutDuration< 数字>所有页面布局的合并持续时间.
  • RecalcStyleDuration< 数字>所有页面样式重新计算的总持续时间.
  • ScriptDuration< 数字> JavaScript执行时间的总和.
  • TaskDuration< 数字>浏览器执行的所有任务的持续时间.
  • JSHeapUsedSize< 数字>使用的JavaScript堆大小.
  • JSHeapTotalSize< 数字> JavaScript堆总大小.

  page.metrics()

  • returns: <Promise<Object>> Object containing metrics as key/value pairs.
    • Timestamp <number> The timestamp when the metrics sample was taken.
    • Documents <number> Number of documents in the page.
    • Frames <number> Number of frames in the page.
    • JSEventListeners <number> Number of events in the page.
    • Nodes <number> Number of DOM nodes in the page.
    • LayoutCount <number> Total number of full or partial page layout.
    • RecalcStyleCount <number> Total number of page style recalculations.
    • LayoutDuration <number> Combined durations of all page layouts.
    • RecalcStyleDuration <number> Combined duration of all page style recalculations.
    • ScriptDuration <number> Combined duration of JavaScript execution.
    • TaskDuration <number> Combined duration of all tasks performed by the browser.
    • JSHeapUsedSize <number> Used JavaScript heap size.
    • JSHeapTotalSize <number> Total JavaScript heap size.

  注意所有时间戳均为单调时间:从过去的任意点开始，以秒为单位单调增加时间.

  NOTE All timestamps are in monotonic time: monotonically increasing time in seconds since an arbitrary point in the past.

  page.queryObjects(prototypeHandle)

  • prototypeHandle< JSHandle >对象原型的句柄.
  • 返回:< 承诺 < JSHandle >>解决的承诺这个原型处理一个对象数组的句柄.

  page.queryObjects(prototypeHandle)

  • prototypeHandle <JSHandle> A handle to the object prototype.
  • returns: <Promise<JSHandle>> Promise which resolves to a handle to an array of objects with this prototype.

  该方法迭代JavaScript堆并查找具有给定原型的所有对象.

  The method iterates the JavaScript heap and finds all the objects with the given prototype.

  // Create a Map object
  await page.evaluate(() => window.map = new Map());
  // Get a handle to the Map object prototype
  const mapPrototype = await page.evaluateHandle(() => Map.prototype);
  // Query all map instances into an array
  const mapInstances = await page.queryObjects(mapPrototype);
  // Count amount of map objects in heap
  const count = await page.evaluate(maps => maps.length, mapInstances);
  await mapInstances.dispose();
  await mapPrototype.dispose();
  

  page.mainFrame().executionContext()的快捷方式.queryObjects(prototypeHandle).

  ---

  page.metrics()方法返回Chrome DevTools协议的结果 Performance.getMetrics :

  ---

  The page.metrics() method returns the result of the Chrome DevTools Protocol Performance.getMetrics:

  Performance.getMetrics

  检索运行时指标的当前值.

  Performance.getMetrics

  Retrieve current values of run-time metrics.

  返回对象

  • metrics 数组指标
    • 运行时指标的当前值.
    • metrics array Metric
      • Current values for run-time metrics.

      另一方面，page.queryObjects()方法随附的Chrome DevTools协议为

      On the other hand, the Chrome DevTools Protocol that accompanies the page.queryObjects() method is Runtime.queryObjects:

      Runtime.queryObjects

      参数

      Runtime.queryObjects

      PARAMETERS

      • prototypeObjectId RemoteObjectId
        • 要为其返回对象的原型的标识符.
        • prototypeObjectId RemoteObjectId
          • Identifier of the prototype to return objects for.
          • 可用于发布结果的符号组名称.

          返回对象

          • objects RemoteObject
            • 带有对象的数组.
            • objects RemoteObject
              • Array with objects.

              ---

              page.matrics() 的源代码和 page.queryObjects() 可以在GitHub上找到.

              ---

              The source code for page.matrics() and page.queryObjects() can be found on GitHub.

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