crossbench/probes/performance_entries.py

# Copyright 2022 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
from __future__ import annotations

import logging
from typing import TYPE_CHECKING

from crossbench.probes import metric
from crossbench.probes.json import JsonResultProbe
from crossbench.probes.probe import ProbeIncompatibleBrowser

if TYPE_CHECKING:
  from crossbench.browsers.browser import Browser
  from crossbench.env import HostEnvironment
  from crossbench.probes.results import ProbeResult
  from crossbench.runner.actions import Actions
  from crossbench.runner.groups import BrowsersRunGroup, StoriesRunGroup
  from crossbench.types import JSON


class PerformanceEntriesProbe(JsonResultProbe):
  """
  Extract all JavaScript PerformanceEntry [1] from a website.
  Website owners can define more entries via `performance.mark()`.

  [1] https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEntry
  """
  NAME = "performance.entries"

  def validate_browser(self, env: HostEnvironment, browser: Browser) -> None:
    super().validate_browser(env, browser)
    if not hasattr(browser, "js"):
      raise ProbeIncompatibleBrowser(self, browser,
                                     "Needs browser with JS-execution support")

  def to_json(self, actions: Actions) -> JSON:
    return actions.js("""
      let data = { __proto__: null, paint: {}, mark: {} };
      for (let entryType of Object.keys(data)) {
        for (let entry of performance.getEntriesByType(entryType)) {
           const typeData = data[entryType];
           let values = typeData[entry.name];
           if (values === undefined) {
             values = typeData[entry.name] = { startTime: [], duration: [] };
           }
           for (let metricName of Object.keys(values)) {
            values[metricName].push(entry[metricName]);
          }
        }
      }
      data.navigation = {};
      const navigationTiming = performance.getEntriesByType("navigation")[0];
      for (let name in navigationTiming) {
        const value = navigationTiming[name];
        if (typeof value !== "number") continue;
        data.navigation[name] = value;
      }
      return data;
      """)

  def merge_stories(self, group: StoriesRunGroup) -> ProbeResult:
    stories = list(group.stories)
    if len(stories) > 1:
      logging.warning(
          "%s: Merging performance.entries from %d possibly unrelated pages %s",
          group.browser.unique_name, len(stories),
          ", ".join(story.name for story in stories))
    merged = metric.MetricsMerger.merge_json_list(
        (story_group.results[self].json
         for story_group in group.repetitions_groups),
        merge_duplicate_paths=True)
    return self.write_group_result(group, merged, write_csv=True)

  def merge_browsers(self, group: BrowsersRunGroup) -> ProbeResult:
    # TODO: recreate the CSV from the merged JSON files since we might not
    # get the same values in all browsers.
    # TODO: Add merged browser data with separate stories.
    return self.merge_browsers_json_list(group).merge(
        self.merge_browsers_csv_list(group))