✨ Generate event specific reports

[ubmarco]

This PR makes it possible to aggregate the runtime of event listeners for all fired Sphinx events.
Tricky part in pyinstrument is that all event listeners appear under EventManager.emit, so the event name is lost.
The PR monkeypatches Sphinx to use a custom Event listener which injects an event specific emit function, so it can be tracked in pyinstrument.

The PR can be tested with sphinx-analysis --project needs --pyinstrument --tree.
A new JSON report of name pyinstrument_sphinx_events.json is created.
It contains all unique combinations of file path, class and function of all event listeners, so it will pick up all extensions that have listeners registered.
The dictionary sphinx_performance/sphinx_events.py:CUSTOM_FRAMES_BY_EVENT can be modified to add more frames of interest (unrelated to events). It is currently used to track the runtime of sphinxcontrib-plantuml.

The generated JSON file can be used for 2 purposes:

• As a support to the pyinstrument HTML report to get a per-event aggregation
• To run in a CI and check how a PR to Sphinx or an extension affects performance

The HTML report now contains event specific function names, so event names can be searched.

[danwos]

I get an error during report generation when I run sphinx-analysis --project needs --pyinstrument --tree:

  File "/home/daniel/workspace/sphinx/sphinx-performance/sphinx_performance/analysis.py", line 268, in cli_analysis
    with Path.open("pyinstrument_profile.html", "w") as events_json_file:
  File "/usr/lib/python3.10/pathlib.py", line 1119, in open
    return self._accessor.open(self, mode, buffering, encoding, errors,
AttributeError: 'str' object has no attribute '_accessor'

[ubmarco]

I can confirm this bug for Python 3.10. For Python 3.11 it works. Need to check.

[ubmarco]

I fixed that problem, I need to instantiate a Path to be consumed by Path.open

[chrisjsewell]

Cheers, yeh I guess ideally it would be nice to have some tests 😅
But as there were already no tests for this package, I won't block on it