Speed up config.__getattr__ with a factor 10 corresponding to 5-10% app speed up.

[MarcSkovMadsen]

Closes #5850

Pytest

I've run the below test on the main branch and this branch.

from pathlib import Path
import pytest
from pyinstrument import Profiler
import panel as pn

TESTS_ROOT = Path.cwd()

@pytest.fixture(autouse=True)
def auto_profile(request):
    PROFILE_ROOT = (TESTS_ROOT / ".profiles")
    # Turn profiling on
    profiler = Profiler()
    profiler.start()

    yield  # Run test

    profiler.stop()
    PROFILE_ROOT.mkdir(exist_ok=True)
    results_file = PROFILE_ROOT / f"{request.node.name}.html"
    profiler.write_html(results_file)

item = pn.pane.Markdown("Hello World")

def method1():
    pn.config.loading_indicator
    pn.config.npm_cdn
    pn.config.sizing_mode
    pn.config.admin

def test_performance():
    N = 100000
    for i in range(N):
        method1()

I've achieved a 75% speed up. Left is main branch, Right is this branch

App

Compared to the profiling of the app in the reported issue, it looks much better. config.__getattribute__ is only in one place with a smaller proportion of 1% compared to the 11% before. Still I think that is too much.

[codecov]

Codecov Report

Merging #5851 (02d6795) into main (51adf14) will increase coverage by 11.54%.
Report is 6 commits behind head on main.
The diff coverage is 92.30%.

@@             Coverage Diff             @@
##             main    #5851       +/-   ##
===========================================
+ Coverage   72.36%   83.90%   +11.54%     
===========================================
  Files         290      290               
  Lines       42236    42264       +28     
===========================================
+ Hits        30562    35460     +4898     
+ Misses      11674     6804     -4870     

Flag	Coverage Δ
ui-tests	40.90% <92.30%> (?)
unitexamples-tests	72.25% <92.30%> (-0.11%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
panel/config.py	71.03% <92.30%> (+4.04%)	⬆️

... and 87 files with indirect coverage changes

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[MarcSkovMadsen]

I cannot do more now. The implementation is quite complicated. Maybe it should really be refactored? For example I don't understand why you want to ask again and again for the os.environ values. Why not set them once on startup?

I am not aware I've broken anything and the tests pass.

I hope you will review and finalize. This needs your knowledge @philippjfr . Thanks.

[philippjfr]

Thanks for looking at this, refactoring config has been on my to-do list for a while. Will review the details and see if we can squeeze out a little more.

[maximlt]

Certainly config was the most difficult piece of code out there I had to deal with when working on Param 2.0.