view hgdemandimport/tracing.py @ 51983:46afce95e5a5

tests: skip `test-wsgicgi.t` on MSYS

The test is attempting to set `PATH_INFO="/rev/\xe2\x80\x94"` into the
environment, which it does.  The problem is that when MSYS sees a leading '/' in
an environment variable, it thinks it's a unix filesystem path, so it "helpfully"
prepends the Windows path to the MSYS root directory before running a non-MSYS
process.  hgweb would then split this value on '/', so it would get 'C:' instead
of 'rev', and return a 400 since that isn't a valid web command.

I tried generating a *.bat file, but had trouble running that via `cmd.exe`
inside the test.  I also tried generating an equivalent *.py launcher that would
set the environment variables itself.  But there is no `os.environb` on Windows,
and the value was getting mangled when put into the script.  So, I give up.  If
it's encoding stuff on Windows, it's probably broken.

# Support code for event tracing in Mercurial. Lives in demandimport
# so it can also be used in demandimport.
#
# Copyright 2018 Google LLC.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import annotations

import contextlib
import os

_pipe = None
_checked = False
_session = 'none'


def _isactive():
    global _pipe, _session, _checked
    if _pipe is None:
        if _checked:
            return False
        _checked = True
        if 'HGCATAPULTSERVERPIPE' not in os.environ:
            return False
        _pipe = open(os.environ['HGCATAPULTSERVERPIPE'], 'w', 1)
        _session = os.environ.get('HGCATAPULTSESSION', 'none')
    return True


@contextlib.contextmanager
def log(whencefmt, *whenceargs):
    if not _isactive():
        yield
        return
    whence = whencefmt % whenceargs
    try:
        # Both writes to the pipe are wrapped in try/except to ignore
        # errors, as we can see mysterious errors in here if the pager
        # is active. Presumably other conditions could trigger
        # problems too.
        try:
            _pipe.write('START %s %s\n' % (_session, whence))
        except IOError:
            pass
        yield
    finally:
        try:
            _pipe.write('END %s %s\n' % (_session, whence))
        except IOError:
            pass


def counter(label, amount, *labelargs):
    if not _isactive():
        return
    l = label % labelargs
    # See above in log() for why this is in a try/except.
    try:
        _pipe.write('COUNTER %s %d %s\n' % (_session, amount, l))
    except IOError:
        pass