Mercurial > hg
view hgdemandimport/tracing.py @ 39254:284440041141
tracing: new module to make tracing events in hg easier
This lives in hgdemandimport because I want to instrument a bunch of
low-level stuff including the bare `hg` script and demandimport, so it
can't live at a higher layer.
Differential Revision: https://phab.mercurial-scm.org/D4344
author | Augie Fackler <augie@google.com> |
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date | Tue, 21 Aug 2018 15:24:20 -0400 |
parents | |
children | 452790284a15 |
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# 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 absolute_import import contextlib import os _pipe = None _checked = False @contextlib.contextmanager def log(whencefmt, *whenceargs): global _pipe, _session, _checked if _pipe is None: if _checked: yield return _checked = True if 'HGCATAPULTSERVERPIPE' not in os.environ: yield return _pipe = open(os.environ['HGCATAPULTSERVERPIPE'], 'w', 1) _session = os.environ.get('HGCATAPULTSESSION', 'none') whence = whencefmt % whenceargs try: _pipe.write('START %s %s\n' % (_session, whence)) yield finally: _pipe.write('END %s %s\n' % (_session, whence))