hgext/logtoprocess.py

run-tests: alias hg to hg.exe on Windows

To enable legacy stdio mode on Windows, hg.exe needs to be updated.  But before
that, we actually have to use it when running the tests.  I *think* what was
happening before was when MSYS invoked `hg`, it looked at the shbang line and
ran python.exe found there.  The test harness must be updating $PATH to include
the python used to launch it, and therefore it ran py3.  As a side note, this
also fixed `py -3 run-tests.py` (without --local), which complained about the
space in the shbang line before this.

This should also help in WSL, because the explicit '.exe' is needed to invoke a
Windows app instead of invoking the Linux app.

I have no idea why this change capitalizes Lib in the tests, as it was
previously lowercase for both py2 and py3.

# logtoprocess.py - send ui.log() data to a subprocess
#
# Copyright 2016 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""send ui.log() data to a subprocess (EXPERIMENTAL)

This extension lets you specify a shell command per ui.log() event,
sending all remaining arguments to as environment variables to that command.

Positional arguments construct a log message, which is passed in the `MSG1`
environment variables. Each keyword argument is set as a `OPT_UPPERCASE_KEY`
variable (so the key is uppercased, and prefixed with `OPT_`). The original
event name is passed in the `EVENT` environment variable, and the process ID
of mercurial is given in `HGPID`.

So given a call `ui.log('foo', 'bar %s\n', 'baz', spam='eggs'), a script
configured for the `foo` event can expect an environment with `MSG1=bar baz`,
and `OPT_SPAM=eggs`.

Scripts are configured in the `[logtoprocess]` section, each key an event name.
For example::

  [logtoprocess]
  commandexception = echo "$MSG1" > /var/log/mercurial_exceptions.log

would log the warning message and traceback of any failed command dispatch.

Scripts are run asynchronously as detached daemon processes; mercurial will
not ensure that they exit cleanly.

"""

from __future__ import absolute_import

import os

from mercurial.utils import (
    procutil,
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'

class processlogger(object):
    """Map log events to external commands

    Arguments are passed on as environment variables.
    """

    def __init__(self, ui):
        self._scripts = dict(ui.configitems(b'logtoprocess'))

    def tracked(self, event):
        return bool(self._scripts.get(event))

    def log(self, ui, event, msg, opts):
        script = self._scripts[event]
        env = {
            b'EVENT': event,
            b'HGPID': os.getpid(),
            b'MSG1': msg,
        }
        # keyword arguments get prefixed with OPT_ and uppercased
        env.update((b'OPT_%s' % key.upper(), value)
                   for key, value in opts.items())
        fullenv = procutil.shellenviron(env)
        procutil.runbgcommand(script, fullenv, shell=True)

def uipopulate(ui):
    ui.setlogger(b'logtoprocess', processlogger(ui))