view hgext/logtoprocess.py @ 51671:6fc31e7bd5db

typing: add some type hints for bundle2 capabilities

Somewhere between hg 3dbc7b1ecaba and hg 8e3f6b5bf720, pytype determined the
signature of `bundle20.capabilities` changed from `Dict[bytes, Tuple[bytes]]` to
`Dict[bytes, Union[List[bytes], Tuple[bytes]]]`.

First, I did try to simply be explicit about the previously inferred type, but
it does seem to mix and match list/tuple now (e.g. in `writenewbundle()`).  I
tried changing the new list usage to tuple, but a couple of things complained,
(and I think lists of one item are a little more clear to read anyway).  So then
I typed the dict value as `Sequence[bytes]`, which worked fine.  But there's
also a module level `capabilities` field, and when that's typed, pytype
complains about `Sequence[bytes]` lacking `__add__`[1].  So I gave up, and just
assigned it the type it wanted, with an alias.  If somebody feels motivated to
make the type consistent, it's simple enough to change the alias.

The mutable default value to the constructor was removed to appease PyCharm's
type checking on the field.  (I didn't bother running the code through pytype
prior to changing it, because we've previously made an effort to remove this
pattern anyway.)

I'm not sure why `getrepocaps()` has a default value for `role` that apparently
raises an exception.  It's just flagged for now so this series can land without
risking additional problems.

[1] https://foss.heptapod.net/mercurial/mercurial-devel/-/jobs/2466903

# 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.

"""


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 = b'ships-with-hg-core'


class processlogger:
    """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]
        maxmsg = 100000
        if len(msg) > maxmsg:
            # Each env var has a 128KiB limit on linux. msg can be long, in
            # particular for command event, where it's the full command line.
            # Prefer truncating the message than raising "Argument list too
            # long" error.
            msg = msg[:maxmsg] + b' (truncated)'
        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))