view mercurial/loggingutil.py @ 44030:5ac0e6f19eb4

ui: refactor `readconfig()` into a form that can consume resources

The old form can't completely go away, because files outside of packages still
need to be read.  The name passed in here is a tuple of `package name, resource`
as needed by the resource API.

I like the idea of stating the config file is embedded in the executable by
listing is as `exe!package.resource`.  This would be consistent with how
`debuginstall` points to the executable for the python executable, lib, and
installed modules.  While in practice the filesystem path is available from the
backing ResourceReader when the resource is opened, it is a relative path on py2
and absolute on py3.  Further, while this would show in the `hg config` output
for each option if set as such here, it doesn't show in the `reading from...`
line when `--debug` is used.  The file isn't actually open where that prints, so
there's no way I see to get that info there.  So I opted for the simple prefix
to distinguish resources from files.

Differential Revision: https://phab.mercurial-scm.org/D7775

# loggingutil.py - utility for logging events
#
# Copyright 2010 Nicolas Dumazet
# Copyright 2013 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.

from __future__ import absolute_import

import errno

from . import pycompat

from .utils import (
    dateutil,
    procutil,
    stringutil,
)


def openlogfile(ui, vfs, name, maxfiles=0, maxsize=0):
    """Open log file in append mode, with optional rotation

    If maxsize > 0, the log file will be rotated up to maxfiles.
    """

    def rotate(oldpath, newpath):
        try:
            vfs.unlink(newpath)
        except OSError as err:
            if err.errno != errno.ENOENT:
                ui.debug(
                    b"warning: cannot remove '%s': %s\n"
                    % (newpath, err.strerror)
                )
        try:
            if newpath:
                vfs.rename(oldpath, newpath)
        except OSError as err:
            if err.errno != errno.ENOENT:
                ui.debug(
                    b"warning: cannot rename '%s' to '%s': %s\n"
                    % (newpath, oldpath, err.strerror)
                )

    if maxsize > 0:
        try:
            st = vfs.stat(name)
        except OSError:
            pass
        else:
            if st.st_size >= maxsize:
                path = vfs.join(name)
                for i in pycompat.xrange(maxfiles - 1, 1, -1):
                    rotate(
                        oldpath=b'%s.%d' % (path, i - 1),
                        newpath=b'%s.%d' % (path, i),
                    )
                rotate(oldpath=path, newpath=maxfiles > 0 and path + b'.1')
    return vfs(name, b'a', makeparentdirs=False)


def _formatlogline(msg):
    date = dateutil.datestr(format=b'%Y/%m/%d %H:%M:%S')
    pid = procutil.getpid()
    return b'%s (%d)> %s' % (date, pid, msg)


def _matchevent(event, tracked):
    return b'*' in tracked or event in tracked


class filelogger(object):
    """Basic logger backed by physical file with optional rotation"""

    def __init__(self, vfs, name, tracked, maxfiles=0, maxsize=0):
        self._vfs = vfs
        self._name = name
        self._trackedevents = set(tracked)
        self._maxfiles = maxfiles
        self._maxsize = maxsize

    def tracked(self, event):
        return _matchevent(event, self._trackedevents)

    def log(self, ui, event, msg, opts):
        line = _formatlogline(msg)
        try:
            with openlogfile(
                ui,
                self._vfs,
                self._name,
                maxfiles=self._maxfiles,
                maxsize=self._maxsize,
            ) as fp:
                fp.write(line)
        except IOError as err:
            ui.debug(
                b'cannot write to %s: %s\n'
                % (self._name, stringutil.forcebytestr(err))
            )


class fileobjectlogger(object):
    """Basic logger backed by file-like object"""

    def __init__(self, fp, tracked):
        self._fp = fp
        self._trackedevents = set(tracked)

    def tracked(self, event):
        return _matchevent(event, self._trackedevents)

    def log(self, ui, event, msg, opts):
        line = _formatlogline(msg)
        try:
            self._fp.write(line)
            self._fp.flush()
        except IOError as err:
            ui.debug(
                b'cannot write to %s: %s\n'
                % (
                    stringutil.forcebytestr(self._fp.name),
                    stringutil.forcebytestr(err),
                )
            )


class proxylogger(object):
    """Forward log events to another logger to be set later"""

    def __init__(self):
        self.logger = None

    def tracked(self, event):
        return self.logger is not None and self.logger.tracked(event)

    def log(self, ui, event, msg, opts):
        assert self.logger is not None
        self.logger.log(ui, event, msg, opts)