view hgext/blackbox.py @ 50336:cf4d2f31660d stable

chg: populate CHGHG if not set

Normally, chg determines which `hg` executable to use by first consulting the
`$CHGHG` and `$HG` environment variables, and if neither are present defaults
to the `hg` found in the user's `$PATH`. If built with the `HGPATHREL` compiler
flag, chg will instead assume that there exists an `hg` executable in the same
directory as the `chg` binary and attempt to use that.

This can cause problems in situations where there are multiple actively-used
Mercurial installations on the same system. When a `chg` client connects to a
running command server, the server process performs some basic validation to
determine whether a new command server needs to be spawned. These checks include
things like checking certain "sensitive" environment variables and config
sections, as well as checking whether the mtime of the extensions, hg's
`__version__.py` module, and the Python interpreter have changed.

Crucially, the command server doesn't explicitly check whether the executable it
is running from matches the executable that the `chg` client would have
otherwise invoked had there been no existing command server process. Without
`HGPATHREL`, this still gets implicitly checked during the validation step,
because the only way to specify an alternate hg executable (apart from `$PATH`)
is via the `$CHGHG` and `$HG` environment variables, both of which are checked.

With `HGPATHREL`, however, the command server has no way of knowing which hg
executable the client would have run. This means that a client located at
`/version_B/bin/chg` will happily connect to a command server running
`/version_A/bin/hg` instead of `/version_B/bin/hg` as expected. A simple
solution is to have the client set `$CHGHG` itself, which then allows the
command server's environment validation to work as intended.

I have tested this manually using two locally built hg installations and it
seems to work with no ill effects. That said, I'm not sure how to write an
automated test for this since the `chg` available to the tests isn't even built
with the `HGPATHREL` compiler flag to begin with.

# blackbox.py - log repository events to a file for post-mortem debugging
#
# 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.

"""log repository events to a blackbox for debugging

Logs event information to .hg/blackbox.log to help debug and diagnose problems.
The events that get logged can be configured via the blackbox.track and
blackbox.ignore config keys.

Examples::

  [blackbox]
  track = *
  ignore = pythonhook
  # dirty is *EXPENSIVE* (slow);
  # each log entry indicates `+` if the repository is dirty, like :hg:`id`.
  dirty = True
  # record the source of log messages
  logsource = True

  [blackbox]
  track = command, commandfinish, commandexception, exthook, pythonhook

  [blackbox]
  track = incoming

  [blackbox]
  # limit the size of a log file
  maxsize = 1.5 MB
  # rotate up to N log files when the current one gets too big
  maxfiles = 3

  [blackbox]
  # Include microseconds in log entries with %f (see Python function
  # datetime.datetime.strftime)
  date-format = %Y-%m-%d @ %H:%M:%S.%f

"""


import re

from mercurial.i18n import _
from mercurial.node import hex

from mercurial import (
    encoding,
    loggingutil,
    registrar,
)
from mercurial.utils import (
    dateutil,
    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'

cmdtable = {}
command = registrar.command(cmdtable)

configtable = {}
configitem = registrar.configitem(configtable)

configitem(
    b'blackbox',
    b'dirty',
    default=False,
)
configitem(
    b'blackbox',
    b'maxsize',
    default=b'1 MB',
)
configitem(
    b'blackbox',
    b'logsource',
    default=False,
)
configitem(
    b'blackbox',
    b'maxfiles',
    default=7,
)
configitem(
    b'blackbox',
    b'track',
    default=lambda: [b'*'],
)
configitem(
    b'blackbox',
    b'ignore',
    default=lambda: [b'chgserver', b'cmdserver', b'extension'],
)
configitem(b'blackbox', b'date-format', default=b'')

_lastlogger = loggingutil.proxylogger()


class blackboxlogger:
    def __init__(self, ui, repo):
        self._repo = repo
        self._trackedevents = set(ui.configlist(b'blackbox', b'track'))
        self._ignoredevents = set(ui.configlist(b'blackbox', b'ignore'))
        self._maxfiles = ui.configint(b'blackbox', b'maxfiles')
        self._maxsize = ui.configbytes(b'blackbox', b'maxsize')
        self._inlog = False

    def tracked(self, event):
        return (
            b'*' in self._trackedevents and event not in self._ignoredevents
        ) or event in self._trackedevents

    def log(self, ui, event, msg, opts):
        # self._log() -> ctx.dirty() may create new subrepo instance, which
        # ui is derived from baseui. So the recursion guard in ui.log()
        # doesn't work as it's local to the ui instance.
        if self._inlog:
            return
        self._inlog = True
        try:
            self._log(ui, event, msg, opts)
        finally:
            self._inlog = False

    def _log(self, ui, event, msg, opts):
        default = ui.configdate(b'devel', b'default-date')
        dateformat = ui.config(b'blackbox', b'date-format')
        if dateformat:
            date = dateutil.datestr(default, dateformat)
        else:
            # We want to display milliseconds (more precision seems
            # unnecessary).  Since %.3f is not supported, use %f and truncate
            # microseconds.
            date = dateutil.datestr(default, b'%Y-%m-%d %H:%M:%S.%f')[:-3]
        user = procutil.getuser()
        pid = b'%d' % procutil.getpid()
        changed = b''
        ctx = self._repo[None]
        parents = ctx.parents()
        rev = b'+'.join([hex(p.node()) for p in parents])
        if ui.configbool(b'blackbox', b'dirty') and ctx.dirty(
            missing=True, merge=False, branch=False
        ):
            changed = b'+'
        if ui.configbool(b'blackbox', b'logsource'):
            src = b' [%s]' % event
        else:
            src = b''
        try:
            fmt = b'%s %s @%s%s (%s)%s> %s'
            args = (date, user, rev, changed, pid, src, msg)
            with loggingutil.openlogfile(
                ui,
                self._repo.vfs,
                name=b'blackbox.log',
                maxfiles=self._maxfiles,
                maxsize=self._maxsize,
            ) as fp:
                fp.write(fmt % args)
        except (IOError, OSError) as err:
            # deactivate this to avoid failed logging again
            self._trackedevents.clear()
            ui.debug(
                b'warning: cannot write to blackbox.log: %s\n'
                % encoding.strtolocal(err.strerror)
            )
            return
        _lastlogger.logger = self


def uipopulate(ui):
    ui.setlogger(b'blackbox', _lastlogger)


def reposetup(ui, repo):
    # During 'hg pull' a httppeer repo is created to represent the remote repo.
    # It doesn't have a .hg directory to put a blackbox in, so we don't do
    # the blackbox setup for it.
    if not repo.local():
        return

    # Since blackbox.log is stored in the repo directory, the logger should be
    # instantiated per repository.
    logger = blackboxlogger(ui, repo)
    ui.setlogger(b'blackbox', logger)

    # Set _lastlogger even if ui.log is not called. This gives blackbox a
    # fallback place to log
    if _lastlogger.logger is None:
        _lastlogger.logger = logger

    repo._wlockfreeprefix.add(b'blackbox.log')


@command(
    b'blackbox',
    [
        (b'l', b'limit', 10, _(b'the number of events to show')),
    ],
    _(b'hg blackbox [OPTION]...'),
    helpcategory=command.CATEGORY_MAINTENANCE,
    helpbasic=True,
)
def blackbox(ui, repo, *revs, **opts):
    """view the recent repository events"""

    if not repo.vfs.exists(b'blackbox.log'):
        return

    limit = opts.get('limit')
    assert limit is not None  # help pytype

    fp = repo.vfs(b'blackbox.log', b'r')
    lines = fp.read().split(b'\n')

    count = 0
    output = []
    for line in reversed(lines):
        if count >= limit:
            break

        # count the commands by matching lines like:
        # 2013/01/23 19:13:36 root>
        # 2013/01/23 19:13:36 root (1234)>
        # 2013/01/23 19:13:36 root @0000000000000000000000000000000000000000 (1234)>
        # 2013-01-23 19:13:36.000 root @0000000000000000000000000000000000000000 (1234)>
        if re.match(
            br'^\d{4}[-/]\d{2}[-/]\d{2} \d{2}:\d{2}:\d{2}(.\d*)? .*> .*', line
        ):
            count += 1
        output.append(line)

    ui.status(b'\n'.join(reversed(output)))