contrib/check-config.py

hgweb: config option to control zlib compression level

Before this patch, the HTTP transport protocol would always zlib
compress certain responses (notably "getbundle" wire protocol commands)
at zlib compression level 6.

zlib can be a massive CPU resource sink for servers. Some server
operators may wish to reduce server-side CPU requirements while
requiring more bandwidth. This is common on corporate intranets, for
example. Others may wish to use more CPU but reduce bandwidth.

This patch introduces a config option to allow server operators
to control the zlib compression level.

On the "mozilla-unified" generaldelta repository, setting this
value to "0" (disable compression) results in server-side CPU
utilization for a `hg clone` going from ~180s to ~124s CPU time on
my i7-6700K.  A level of "1" (which increases the transfer size from
~1,074 MB at level 6 to ~1,222 MB) utilizes ~132s CPU time.

#!/usr/bin/env python
#
# check-config - a config flag documentation checker for Mercurial
#
# Copyright 2015 Matt Mackall <[e-mail]>
#
# 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, print_function
import re
import sys

foundopts = {}
documented = {}

configre = (r"""ui\.config(|int|bool|list)\(['"](\S+)['"],\s*"""
            r"""['"](\S+)['"](,\s+(?:default=)?(\S+?))?\)""")
configpartialre = (r"""ui\.config""")

def main(args):
    for f in args:
        sect = ''
        prevname = ''
        confsect = ''
        carryover = ''
        for l in open(f):

            # check topic-like bits
            m = re.match('\s*``(\S+)``', l)
            if m:
                prevname = m.group(1)
            if re.match('^\s*-+$', l):
                sect = prevname
                prevname = ''

            if sect and prevname:
                name = sect + '.' + prevname
                documented[name] = 1

            # check docstring bits
            m = re.match(r'^\s+\[(\S+)\]', l)
            if m:
                confsect = m.group(1)
                continue
            m = re.match(r'^\s+(?:#\s*)?(\S+) = ', l)
            if m:
                name = confsect + '.' + m.group(1)
                documented[name] = 1

            # like the bugzilla extension
            m = re.match(r'^\s*(\S+\.\S+)$', l)
            if m:
                documented[m.group(1)] = 1

            # like convert
            m = re.match(r'^\s*:(\S+\.\S+):\s+', l)
            if m:
                documented[m.group(1)] = 1

            # quoted in help or docstrings
            m = re.match(r'.*?``(\S+\.\S+)``', l)
            if m:
                documented[m.group(1)] = 1

            # look for ignore markers
            m = re.search(r'# (?:internal|experimental|deprecated|developer)'
                          ' config: (\S+\.\S+)$', l)
            if m:
                documented[m.group(1)] = 1

            # look for code-like bits
            line = carryover + l
            m = re.search(configre, line, re.MULTILINE)
            if m:
                ctype = m.group(1)
                if not ctype:
                    ctype = 'str'
                name = m.group(2) + "." + m.group(3)
                default = m.group(5)
                if default in (None, 'False', 'None', '0', '[]', '""', "''"):
                    default = ''
                if re.match('[a-z.]+$', default):
                    default = '<variable>'
                if name in foundopts and (ctype, default) != foundopts[name]:
                    print(l)
                    print("conflict on %s: %r != %r" % (name, (ctype, default),
                                                        foundopts[name]))
                foundopts[name] = (ctype, default)
                carryover = ''
            else:
                m = re.search(configpartialre, line)
                if m:
                    carryover = line
                else:
                    carryover = ''

    for name in sorted(foundopts):
        if name not in documented:
            if not (name.startswith("devel.") or
                    name.startswith("experimental.") or
                    name.startswith("debug.")):
                ctype, default = foundopts[name]
                if default:
                    default = ' [%s]' % default
                print("undocumented: %s (%s)%s" % (name, ctype, default))

if __name__ == "__main__":
    if len(sys.argv) > 1:
        sys.exit(main(sys.argv[1:]))
    else:
        sys.exit(main([l.rstrip() for l in sys.stdin]))