130 lines
4.6 KiB
Python
130 lines
4.6 KiB
Python
from __future__ import with_statement
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import os
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import re
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import pytz
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_cache_tz = None
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def _tz_from_env(tzenv):
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if tzenv[0] == ':':
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tzenv = tzenv[1:]
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# TZ specifies a file
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if os.path.exists(tzenv):
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with open(tzenv, 'rb') as tzfile:
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return pytz.tzfile.build_tzinfo('local', tzfile)
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# TZ specifies a zoneinfo zone.
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try:
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tz = pytz.timezone(tzenv)
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# That worked, so we return this:
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return tz
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except pytz.UnknownTimeZoneError:
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raise pytz.UnknownTimeZoneError(
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"tzlocal() does not support non-zoneinfo timezones like %s. \n"
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"Please use a timezone in the form of Continent/City")
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def _get_localzone(_root='/'):
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"""Tries to find the local timezone configuration.
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This method prefers finding the timezone name and passing that to pytz,
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over passing in the localtime file, as in the later case the zoneinfo
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name is unknown.
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The parameter _root makes the function look for files like /etc/localtime
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beneath the _root directory. This is primarily used by the tests.
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In normal usage you call the function without parameters."""
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tzenv = os.environ.get('TZ')
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if tzenv:
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try:
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return _tz_from_env(tzenv)
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except pytz.UnknownTimeZoneError:
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pass
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# Now look for distribution specific configuration files
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# that contain the timezone name.
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for configfile in ('etc/timezone', 'var/db/zoneinfo'):
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tzpath = os.path.join(_root, configfile)
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if os.path.exists(tzpath):
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with open(tzpath, 'rb') as tzfile:
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data = tzfile.read()
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# Issue #3 was that /etc/timezone was a zoneinfo file.
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# That's a misconfiguration, but we need to handle it gracefully:
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if data[:5] != 'TZif2':
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etctz = data.strip().decode()
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# Get rid of host definitions and comments:
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if ' ' in etctz:
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etctz, dummy = etctz.split(' ', 1)
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if '#' in etctz:
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etctz, dummy = etctz.split('#', 1)
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return pytz.timezone(etctz.replace(' ', '_'))
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# CentOS has a ZONE setting in /etc/sysconfig/clock,
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# OpenSUSE has a TIMEZONE setting in /etc/sysconfig/clock and
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# Gentoo has a TIMEZONE setting in /etc/conf.d/clock
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# We look through these files for a timezone:
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zone_re = re.compile('\s*ZONE\s*=\s*\"')
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timezone_re = re.compile('\s*TIMEZONE\s*=\s*\"')
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end_re = re.compile('\"')
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for filename in ('etc/sysconfig/clock', 'etc/conf.d/clock'):
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tzpath = os.path.join(_root, filename)
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if not os.path.exists(tzpath):
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continue
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with open(tzpath, 'rt') as tzfile:
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data = tzfile.readlines()
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for line in data:
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# Look for the ZONE= setting.
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match = zone_re.match(line)
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if match is None:
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# No ZONE= setting. Look for the TIMEZONE= setting.
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match = timezone_re.match(line)
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if match is not None:
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# Some setting existed
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line = line[match.end():]
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etctz = line[:end_re.search(line).start()]
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# We found a timezone
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return pytz.timezone(etctz.replace(' ', '_'))
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# systemd distributions use symlinks that include the zone name,
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# see manpage of localtime(5) and timedatectl(1)
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tzpath = os.path.join(_root, 'etc/localtime')
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if os.path.exists(tzpath) and os.path.islink(tzpath):
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tzpath = os.path.realpath(tzpath)
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start = tzpath.find("/")+1
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while start is not 0:
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tzpath = tzpath[start:]
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try:
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return pytz.timezone(tzpath)
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except pytz.UnknownTimeZoneError:
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pass
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start = tzpath.find("/")+1
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# No explicit setting existed. Use localtime
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for filename in ('etc/localtime', 'usr/local/etc/localtime'):
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tzpath = os.path.join(_root, filename)
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if not os.path.exists(tzpath):
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continue
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with open(tzpath, 'rb') as tzfile:
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return pytz.tzfile.build_tzinfo('local', tzfile)
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raise pytz.UnknownTimeZoneError('Can not find any timezone configuration')
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def get_localzone():
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"""Get the computers configured local timezone, if any."""
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global _cache_tz
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if _cache_tz is None:
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_cache_tz = _get_localzone()
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return _cache_tz
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def reload_localzone():
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"""Reload the cached localzone. You need to call this if the timezone has changed."""
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global _cache_tz
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_cache_tz = _get_localzone()
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return _cache_tz
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