# -*- coding: UTF-8 -*-
# Copyright (c) 2007 - 2010, Pascal Volk
# See COPYING for distribution information.
"""vmm's configuration module for simplified configuration access.
This module defines a few classes:
``LazyConfig``
This class provides the following additonal methods
* `LazyConfig.pget()`
polymorphic getter which returns the value with the appropriate
type.
* `LazyConfig.dget()`
like *pget()*, but checks additonal for default values in
`LazyConfig._cfg`.
* `LazyConfig.set()`
like `RawConfigParser.set()`, but converts the new value to the
appropriate type/class and optional validates the new value.
* `LazyConfig.bool_new()`
converts data from raw_input into boolean values.
* `LazyConfig.get_boolean()`
like `RawConfigParser.getboolean()`, but doesn't fail on real
`bool` values.
``Config``
The Config class used by vmm.
``LazyConfigOption``
The class for the configuration objects in the ``Config`` class'
``_cfg`` dictionary.
"""
from shutil import copy2
from ConfigParser import (Error, MissingSectionHeaderError, NoOptionError,
NoSectionError, ParsingError, RawConfigParser)
from cStringIO import StringIO
from __main__ import os, ENCODING, ERR, get_unicode, w_std
from Exceptions import VMMConfigException
class BadOptionError(Error):
"""Raised when a option isn't in the format 'section.option'."""
pass
class ConfigValueError(Error):
"""Raised when creating or validating of new values fails."""
pass
class NoDefaultError(Error):
"""Raised when the requested option has no default value."""
def __init__(self, section, option):
Error.__init__(self, 'Option %r in section %r has no default value' %(
option, section))
class LazyConfig(RawConfigParser):
"""The **lazy** derivate of the `RawConfigParser`.
There are two additional getters:
`LazyConfig.pget()`
The polymorphic getter, which returns a option's value with the
appropriate type.
`LazyConfig.dget()`
Like `LazyConfig.pget()`, but returns the option's default, from
`LazyConfig._cfg['sectionname']['optionname'].default`, if the
option is not configured in a ini-like configuration file.
`LazyConfig.set()` differs from ``RawConfigParser``'s ``set()`` method.
``LazyConfig.set()`` takes the ``section`` and ``option`` arguments
combined to a single string in the form
"``section``\ **.**\ ``option``".
"""
def __init__(self):
RawConfigParser.__init__(self)
self._modified = False
self._cfg = {
'sectionname': {
'optionname': LazyConfigOption(int, 1, self.getint)
}
}
"""sample _cfg dictionary. Create your own in your derived class."""
def bool_new(self, value):
"""Converts the string `value` into a `bool` and returns it.
| '1', 'on', 'yes' and 'true' will become ``True``
| '0', 'off', 'no' and 'false' will become ``False``
Throws a `ConfigValueError` for all other values, except ``bool``\ s.
"""
if isinstance(value, bool):
return value
if value.lower() in self._boolean_states:
return self._boolean_states[value.lower()]
else:
raise ConfigValueError(_(u'Not a boolean: “%s”') % \
get_unicode(value))
def get_boolean(self, section, option):
# if the setting was not written to the configuration file, it may
# be still a boolean value - lets see
if self._modified:
tmp = self.get(section, option)
if isinstance(tmp, bool):
return tmp
return self.getboolean(section, option)
def __get_section_option(self, section_option):
"""splits ``section_option`` (section\ **.**\ option) in two parts
and returns them as list ``[section, option]``, if:
* it likes the format of ``section_option``
* the ``section`` is known
* the ``option`` is known
Else one of the following exceptions will be thrown:
* `BadOptionError`
* `NoSectionError`
* `NoOptionError`
"""
sect_opt = section_option.lower().split('.')
if len(sect_opt) != 2:# do we need a regexp to check the format?
raise BadOptionError(
_(u'Bad format: “%s” - expected: section.option') % \
get_unicode(section_option))
if not sect_opt[0] in self._cfg:
raise NoSectionError(sect_opt[0])
if not sect_opt[1] in self._cfg[sect_opt[0]]:
raise NoOptionError(sect_opt[1], sect_opt[0])
return sect_opt
def items(self, section):
"""returns an iterable that returns key, value ``tuples`` from the
given ``section``."""
if section in self._sections:# check if the section was parsed
d2 = self._sections[section]
elif not section in self._cfg:
raise NoSectionError(section)
else:
return ((k, self._cfg[section][k].default) \
for k in self._cfg[section].iterkeys())
# still here? Get defaults and merge defaults with configured setting
d = dict((k, self._cfg[section][k].default) \
for k in self._cfg[section].iterkeys())
d.update(d2)
if '__name__' in d: del d['__name__']
return d.iteritems()
def dget(self, option):
"""Returns the value of the `option`.
If the option could not be found in the configuration file, the
configured default value, from ``LazyConfig._cfg`` will be
returned.
Arguments:
`option` : string
the configuration option in the form
"``section``\ **.**\ ``option``"
Throws a `NoDefaultError`, if no default value was passed to
`LazyConfigOption.__init__()` for the `option`.
"""
section, option = self.__get_section_option(option)
try:
return self._cfg[section][option].getter(section, option)
except (NoSectionError, NoOptionError):
if not self._cfg[section][option].default is None:
return self._cfg[section][option].default
else:
raise NoDefaultError(section, option)
def pget(self, option):
"""Returns the value of the `option`."""
section, option = self.__get_section_option(option)
return self._cfg[section][option].getter(section, option)
def set(self, option, value):
"""Set the value of an option.
Throws a ``ValueError`` if `value` couldn't be converted to
``LazyConfigOption.cls``"""
section, option = self.__get_section_option(option)
val = self._cfg[section][option].cls(value)
if not self._cfg[section][option].validate is None:
val = self._cfg[section][option].validate(val)
if not RawConfigParser.has_section(self, section):
self.add_section(section)
RawConfigParser.set(self, section, option, val)
self._modified = True
def has_section(self, section):
"""Checks if ``section`` is a known configuration section."""
return section.lower() in self._cfg
def has_option(self, option):
"""Checks if the option (section\ **.**\ option) is a known
configuration option."""
try:
self.__get_section_option(option)
return True
except(BadOptionError, NoSectionError, NoOptionError):
return False
class LazyConfigOption(object):
"""A simple container class for configuration settings.
``LazyConfigOption`` instances are required by `LazyConfig` instances,
and instances of classes derived from ``LazyConfig``, like the
`Config` class.
"""
__slots__ = ('cls', 'default', 'getter', 'validate')
def __init__(self, cls, default, getter, validate=None):
"""Creates a new ``LazyConfigOption`` instance.
Arguments:
``cls`` : type
The class/type of the option's value
``default``
Default value of the option. Use ``None`` if the option should
not have a default value.
``getter`` : callable
A method's name of `RawConfigParser` and derived classes, to
get a option's value, e.g. `self.getint`.
``validate`` : NoneType or a callable
None or any method, that takes one argument, in order to check
the value, when `LazyConfig.set()` is called.
"""
self.cls = cls
"""The class of the option's value e.g. `str`, `unicode` or `bool`"""
self.default = default
"""The option's default value, may be ``None``"""
if callable(getter):
self.getter = getter
"""The getter method to get the option's value"""
else:
raise TypeError('getter has to be a callable, got a %r'\
% getter.__class__.__name__)
if validate is None or callable(validate):
self.validate = validate
"""A method to validate the value"""
else:
raise TypeError('validate has to be callable or None, got a %r'\
% validate.__class__.__name__)
class Config(LazyConfig):
"""This class is for reading and modifying vmm's configuration file."""
def __init__(self, filename):
"""Creates a new Config instance
Arguments:
``filename``
path to the configuration file
"""
LazyConfig.__init__(self)
self.__cfgFileName = filename
self.__cfgFile = None
self.__missing = {}
LCO = LazyConfigOption
bool_t = self.bool_new
self._cfg = {
'account': {
'delete_directory': LCO(bool_t, False, self.get_boolean),
'directory_mode': LCO(int, 448, self.getint),
'disk_usage': LCO(bool_t, False, self.get_boolean),
'password_length': LCO(int, 8, self.getint),
'random_password': LCO(bool_t, False, self.get_boolean),
'imap' : LCO(bool_t, True, self.get_boolean),
'pop3' : LCO(bool_t, True, self.get_boolean),
'sieve': LCO(bool_t, True, self.get_boolean),
'smtp' : LCO(bool_t, True, self.get_boolean),
},
'bin': {
'dovecotpw': LCO(str, '/usr/sbin/dovecotpw', self.get,
self.exec_ok),
'du': LCO(str, '/usr/bin/du', self.get, self.exec_ok),
'postconf': LCO(str, '/usr/sbin/postconf', self.get,
self.exec_ok),
},
'database': {
'host': LCO(str, 'localhost', self.get),
'name': LCO(str, 'mailsys', self.get),
'pass': LCO(str, None, self.get),
'user': LCO(str, None, self.get),
},
'domain': {
'auto_postmaster': LCO(bool_t, True, self.get_boolean),
'delete_directory': LCO(bool_t, False, self.get_boolean),
'directory_mode': LCO(int, 504, self.getint),
'force_deletion': LCO(bool_t, False, self.get_boolean),
},
'maildir': {
'folders': LCO(str, 'Drafts:Sent:Templates:Trash', self.get),
'name': LCO(str, 'Maildir', self.get),
},
'misc': {
'base_directory': LCO(str, '/srv/mail', self.get, self.is_dir),
'dovecot_version': LCO(int, 12, self.getint),
'gid_mail': LCO(int, 8, self.getint),
'password_scheme': LCO(str, 'CRAM-MD5', self.get,
self.known_scheme),
'transport': LCO(str, 'dovecot:', self.get),
},
}
def load(self):
"""Loads the configuration, read only.
Raises a VMMConfigException if the configuration syntax is invalid.
"""
try:
self.__cfgFile = open(self.__cfgFileName, 'r')
self.readfp(self.__cfgFile)
except (MissingSectionHeaderError, ParsingError), e:
raise VMMConfigException(str(e), ERR.CONF_ERROR)
finally:
if not self.__cfgFile is None and not self.__cfgFile.closed:
self.__cfgFile.close()
def check(self):
"""Performs a configuration check.
Raises a VMMConfigException if the check fails.
"""
if not self.__chkCfg():
errmsg = StringIO()
errmsg.write(_(u'Missing options, which have no default value.\n'))
errmsg.write(_(u'Using configuration file: %s\n') %\
self.__cfgFileName)
for section, options in self.__missing.iteritems():
errmsg.write(_(u'* Section: %s\n') % section)
for option in options:
errmsg.write((u' %s\n') % option)
raise VMMConfigException(errmsg.getvalue(), ERR.CONF_ERROR)
def getsections(self):
"""Returns an iterator object for all configuration sections."""
return self._cfg.iterkeys()
def is_dir(self, path):
"""Checks if ``path`` is a directory.
Throws a `ConfigValueError` if ``path`` is not a directory.
"""
path = self.__expand_path(path)
if not os.path.isdir(path):
raise ConfigValueError(_(u'“%s” is not a directory') % \
get_unicode(path))
return path
def exec_ok(self, binary):
"""Checks if the ``binary`` exists and if it is executable.
Throws a `ConfigValueError` if the ``binary`` isn't a file or is
not executable.
"""
binary = self.__expand_path(binary)
if not os.path.isfile(binary):
raise ConfigValueError(_(u'“%s” is not a file') % \
get_unicode(binary))
if not os.access(binary, os.X_OK):
raise ConfigValueError(_(u'File is not executable: “%s”') % \
get_unicode(binary))
return binary
def known_scheme(self, scheme):
"""Converts ``scheme`` to upper case and checks if is known by
Dovecot (listed in VirtualMailManager.SCHEMES).
Throws a `ConfigValueError` if the scheme is not listed in
VirtualMailManager.SCHEMES.
"""
scheme = scheme.upper()
# TODO: VMM.SCHEMES
def unicode(self, section, option):
"""Returns the value of the ``option`` from ``section``, converted
to Unicode.
"""
return get_unicode(self.get(section, option))
def configure(self, sections):
"""Interactive method for configuring all options in the given sections
Arguments:
sections -- list of strings with section names
"""
input_fmt = _(u'Enter new value for option %(option)s \
[%(current_value)s]: ')
failures = 0
w_std(_(u'Using configuration file: %s\n') % self.__cfgFileName)
for s in sections:
w_std(_(u'* Configuration section: “%s”') % s )
for opt, val in self.items(s):
failures = 0
while True:
newval = raw_input(input_fmt.encode(ENCODING,'replace') %{
'option': opt, 'current_value': val})
if newval and newval != val:
try:
self.set('%s.%s' % (s, opt), newval)
break
except (ValueError, ConfigValueError), e:
w_std(_(u'Warning: %s') % e)
failures += 1
if failures > 2:
raise VMMConfigException(
_(u'Too many failures - try again later.'),
ERR.VMM_TOO_MANY_FAILURES)
else:
break
print
if self._modified:
self.__saveChanges()
def __saveChanges(self):
"""Writes changes to the configuration file."""
copy2(self.__cfgFileName, self.__cfgFileName+'.bak')
self.__cfgFile = open(self.__cfgFileName, 'w')
self.write(self.__cfgFile)
self.__cfgFile.close()
def __chkCfg(self):
"""Checks all section's options for settings w/o default values.
Returns ``True`` if everything is fine, else ``False``."""
errors = False
for section in self._cfg.iterkeys():
missing = []
for option, value in self._cfg[section].iteritems():
if (value.default is None
and not RawConfigParser.has_option(self, section, option)):
missing.append(option)
errors = True
if len(missing):
self.__missing[section] = missing
return not errors
def __expand_path(self, path):
"""Expands paths, starting with ``.`` or ``~``, to an absolute path."""
if path.startswith('.'):
return os.path.abspath(path)
if path.startswith('~'):
return os.path.expanduser(path)
return path