VirtualMailManager/config.py
changeset 571 a4aead244f75
parent 568 14abdd04ddf5
child 611 8e9b0046bc8f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/VirtualMailManager/config.py	Thu Jun 28 19:26:50 2012 +0000
@@ -0,0 +1,540 @@
+# -*- coding: UTF-8 -*-
+# Copyright (c) 2007 - 2012, Pascal Volk
+# See COPYING for distribution information.
+"""
+    VirtualMailManager.config
+    ~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    VMM's configuration module for simplified configuration access.
+"""
+
+from ConfigParser import \
+     Error, MissingSectionHeaderError, NoOptionError, NoSectionError, \
+     ParsingError, RawConfigParser
+from cStringIO import StringIO
+
+from VirtualMailManager.common import VERSION_RE, \
+     exec_ok, expand_path, get_unicode, lisdir, size_in_bytes, version_hex
+from VirtualMailManager.constants import CONF_ERROR
+from VirtualMailManager.errors import ConfigError, VMMError
+from VirtualMailManager.maillocation import known_format
+from VirtualMailManager.password import verify_scheme as _verify_scheme
+
+DB_MODULES = ('psycopg2', 'pypgsql')
+DB_SSL_MODES = ('allow', 'disabled', 'prefer', 'require', 'verify-ca',
+                'verify-full')
+
+_ = lambda msg: msg
+
+
+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:
+
+    `pget()`
+      The polymorphic getter, which returns a option's value with the
+      appropriate type.
+    `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.
+
+    `set()` differs from `RawConfigParser`'s `set()` method. `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
+        # sample _cfg dict.  Create your own in your derived class.
+        self._cfg = {
+            'sectionname': {
+                'optionname': LazyConfigOption(int, 1, self.getint),
+            }
+        }
+
+    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 bools.
+        """
+        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 getboolean(self, section, option):
+        """Returns the boolean value of the option, in the given
+        section.
+
+        For a boolean True, the value must be set to '1', 'on', 'yes',
+        'true' or True. For a boolean False, the value must set to '0',
+        'off', 'no', 'false' or False.
+        If the option has another value assigned this method will raise
+        a ValueError.
+        """
+        # if the setting was modified it may be still a boolean value lets see
+        tmp = self.get(section, option)
+        if isinstance(tmp, bool):
+            return tmp
+        if not tmp.lower() in self._boolean_states:
+            raise ValueError('Not a boolean: %s' % tmp)
+        return self._boolean_states[tmp.lower()]
+
+    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('.')
+        # TODO: cache it
+        if len(sect_opt) != 2 or not sect_opt[0] or not sect_opt[1]:
+            raise BadOptionError(_(u"Bad format: '%s' - expected: "
+                                   u"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
+            sect = 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
+        defaults = dict((k, self._cfg[section][k].default) \
+                        for k in self._cfg[section].iterkeys())
+        defaults.update(sect)
+        if '__name__' in defaults:
+            del defaults['__name__']
+        return defaults.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:  # may be False
+                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 the `option`.
+
+        Throws a `ValueError` if `value` couldn't be converted using
+        `LazyConfigOption.cls`.
+        """
+        # pylint: disable=W0221
+        # @pylint: _L A Z Y_
+        section, option = self._get_section_option(option)
+        val = self._cfg[section][option].cls(value)
+        if self._cfg[section][option].validate:
+            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.
+        """
+        # pylint: disable=W0221
+        # @pylint: _L A Z Y_
+        try:
+            self._get_section_option(option)
+            return True
+        except(BadOptionError, NoSectionError, NoOptionError):
+            return False
+
+    def sections(self):
+        """Returns an iterator object for all configuration sections."""
+        return self._cfg.iterkeys()
+
+
+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
+        if not default is None:  # enforce the type of the default value
+            self.__default = self.__cls(default)
+        else:
+            self.__default = default
+        if not callable(getter):
+            raise TypeError('getter has to be a callable, got a %r' %
+                            getter.__class__.__name__)
+        self.__getter = getter
+        if validate and not callable(validate):
+            raise TypeError('validate has to be callable or None, got a %r' %
+                            validate.__class__.__name__)
+        self.__validate = validate
+
+    @property
+    def cls(self):
+        """The class of the option's value e.g. `str`, `unicode` or `bool`."""
+        return self.__cls
+
+    @property
+    def default(self):
+        """The option's default value, may be `None`"""
+        return self.__default
+
+    @property
+    def getter(self):
+        """The getter method or function to get the option's value"""
+        return self.__getter
+
+    @property
+    def validate(self):
+        """A method or function to validate the value"""
+        return self.__validate
+
+
+class Config(LazyConfig):
+    """This class is for reading vmm's configuration file."""
+
+    def __init__(self, filename):
+        """Creates a new Config instance
+
+        Arguments:
+
+        `filename` : str
+          path to the configuration file
+        """
+        LazyConfig.__init__(self)
+        self._cfg_filename = filename
+        self._cfg_file = None
+        self._missing = {}
+
+        LCO = LazyConfigOption
+        bool_t = self.bool_new
+        self._cfg = {
+            'account': {
+                'delete_directory': LCO(bool_t, False, self.getboolean),
+                'directory_mode': LCO(int, 448, self.getint),
+                'disk_usage': LCO(bool_t, False, self.getboolean),
+                'password_length': LCO(int, 8, self.getint),
+                'random_password': LCO(bool_t, False, self.getboolean),
+            },
+            'bin': {
+                'dovecotpw': LCO(str, '/usr/sbin/dovecotpw', self.get,
+                                 exec_ok),
+                'du': LCO(str, '/usr/bin/du', self.get, exec_ok),
+                'postconf': LCO(str, '/usr/sbin/postconf', self.get, exec_ok),
+            },
+            'database': {
+                'host': LCO(str, 'localhost', self.get),
+                'module': LCO(str, 'psycopg2', self.get, check_db_module),
+                'name': LCO(str, 'mailsys', self.get),
+                'pass': LCO(str, None, self.get),
+                'port': LCO(int, 5432, self.getint),
+                'sslmode': LCO(str, 'prefer', self.get, check_db_ssl_mode),
+                'user': LCO(str, None, self.get),
+            },
+            'domain': {
+                'auto_postmaster': LCO(bool_t, True, self.getboolean),
+                'delete_directory': LCO(bool_t, False, self.getboolean),
+                'directory_mode': LCO(int, 504, self.getint),
+                'force_deletion': LCO(bool_t, False, self.getboolean),
+                'imap': LCO(bool_t, True, self.getboolean),
+                'pop3': LCO(bool_t, True, self.getboolean),
+                'sieve': LCO(bool_t, True, self.getboolean),
+                'smtp': LCO(bool_t, True, self.getboolean),
+                'quota_bytes': LCO(str, '0', self.get_in_bytes,
+                                   check_size_value),
+                'quota_messages': LCO(int, 0, self.getint),
+                'transport': LCO(str, 'dovecot:', self.get),
+            },
+            'mailbox': {
+                'folders': LCO(str, 'Drafts:Sent:Templates:Trash',
+                               self.unicode),
+                'format': LCO(str, 'maildir', self.get, check_mailbox_format),
+                'root': LCO(str, 'Maildir', self.unicode),
+                'subscribe': LCO(bool_t, True, self.getboolean),
+            },
+            'misc': {
+                'base_directory': LCO(str, '/srv/mail', self.get, is_dir),
+                'crypt_blowfish_rounds': LCO(int, 5, self.getint),
+                'crypt_sha256_rounds': LCO(int, 5000, self.getint),
+                'crypt_sha512_rounds': LCO(int, 5000, self.getint),
+                'dovecot_version': LCO(str, None, self.hexversion,
+                                       check_version_format),
+                'password_scheme': LCO(str, 'CRAM-MD5', self.get,
+                                       verify_scheme),
+            },
+        }
+
+    def load(self):
+        """Loads the configuration, read only.
+
+        Raises a ConfigError if the configuration syntax is
+        invalid.
+        """
+        self._cfg_file = open(self._cfg_filename, 'r')
+        try:
+            self.readfp(self._cfg_file)
+        except (MissingSectionHeaderError, ParsingError), err:
+            raise ConfigError(str(err), CONF_ERROR)
+        self._cfg_file.close()
+
+    def check(self):
+        """Performs a configuration check.
+
+        Raises a ConfigError if settings w/o a default value are missed.
+        Or some settings have a invalid value.
+        """
+        def iter_dict():
+            for section, options in self._missing.iteritems():
+                errmsg.write(_(u'* Section: %s\n') % section)
+                errmsg.writelines(u'    %s\n' % option for option in options)
+            self._missing.clear()
+
+        errmsg = None
+        self._chk_non_default()
+        miss_vers = 'misc' in self._missing and \
+                    'dovecot_version' in self._missing['misc']
+        if self._missing:
+            errmsg = StringIO()
+            errmsg.write(_(u'Check of configuration file %s failed.\n') %
+                         self._cfg_filename)
+            errmsg.write(_(u'Missing options, which have no default value.\n'))
+            iter_dict()
+        self._chk_possible_values(miss_vers)
+        if self._missing:
+            if not errmsg:
+                errmsg = StringIO()
+                errmsg.write(_(u'Check of configuration file %s failed.\n') %
+                             self._cfg_filename)
+                errmsg.write(_(u'Invalid configuration values.\n'))
+            else:
+                errmsg.write('\n' + _(u'Invalid configuration values.\n'))
+            iter_dict()
+        if errmsg:
+            raise ConfigError(errmsg.getvalue(), CONF_ERROR)
+
+    def hexversion(self, section, option):
+        """Converts the version number (e.g.: 1.2.3) from the *option*'s
+        value to an int."""
+        return version_hex(self.get(section, option))
+
+    def get_in_bytes(self, section, option):
+        """Converts the size value (e.g.: 1024k) from the *option*'s
+        value to a long"""
+        return size_in_bytes(self.get(section, option))
+
+    def unicode(self, section, option):
+        """Returns the value of the `option` from `section`, converted
+        to Unicode."""
+        return get_unicode(self.get(section, option))
+
+    def _chk_non_default(self):
+        """Checks all section's options for settings w/o a default
+        value. Missing items will be stored in _missing.
+        """
+        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)
+            if missing:
+                self._missing[section] = missing
+
+    def _chk_possible_values(self, miss_vers):
+        """Check settings for which the possible values are known."""
+        if not miss_vers:
+            value = self.get('misc', 'dovecot_version')
+            if not VERSION_RE.match(value):
+                self._missing['misc'] = ['version: ' +\
+                        _(u"Not a valid Dovecot version: '%s'") % value]
+        # section database
+        db_err = []
+        value = self.dget('database.module').lower()
+        if value not in DB_MODULES:
+            db_err.append('module: ' + \
+                          _(u"Unsupported database module: '%s'") % value)
+        if value == 'psycopg2':
+            value = self.dget('database.sslmode')
+            if value not in DB_SSL_MODES:
+                db_err.append('sslmode: ' + \
+                              _(u"Unknown pgsql SSL mode: '%s'") % value)
+        if db_err:
+            self._missing['database'] = db_err
+        # section mailbox
+        value = self.dget('mailbox.format')
+        if not known_format(value):
+            self._missing['mailbox'] = ['format: ' +\
+                              _(u"Unsupported mailbox format: '%s'") % value]
+        # section domain
+        try:
+            value = self.dget('domain.quota_bytes')
+        except (ValueError, TypeError), err:
+            self._missing['domain'] = [u'quota_bytes: ' + str(err)]
+
+
+def is_dir(path):
+    """Check if the expanded path is a directory.  When the expanded path
+    is a directory the expanded path will be returned.  Otherwise a
+    ConfigValueError will be raised.
+    """
+    path = expand_path(path)
+    if lisdir(path):
+        return path
+    raise ConfigValueError(_(u"No such directory: %s") % get_unicode(path))
+
+
+def check_db_module(module):
+    """Check if the *module* is a supported pgsql module."""
+    if module.lower() in DB_MODULES:
+        return module
+    raise ConfigValueError(_(u"Unsupported database module: '%s'") %
+                           get_unicode(module))
+
+
+def check_db_ssl_mode(ssl_mode):
+    """Check if the *ssl_mode* is one of the SSL modes, known by pgsql."""
+    if ssl_mode in DB_SSL_MODES:
+        return ssl_mode
+    raise ConfigValueError(_(u"Unknown pgsql SSL mode: '%s'") %
+                           get_unicode(ssl_mode))
+
+
+def check_mailbox_format(format):
+    """
+    Check if the mailbox format *format* is supported.  When the *format*
+    is supported it will be returned, otherwise a `ConfigValueError` will
+    be raised.
+    """
+    format = format.lower()
+    if known_format(format):
+        return format
+    raise ConfigValueError(_(u"Unsupported mailbox format: '%s'") %
+                           get_unicode(format))
+
+
+def check_size_value(value):
+    """Check if the size value *value* has the proper format, e.g.: 1024k.
+    Returns the validated value string if it has the expected format.
+    Otherwise a `ConfigValueError` will be raised."""
+    try:
+        tmp = size_in_bytes(value)
+    except (TypeError, ValueError), err:
+        raise ConfigValueError(_(u"Not a valid size value: '%s'") %
+                               get_unicode(value))
+    return value
+
+
+def check_version_format(version_string):
+    """Check if the *version_string* has the proper format, e.g.: '1.2.3'.
+    Returns the validated version string if it has the expected format.
+    Otherwise a `ConfigValueError` will be raised.
+    """
+    if not VERSION_RE.match(version_string):
+        raise ConfigValueError(_(u"Not a valid Dovecot version: '%s'") %
+                               get_unicode(version_string))
+    return version_string
+
+
+def verify_scheme(scheme):
+    """Checks if the password scheme *scheme* can be accepted and returns
+    the verified scheme.
+    """
+    try:
+        scheme, encoding = _verify_scheme(scheme)
+    except VMMError, err:  # 'cast' it
+        raise ConfigValueError(err.msg)
+    if not encoding:
+        return scheme
+    return '%s.%s' % (scheme, encoding)
+
+del _