terom@0: """
terom@0:     Configuration file output for the ISC DHCP server
terom@0: """
terom@0: 
terom@0: import conf
terom@0: 
terom@0: import itertools
terom@0: 
terom@1: class Section (conf.ConfObject) :
terom@1:     """
terom@1:         A section holds a list of params and a list of decls
terom@1:     """
terom@1: 
terom@1:     def __init__ (self, params=None, decls=None) :
terom@0:         """
terom@1:             If params/decls are given, those are the used as the initial contents of this section
terom@1:         """
terom@0: 
terom@1:         self.params = params or []
terom@1:         self.decls = decls or []
terom@1: 
terom@1:     def add_param (self, param) :
terom@1:         """
terom@1:             Add the given Parameter to the end of this section's params
terom@1:         """
terom@1: 
terom@1:         self.params.append(param)
terom@1: 
terom@1:     def add_params (self, params) :
terom@1:         for param in params :
terom@1:             self.add_param(param)
terom@1: 
terom@1:     def add_decl (self, decl) :
terom@1:         """
terom@1:             Add the given Declaration to the end of this section's decls
terom@1:         """
terom@1: 
terom@1:         self.decls.append(decl)
terom@1: 
terom@1:     def add_decls (self, decls) :
terom@1:         for decl in decls :
terom@1:             self.add_decl(decl)
terom@1: 
terom@1:     def fmt_lines (self) :
terom@1:         """
terom@1:             Format all of our params and decls, in that order
terom@1:         """
terom@1: 
terom@1:         # then output each content line
terom@1:         for stmt in itertools.chain(self.params, self.decls) :
terom@1:             # skip Nones
terom@1:             if stmt is None :
terom@1:                 continue
terom@1: 
terom@1:             for line in stmt.fmt_lines() :
terom@1:                 yield line
terom@1: 
terom@1: class ConfFile (Section, conf.File) :
terom@1:     DEFAULT_NAME = "dhcpd.conf"
terom@1:     DEFAULT_PATH = "/etc/dhcp3/dhcpd.conf"
terom@1: 
terom@1:     def __init__ (self, name=DEFAULT_NAME, path=DEFAULT_PATH, params=None, decls=None) :
terom@1:         """
terom@1:             Initialize the dhcpd config file, but don't open it yet.
terom@0:         """
terom@0:         
terom@1:         conf.File.__init__(self, name, path)
terom@1:         Section.__init__(self, params, decls)
terom@0: 
terom@1: class Statement (conf.ConfObject) :
terom@0:     """
terom@1:         A statement is a single line in the config file
terom@0:     """
terom@0: 
terom@0:     def __init__ (self, name, *args) :
terom@0:         """
terom@0:             The statement will be formatted like this:
terom@0:                 <name> [ <arg> [ ... ] ] ";"
terom@1: 
terom@1:             Arguments given as None will be ignored.
terom@0:         """
terom@0: 
terom@0:         self.name = name
terom@0:         self.args = args
terom@0:     
terom@0:     def _fmt_arg (self, arg) :
terom@0:         """
terom@0:             Formats a arg for use in output, the following types are supported:
terom@0: 
terom@0:                 list/tuple/iter:    results in a comma-and-space separated list of formatted values
terom@0:                 unicode:            results in an encoded str
terom@0:                 str:                results in the string itself, quoted if needed
terom@0:                 other:              attempt to convert to a str, and then format that
terom@0:         """
terom@0:         
terom@0:         # format lists specially
terom@0:         # XXX: iterators?
terom@0:         if isinstance(arg, (list, tuple)) :
terom@0:             # recurse as a comma-and-space separated list
terom@0:             return ', '.join(self._fmt_arg(a) for a in arg)
terom@0: 
terom@0:         elif isinstance(arg, Literal) :
terom@0:             # use what it specifies
terom@0:             return arg.fmt_arg()
terom@0: 
terom@0:         elif isinstance(arg, unicode) :
terom@0:             # recurse with the str version
terom@0:             # XXX: what encoding to use?
terom@0:             return self._fmt_arg(arg.encode('utf8'))
terom@0: 
terom@0:         elif isinstance(arg, str) :
terom@0:             # XXX: quoting
terom@0:             return arg
terom@0:         
terom@0:         else :
terom@0:             # try and use it as a string
terom@0:             return self._fmt_arg(str(arg))
terom@0:     
terom@0:     def _fmt_data (self) :
terom@0:         """
terom@1:             Formats the statement name/params as a single line, ignoring None
terom@0:         """
terom@0: 
terom@1:         return "%s%s" % (self.name, (' ' + ' '.join(self._fmt_arg(a) for a in self.args if a is not None)) if self.args else '')
terom@0: 
terom@0: class Literal (Statement) :
terom@0:     """
terom@0:         A literal is something that goes into the config file as-is, with no formatting or escaping applied.
terom@0:     """
terom@0: 
terom@0:     def __init__ (self, literal) :
terom@0:         self.literal = literal
terom@0:     
terom@0:     def fmt_arg (self) :
terom@0:         return self.literal
terom@0: 
terom@0:     def fmt_lines (self) :
terom@0:         yield self.literal
terom@0: 
terom@0: class Parameter (Statement) :
terom@0:     """
terom@0:         A parameter is a single statement that configures the behaviour of something.
terom@0: 
terom@0:         Parameters have a name, and optionally, a number of arguments, and are formatted as statements terminated with
terom@1:         a semicolon. For convenience, params/decls that are None are ignored.
terom@0:     """
terom@0:     
terom@0:     def fmt_lines (self) :
terom@0:         """
terom@0:             Yields a single ;-terminated line
terom@0:         """
terom@0: 
terom@0:         yield "%s;" % self._fmt_data()
terom@0: 
terom@1: class Declaration (Section, Statement) :
terom@0:     """
terom@1:         A declaration begins like a statement (with name and args), but then contains a curly-braces-delimited block
terom@1:         that acts like a Section.
terom@0: 
terom@0:         <name> [ <args> [ ... ] ] {
terom@1:             [ <Section> ]
terom@0:         }
terom@0:         
terom@0:     """
terom@0: 
terom@1:     def __init__ (self, name, args=[], params=None, decls=None) :
terom@0:         """
terom@0:             The name/args will be formatted as in Statement, but params should be an iterable of Parameters, and decls
terom@0:             an iterable of Declarations.
terom@0:         """
terom@0:         
terom@0:         # init the statement bit
terom@1:         Section.__init__(self, params, decls)
terom@0:         Statement.__init__(self, name, *args)
terom@0: 
terom@0:     def fmt_lines (self) :
terom@0:         """
terom@0:             Yields a header line, a series of indented body lines, and the footer line
terom@0:         """
terom@0:         
terom@0:         # the header to open the block
terom@0:         yield "%s {" % self._fmt_data()
terom@0:         
terom@1:         # then output the section stuff, indented
terom@1:         for line in Section.fmt_lines(self) :
terom@1:             yield "\t%s" % line
terom@1: 
terom@0:         # and then close the block
terom@0:         yield "}"
terom@0: 
terom@0: class SharedNetwork (Declaration) :
terom@0:     """
terom@0:         A shared-network declaration is used to define a set of subnets that share the same physical network,
terom@0:         optionally with some shared params.
terom@0: 
terom@0:         shared-network <name> {
terom@0:             [ parameters ]
terom@0:             [ declarations ]
terom@0:         }
terom@0:     """
terom@0: 
terom@0:     def __init__ (self, name, params=[], decls=[]) :
terom@0:         """
terom@0:             @param name the name of the shared-subnet
terom@0:             @param params optional parameters
terom@0:             @param decls the iterable of subnets or other declarations in the shared network
terom@0:         """
terom@0: 
terom@0:         super(SharedNetwork, self).__init__("shared-network", [name], params, decls)
terom@0: 
terom@0: class Subnet (Declaration) :
terom@0:     """
terom@0:         A subnet is used to provide the information about a subnet required to identify whether or not an IP address is
terom@0:         on that subnet, and may also be used to specify parameters/declarations for that subnet.
terom@0:         
terom@0:         subnet <subnet-number> netmask <netmask> {
terom@0:             [ parameters ]
terom@0:             [ declarations ]
terom@0:         }
terom@0:     """
terom@0: 
terom@1:     def __init__ (self, network, params=None, decls=None) :
terom@0:         """
terom@0:             @param network the addr.Network for the subnet
terom@0:             @param params optional parameters
terom@0:             @param decls optional decls, e.g. subnets
terom@0:         """
terom@0: 
terom@0:         super(Subnet, self).__init__("subnet", [network.net(), "netmask", network.netmask()], params, decls)
terom@0: 
terom@0: class Group (Declaration) :
terom@0:     """
terom@0:         A group is simply used to apply a set of parameters to a set of declarations.
terom@0: 
terom@0:         group {
terom@0:             [ parameters ]
terom@0:             [ declarations ]
terom@0:         }
terom@0:     """
terom@0: 
terom@1:     def __init__ (self, params=None, decls=None) :
terom@0:         super(Group, self).__init__("group", [], params, decls)
terom@0: 
terom@0: 
terom@0: class Host (Declaration) :
terom@0:     """
terom@0:         A host is used to match a request against specific host, and then apply settings for that host.
terom@0: 
terom@0:         The "hostname" is the DHCP name to identify the host. 
terom@0: 
terom@0:         If no dhcp-client-identifier option is specified in the parameters, then the host is matched using the
terom@0:         "hardware" parameter.
terom@0: 
terom@0:         host <hostname> {
terom@0:             [ parameters ]
terom@0:             [ declarations ]
terom@0:         }
terom@0:     """
terom@0: 
terom@1:     def __init__ (self, hostname, params=None, decls=None) :
terom@0:         super(Host, self).__init__("host", [hostname], params, decls)
terom@0: 
terom@0: class Option (Parameter) :
terom@0:     """
terom@0:         A generic 'option' parameter for a dhcpd.conf file
terom@0:     """
terom@0: 
terom@0:     def __init__ (self, name, *args) :
terom@0:         """
terom@0:             Formatted as a Satement with a name of "option <name>".
terom@0:         """
terom@0: 
terom@0:         super(Option, self).__init__("option %s" % name, *args)
terom@0: