terom@36: """
terom@36:     Support for loading config files with twisted.python.usage
terom@36: """
terom@36: 
terom@36: from twisted.python import usage
terom@36: 
terom@36: import traceback
terom@36: 
terom@36: class ConfigMapper (dict) :
terom@36:     """
terom@36:         Provides access to a usage.Options's keys via python names.
terom@36:     """
terom@36: 
terom@36:     IGNORED_NAMES = ('__doc__', )
terom@36: 
terom@36:     def __init__ (self, opts, defaults=None) :
terom@36:         """
terom@36:             opts        - store the values from the config file into the given dict
terom@36:             defaults    - (optional) update any pre-exisitng values from the config file into the given dict
terom@36:         """
terom@36: 
terom@36:         self.opts = opts
terom@36:         self.defaults = defaults
terom@36: 
terom@38:         # temp. vars
terom@38:         self.locals = {}
terom@38: 
terom@38:     def optname (self, name) :
terom@36:         return name.replace('_', '-')
terom@36: 
terom@36:     def __getitem__ (self, name) :
terom@36:         """
terom@36:             Map from foo_bar -> foo-bar
terom@36:         """
terom@36: 
terom@38:         # translate
terom@38:         optname = self.optname(name)
terom@38:         
terom@38:         if optname in self.opts :
terom@38:             # normal long opt
terom@38:             return self.opts[optname]
terom@38: 
terom@38:         elif name in self.locals :
terom@38:             # temp local
terom@38:             return self.locals[name]
terom@38: 
terom@38:         else :
terom@38:             # unknown
terom@38:             raise NameError(name)
terom@36: 
terom@36:     def __setitem__ (self, name, value) :
terom@36:         """
terom@36:             Map from foo_bar -> foo-bar
terom@36:         """
terom@36:         
terom@36:         store = self.opts
terom@36:         
terom@36:         # filter out certain keys
terom@36:         if name in self.IGNORED_NAMES :
terom@36:             # skip things like __doc__
terom@36:             return
terom@36:         
terom@36:         # translate name
terom@38:         optname = self.optname(name)
terom@36: 
terom@38:         if optname in self.opts :
terom@36:             # normal long opt
terom@38:             name = optname
terom@36: 
terom@36:         else :
terom@38:             # store as a local
terom@38:             store = self.locals
terom@36:         
terom@36:         # store
terom@36:         store[name] = value
terom@36: 
terom@36:         if self.defaults is not None and name in self.defaults :
terom@36:             self.defaults[name] = value
terom@36: 
terom@36: class ConfigOptions (usage.Options) :
terom@36:     """
terom@36:         Provide a --config param to read in new values/defaults for any defined options from the given config file
terom@36:     """
terom@36: 
terom@36:     def opt_config (self, path) :
terom@36:         """
terom@36:             Read the given configuration file
terom@36:         """
terom@36: 
terom@36:         # set up env for the config module
terom@36:         globals = {}
terom@36:         locals = ConfigMapper(self.opts, self.defaults)
terom@36:         
terom@36:         try :
terom@36:             # run config
terom@36:             execfile(path, globals, locals)
terom@36: 
terom@36:         except :
terom@36:             # XXX: raising a usage.error prints out --help
terom@36:             raise usage.error("Error reading config file: %s\n%s" % (path, traceback.format_exc()))
terom@36:     
terom@36:     opt_c = opt_config
terom@36: