Source Code for Module haizea.common.config

  1  # -------------------------------------------------------------------------- # 
  2  # Copyright 2006-2009, University of Chicago                                 # 
  3  # Copyright 2008-2009, Distributed Systems Architecture Group, Universidad   # 
  4  # Complutense de Madrid (dsa-research.org)                                   # 
  5  #                                                                            # 
  6  # Licensed under the Apache License, Version 2.0 (the "License"); you may    # 
  7  # not use this file except in compliance with the License. You may obtain    # 
  8  # a copy of the License at                                                   # 
  9  #                                                                            # 
 10  # http://www.apache.org/licenses/LICENSE-2.0                                 # 
 11  #                                                                            # 
 12  # Unless required by applicable law or agreed to in writing, software        # 
 13  # distributed under the License is distributed on an "AS IS" BASIS,          # 
 14  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   # 
 15  # See the License for the specific language governing permissions and        # 
 16  # limitations under the License.                                             # 
 17  # -------------------------------------------------------------------------- # 
 18   
 19  import ConfigParser 
 20  from mx.DateTime import ISO 
 21  from mx.DateTime import TimeDelta 
 22  import textwrap 
 23           
 24  OPTTYPE_INT = 0 
 25  OPTTYPE_FLOAT = 1 
 26  OPTTYPE_STRING = 2 
 27  OPTTYPE_BOOLEAN = 3 
 28  OPTTYPE_DATETIME = 4 
 29  OPTTYPE_TIMEDELTA = 5 
 30   
 31 -class ConfigException(Exception): 
 32      """A simple exception class used for configuration exceptions""" 
 33      pass 
 34   
 35 -class Section(object): 
 36 -    def __init__(self, name, required, required_if=None, doc=None): 
 37          self.name = name 
 38          self.required = required 
 39          self.required_if = required_if 
 40          self.doc = doc 
 41          self.options = {} 
 42           
 43 -    def get_doc(self): 
 44          return textwrap.dedent(self.doc).strip() 
 45   
 46   
 47 -class Option(object): 
 48 -    def __init__(self, name, getter, type, required, required_if=None, default=None, valid=None, doc=None): 
 49          self.name = name 
 50          self.getter = getter 
 51          self.type = type 
 52          self.required = required 
 53          self.required_if = required_if 
 54          self.default = default 
 55          self.valid = valid 
 56          self.doc = doc 
 57           
 58 -    def get_doc(self): 
 59          return textwrap.dedent(self.doc).strip() 
 60   
 61 -class Config(object): 
 62 -    def __init__(self, config, sections): 
 63          self.config = config 
 64          self.sections = sections 
 65          self._options = {} 
 66           
 67          self.__load_all() 
 68           
 69 -    def __load_all(self): 
 70          required_sections = [s for s in self.sections if s.required] 
 71          conditional_sections = [s for s in self.sections if not s.required and s.required_if != None] 
 72          optional_sections = [s for s in self.sections if not s.required and s.required_if == None] 
 73           
 74          sections = required_sections + conditional_sections + optional_sections 
 75           
 76          for sec in sections: 
 77              has_section = self.config.has_section(sec.name) 
 78               
 79              # If the section is required, check if it exists 
 80              if sec.required and not has_section: 
 81                  raise ConfigException, "Required section [%s] not found" % sec.name 
 82               
 83              # If the section is conditionally required, check that 
 84              # it meets the conditions 
 85              if sec.required_if != None: 
 86                  for req in sec.required_if: 
 87                      (condsec,condopt) = req[0] 
 88                      condvalue = req[1] 
 89                       
 90                      if self.config.has_option(condsec,condopt) and self.config.get(condsec,condopt) == condvalue: 
 91                          if not has_section: 
 92                              raise ConfigException, "Section '%s' is required when %s.%s==%s" % (sec.name, condsec, condopt, condvalue) 
 93                       
 94              # Load options 
 95              if has_section: 
 96                  for opt in sec.options: 
 97                      self.__load_option(sec, opt) 
 98   
 99       
100 -    def __load_option(self, sec, opt): 
101          # Load a single option 
102          secname = sec.name 
103          optname = opt.name 
104           
105          has_option = self.config.has_option(secname, optname) 
106           
107          if not has_option: 
108              if opt.required: 
109                  raise ConfigException, "Required option '%s.%s' not found" % (secname, optname) 
110              if opt.required_if != None: 
111                  for req in opt.required_if: 
112                      (condsec,condopt) = req[0] 
113                      condvalue = req[1] 
114                       
115                      if self.config.has_option(condsec,condopt) and self.config.get(condsec,condopt) == condvalue: 
116                          raise ConfigException, "Option '%s.%s' is required when %s.%s==%s" % (secname, optname, condsec, condopt, condvalue) 
117               
118              value = opt.default 
119          else: 
120              if opt.type == OPTTYPE_INT: 
121                  value = self.config.getint(secname, optname) 
122              elif opt.type == OPTTYPE_FLOAT: 
123                  value = self.config.getfloat(secname, optname) 
124              elif opt.type == OPTTYPE_STRING: 
125                  value = self.config.get(secname, optname) 
126              elif opt.type == OPTTYPE_BOOLEAN: 
127                  value = self.config.getboolean(secname, optname) 
128              elif opt.type == OPTTYPE_DATETIME: 
129                  value = self.config.get(secname, optname) 
130                  value = ISO.ParseDateTime(value) 
131              elif opt.type == OPTTYPE_TIMEDELTA: 
132                  value = self.config.getint(secname, optname) 
133                  value = TimeDelta(seconds=value) 
134                   
135              if opt.valid != None: 
136                  if not value in opt.valid: 
137                      raise ConfigException, "Invalid value '%s' specified for '%s.%s'. Valid values are %s" % (value, secname, optname, opt.valid) 
138                     
139          self._options[opt.getter] = value 
140           
141 -    def get(self, opt): 
142          return self._options[opt] 
143           
144      @classmethod 
145 -    def from_file(cls, configfile): 
146          file = open (configfile, "r") 
147          c = ConfigParser.ConfigParser() 
148          c.readfp(file) 
149          cfg = cls(c) 
150          return cfg 
151