Source Code for Module wtf.ext.db._config

  1  # -*- coding: ascii -*- 
  2  # 
  3  # Copyright 2010-2012 
  4  # Andr\xe9 Malo or his licensors, as applicable 
  5  # 
  6  # Licensed under the Apache License, Version 2.0 (the "License"); 
  7  # you may not use this file except in compliance with the License. 
  8  # You may obtain 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   DB access module 
 20  ================== 
 21   
 22  DB access module. 
 23  """ 
 24  __author__ = u"Andr\xe9 Malo" 
 25  __docformat__ = "restructuredtext en" 
 26   
 27  import ConfigParser as _config_parser 
 28  import os as _os 
 29   
 30  from wtf.ext.db._exceptions import DBConfigurationError 
 31  from wtf import util as _wtf_util 
 32   
 33   
 34  #: Default conf file location 
 35  #: 
 36  #: :Type: ``str`` 
 37  DEFAULT_CONF = '/etc/wtf/ext/db.conf' 
 38   
 39   
 40 -def load_from_file(dbconf): 
 41      """ 
 42      Load config 
 43   
 44      :Parameters: 
 45        `dbconf` : ``str`` 
 46          DB config filename 
 47   
 48      :Return: Config dict 
 49      :Rtype: ``dict`` 
 50      """ 
 51      parser = _config_parser.RawConfigParser() 
 52      try: 
 53          fp = open(dbconf, 'rb') 
 54          try: 
 55              parser.readfp(fp) 
 56          finally: 
 57              fp.close() 
 58      except IOError, e: 
 59          raise DBConfigurationError(str(e)) 
 60   
 61      config = dict((section, dict((opt, parser.get(section, opt)) 
 62          for opt in parser.options(section) 
 63      )) for section in parser.sections()) 
 64   
 65      for _, opts in config.items(): 
 66          if 'alias' in opts: 
 67              alias = opts['alias'] 
 68              opts.clear() 
 69              opts.update(config[alias]) 
 70   
 71      return config 
 72   
 73   
 74 -def configure(dbconf=None, unpack_password=None): 
 75      """ 
 76      Configure the databases 
 77   
 78      This function is called automatically at import time. But configuration 
 79      errors are ignored this first time. 
 80   
 81      :Parameters: 
 82        `dbconf` : ``str`` 
 83          Config file name. If omitted or ``None``, the environment variable 
 84          ``WTF_EXT_DB_CONF`` is queried. If that's unset, too, it defaults to 
 85          `DEFAULT_CONF`. 
 86   
 87        `unpack_password` : callable 
 88          Password unpacker. If omitted or ``None``, no password unpacker is 
 89          applied. 
 90   
 91      :Exceptions: 
 92        - `DBConfigurationError` : Config error 
 93      """ 
 94      def resolve(arg, env, default): 
 95          """ Resolve path """ 
 96          if arg is not None: 
 97              return arg 
 98          return _os.path.expanduser(_os.environ.get(env, default)) 
 99   
100      dbconf = resolve(dbconf, 'WTF_EXT_DB_CONF', DEFAULT_CONF) 
101      config = load_from_file(dbconf) 
102   
103      def driver(dbname): 
104          """ 
105          Determine driver module 
106   
107          :Parameters: 
108            `dbname` : ``str`` 
109              DB name (section token in db.conf) 
110   
111          :Return: Driver module 
112          :Rtype: ``module`` 
113   
114          :Exceptions: 
115            - `DBConfigurationError` : DB not configured 
116            - `KeyError` : DB name not found 
117            - `ImportError` : Driver not found 
118          """ 
119          return _wtf_util.load_dotted( 
120              'wtf.ext.db._driver_%s' % config[dbname]['driver'] 
121          ) 
122   
123      def connect(dbname, **kwargs): 
124          """ 
125          Connect to database 
126   
127          :Parameters: 
128            `dbname` : ``str`` 
129              DB name (section token in db.conf) 
130   
131            `kwargs` : ``dict`` 
132              Additional parameters for adapter connect() call 
133   
134          :Return: new connection 
135          :Rtype: connection object (DBAPI 2) 
136   
137          :Exceptions: 
138            - `DBConfigurationError` : DB not configured 
139            - `KeyError` : DB name not found 
140            - `ImportError` : Driver not found 
141          """ 
142          conf = config[dbname].copy() 
143          db_driver = driver(dbname) 
144          conf.pop('driver', None) 
145          if 'passwd' in conf and unpack_password is not None: 
146              passwd = conf['passwd'] 
147              conf['passwd'] = lambda: unpack_password(passwd) 
148          return db_driver.connect(conf, kwargs) 
149      connect.config = config 
150   
151      return driver, connect 
152