ifupdown/template.py

   1 #!/usr/bin/python
   2 #
   3 # Copyright 2014 Cumulus Networks, Inc. All rights reserved.
   4 # Author: Roopa Prabhu, roopa@cumulusnetworks.com
   5 #
   6 # template --
   7 #    helper class to render templates
   8 #
   9
  10 import logging
  11 import traceback
  12 from utils import *
  13
  14 class templateEngine():
  15     """ provides template rendering methods """
  16
  17     def __init__(self, template_engine, template_enable='0',
  18                  template_lookuppath=None):
  19         self.logger = logging.getLogger('ifupdown.' +
  20                     self.__class__.__name__)
  21         self.tclass = None
  22         self.tclassargs = {}
  23         self.render = self._render_default
  24         if template_enable == '0':
  25             return
  26         if template_engine == 'mako':
  27             try:
  28                 self.tclass = utils.importName('mako.template', 'Template')
  29             except Exception, e:
  30                 self.logger.warn('unable to load template engine %s (%s)'
  31                         %(template_engine, str(e)))
  32                 pass
  33             if template_lookuppath:
  34                 try:
  35                     self.logger.debug('setting template lookuppath to %s'
  36                             %template_lookuppath)
  37                     lc = utils.importName('mako.lookup', 'TemplateLookup')
  38                     self.tclassargs['lookup'] = lc(
  39                                 directories=template_lookuppath.split(':'))
  40                 except Exception, e:
  41                     self.logger.warn('unable to set template lookup path'
  42                                      ' %s (%s): are you sure \'python-mako\''
  43                                      'is installed?'
  44                                      % (template_lookuppath, str(e)))
  45             self.render = self._render_mako
  46         else:
  47             self.logger.info('skip template processing.., ' +
  48                     'template engine not found')
  49
  50     def _render_default(self, textdata):
  51         return textdata
  52
  53     def _render_mako(self, textdata):
  54         """ render textdata passed as argument using mako
  55
  56         Returns rendered textdata """
  57
  58         if not self.tclass:
  59             return textdata
  60         self.logger.info('template processing on interfaces file ...')
  61         t = self.tclass(text=textdata, output_encoding='utf-8',
  62                      lookup=self.tclassargs.get('lookup'))
  63         return t.render()