Source code for Bcfg2.Server.Plugins.Cfg.CfgJinja2Generator

""" The CfgJinja2Generator allows you to use the `Jinja2
<http://jinja.pocoo.org/>`_ templating system to generate
:ref:`server-plugins-generators-cfg` files. """

import os
import sys
import Bcfg2.Options
from Bcfg2.Server.Plugin import PluginExecutionError, \
    DefaultTemplateDataProvider, get_template_data
from Bcfg2.Server.Plugins.Cfg import CfgGenerator

try:
    from jinja2 import Environment, FileSystemLoader
    HAS_JINJA2 = True

    class RelEnvironment(Environment):
        """Override join_path() to enable relative template paths."""
        def join_path(self, template, parent):
            return os.path.join(os.path.dirname(parent), template)

except ImportError:
    HAS_JINJA2 = False


class DefaultJinja2DataProvider(DefaultTemplateDataProvider):
    """ Template data provider for Jinja2 templates. Jinja2 and
    Genshi currently differ over the value of the ``path`` variable,
    which is why this is necessary. """

    def get_template_data(self, entry, metadata, template):
        rv = DefaultTemplateDataProvider.get_template_data(self, entry,
                                                           metadata, template)
        rv['path'] = rv['name']
        return rv


[docs]class CfgJinja2Generator(CfgGenerator): """ The CfgJinja2Generator allows you to use the `Jinja2 <http://jinja.pocoo.org/>`_ templating system to generate :ref:`server-plugins-generators-cfg` files. """ #: Handle .jinja2 files __extensions__ = ['jinja2'] if HAS_JINJA2: #: ``__loader_cls__`` is the class that will be instantiated to #: load the template files. It must implement one public function, #: ``load()``, as :class:`genshi.template.TemplateLoader`. __loader_cls__ = FileSystemLoader #: ``__environment_cls__`` is the class that will be instantiated to #: store the jinja2 environment. It must implement one public #: function, ``get_template()``, as :class:`jinja2.Environment`. __environment_cls__ = RelEnvironment #: Ignore ``.jinja2_include`` files so they can be used with the #: Jinja2 ``{% include ... %}`` directive without raising warnings. __ignore__ = ["jinja2_include"] #: Low priority to avoid matching host- or group-specific #: .crypt.jinja2 files __priority__ = 50 def __init__(self, fname, spec): CfgGenerator.__init__(self, fname, spec) if not HAS_JINJA2: raise PluginExecutionError("Jinja2 is not available") self.template = None encoding = Bcfg2.Options.setup.encoding self.loader = self.__loader_cls__('/', encoding=encoding) try: # keep_trailing_newline is new in Jinja2 2.7, and will # fail with earlier versions self.environment = \ self.__environment_cls__(loader=self.loader, keep_trailing_newline=True) except TypeError: self.environment = \ self.__environment_cls__(loader=self.loader) __init__.__doc__ = CfgGenerator.__init__.__doc__
[docs] def get_data(self, entry, metadata): if self.template is None: raise PluginExecutionError("Failed to load template %s" % self.name) return self.template.render( get_template_data(entry, metadata, self.name, default=DefaultJinja2DataProvider()))
get_data.__doc__ = CfgGenerator.get_data.__doc__
[docs] def handle_event(self, event): CfgGenerator.handle_event(self, event) try: self.template = \ self.environment.get_template(self.name) except: raise PluginExecutionError("Failed to load template: %s" % sys.exc_info()[1])
handle_event.__doc__ = CfgGenerator.handle_event.__doc__