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__