Source code for sceptre.template_handlers

# -*- coding: utf-8 -*-
import abc
import logging

import six
from jsonschema import validate, ValidationError

from sceptre.exceptions import TemplateHandlerArgumentsInvalidError


[docs]@six.add_metaclass(abc.ABCMeta) class TemplateHandler: """ TemplateHandler is an abstract base class that should be inherited by all Template Handlers. :param name: Name of the template :type name: str :param arguments: The arguments of the template handler :type arguments: dict :param sceptre_user_data: Sceptre user data in stack config :type sceptre_user_data: dict :param connection_manager: Connection manager used to call AWS :type connection_manager: sceptre.connection_manager.ConnectionManager :param stack_group_config: The Stack group config to use as defaults. :type stack_group_config: dict """ __metaclass__ = abc.ABCMeta standard_template_extensions = [".json", ".yaml", ".template"] jinja_template_extensions = [".j2"] python_template_extensions = [".py"] supported_template_extensions = standard_template_extensions + \ jinja_template_extensions + python_template_extensions def __init__(self, name, arguments=None, sceptre_user_data=None, connection_manager=None, stack_group_config=None): self.logger = logging.getLogger(__name__) self.name = name self.arguments = arguments self.sceptre_user_data = sceptre_user_data self.connection_manager = connection_manager if stack_group_config is None: stack_group_config = {} self.stack_group_config = stack_group_config
[docs] @abc.abstractmethod def schema(self): """ Returns the schema for the arguments of this Template Resolver. This will be used to validate that the arguments passed in the stack config are what the Template Handler expects. :return: JSON schema that can be validated :rtype: object """ pass
[docs] @abc.abstractmethod def handle(self): """ An abstract method which must be overwritten by all inheriting classes. This method is called to retrieve the template. Implementation of this method in subclasses must return a string that can be interpreted by Sceptre (CloudFormation YAML / JSON, Jinja or Python) """ pass # pragma: no cover
[docs] def validate(self): """ Validates if the current arguments are correct according to the schema. If this does not raise an exception, the template handler's arguments are valid. """ try: validate(instance=self.arguments, schema=self.schema()) except ValidationError as e: raise TemplateHandlerArgumentsInvalidError(e)