cfn_custom_resource provides an abstract base class to make it easier to implement
AWS CloudFormation custom resources.
It was developed from Gene Wood's cfnlambda, which provides lower-level functions and decorators for the same purpose.
At its simplest, you subclass the CloudFormationCustomResource and implement three methods:
create, update, and delete, for each of the respective CloudFormation actions. Indicate failure by raising an exception. If you want attributes available on the resource within CloudFormation, return them as a dictionary. Your subclass has a class method get_handler, which will return a Lambda handler function.
Logging to CloudWatch is provided by the logger field.
from cfn_custom_resource import CloudFormationCustomResource
# For resources of type Custom::MyCustomResource
class MyCustomResource(CloudFormationCustomResource):
def create(self):
# Implement
# For AWS SDKs, use:
# self.get_boto3_client(service_name)
# self.get_boto3_resource(service_name)
# Set the name of what you are creating to the value in
# self.physical_resource_id
# This id is autogenerated for you, but you can set it if you want or need
# This id is what CloudFormation uses for Ref
# The resource properties defined in the template are in
# self.resource_properties
# Attributes can be set by returning a dictionary
def update(self):
# Implement
# The name of what you previously created is
# self.physical_resource_id
# The updated properties are in
# self.resource_properties
# To check what's changed, compare with
# self.old_resource_properties
# If you set attributes in create(), you need to set them here too
def delete(self):
# implement
handler = MyCustomResource.get_handler()See more details in the wiki
Feel free to open issues or fork and submit PRs.