SQS::Worker::CloudFormationResource - A helper to develop your own custom CloudFormation resources
This is a SQS::Worker role that helps you develop SNS-based CloudFormation Custom Resources that deliver to an SQS queue.
More information on SNS based Custom Resources here: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-custom-resources-sns.html
This module takes care of lots of repetitive work when building an SNS-based CloudFormation Custom Resource.
package MyCustomResource {
use Moose;
with 'SQS::Worker', 'SQS::Worker::SNS', 'SQS::Worker::CloudFormationResource';
sub create_resource {
my ($self, $request, $result) = @_;
# $request is a SQS::Worker::CloudFormationResource::Request
# $result is a SQS::Worker::CloudFormationResource::Response
}
sub update_resource {
my ($self, $request, $result) = @_;
}
sub delete_resource {
my ($self, $request, $result) = @_;
}
}
The worker will poll the SQS queue for you, invoking create_resource
, update_resource
or delete_resource
in function of what is happening in CloudFormation, passing them a
request object with all the information coming from CloudFormation. Look at SQS::Worker::CloudFormationResource::Request
for more information on what information a request has. result is an object that has SQS::Worker::CloudFormationResource::Response.
Set the appropiate properties of the response object. The response object will be returned to CloudFormation.
$result->set_success('Created resource'); # the success message will show in the cloudformation log
$result->PhysicalResourceId('resource-123456');
$result->Data({
Color => 'Blue',
});
When calling update_resource: PhysicalResourceId
will already be initialized to the PhisicalResourceId that was set in create_resource
,
meaning that if it isn't updated, CloudFormation considers the update as a in-place replacement. If a new PhysicalResourceId
is assigned,
CloudFormation considers the operation as a replacement. Later on, CloudFormation will send a Delete for the old PhysicalResourceId, which
shouldn't be handled as any special case: the delete_resource
will be invoked.
Unhandled exceptions in any resource_*
methods will be handled, returning a generic "Internal Error" text to CloudFormation,
considering the resource FAILED.
Unhandled exceptions in resource_create
will treat the resource creation as a special case. Since CloudFormation requires a Physical ID to
be sent, even if we're signalling a FAILURE, SQS::Worker::CloudFormationResource will use an internal Physical ID, that will never be delivered
to the delete_resource
method (it will be intercepted and dropped before getting processed).
To use the resource in CloudFormation, you have to provision an SNS topic that delivers it's messages
to an SQS queue. You can setup an SNS topic with the bundled examples/sns-topic-for-cloudformation.json
file (which will output
all the data you need to run the worker
spawn_worker --worker CustomResourceExample1 --queue_url=http://..../QueueURL --region=eu-west-1 --log_conf log.conf
{ "resources": [
"Custom1": {
"Type": "Custom::MyCustomResource",
"Version": "1.0",
"Properties": {
"ServiceToken": "arn:of the SNS topic for the custom resource",
... Resource Properties ...
}
}
] }
The data you have set in the Data
property of the response object will be accessible in CloudFormation templates via the GetAtt
function.
{ "Fn::GetAtt": [ "Custom1", "Color" ] }
Implement this method in your Custom Resource worker class. All properties sent by CloudFormation will be in $request
of type
SQS::Worker::CloudFormationResource::Request. This method should modify $response
to control what will be sent to CloudFormation.
The following can be done:
Either call set_success
or set_failed
Set attribute PhysicalResourceId
($response->('resource-123456');
)
Set attribute Data
to a Hashref with the keys and values that CloudFormation will treat as this objects attributes
Implement this method in your Custom Resource worker class.
Implement this method in your Custom Resource worker class.
Either call set_success
or set_failed
to indicate that the resource was deleted or not
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/template-custom-resources-sns.html
Copyright (c) 2018 by CAPSiDE
This code is distributed under the Apache 2 License. The full text of the license can be found in the LICENSE file included with this module.
Jose Luis Martinez
JLMARTIN
[email protected]