gordon.contrib¶
When using gordon, you’ll quickly see contrib apps take an important role while
deploying and wiring your lambdas.
Gordon uses CloudFormation a lot. It is a great AWS service, but it’s API doesn’t
always include the latest services AWS is releasing almost every week! These services
will eventually make it into CloudFormation, but in the meantime we need to use
low-level APIs to interact with them.
We could (as some other projects) decide to fill the gaps streaming API commands… but we decided to do things differently.
We believe CloudFormation is the way to move forward, and the advantages it provides
surpass some of the gotchas, so we decided to fill the gaps using Lambdas and custom
CloudFormation resources.
But… how could you use Lambdas and CloudFormation to create Lambdas in CloudFormation?
Easy - eating your own dog food; That’s gordon.contrib!
gordon.contrib is a set of reusable gordon applications your gordon projects use to
be able to deploy your resources and fill the gaps in CloudFormation until AWS fills them.
When will AWS allow us to create those resources “natively”?¶
We have no idea, but we have make a big effort trying to make our Custom CloudFormation
resources look as similar as possible to what we think those resources will look like. Once
AWS releases those APIs in CloudFormation, subsequent versions of gordon will stop
using our lambda-based Resources and use native ones.
Available contrib apps¶
contrib.lambdas¶
This application exposes two CloudFormation resources:
- version: Creates Versions for our lambda functions. Nothing super fancy under the hood: https://github.com/jorgebastida/gordon/blob/master/gordon/contrib/lambdas/version/version.py
contrib.s3¶
This application exposes one CloudFormation resource:
- bucket_notification_configuration: This resource allows us to manage S3 bucket notifications. This is a complex resource because the API AWS has develop around… it is not very nice (imho). You can see more details here: https://github.com/jorgebastida/gordon/blob/master/gordon/contrib/s3/bucket_notification_configuration/bucket_notification_configuration.py
contrib.helpers¶
This application exposes one simple CloudFormation resource called Sleep. Yes, this is lame ¯\_(ツ)_/¯ but
it was the only possible way to make resilient integrations with streams such as kinesis and dynamodb.
This is because the IAM role of the lambda is not propagated fast enough uppon creation, and CloudFormation checks
if the referenced lambda has permission to consume this stream on creation time. A small sleep fixes the problem. We
will probably try fix this in the future with a generic make-sure-this-is-ready lambda.
