Ok, ok, AWS hasn’t announced a whole new class of intrinsic functions for you to use in CloudFormation. But if you’re using the Serverless framework then I have a treat for you :-) I created a plugin for the Serverless framework that lets you use a number of custom Fn:: functions in your serverless.yml.
The available set of Condition functions is fairly constrained. Even simple logic such as the one described above proved tricky and the code was not easily comprehensible.
This plugin lets you use a number of custom functions anywhere in your serverless.yml as if they’re CloudFormation’s intrinsic functions. For example, you can use them as part of CloudFormation Conditions. To implement the startsWith logic, we can simply use the Fn::StartsWith function:
All and all, 8 custom functions are supported out-of-the-box. And it’s pretty trivial to add support for additional functions in the future. Let me know in the comments below if you have use cases that are difficult to implement with CloudFormation’s intrinsic functions. Maybe I can make your life easier by supporting them as extrinsic functions
I specialise in rapidly transitioning teams to serverless and building production-ready services on AWS.
Are you struggling with serverless or need guidance on best practices? Do you want someone to review your architecture and help you avoid costly mistakes down the line? Whatever the case, I’m here to help.
Check out my new course, Complete Guide to AWS Step Functions. In this course, we’ll cover everything you need to know to use AWS Step Functions service effectively. Including basic concepts, HTTP and event triggers, activities, callbacks, nested workflows, design patterns and best practices.
Come learn about operational BEST PRACTICES for AWS Lambda: CI/CD, testing & debugging functions locally, logging, monitoring, distributed tracing, canary deployments, config management, authentication & authorization, VPC, security, error handling, and more.
You can also get 40% off the face price with the code ytcui.
Here is a complete list of all my posts on serverless and AWS Lambda. In the meantime, here are a few of my most popular blog posts.
- Lambda optimization tip – enable HTTP keep-alive
- You are thinking about serverless costs all wrong
- Many faced threats to Serverless security
- We can do better than percentile latencies
- I’m afraid you’re thinking about AWS Lambda cold starts all wrong
- Yubl’s road to Serverless
- AWS Lambda – should you have few monolithic functions or many single-purposed functions?
- AWS Lambda – compare coldstart time with different languages, memory and code sizes
- Guys, we’re doing pagination wrong