Last year I attended the awesome AWS Community Summit where I gave this talk on one of the fundamental questions of software architecture: how do we define the boundaries of things?

A lot of people I talk to are confused about how serverless applications change the way we design stuff, but my answer is that the basics are exactly the same, and even more important.

Generally when deploying Lambda functions, I use the Serverless Framework. This is a wrapper around AWS Cloudformation that makes it easier for engineers to author and deploy code. It's much easier to get started when using an abstraction like this, but sometimes we need to drop down and work at a lower-level.

I recently needed to deploy a Lambda function with a large number of triggers, and the Cloudformation template generated by the serverless framework was too large to deploy. Instead I ended up configuring everything in plain Terraform. There are more moving pieces to understand, but in return for that overhead, we gain a lot of flexibility. In this post I want to show you how to configure and deploy a simple Lambda function, configuring everything ourselves in Terraform so we can see how it all fits together.