lenticular

A particular CloudFormation helper.

What is this thing?

This is my attempt at making CloudFormation sane. I want nice and short-as-possible names for my AWS resources. I want semantic names for artifacts in my S3 buckets, instead of hex strings. And I want continuous deployment of my product’s infrastructure side-by-side with my product’s code.

So what lenticular does is provide a little command line utility that helps with these goals and writes some boilerplate for you, hopefully putting you on a good path.

I’m learning infrastructure-as-code as I go along, so if you see something that might be done better another way, please open an issue!

Setup

The very first thing you need is a product name for your product. This should be a relatively unique identifier to avoid S3 bucket name collisions (keeping in mind that S3 buckets are a global, publicly-shared namespace). It should be all lowercase, with dashes (-) separating words.

Now, assuming you’ve got a git repo and an npm package.json all set up in a directory with the same name as your product, run the following in that directory:

npm install --save-dev lenticular      # Local CLI install.
sudo npm install --global lenticular   # Global CLI always falls back to local.
lenticular init                        # Creates .lenticularrc and ./infra/

Now, take a look at the newly created .lenticularrc, infra/pipeline.yaml and buildspec.yml files.

…

Writing CloudFormation Templates

I like to put my main CloudFormation template in /infra/index.yaml. You can override this with the indexTemplate configuration property.

By default CloudFormation gives your resources random names that are useless. Lenticular gives you two functions to help with giving your resources meaningful, short-as-possible, and non-colliding names. For example, in the following template, your lambda function would get a FunctionName value of projectx-ProcessUpload:

Resources:
  ProcessUploadFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Lenticular::ResourceName 'ProcessUpload'

Or the following for an S3 bucket or other resources in a global namespace, to generate a value of projectx-UserData-us-west-2:

Resources:
  UserDataBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Lenticular::ResourceNameWithRegion 'UserData'