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Fri 25 Jun 2021

Dynamically create cloudformation stack using AWS CDK

Tags: aws cdk cloudformation typescript tutorial

AWS CDK is a great framework to programmatically deploy cloudformation stack. If you are unfamiliar with AWS CDK, I would recommend first to check out Getting started with AWS CDK.

One of the pet peeves I have while designing cloudformation template is redundancy. I have to manually copy-paste the same properties across multiple resources. I wanted to leverage AWS CDK to create an interface that would allow tto dynamically create cloudformation. For the interface, I harked back to the good old CSV file.

For a simple example, let’s consider a simple cloudformation template

Parameters:
  Environment:
    Type: String
    Default: dev
    AllowedValues:
      - dev
      - qa
      - prod
    Description: Enter your environment
  Project:
    Type: String
    Default: version
    Description: Enter your version

What if we have to maintain 100 parameters, resources, etc in our project. Soon it will become tedious to maintain multiple resources. Instead, we create a class called Parameter that we instantiate multiple times using different parameters. Here is a class diagram for our Parameter class.

class diagram

Using typescript, we can define the class as


We will create a `CSV` file under folder `resources` which would contain information for each instance of our class.

resource create category default description allowed_values
Environment yes parameter dev Enter your environment dev | qa | prod
Project yes parameter version1 Enter version

First, we will read our CSV file into our project. We would need to install an additional library to read the file.

$ npm i --save csvtojson

We will edit the lib/project_cdk-stack.ts file.

Then we will create lib/helpers.ts file.

Our code till now will not generate any cloudformation. However, we can test it for any compile errors

$ cdk synth --quiet

Next, we will implement our generateTemplate function.


Lastly, we can deploy our cloudformation stack using

$ cdk deploy

In the next article, we will update our code to add additional classes to handle resources, output, etc for our cloudformation template.


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