Cloudformation service in AWS allows you to describe an entire set of resources required to make a pipeline. The cloudformation template can be described in JSON or YAML format. Updating the cloudformation template was not a pleasant experience. I wanted to discover alternative ways to generate cloudformation template programmatically.
Just a quick referesher to few concepts before we delve into AWS CDK
Cloudformation template describes AWS resources. A running instance of cloudformation is called a stack.
Constructs are the basic building blocks of AWS CDK apps.
L1 construct are named CfnXyz, where Xyz is name of the resource. They are low-level construct which directly represent cloudformation resources.
L2 construct provide common boilerplates and glue logic. These will come with convenient defaults and reduces the amount of knowledge you need to know about them.
L3 construct are called high-level patterns. These constructs are designed to help you complete common tasks in AWS, often involving multiple kinds of resources.
For this tutorial, we will use L1 construct. However same concept can be used for L2 construct.
First, install the AWS CDK CLI from command line using
$ npm i -g aws-cdk@latest
Let's create a project
Then you can verify
For our first use case, will add Parameters to our cloudformation. We need to edit file
lib\test-cdk-stack.ts for typescript or
lib\test_cdk_stack.py for python.
We can see the output of the cloudformation template by using the following command
$ cdk synth
If you want to generate cloudformation template without metadata
$ cdk synth --version-reporting false --path-metadata false
The output is
For CDK v2, CheckBootstrapVersion rule is added to the Stack's template as a safety check, to verify that the bootstrap stack in the target environment meets the minimum requirements of the current stack1.
The cloudformation template needs at least one resource to validate. We will add a
stepfunction to our cloudformation. We will define our stepfunction inside a json file,
"Comment" : "A very very simple StepFunction",
If you are not familiar with Stepfunction, AWS Stepfunction console has a nice visualization
Next we need to upload the
helloworld.asl.json to s3 bucket. We also need to define a mapping to access this
Our output will still be the same since our mapping is lazy. Next, we will add stepfunction to our resources
The final cloudformation template is
The cloudformation template is generated under
# for typescript
# for python
Or you can simply deploy it using
$ cdk deploy