First step to AWS CDK

This is my first step of using AWS CDK in macOS. I am using Pyenv tool to create python enviroment as explained in the Python my workflow.

Here the simple example created using AWS CDK.

Followed AWS CDK Python workshop.

• Prepare the development env
• Initialse the project
• Synthesize a Cloudformation template
• Bootstrapping and deployment
• Create a real application

Prepare the development env

First, you have to verify that, you have installed the AWS CDK.

1. in the macOS, install AWS CLI using Homebrew
2. install NodeJS
3. install AWS CDK using NodeJS

If all the above is good, now install the python enviroment to use with the AWS SDK:

1. install Python version 3
2. create virtual enviroment p3 using pyenv tool
3. You can use any directory to creat your scripts, I use Visual Studio Code as my editor
4. In case, I can use the following command to set the global version of the python to version 3:

pyenv global 3.8.0

Initialse the project

Create a directory as you want, in my case

mkdir helloaws

Use cdk init to create the project

cdk  init sample-app --language python

As given in the output of the above command, you have to activate the Virtualenv

source  .env/bin/activate

Now install the requirments:

pip  install -r requirements.txt

The default application entry point is app.py which impor the helloaws_stack.py. According to the helloaws_stack.py, following will be created default:

• sqs queue
• sns topic

Synthesize a Cloudformation template

To list the availble stacks

cdk ls

In my case I get the result helloaws. To synthesize:

cdk synth

Here the ouput

Resources:
  HelloawsQueue99542750:
    Type: AWS::SQS::Queue
    Properties:
      VisibilityTimeout: 300
    Metadata:
      aws:cdk:path: helloaws/HelloawsQueue/Resource
  HelloawsQueuePolicy3ED87862:
    Type: AWS::SQS::QueuePolicy
    Properties:
      PolicyDocument:
        Statement:
          - Action: sqs:SendMessage
            Condition:
              ArnEquals:
                aws:SourceArn:
                  Ref: HelloawsTopic419BCE5E
            Effect: Allow
            Principal:
              Service: sns.amazonaws.com
            Resource:
              Fn::GetAtt:
                - HelloawsQueueN95NNN50
                - Arn
        Version: "2012-10-17"
      Queues:
        - Ref: HelloawsQueueN95NNN50
    Metadata:
      aws:cdk:path: helloaws/HelloawsQueue/Policy/Resource
  HelloawsQueuehelloawsHelloawsTopic05A44NNA13C4E1C5:
    Type: AWS::SNS::Subscription
    Properties:
      Protocol: sqs
      TopicArn:
        Ref: HelloawsTopic419BCE5E
      Endpoint:
        Fn::GetAtt:
          - HelloawsQueue9N95NNN50
          - Arn
    Metadata:
      aws:cdk:path: helloaws/HelloawsQueue/helloawsHelloawsTopic05A4499A/Resource
  HelloawsTopic418BCE5E:
    Type: AWS::SNS::Topic
    Metadata:
      aws:cdk:path: helloaws/HelloawsTopic/Resource
  CDKMetadata:
    Type: AWS::CDK::Metadata
    Properties:
      Modules: ...

Bootstrapping and deployment

First titme you have have to install the bootstrap stack which is necessary for the toolkit.

cdk bootstrap

Now time to deply as follows:

cdk  deploy helloaws

Now you are ready to create your own application

Create a real application

You have to clean up the sample-app SNS and the SQS form the helloaws_stack.py. It is better to use the following command to see the impact when you deploy new stack compared to existing:

cdk diff

if you are starisfied, run the following command to update the stack:

cdk deploy

I have followed the AWS CDK Python workshop form this point onwards.

To delete the stack

cdk destroy