AWS CDK apps are effectively only a definition of your infrastructure using code. When CDK apps are executed, they produce (or “synthesize”, in CDK parlance) an AWS CloudFormation template for each stack defined in your application.
To synthesize a CDK app, use the
cdk synth command. Let’s check out the
template synthesized from the sample app:
Will output the following CloudFormation template:
Resources: CdkWorkshopQueue50D9D426: Type: 'AWS::SQS::Queue' Properties: VisibilityTimeout: 300 CdkWorkshopQueuePolicyAF2494A5: Type: 'AWS::SQS::QueuePolicy' Properties: PolicyDocument: Statement: - Action: 'sqs:SendMessage' Condition: ArnEquals: 'aws:SourceArn': Ref: CdkWorkshopTopicD368A42F Effect: Allow Principal: Service: sns.amazonaws.com Resource: 'Fn::GetAtt': - CdkWorkshopQueue50D9D426 - Arn Version: '2012-10-17' Queues: - Ref: CdkWorkshopQueue50D9D426 CdkWorkshopTopicD368A42F: Type: 'AWS::SNS::Topic' CdkWorkshopTopicCdkWorkshopQueueSubscription88D211C7: Type: 'AWS::SNS::Subscription' Properties: Endpoint: 'Fn::GetAtt': - CdkWorkshopQueue50D9D426 - Arn Protocol: sqs TopicArn: Ref: CdkWorkshopTopicD368A42F CDKMetadata: Type: 'AWS::CDK::Metadata' Properties: Modules: >- aws-cdk=0.39.0,jsii-runtime=node.js/v12.2.0
As you can see, this template includes four resources:
The AWS::CDK::Metadata resource is automatically added by the toolkit to every stack. It is used by the AWS CDK team for analytics and to allow us to identify versions with security issues. See Version Reporting in the AWS CDK User Guide for more details. We will omit the metadata resource in diff views for the rest of this workshop