cdk synth

Why cdk synth?

The AWS CDK utilizes the AWS CloudFormation service to perform deployments.

AWS CDK apps are effectively only a definition of your infrastructure using CloudFormation 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.

Synthesize CloudFormation template for your cdk-workshop stack

  • Synthesize the CloudFormation template from the cdk-workshop stack

    cdk synth

    # Output
Resources:
  CdkWorkshopQueue50D9D426:
    Type: AWS::SQS::Queue
    Properties:
      VisibilityTimeout: 300
    UpdateReplacePolicy: Delete
    DeletionPolicy: Delete
    Metadata:
      aws:cdk:path: CdkWorkshopStack/CdkWorkshopQueue/Resource
  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
    Metadata:
      aws:cdk:path: CdkWorkshopStack/CdkWorkshopQueue/Policy/Resource
  CdkWorkshopQueueCdkWorkshopStackCdkWorkshopTopicD7BE96438B5AD106:
    Type: AWS::SNS::Subscription
    Properties:
      Endpoint:
        Fn::GetAtt:
          - CdkWorkshopQueue50D9D426
          - Arn
      Protocol: sqs
      TopicArn:
        Ref: CdkWorkshopTopicD368A42F
    DependsOn:
      - CdkWorkshopQueuePolicyAF2494A5
    Metadata:
      aws:cdk:path: CdkWorkshopStack/CdkWorkshopQueue/CdkWorkshopStackCdkWorkshopTopicD7BE9643/Resource
  CdkWorkshopTopicD368A42F:
    Type: AWS::SNS::Topic
    Metadata:
      aws:cdk:path: CdkWorkshopStack/CdkWorkshopTopic/Resource
  CDKMetadata:
    Type: AWS::CDK::Metadata
    Properties:
      Analytics: v2:deflate64:H4sIAAAAAAAA/22QTU/DMAyGfws+TmlgPSDRI+wIErBJHKoJpY03vGVJG6etqqj/HfUDqQcusV77if3aqdw+PcqHO9VxUuprYqiQcR9UeRWq4+/INcv40WCDeYSWmAoyFPoD3dA1ATLYwHAULyc7MWJ6352hss8j1KNiyHLYwHGFzcAg2LKM+6bg0lMVyNk8QnAVlVNfAWh15ciGRVbeBVc6AxlwzSDAq+4NmdUZd2ioRd8v5IlMQD+P+Sf1ReFn+fjs9B/h8UzOLkKj0q8YAvrJ8WrRtV9xGN1O642lSQ3DIKzTKC9836ap3I7nvTBR4hsb6Ibyc46/LeCGIXsBAAA=
    Metadata:
      aws:cdk:path: CdkWorkshopStack/CDKMetadata/Default
    Condition: CDKMetadataAvailable
Conditions:
  CDKMetadataAvailable:
    # ...
Parameters:
  BootstrapVersion:
    Type: AWS::SSM::Parameter::Value<String>
    Default: /cdk-bootstrap/hnb659fds/version
    Description: Version of the CDK Bootstrap resources in this environment, automatically retrieved from SSM Parameter Store. [cdk:skip]

    The structure of the CloudFormation template synthesized from the example CDK app looks like this:

    alt text

    • CdkWorkshopQueueXXXXXXXX is the SQS queue.
    • CdkWorkshopTopicXXXXXXXX is the SNS topic.
    • CdkWorkshopQueuePolicyXXXXXXXX is the IAM policy which allows this topic to send messages to the queue.
    • CdkWorkshopQueueCdkWorkshopStackCdkWorkshopTopicXXXXXXXXXXXXXXXX is the subscription between the queue and the topic..