AWS CDK Scala

This library is now archived, no further changes will be accepted.

• Overview
• Installation
• Usage
• Limitations
• Acknowledgements

Overview

Scala DSL for AWS CDK v2.

Purpose

• Pass around app & stack scope implicitly.
• Avoid using Java concepts.
  • No builder syntax.
  • Required & optional parameters.
  • ADTs instead of enums.
  • Scala collections (i.e. List & Map).

Disclaimer

This library solely provides a lightweight DSL over the AWS CDK using metaprogramming. Please refer to the underlying types from the AWS CDK along with the associated CloudFormation types for official & up-to-date service documentation.

Release Cadence

• Major, minor and patch versions are increased each time aws-cdk-lib increases associated versions.
• Patch version is increased for any non-breaking changes made to the DSL itself.

Scala Support

Version	Supported?
<= 2.11	❌
2.12	✔️
2.13	✔️
3	✔️

Anything <= 2.11 will not be supported. Please do not ask or submit PRs for those versions.

Installation

CDK CLI

You must install v2 of the CDK CLI to synthesize CloudFormation templates.

npm install -g aws-cdk

Library

Just like CDK v2, a single dependency is published for the DSL.

The latest version can be found on mvn and on the releases page.

val cdkVersion: String = ???

libraryDependencies += "io.burkard" %% "aws-cdk-scala" % cdkVersion

Usage

Scala

Create a CDK app within a module of your project.

package io.burkard.cdk.example

import cats.syntax.option._
import io.burkard.cdk._
import io.burkard.cdk.metadata._
import io.burkard.cdk.services.kinesisanalytics._
import io.burkard.cdk.services.kinesisanalytics.cfnApplicationV2._
import io.burkard.cdk.services.s3._

object ExampleApp extends CdkApp {
  CdkStack(id = "ExampleStack".some) { implicit stackCtx =>
    val envParameter = CfnTypedParameter.CfnStringParameter(
      name = "env",
      allowedValues = List("dev", "qa", "prod").some
    )
    val regionParameter = CfnTypedParameter.CfnStringParameter(
      name = "region",
      allowedValues = List("us-east-1", "us-west-2", "eu-west-1").some
    )

    val env = envParameter.value
    val region = regionParameter.value

    val bucket = Bucket(
      internalResourceId = "Code",
      accessControl = BucketAccessControl.Private.some,
      enforceSsl = true.some,
      encryption = BucketEncryption.S3Managed.some,
      versioned = true.some
    )

    CfnApplicationV2(
      internalResourceId = "Runtime",
      serviceExecutionRole = "arn:example-role",
      runtimeEnvironment = "FLINK-1_13",
      tags = List(
        CfnTag(key = "env", value = env),
        CfnTag(key = "region", value = region)
      ).some,
      applicationName = s"prefix-$env-app-name-$region".some,
      applicationConfiguration = ApplicationConfigurationProperty(
        applicationCodeConfiguration = ApplicationCodeConfigurationProperty(
          codeContent = CodeContentProperty(
            s3ContentLocation = S3ContentLocationProperty(
              fileKey = "code-key-in-s3",
              bucketArn = bucket.getBucketArn,
              objectVersion = "code-version".some
            ).some
          ),
          codeContentType = "ZIPFILE"
        ).some
      ).some
    )
  }
}

CDK Configuration

Create a cdk.json file at the root of your project, specifying the command to run your CDK app.

{
  "app": "sbt \"example/runMain io.burkard.cdk.example.ExampleApp\""
}

Synthesis

Synthesize the application.

cdk synth

The result is a CloudFormation template in YAML.

Parameters:
  env:
    Type: String
    AllowedValues:
      - dev
      - qa
      - prod
    NoEcho: false
  region:
    Type: String
    AllowedValues:
      - us-east-1
      - us-west-2
      - eu-west-1
    NoEcho: false
  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]
Resources:
  Code5B760EEF:
    Type: AWS::S3::Bucket
    Properties:
      AccessControl: Private
      BucketEncryption:
        ServerSideEncryptionConfiguration:
          - ServerSideEncryptionByDefault:
              SSEAlgorithm: AES256
      VersioningConfiguration:
        Status: Enabled
    UpdateReplacePolicy: Retain
    DeletionPolicy: Retain
    Metadata:
      aws:cdk:path: ExampleStack/Code/Resource
  CodePolicyAA48735C:
    Type: AWS::S3::BucketPolicy
    Properties:
      Bucket:
        Ref: Code5B760EEF
      PolicyDocument:
        Statement:
          - Action: s3:*
            Condition:
              Bool:
                aws:SecureTransport: "false"
            Effect: Deny
            Principal:
              AWS: "*"
            Resource:
              - Fn::GetAtt:
                  - Code5B760EEF
                  - Arn
              - Fn::Join:
                  - ""
                  - - Fn::GetAtt:
                        - Code5B760EEF
                        - Arn
                    - /*
        Version: "2012-10-17"
    Metadata:
      aws:cdk:path: ExampleStack/Code/Policy/Resource
  Runtime:
    Type: AWS::KinesisAnalyticsV2::Application
    Properties:
      RuntimeEnvironment: FLINK-1_13
      ServiceExecutionRole: arn:example-role
      ApplicationConfiguration:
        ApplicationCodeConfiguration:
          CodeContent:
            S3ContentLocation:
              BucketARN:
                Fn::GetAtt:
                  - Code5B760EEF
                  - Arn
              FileKey: code-key-in-s3
              ObjectVersion: code-version
          CodeContentType: ZIPFILE
      ApplicationName:
        Fn::Join:
          - ""
          - - prefix-
            - Ref: env
            - -app-name-
            - Ref: region
      Tags:
        - Key: env
          Value:
            Ref: env
        - Key: region
          Value:
            Ref: region
    Metadata:
      aws:cdk:path: ExampleStack/Runtime

Limitations

• Builders which use overloading for optional parameters (same name but different types) are represented as paramName0, paramName1, etc..

Acknowledgements

• Inspired by AWS CDK Kotlin DSL.