「AWSのリソースをTypeScriptで定義できるらしい」という噂を聞いたので、早速触ってみました。

AWS CDKのインストール

npmで配布されているので、npm i -gでインストールしましょう。

$ npm i -g aws-cdk
$ cdk --version
0.13.0 (build bf73b09)

新規プロジェクト作成

新しくプロジェクトを始める場合は、cdk initを実行します。

$ cdk init --help
/usr/local/opt/nvm/versions/node/v10.5.0/bin/cdk init [TEMPLATE]

オプション:
  --app, -a            REQUIRED: Command-line for executing your CDK app (e.g.
                       "node bin/my-app.js")                            [文字列]
  --context, -c        Add contextual string parameter.                   [配列]
  --plugin, -p         Name or path of a node package that extend the CDK
                       features. Can be specified multiple times          [配列]
  --rename             Rename stack name if different then the one defined in
                       the cloud executable                             [文字列]
  --trace              Print trace for stack warnings                     [真偽]
  --strict             Do not construct stacks with warnings              [真偽]
  --ignore-errors      Ignores synthesis errors, which will likely produce an
                       invalid output                 [真偽] [デフォルト: false]
  --json, -j           Use JSON output instead of YAML                    [真偽]
  --verbose, -v        Show debug logs                                    [真偽]
  --profile            Use the indicated AWS profile as the default environment
                                                                        [文字列]
  --proxy              Use the indicated proxy. Will read from HTTPS_PROXY
                       environment variable if not specified.           [文字列]
  --ec2creds, -i       Force trying to fetch EC2 instance credentials. Default:
                       guess EC2 instance status.                         [真偽]
  --version-reporting  Disable insersion of the CDKMetadata resource in
                       synthesized templates                              [真偽]
  --role-arn, -r       ARN of Role to use when invoking CloudFormation  [文字列]
  --version            バージョンを表示                                   [真偽]
  --help               ヘルプを表示                                       [真偽]
  --language, -l       the language to be used for the new project (default can
                       be configured in ~/.cdk.json)
                     [文字列] [選択してください: "dotnet", "java", "typescript"]
  --list               list the available templates                       [真偽]

TypeScript / Java / .NETの３つが使えるみたいですね。

$ cdk init -l typescript
Applying project template app for typescript
Initializing a new git repository...
Executing npm install...
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN [email protected] No repository field.
npm WARN [email protected] No license field.

# Useful commands

 * `npm run build`   compile typescript to js
 * `npm run watch`   watch for changes and compile
 * `cdk deploy`      deploy this stack to your default AWS account/region
 * `cdk diff`        compare deployed stack with current state
 * `cdk synth`       emits the synthesized CloudFormation template

ディレクトリ構成です。

$ tree -I node_modules
.
├── README.md
├── bin
│   └── cdk.ts
├── cdk.json
├── package-lock.json
├── package.json
└── tsconfig.json

1 directory, 6 files

./bin/cdk.tsにサンプルが用意されています。

#!/usr/bin/env node
import sns = require('@aws-cdk/aws-sns');
import sqs = require('@aws-cdk/aws-sqs');
import cdk = require('@aws-cdk/cdk');

class CdkStack extends cdk.Stack {
  constructor(parent: cdk.App, name: string, props?: cdk.StackProps) {
    super(parent, name, props);

    const queue = new sqs.Queue(this, 'CdkQueue', {
      visibilityTimeoutSec: 300
    });

    const topic = new sns.Topic(this, 'CdkTopic');

    topic.subscribeQueue(queue);
  }
}

const app = new cdk.App();

new CdkStack(app, 'CdkStack');

app.run();

CloudFormationに出力する

空き時間の都合でそろそろこの記事を締めたいので、最後にCloudFormationのテンプレートへ変換します。変換はcdk synthで実行できます。cdk synth > template.yml

$ cdk synth
Resources:
    CdkQueueBA7F247D:
        Type: 'AWS::SQS::Queue'
        Properties:
            VisibilityTimeout: 300
    CdkQueuePolicy9CB1D142:
        Type: 'AWS::SQS::QueuePolicy'
        Properties:
            PolicyDocument:
                Statement:
                    -
                        Action: 'sqs:SendMessage'
                        Condition:
                            ArnEquals:
                                'aws:SourceArn':
                                    Ref: CdkTopic7E7E1214
                        Effect: Allow
                        Principal:
                            Service: sns.amazonaws.com
                        Resource:
                            'Fn::GetAtt':
                                - CdkQueueBA7F247D
                                - Arn
                Version: '2012-10-17'
            Queues:
                -
                    Ref: CdkQueueBA7F247D
    CdkTopic7E7E1214:
        Type: 'AWS::SNS::Topic'
    CdkTopicCdkQueueSubscriptionA1BA14FA:
        Type: 'AWS::SNS::Subscription'
        Properties:
            Endpoint:
                'Fn::GetAtt':
                    - CdkQueueBA7F247D
                    - Arn
            Protocol: sqs
            TopicArn:
                Ref: CdkTopic7E7E1214
    CDKMetadata:
        Type: 'AWS::CDK::Metadata'
        Properties:
            Modules: >-
                @aws-cdk/aws-cloudwatch=0.13.0,@aws-cdk/aws-iam=0.13.0,@aws-cdk/aws-kms=0.13.0,@aws-cdk/aws-s3-notifications=0.13.0,@aws-cdk/aws-sns=0.13.0,@aws-cdk/aws-sqs=0.13.0,@aws-cdk/cdk=0.13.0,@aws-cdk/cx-api=0.13.0,cdk=0.1.0

実際に利用する際はcdk synth > template.ymlのようにするとよいでしょう。

$ cdk synth > template.yml
$ aws cloudformation validate-template --template-body file://$(pwd)/template.yml
{
    "Parameters": []
}

バリデーションもうまくいきましたね。