2020/03/03 AWS CDK meetup #2 で発表したLT資料です。

1. CDKで
ワークフローを構築しよう
1

2. ⾃⼰紹介
2
▸⽊次 恭⼀ （@kitsugin）
▸所属
▸株式会社サーバーワークス
▸クラウドインテグレーション部 技術課
▸仕事
▸AWSエンジニア （主にサーバーレス関連）
▸AWSトレーナー
▸趣味
▸登⼭
▸サッカー観戦 (J2⼤宮)
▸サウナでととのえる

3. 本⽇のお話
AWS Step Functions
AWS CDK

4. AWS Step Functions とは
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▸フルマネージドなワークフローサービス
▸ステートマシンをASLで定義
▸ワークフローを可視化
▸実⾏履歴をログから追跡
ASL (Amazon States Language)

5. ステートマシン（サンプル）
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▸Step Functions コンソール
▸CloudFormation
▸AWS CDK

6. Step Functionsコンソールの場合

7. Step Functions コンソール
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UIのサポート

8. Step Functions コンソール
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9. ステートマシン定義
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{
"StartAt": "Parallel",
"States": {
"Parallel": {
"Type": "Parallel",
"End": true,
"Catch": [
{
"ErrorEquals": ["States.ALL"],
"ResultPath": "$.error",
"Next": "ErrorMail"
}
],
"Branches": [
{
"StartAt": "SampleTask1",
"States": {
"SampleTask1": {
"Next": "SampleTask2",
"Type": "Task",
"Resource": "arn:aws:lambda:<region>:<account-id>:function:sample-func1"
},
"SampleTask2": {
"End": true,
"Type": "Task",
"Resource": "arn:aws:lambda:<region>:<account-id>:function:sample-func2"
}
}
}
]
},
"ErrorMail": {
"Next": "Fail",
"Parameters": {
"TopicArn": "arn:aws:sns:<region>:<account-id>:sample-topic",
"Message.$": "$.*",
"Subject": "Error"
},
"Type": "Task",
"Resource": "arn:aws:states:::sns:publish"
},
"Fail": {
"Type": "Fail"
}
},
"TimeoutSeconds": 300
}

10. ポリシードキュメント、ポリシー
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{
"Version": "2012-10-17",
"Statement": [
{
"Action": "sns:Publish",
"Resource": "arn:aws:sns:<region>:<account-id>:sample-topic",
"Effect": "Allow"
},
{
"Action": "lambda:InvokeFunction",
"Resource": "arn:aws:lambda:<region>:<account-id>:function:sample-func1",
"Effect": "Allow"
},
{
"Action": "lambda:InvokeFunction",
"Resource": "arn:aws:lambda:<region>:<account-id>:function:sample-func2",
"Effect": "Allow"
}
]
}
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Principal": {
"Service": "states.<region>.amazonaws.com"
},
"Action": "sts:AssumeRole"
}
]
}

11. CloudFormationの場合

12. ロール&ポリシー定義
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MyStateMachineRoleDefaultPolicy:
Type: AWS::IAM::Policy
Properties:
PolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Action: sns:Publish
Resource:
Ref: MyTopic
- Effect: Allow
Action: lambda:InvokeFunction
Resource:
Fn::GetAtt:
- MySampleFunc1
- Arn
- Effect: Allow
Action: lambda:InvokeFunction
Resource:
Fn::GetAtt:
- MySampleFunc2
- Arn
PolicyName: MyStateMachineRoleDefaultPolicy
Roles:
- Ref: MyStateMachineRole
Resources:
MyStateMachineRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: "2012-10-17"
Statement:
- Effect: Allow
Principal:
Service:
- !Sub states.${AWS::Region}.amazonaws.com
Action: sts:AssumeRole

13. Step Functions定義
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MyStateMachine:
Type: AWS::StepFunctions::StateMachine
Properties:
DefinitionString:
Fn::Join:
- ""
- -
'{"StartAt":"Parallel","States":{"Parallel":{"Type":"Parallel","End":true,"Catch":[{"ErrorEquals":["States.ALL"],"ResultPath":"$.error","Nex
t":"ErrorMail"}],"Branches":[{"StartAt":"SampleTask1","States":{"SampleTask1":{"Next":"SampleTask2","Type":"Task","Resource":"'
- Fn::GetAtt:
- MyFunc1
- Arn
- '"},"SampleTask2":{"End":true,"Type":"Task","Resource":"'
- Fn::GetAtt:
- MyFunc2
- Arn
- '"}}}]},"ErrorMail":{"Next":"Fail","Parameters":{"TopicArn":"'
- Ref: MyTopic
- '","Message.$":"$.*","Subject":"Error"},"Type":"Task","Resource":"arn:'
- Ref: AWS::Partition
- :states:::sns:publish"},"Fail":{"Type":"Fail"}},"TimeoutSeconds":300}
RoleArn:
Fn::GetAtt:
- MyStateMachineRole
- Arn
DependsOn:
- MyStateMachineRoleDefaultPolicy
- MyStateMachineRole

14. Step Functions定義
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MyStateMachine:
Type: AWS::StepFunctions::StateMachine
Properties:
DefinitionString:
Fn::Join:
- ""
- -
'{"StartAt":"Parallel","States":{"Parallel":{"Type":"Parallel","End":true,"Catch":[{"ErrorEquals":["States.ALL"],"ResultPath":"$.error","Nex
t":"ErrorMail"}],"Branches":[{"StartAt":"SampleTask1","States":{"SampleTask1":{"Next":"SampleTask2","Type":"Task","Resource":"'
- Fn::GetAtt:
- MyFunc1
- Arn
- '"},"SampleTask2":{"End":true,"Type":"Task","Resource":"'
- Fn::GetAtt:
- MyFunc2
- Arn
- '"}}}]},"ErrorMail":{"Next":"Fail","Parameters":{"TopicArn":"'
- Ref: MyTopic
- '","Message.$":"$.*","Subject":"Error"},"Type":"Task","Resource":"arn:'
- Ref: AWS::Partition
- :states:::sns:publish"},"Fail":{"Type":"Fail"}},"TimeoutSeconds":300}
RoleArn:
Fn::GetAtt:
- MyStateMachineRole
- Arn
DependsOn:
- MyStateMachineRoleDefaultPolicy
- MyStateMachineRole
ASL

15. AWS CDKの場合

16. ステートマシン
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import * as sfn from ‘@aws-cdk/aws-stepfunctions’;
const sampleTask1 = new sfn.Task(this, ‘SampleTask1’, { // ①
task: new tasks.InvokeFunction(sampleFunc1),
});
const sampleTask2 = new sfn.Task(this, ‘SampleTask2’, { // ②
task: new tasks.InvokeFunction(sampleFunc2),
});
const errorTask = new sfn.Task(this, ‘ErrorMail’, { // ③
task: new tasks.PublishToTopic(emailTopic, {
subject: `Error`,
message: sfn.TaskInput.fromDataAt('$.*'),
}),
});
const fail = new sfn.Fail(this, 'Fail’); // ④
errorTask.next(fail); // ⑤
①
②
③
④
⑤

17. ステートマシン
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const mainFlow = sampleTask1.next(sampleTask2); // ⑥
const parallel = new sfn.Parallel(this, 'Parallel’); // ⑦
parallel.branch(mainFlow);
parallel.addCatch(errorTask, { resultPath: '$.error' }); // ⑧
const stateMachine = new sfn.StateMachine(this, 'StateMachine', {
definition: parallel,
timeout: cdk.Duration.minutes(5),
});
⑥
⑦
⑧

18. StepFunctionモジュール
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19. まとめ

20. まとめ
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▸AWS Step Functions の ステートマシン定義(ASL)
▸CDK を使うと
▸コード量を減らせる
▸拡張しやすい
▸しあわせ

21. 21
3⽉7⽇「技術書典 応援祭」に電⼦版で頒布予定
合わせてBOOTH販売予定

22. 22
最終調整中のため、ページ数が変わる
場合があります

23. Thatʼs all.
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