これはなに
- Step Functions Local の使い方と利用のイメージのメモ
導入方法
ドキュメントに書かれているとおりに実行します: Step Functions (ダウンロード可能バージョン) と Docker – AWS Step Functions
docker pull コマンドでサクッと導入できます
$ docker pull amazon/aws-stepfunctions-local
docker run コマンドで Step Functions Local を立ち上げます
$ docker run -p 8083:8083 amazon/aws-stepfunctions-local
Lambda 関数のローカル実行
Step Functions Local のステートマシン実行前に Lambda 関数をローカルで動かしておきます。
Lambda 関数の実装はこんな感じ
$ cat ./functions/hello/app.py
# -*- coding: utf-8 -*-
def lambda_handler(_, __):
return {
'result': 'hello'
}
SAM テンプレートはこんな感じ
$ cat ./template.yaml
AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
hello-world python 3.8
Resources:
HelloFunction:
Type: AWS::Serverless::Function
Properties:
Timeout: 10
Runtime: python3.8
CodeUri: functions/hello/
Handler: app.lambda_handler
HelloFunctionLogGroup:
Type: AWS::Logs::LogGroup
Properties:
LogGroupName: !Sub /aws/lambda/${HelloFunction}
RetentionInDays: 1
Lambda 関数をローカルで実行します
$ sam local start-lambda
$ aws lambda invoke --function-name "HelloFunction" --endpoint-url "http://127.0.0.1:3001" --no-verify-ssl /tmp/out.txt
{
"StatusCode": 200
}
$ cat /tmp/out.txt
{"result":"hello"}
以上のようにローカルでの Lambda 関数の稼働が確認できました
Lambda 関数実行タスクを含むステートマシンのローカル実行
いよいよ Lambda 関数実行タスクを含むステートマシンをローカルで動かします
Step Functions Local 側から Lambda Local 側への通信ができるようにまずは環境変数を以下のように設定
$ cat environment.txt
LAMBDA_ENDPOINT=http://host.docker.internal:3001
そして該当の環境変数を用いて Step Functions Local を起動します
$ docker run -p 8083:8083 --env-file environment.txt amazon/aws-stepfunctions-local
ステートマシンの定義は以下のような感じにしておきます
$ cat ./statemachine/hello_world.asl.json
{
"Comment": "A state machine that does mock stock trading.",
"StartAt": "InvokeHello",
"States": {
"InvokeHello": {
"Type": "Task",
"Resource": "arn:aws:lambda:us-east-1:123456789012:function:HelloFunction",
"Next": "InvokeWorld"
},
"InvokeWorld": {
"Type": "Task",
"Resource": "arn:aws:lambda:us-east-1:123456789012:function:WorldFunction",
"End": true
}
}
}
このような状況のもと、ステートマシンをローカル上に作成します
$ aws stepfunctions --endpoint http://localhost:8083 create-state-machine --name "HelloWorld" --role-arn "arn:aws:iam::012345678901:role/DummyRole" --definition file://./statemachine/hello_world.local.asl.json
{
"stateMachineArn": "arn:aws:states:us-east-1:123456789012:stateMachine:HelloWorld",
"creationDate": 1608790957.674
}
最後にローカルでステートマシンを実行するコマンドを叩きます
$ aws stepfunctions --endpoint http://localhost:8083 start-execution --state-machine arn:aws:states:us-east-1:123456789012:stateMachine:HelloWorld --name test
{
"executionArn": "arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test",
"startDate": 1608791078.365
}
すると Step Functions Local 側のコンソールに以下のようにステートマシンの実行結果が出力されます
2020-12-XX XX:XX:10.485: StartExecution => {"requestClientOptions":{"readLimit":131073,"skipAppendUriPath":false},"requestMetricCollector":null,"customRequestHeaders":null,"customQueryParameters":null,"cloneSource":null,"sdkRequestTimeout":null,"sdkClientExecutionTimeout":null,"stateMachineArn":"arn:aws:states:us-east-1:123456789012:stateMachine:HelloWorld","name":"test2","input":null,"traceHeader":null,"requestCredentials":null,"requestCredentialsProvider":null,"generalProgressListener":{"syncCallSafe":true},"readLimit":131073,"cloneRoot":null}
2020-12-XX XX:XX:10.525: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"ExecutionStarted","PreviousEventId":0,"ExecutionStartedEventDetails":{"Input":"{}","RoleArn":"arn:aws:iam::123456789012:role/DummyRole"}}
2020-12-XX XX:XX:10.527: [200] StartExecution <= {"sdkResponseMetadata":null,"sdkHttpMetadata":null,"executionArn":"arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2","startDate":1608792910520}
2020-12-XX XX:XX:10.528: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"TaskStateEntered","PreviousEventId":0,"StateEnteredEventDetails":{"Name":"InvokeHello","Input":"{}"}}
2020-12-XX XX:XX:10.530: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"LambdaFunctionScheduled","PreviousEventId":2,"LambdaFunctionScheduledEventDetails":{"Resource":"arn:aws:lambda:us-east-1:123456789012:function:HelloFunction","Input":"{}"}}
2020-12-XX XX:XX:10.569: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"LambdaFunctionStarted","PreviousEventId":3}
2020-12-XX XX:XX:16.394: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"LambdaFunctionSucceeded","PreviousEventId":4,"LambdaFunctionSucceededEventDetails":{"Output":"{\"result\":\"hello\"}"}}
2020-12-XX XX:XX:16.395: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"TaskStateExited","PreviousEventId":5,"StateExitedEventDetails":{"Name":"InvokeHello","Output":"{\"result\":\"hello\"}"}}
2020-12-XX XX:XX:16.396: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"TaskStateEntered","PreviousEventId":6,"StateEnteredEventDetails":{"Name":"InvokeWorld","Input":"{\"result\":\"hello\"}"}}
2020-12-XX XX:XX:16.396: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"LambdaFunctionScheduled","PreviousEventId":7,"LambdaFunctionScheduledEventDetails":{"Resource":"arn:aws:lambda:us-east-1:123456789012:function:WorldFunction","Input":"{\"result\":\"hello\"}"}}
2020-12-XX XX:XX:16.397: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"LambdaFunctionStarted","PreviousEventId":8}
2020-12-XX XX:XX:22.222: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"LambdaFunctionSucceeded","PreviousEventId":9,"LambdaFunctionSucceededEventDetails":{"Output":"{\"result\":\"helloworld\"}"}}
2020-12-XX XX:XX:22.222: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"TaskStateExited","PreviousEventId":10,"StateExitedEventDetails":{"Name":"InvokeWorld","Output":"{\"result\":\"helloworld\"}"}}
2020-12-XX XX:XX:22.223: arn:aws:states:us-east-1:123456789012:execution:HelloWorld:test2 : {"Type":"ExecutionSucceeded","PreviousEventId":11,"ExecutionSucceededEventDetails":{"Output":"{\"result\":\"helloworld\"}"}}
ステートマシン実行の結果、最終的に {"result":"helloworld"} が得られました