CloudWatch Alarmでアラーム発生時にStep Functionsステートマシンを起動する

			
			
import * as cdk from '@aws-cdk/core';
import * as sfn from '@aws-cdk/aws-stepfunctions';
import * as cloudwatch from '@aws-cdk/aws-cloudwatch';
import * as cloudwatchActions from '@aws-cdk/aws-cloudwatch-actions';
import * as sns from '@aws-cdk/aws-sns';
import * as lambda from '@aws-cdk/aws-lambda';
import * as lambdaNodejs from '@aws-cdk/aws-lambda-nodejs';
import { SnsEventSource } from '@aws-cdk/aws-lambda-event-sources';
import * as iam from '@aws-cdk/aws-iam';

export class AwsCdkAppStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    //SNS Topic
    const cloudwatchAlarmNotifyTopic = new sns.Topic(
      this,
      'cloudwatchAlarmNotifyTopic'
    );

    //CloudWatch Alarm
    const sampleAlarm = new cloudwatch.Alarm(this, 'sampleAlarm', {
      alarmName: 'sampleAlarm',
      metric: new cloudwatch.Metric({
        namespace: 'StateMachinePublish',
        metricName: 'temperature',
      }),
      evaluationPeriods: 1,
      threshold: 5,
      statistic: cloudwatch.Statistic.MAXIMUM,
      comparisonOperator:
        cloudwatch.ComparisonOperator.LESS_THAN_OR_EQUAL_TO_THRESHOLD,
      period: cdk.Duration.minutes(3),
    });

    //Alarmアクション追加
    sampleAlarm.addAlarmAction(
      new cloudwatchActions.SnsAction(cloudwatchAlarmNotifyTopic)
    );

    //ステートマシン
    const stateMachine = new sfn.StateMachine(this, 'sampleStateMachine', {
      stateMachineName: 'sampleStateMachine',
      definition: new sfn.Pass(this, 'pass', {}),
    });

    //Lambda関数
    const startStateMachineFunc = new lambdaNodejs.NodejsFunction(
      this,
      'startStateMachineFunc',
      {
        functionName: 'startStateMachineFunc',
        entry: 'src/lambda/startStateMachineHandler.ts',
        handler: 'handler',
        runtime: lambda.Runtime.NODEJS_14_X,
        environment: {
          STATE_MACHINE_ARN: stateMachine.stateMachineArn,
        },
      }
    );

    //ステートマシン起動権限付与
    startStateMachineFunc.addToRolePolicy(
      new iam.PolicyStatement({
        actions: ['states:StartExecution'],
        resources: [stateMachine.stateMachineArn],
      })
    );

    //Lambdaイベントソース追加
    startStateMachineFunc.addEventSource(
      new SnsEventSource(cloudwatchAlarmNotifyTopic)
    );
  }
}

		

			
			
import * as AWS from 'aws-sdk';

const STATE_MACHINE_ARN = process.env.STATE_MACHINE_ARN!;

const sfn = new AWS.StepFunctions();

export const handler = async () => {
  await sfn
    .startExecution({
      stateMachineArn: STATE_MACHINE_ARN,
    })
    .promise();
};