Step Functionsを使ったLambdaのDR構成 HTTPレスポンスで東京/大阪に自動切替

import os
import json
import boto3
from botocore.exceptions import ClientError
cloudwatch = boto3.client("cloudwatch")
ALARM_NAME = os.getenv("ALARM_NAME")
def lambda_handler(event, context):
    try:
        response = cloudwatch.describe_alarms(
            AlarmNames=[ALARM_NAME]
        )
        if not response['MetricAlarms']:
            return {
                'statusCode': 404,
                'body': json.dumps({'message': f'Alarm {ALARM_NAME} not found'})
            }
        state_value = response['MetricAlarms'][0]['StateValue']
        location = 'Osaka' if state_value == 'ALARM' else "Tokyo"
        return{
            'statusCode': 200,
            'headers': {
                'Content-Type': 'application/json; charset=utf-8'
            },
            'body': json.dumps({'location': location, 'state': state_value}, ensure_ascii=False)
        }
    except Exception as e:
        print(f"Error: {e}")
        return {
            'statusCode': 500,
            'body': json.dumps({'message': 'Internal Server Error'})
        }

{
  "Comment": "A description of my state machine",
  "StartAt": "Call HTTPS APIs",
  "States": {
    "Call HTTPS APIs": {
      "Type": "Task",
      "Resource": "arn:aws:states:::http:invoke",
      "Parameters": {
        "ApiEndpoint": "https://xxxxxxxxxxxx.execute-api.us-east-1.amazonaws.com/prod/",
        "Method": "GET",
        "Authentication": {
          "ConnectionArn": "arn:aws:events:ap-northeast-1:xxxxxxxxxxxx:connection/test/5a7c61aa-84f5-44b0-9b0c-3d1967f19539"
        }
      },
      "Retry": [
        {
          "ErrorEquals": [
            "States.Http.StatusCode.429",
            "States.Http.StatusCode.503",
            "States.Timeout"
          ],
          "BackoffRate": 2,
          "IntervalSeconds": 2,
          "MaxAttempts": 3
        }
      ],
      "Next": "Evaluate the alarm status.",
      "Catch": [
        {
          "ErrorEquals": [
            "States.ALL"
          ],
          "Next": "Lambda Invoke"
        }
      ]
    },
    "Lambda Invoke": {
      "Type": "Task",
      "Resource": "arn:aws:states:::lambda:invoke",
      "OutputPath": "$.Payload",
      "Parameters": {
        "Payload.$": "$",
        "FunctionName": "arn:aws:lambda:ap-northeast-1:xxxxxxxx:function:getlambda:$LATEST"
      },
      "Retry": [
        {
          "ErrorEquals": [
            "Lambda.ServiceException",
            "Lambda.AWSLambdaException",
            "Lambda.SdkClientException",
            "Lambda.TooManyRequestsException"
          ],
          "IntervalSeconds": 1,
          "MaxAttempts": 3,
          "BackoffRate": 2,
          "JitterStrategy": "FULL"
        }
      ],
      "End": true
    },
    "Evaluate the alarm status.": {
      "Type": "Choice",
      "Choices": [
        {
          "Next": "Stop Workflow",
          "Variable": "$.ResponseBody.location",
          "StringEquals": "Osaka"
        }
      ],
      "Default": "Lambda Invoke"
    },
    "Stop Workflow": {
      "Type": "Succeed"
    }
  },
  "QueryLanguage": "JSONPath"
}

{
  "Comment": "A description of my state machine",
  "StartAt": "Call HTTPS APIs",
  "States": {
    "Call HTTPS APIs": {
      "Type": "Task",
      "Resource": "arn:aws:states:::http:invoke",
      "Parameters": {
        "ApiEndpoint": "https://xxxxxxxxxxxx.execute-api.us-east-1.amazonaws.com/prod/",
        "Method": "GET",
        "Authentication": {
          "ConnectionArn": "arn:aws:events:ap-northeast-3:xxxxxxxxxxxx:connection/osaka-connection/01ba4523-77fa-4f28-8436-4421e86f256a"
        }
      },
      "Retry": [
        {
          "ErrorEquals": [
            "States.Http.StatusCode.429",
            "States.Http.StatusCode.503",
            "States.Timeout"
          ],
          "BackoffRate": 2,
          "IntervalSeconds": 2,
          "MaxAttempts": 3
        }
      ],
      "Next": "Evaluate the alarm status.",
      "Catch": [
        {
          "ErrorEquals": [
            "States.ALL"
          ],
          "Next": "Stop Workflow"
        }
      ]
    },
    "Lambda Invoke": {
      "Type": "Task",
      "Resource": "arn:aws:states:::lambda:invoke",
      "OutputPath": "$.Payload",
      "Parameters": {
        "Payload.$": "$",
        "FunctionName": "arn:aws:lambda:ap-northeast-3:xxxxxxxxxxxx:function:getlambda:$LATEST"
      },
      "Retry": [
        {
          "ErrorEquals": [
            "Lambda.ServiceException",
            "Lambda.AWSLambdaException",
            "Lambda.SdkClientException",
            "Lambda.TooManyRequestsException"
          ],
          "IntervalSeconds": 1,
          "MaxAttempts": 3,
          "BackoffRate": 2,
          "JitterStrategy": "FULL"
        }
      ],
      "End": true
    },
    "Evaluate the alarm status.": {
      "Type": "Choice",
      "Choices": [
        {
          "Next": "Lambda Invoke",
          "Variable": "$.ResponseBody.location",
          "StringEquals": "Osaka"
        }
      ],
      "Default": "Stop Workflow"
    },
    "Stop Workflow": {
      "Type": "Succeed"
    }
  },
  "QueryLanguage": "JSONPath"
}