[Twilio+Python+AWS Lambda] サーバー通知を SMS で自動配信する Web アプリケーションの作成

import os
import json
import traceback
from twilio.rest import Client

class TwilioNotificationsMiddleware:
    """Twilio を使った通知を送信するミドルウェア"""
    def __init__(self, next_handler):
        self.next_handler = next_handler

        # 各環境変数については本記事にて後述
        self.twilio_client = Client(
            os.environ['TWILIO_ACCOUNT_SID'],
            os.environ['TWILIO_AUTH_TOKEN']
        )
        self.twilio_phone_number = os.environ['TWILIO_PHONE_NUMBER']
        self.admin_phone_number = os.environ['ADMIN_PHONE_NUMBER']  

    def send_sms(self, message):
        """Twilio を使って SMS 送信する"""
        try:
            self.twilio_client.messages.create(
                body=message,
                from_=self.twilio_phone_number,
                to=self.admin_phone_number
            )
        except Exception as e:
            print(f"Failed to send SMS: {e}")

    def __call__(self, event, context):
        """Lambda のリクエストを処理し、エラー時に通知を送信"""
        try:
            response = self.next_handler(event, context)
            return response
        except Exception as e:
            error_message = f"Lambda Error: {str(e)}\n{traceback.format_exc()}"
            self.send_sms(error_message)
            return {
                "statusCode": 500,
                "body": json.dumps({"error": "Internal Server Error"})
            }

import json
from twilio_middleware import TwilioNotificationsMiddleware

def lambda_handler(event, context):
    """メインの Lambda 関数"""
    body = json.loads(event['body']) if isinstance(event['body'], str) else event['body']
    message = body.get('message', 'Hello from AWS Lambda!')

    # "error" というメッセージが送られた場合、意図的に例外を発生させる
    if message.lower() == "error":
        raise ValueError("Intentional error for testing Twilio SMS notifications")

    return {
        "statusCode": 200,
        "body": json.dumps({"message": message})
    }

# ミドルウェアを適用
lambda_handler = TwilioNotificationsMiddleware(lambda_handler)

{
  "body": "{\"message\": \"error\"}"
}

$ curl https://****.amazonaws.com/test-twilio-notification -H "Content-Type: application/json" -d '{"message": "error"}'
{"error": "Internal Server Error"}