CloudWatchアラーム + SNSからのメール本文をカスタマイズする(2)

import boto3
import json
import os
import re
from botocore.exceptions import ClientError

print('Loading function')

sns_arn = os.environ['SNS_TOPIC_ARN']

def lambda_handler(event, context):
    data = event
    s = json.dumps(data)
    e = json.loads(s)
    print(e)
    
    # eventから項目を抽出
    t = e['time']
    trig = e['detail-type']
    alarm = e['resources'] #これはリスト。文字列にするにはalarm[0]
    
    # 「理由」となる詳細抽出
    reason = e['detail']['state']['reason']
    
    # リソース（ここではインスタンスID)を抽出し、文字列整形
    resource = e['detail']['configuration']['metrics'][0]['metricStat']['metric']['dimensions']
    res_str = json.dumps(resource)
    res = re.sub(r"[{}\"]", "", res_str)
    
    # 件名整形
    subject_str = "本番環境 - アラーム " + trig + " - " + res
    
    # メッセージ本文整形
    fix_msg = "以下のアラームが発生しました" + "\n"
    trig_msg = "発生契機:" + "\n" + trig
    time_msg = "発生時刻:" + "\n" + t
    alm_msg = "アラーム:" + "\n" + alarm[0]
    res_msg ="対象リソース:" "\n" + res
    dtl_msg ="理由:" "\n" + reason
    msg = fix_msg + "\n\n" + trig_msg + "\n\n" + time_msg + "\n\n" + alm_msg + "\n\n" + res_msg + "\n\n" + dtl_msg
    
    try:
        sns = boto3.client('sns')
        
        #SNS Publish
        publishResponse = sns.publish(
            TopicArn = os.environ['SNS_TOPIC_ARN'],
            Message = msg,
            Subject = subject_str
        )
    
    except Exception as e:
        print(e)