SES -> S3 -> Lambda -> Slack

config.ini

[slack]
hook_url = https://hooks.slack.com/services/xxxxxxx/yyyyyyyy/zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
username = alert_bot
channel = #alert
icon_emoji = :guardsman:

lambda_function_ses-s3-event.py

# coding: utf-8
import boto3
import json
import ConfigParser
from email.parser import FeedParser
from email.header import decode_header
import slackweb

def lambda_handler(event, context):
  try:
    record = event["Records"][0]
    bucket_region = record["awsRegion"]
    bucket_name =  record["s3"]["bucket"]["name"]
    mail_object_key = record["s3"]["object"]["key"]
  
    s3 = boto3.client('s3', region_name=bucket_region)
    mail_object = s3.get_object(Bucket = bucket_name, Key = mail_object_key)
    mail_body = ''
    try:
      mail_body = mail_object["Body"].read().decode('utf-8')
    except:
      try:
        mail_body = mail_object["Body"].read().decode('iso-2022-jp')
      except:
        mail_body = mail_object["Body"].read()
  
    parser = FeedParser()
    parser.feed(mail_body)
    parsed_mail = parser.close()
  
    (d_sub, sub_charset) = decode_header(parsed_mail['Subject'])[0]
    subject = d_sub.decode(sub_charset)
    payload = parsed_mail.get_payload(decode=parsed_mail['Content-Transfer-Encoding'])
    body_charset = parsed_mail.get_content_charset()
    body = payload.decode(body_charset)
 
  except:
    subject = u"Error!"
    body = u"メールを受信しましたが、エラーが発生しました。"

  inifile = ConfigParser.SafeConfigParser()
  inifile.read("./config.ini")
  attachments = []
  attachment = {
                 "fallback": u"メールです。",
		 "pretext": u"メールです。 (key: %s)" % mail_object_key,
                 "color": "#aaaaaa",
                 "fields": [
                   {
                     "title": subject,
                     "value": body,
                     "short": False
                   }
                 ]
               } 
  attachments.append(attachment)

  slack = slackweb.Slack(url=inifile.get('slack', 'hook_url'))
  slack.notify(attachments=attachments,
               channel=inifile.get('slack', 'channel'),
               username=inifile.get('slack', 'username'),
               icon_emoji=inifile.get('slack', 'icon_emoji'))

  return "CONTINUE"