import os
import smtplib
import email.utils
from email.mime.text import MIMEText

# 環境変数
mail_from = os.environ['MAIL_FROM']
rcpt_to = os.environ['RCPT_TO']
smtp_server = 'smtp.gmail.com'
smtp_port = 587
smtp_user = os.environ['SMTP_USER']
smtp_password = os.environ['SMTP_PASSWORD']

# Body
msg = MIMEText('テストメッセージ\n' + '送信テスト\n')
msg['To'] = email.utils.formataddr(('テスト宛先', mail_from))
msg['From'] = email.utils.formataddr(('テスト送信元', rcpt_to))
msg['Subject'] = 'テストメール'

# smtplib を使ったメール送信
server = smtplib.SMTP(smtp_server, smtp_port)
server.set_debuglevel(True)
try:
    server.ehlo()
    server.starttls()
    server.login(smtp_user, smtp_password)
    server.sendmail(mail_from, rcpt_to, msg.as_string())
finally:
    server.quit()

smtplib.SMTPAuthenticationError: (535, b'5.7.8 Username and Password not accepted. Learn more at\n5.7.8  https://support.google.com/mail/?p=BadCredentials xxxxxxxxxxxxxxxx.xx - gsmtp')

import os
import json
import logging.config

# 環境変数
mail_from = os.environ['MAIL_FROM']
rcpt_to = os.environ['RCPT_TO']
smtp_server = 'smtp.gmail.com'
smtp_port = 587
smtp_user = os.environ['SMTP_USER']
smtp_password = os.environ['SMTP_PASSWORD']

# json.load() で読み込むとタプルとリストの区別がつかないので、 json.load()で読み込めない
config = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'simple': {
            'format': '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
        }
    },
    'handlers': {
        'consoleHandler': {
            'level': 'DEBUG',
            'formatter': 'simple',
            'class': 'logging.StreamHandler',
        },
        'smtpHandler': {
            'level': 'ERROR',
            'formatter': 'simple',
            'class': 'logging.handlers.SMTPHandler',
            'mailhost': (smtp_server, smtp_port),
            'fromaddr': mail_from,
            'toaddrs': [rcpt_to],
            'subject': "error log",
            'credentials': (smtp_user, smtp_password),
            'secure': (),
        }
    },
    'loggers': {
        '': {
            'handlers': ['consoleHandler', 'smtpHandler'],
            'level': "INFO",
        }
    }
}

logger = logging.getLogger(__name__)
logging.config.dictConfig(config)
logger.debug('Debug log message')
logger.info('Info log message')
logger.warning('Warning log message')
logger.error('Error log message')

import keyring

keyring.set_password('test', 'testuser', 'passpasstest')
print(keyring.get_password('test', 'testuser'))

keyring.delete_password('test', 'testuser')
print(keyring.get_password('test', 'testuser'))