Send email with SMTP over STARTTLS in Python

smtp.py

#!/usr/bin/env python
# coding=utf8
"""
Send email with SMTP

Add env vars in your ~/.bashrc and source it:

    export EMAIL_HOST=smtp.example.com
    export EMAIL_PORT=587
    export EMAIL_USERNAME=sender@example.com
    export EMAIL_PASSWORD=PASSWORD
    export EMAIL_TO_LIST=foo@gmail.com,bar@example.com

"""
import os
import smtplib

EMAIL_HOST = os.environ['EMAIL_HOST']
EMAIL_PORT = int(os.environ['EMAIL_PORT'])

EMAIL_USERNAME = os.environ['EMAIL_USERNAME']
EMAIL_PASSWORD = os.environ['EMAIL_PASSWORD']

# comma separated email list
EMAIL_TO_LIST = os.environ['EMAIL_TO_LIST'].split(',')

EMAIL_MESSAGE = "From: {}\r\nTo: {}\r\nSubject:{}\r\n\r\n{}".format(
    EMAIL_USERNAME,
    ','.join(EMAIL_TO_LIST),
    'this is email subject',
    'this is email body')

if EMAIL_PORT == 25:
    # smtp default, may be deprecated
    server = smtplib.SMTP(EMAIL_HOST, EMAIL_PORT)
elif EMAIL_PORT == 587:
    # smtp over starttls, a improved solution
    server = smtplib.SMTP(EMAIL_HOST, EMAIL_PORT)
    server.starttls()
elif EMAIL_PORT == 465:
    # smtp over ssl, a final solution
    server = smtplib.SMTP_SSL(EMAIL_HOST, EMAIL_PORT)

server.set_debuglevel(1)
server.login(EMAIL_USERNAME, EMAIL_PASSWORD)
server.sendmail(EMAIL_USERNAME, EMAIL_TO_LIST, EMAIL_MESSAGE)
server.quit()