Simple send_mail function to using environment variables.

emailer.py

import os
import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart


# Check older version compatibility
if not hasattr(smtplib, "SMTPNotSupportedError"):
    smtplib.SMTPNotSupportedError = smtplib.SMTPDataError


os.environ.setdefault('SMTP_SERVER', '')
os.environ.setdefault('SMTP_PORT', '465')
os.environ.setdefault('SMTP_USERNAME', '')
os.environ.setdefault('SMTP_PASSWORD', '')


def send_mail(subject, message, from_email, recipient_list, fail_silently=False, html_message=None, **kwargs):
    """Send an email. This method should be somewhat compatible with django and was made to have the same input
    arguments as django.

    Args:
        subject (str): Subject line of the email.
        message (str): Body of the email message.
        from_email (str): Email address of the person sending the email
        recipient_list (list): Who the email is going to.
        fail_silently (bool)[True]: A boolean. When it’s False, send_mail() will raise an smtplib.SMTPException
            if an error occurs. See the smtplib docs for a list of possible exceptions, all of which are subclasses
            of SMTPException.
        html_message (str)[None]: Seconary form of sending email. Try to send this html message or use the regular
            message as just plain text.

    Kwargs:
        auth_server (str)[None]: The optional smtp server name if SMTP_SERVER is not set.
        auth_user (str)[None]: The optional username to use to authenticate to the SMTP server.
        auth_password (str)[None]: The optional password to use to authenticate to the SMTP server.


    Raises:
        error (smtplib.SMTPException): If the email cannot be sent and the given display_method is None.
    """
    auth_server = kwargs.get('auth_server', os.environ['SMTP_SERVER'])
    auth_port = int(kwargs.get('auth_port', os.environ['SMTP_PORT']))
    auth_user = kwargs.get('auth_user', os.environ['SMTP_USERNAME'])
    auth_password = kwargs.get('auth_password', os.environ['SMTP_PASSWORD'])

    if not isinstance(recipient_list, (list, tuple)):
        raise ValueError('The recipient list argument must be a list!')

    msg = MIMEMultipart('alternative')
    msg['subject'] = str(subject)
    msg['From'] = from_email
    msg['To'] = ",".join(recipient_list)

    msg.attach(MIMEText(message, 'plain'))
    if html_message:
        # According to RFC 2046, the last part of a multipart message, in this case the HTML message,
        # is best and preferred.
        msg.attach(MIMEText(str(html_message), 'html'))

    # Setup the SMTP server and send the message
    catch_errors = (OverflowError, )  # Fake Don't catch any error
    if fail_silently:
        # Catch all
        catch_errors = (smtplib.SMTPRecipientsRefused, smtplib.SMTPHeloError, smtplib.SMTPSenderRefused,
                        smtplib.SMTPDataError, smtplib.SMTPNotSupportedError, smtplib.SMTPConnectError, Exception)

    try:
        with smtplib.SMTP_SSL(auth_server, auth_port) as smtp:
            if auth_user:
                smtp.login(auth_user, auth_password)
            smtp.set_debuglevel(False)
            smtp.sendmail(from_email, recipient_list, msg.as_string())
    except catch_errors:
        pass