lint smtp mailer file

src/smtp_mailer.py

@@ -1,78 +1,91 @@
-import boto3
+"""
+Send email through SMTP server
+"""
+
 import os
 import smtplib
 import ssl
 import logging
+import boto3
 
 from email.mime.text import MIMEText
 from email.mime.multipart import MIMEMultipart
 
-ssm = boto3.client('ssm', region_name=os.environ.get('AWS_REGION'))
+ssm = boto3.client("ssm", region_name=os.environ.get("AWS_REGION"))
 
-logger = logging.getLogger('smtp-mailer')
+logger = logging.getLogger("smtp-mailer")
 logger.setLevel(logging.INFO)
 
 # Whether to use SSL or TLS for sending mail
-SMTP_PROTOCOL = os.environ.get('SMTP_PROTOCOL', 'ssl')
+SMTP_PROTOCOL = os.environ.get("SMTP_PROTOCOL", "ssl")
 
 # Port number to use for connecting to SMTP server
-SMTP_PORT = os.environ.get('SMTP_PORT', 465)
+SMTP_PORT = os.environ.get("SMTP_PORT", 465)
 
 # Host name of server to connect
-SMTP_SERVER = os.environ.get('SMTP_SERVER', None)
+SMTP_SERVER = os.environ.get("SMTP_SERVER", None)
 
 # SSM Parameter name which holds SMTP server password
-SMTP_PASSWORD_PARAMETER = os.environ.get('SMTP_PASSWORD_PARAMETER')
+SMTP_PASSWORD_PARAMETER = os.environ.get("SMTP_PASSWORD_PARAMETER")
 
-def send_via_ssl(userName, mailFrom, smtpPassword, mailTo, mailBody):
+def send_via_ssl(user_name, mail_from, smtp_password, mail_to, mail_body):
+    """
+    Send email via SMTP over SSL
+    """
     try:
-        logger.info('Sending mail to {} ({}) via SMTP over SSL'.format(userName, mailTo))
+        logger.info("Sending mail to %f (%f) via SMTP over SSL", user_name, mail_to)
         context = ssl.create_default_context()
         with smtplib.SMTP_SSL(SMTP_SERVER, SMTP_PORT, context=context) as server:
-            server.login(mailFrom, smtpPassword)
-            server.sendmail(mailFrom, mailTo, mailBody)
-        logger.info('Mail sent to {} ({}) via SMTP over SSL'.format(userName, mailTo))
+            server.login(mail_from, smtp_password)
+            server.sendmail(mail_from, mail_to, mail_body)
+        logger.info("Mail sent to %s (%s) via SMTP over SSL", user_name, mail_to)
     except Exception as e:
-        logger.error('Unable to send mail via SSL to {}. Reason: {}'.format(mailTo, e))
+        logger.error("Unable to send mail via SSL to %s. Reason: %s", mail_to, e)
 
-def send_via_tls(userName, mailFrom, smtpPassword, mailTo, mailBody):
+def send_via_tls(user_name, mail_from, smtp_password, mail_to, mail_body):
+    """
+    Send email via SMTP over TLS
+    """
     try:
-        logger.info('Sending mail to {} ({}) via SMTP over TLS'.format(userName, mailTo))
+        logger.info("Sending mail to %s (%s) via SMTP over TLS", user_name, mail_to)
         context = ssl.create_default_context()
         with smtplib.SMTP(SMTP_SERVER, SMTP_PORT) as server:
             server.starttls(context=context)
-            server.login(mailFrom, smtpPassword)
-            server.sendmail(mailFrom, mailTo, mailBody)
-        logger.info('Mail sent to {} ({}) via SMTP over TLS'.format(userName, mailTo))
+            server.login(mail_from, smtp_password)
+            server.sendmail(mail_from, mail_to, mail_body)
+        logger.info("Mail sent to %s (%s) via SMTP over TLS", user_name, mail_to)
     except Exception as e:
-        logger.error('Unable to send mail via TLS to {}. Reason: {}'.format(mailTo, e))
+        logger.error("Unable to send mail via TLS to %s. Reason: %s", mail_to, e)
 
-def send_email(mailTo, userName, mailSubject, mailFrom, mailBodyPlain, mailBodyHtml):
+def send_email(mail_to, user_name, mail_subject, mail_from, mail_body_plain, mail_body_html):
+    """
+    Prepares message and decides if email will be sent over SSL or TLS
+    """
     if SMTP_SERVER is None:
-        logger.error('SMTP_SERVER value cannot be blank')
+        logger.error("SMTP_SERVER value cannot be blank")
         return False
 
-    logger.info('Fetching SMTP password from SSM')
+    logger.info("Fetching SMTP password from SSM")
     resp = ssm.get_parameter(
         Name=SMTP_PASSWORD_PARAMETER,
         WithDecryption=True
     )
-    smtpPassword = resp['Parameter']['Value']
+    smtp_password = resp["Parameter"]["Value"]
 
     message = MIMEMultipart("alternative")
-    message["Subject"] = mailSubject
-    message["From"] = mailFrom
-    message["To"] = mailTo
+    message["Subject"] = mail_subject
+    message["From"] = mail_from
+    message["To"] = mail_to
 
-    mailBodyPlain = MIMEText(mailBodyPlain, 'plain')
-    mailBodyHtml = MIMEText(mailBodyHtml, 'html')
+    mail_body_plain = MIMEText(mail_body_plain, "plain")
+    mail_body_html = MIMEText(mail_body_html, "html")
 
-    message.attach(mailBodyPlain)
-    message.attach(mailBodyHtml)
+    message.attach(mail_body_plain)
+    message.attach(mail_body_html)
 
-    if SMTP_PROTOCOL.lower() == 'ssl':
-        send_via_ssl(userName, mailFrom, smtpPassword, mailTo, message.as_string())
-    elif SMTP_PROTOCOL.lower() == 'tls':
-        send_via_tls(userName, mailFrom, smtpPassword, mailTo, message.as_string())
+    if SMTP_PROTOCOL.lower() == "ssl":
+        send_via_ssl(user_name, mail_from, smtp_password, mail_to, message.as_string())
+    elif SMTP_PROTOCOL.lower() == "tls":
+        send_via_tls(user_name, mail_from, smtp_password, mail_to, message.as_string())
     else:
-        logger.error('{} is not a supported SMTP protocol'.format(SMTP_PROTOCOL))
+        logger.error("%s is not a supported SMTP protocol", SMTP_PROTOCOL)