Creating a custom Lambda function for Amazon IoT Events

You can create a Lambda function or modify the one provided by Amazon IoT Events.

The following requirements apply when you create a custom Lambda function.

Example Lambda function:

import boto3
import json
import logging
import datetime
logger = logging.getLogger()
logger.setLevel(logging.INFO)
ses = boto3.client('ses')
sns = boto3.client('sns')
def check_value(target):
  if target:
    return True
  return False

# Check whether email is verified. Only verified emails are allowed to send emails to or from.
def check_email(email):
  if not check_value(email):
    return False
  result = ses.get_identity_verification_attributes(Identities=[email])
  attr = result['VerificationAttributes']
  if (email not in attr or attr[email]['VerificationStatus'] != 'Success'):
      logging.info('Verification email for {} sent. You must have all the emails verified before sending email.'.format(email))
      ses.verify_email_identity(EmailAddress=email)
      return False
  return True

# Check whether the phone holder has opted out of receiving SMS messages from your account
def check_phone_number(phone_number):
  try:
    result = sns.check_if_phone_number_is_opted_out(phoneNumber=phone_number)
    if (result['isOptedOut']):
        logger.info('phoneNumber {} is not opt in of receiving SMS messages. Phone number must be opt in first.'.format(phone_number))
        return False
    return True
  except Exception as e:
    logging.error('Your phone number {} must be in E.164 format in SSO. Exception thrown: {}'.format(phone_number, e))
    return False

def check_emails(emails):
  result = True
  for email in emails:
      if not check_email(email):
          result = False
  return result

def lambda_handler(event, context):
  logging.info('Received event: ' + json.dumps(event))
  nep = json.loads(event.get('notificationEventPayload'))
  alarm_state = nep['alarmState']
  default_msg = 'Alarm ' + alarm_state['stateName'] + '\n'
  timestamp = datetime.datetime.utcfromtimestamp(float(nep['stateUpdateTime'])/1000).strftime('%Y-%m-%d %H:%M:%S')
  alarm_msg = "{} {} {} at {} UTC ".format(nep['alarmModelName'], nep.get('keyValue', 'Singleton'), alarm_state['stateName'], timestamp)
  default_msg += 'Sev: ' + str(nep['severity']) + '\n'
  if (alarm_state['ruleEvaluation']):
    property = alarm_state['ruleEvaluation']['simpleRule']['inputProperty']
    default_msg += 'Current Value: ' + str(property) + '\n'
    operator = alarm_state['ruleEvaluation']['simpleRule']['operator']
    threshold = alarm_state['ruleEvaluation']['simpleRule']['threshold']
    alarm_msg += '({} {} {})'.format(str(property), operator, str(threshold))
  default_msg += alarm_msg + '\n'

  emails = event.get('emailConfigurations', [])
  logger.info('Start Sending Emails')
  for email in emails:
    from_adr = email.get('from')
    to_adrs = email.get('to', [])
    cc_adrs = email.get('cc', [])
    bcc_adrs = email.get('bcc', [])
    msg = default_msg + '\n' + email.get('additionalMessage', '')
    subject = email.get('subject', alarm_msg)
    fa_ver = check_email(from_adr)
    tas_ver = check_emails(to_adrs)
    ccas_ver = check_emails(cc_adrs)
    bccas_ver = check_emails(bcc_adrs)
    if (fa_ver and tas_ver and ccas_ver and bccas_ver):
      ses.send_email(Source=from_adr,
                     Destination={'ToAddresses': to_adrs, 'CcAddresses': cc_adrs, 'BccAddresses': bcc_adrs},
                     Message={'Subject': {'Data': subject}, 'Body': {'Text': {'Data': msg}}})
      logger.info('Emails have been sent')

  logger.info('Start Sending SNS message to SMS')
  sns_configs = event.get('smsConfigurations', [])
  for sns_config in sns_configs:
    sns_msg = default_msg + '\n' + sns_config.get('additionalMessage', '')
    phone_numbers = sns_config.get('phoneNumbers', [])
    sender_id = sns_config.get('senderId')
    for phone_number in phone_numbers:
        if check_phone_number(phone_number):
          if check_value(sender_id):
            sns.publish(PhoneNumber=phone_number, Message=sns_msg, MessageAttributes={'AWS.SNS.SMS.SenderID':{'DataType': 'String','StringValue': sender_id}})
          else:
            sns.publish(PhoneNumber=phone_number, Message=sns_msg)
          logger.info('SNS messages have been sent')