Managing alarm notifications

Amazon IoT Events uses a Lambda function to manage alarm notifications. You can use the Lambda function provided by Amazon IoT Events or create a new one.

Note

The alarm notifications feature isn't available in the China (Beijing) Region.

Creating a Lambda function

Amazon IoT Events provides a Lambda function that enables alarms to send and receive email and SMS notifications.

Requirements

The following requirements apply when you create a Lambda function for alarms:

If your alarm sends email or SMS notifications, you must have an IAM role that allows Amazon Lambda to work with Amazon SES and Amazon SNS.

Example policy:


{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "ses:GetIdentityVerificationAttributes",
                "ses:SendEmail",
                "ses:VerifyEmailIdentity"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Allow",
            "Action": [
                "sns:Publish",
                "sns:OptInPhoneNumber",
                "sns:CheckIfPhoneNumberIsOptedOut"
            ],
            "Resource": "*"
        },
        {
            "Effect": "Deny",
            "Action": [
                "sns:Publish"
            ],
            "Resource": "arn:aws:sns:*:*:*"
        }
    ]
}

You must choose the same Amazon Region for both Amazon IoT Events and Amazon Lambda. For the list of supported Regions, see Amazon IoT Events endpoints and quotas and Amazon Lambda endpoints and quotas in the Amazon Web Services General Reference.

Deploying a Lambda function

This tutorial uses an Amazon CloudFormation template to deploy a Lambda function. This template automatically creates an IAM role that allows the Lambda function to work with Amazon SES and Amazon SNS.

The following shows you how to use the Amazon Command Line Interface (Amazon CLI) to create a CloudFormation stack.

In your device's terminal, run aws --version to check if you installed the Amazon CLI. For more information, see Installing the Amazon CLI in the Amazon Command Line Interface User Guide.
Run aws configure list to check if you configured the Amazon CLI in the Amazon Region that has all your Amazon resources for this tutorial. For more information, see Configuring the Amazon CLI in the Amazon Command Line Interface User Guide
Download the CloudFormation template, notificationLambda.template.yaml.zip.

Note
If you have difficulty downloading the file, the template is also available in the CloudFormation template.
Unzip the content and save it locally as notificationLambda.template.yaml.
Open a terminal on your device and navigate to the directory where you downloaded the notificationLambda.template.yaml file.

To create a CloudFormation stack, run the following command:


aws cloudformation create-stack --stack-name notificationLambda-stack --template-body file://notificationLambda.template.yaml --capabilities CAPABILITY_IAM

You might modify this CloudFormation template to customize the Lambda function and its behavior.

Note

Amazon Lambda retries function errors twice. If the function doesn't have enough capacity to handle all incoming requests, events might wait in the queue for hours or days to be sent to the function. You can configure an undelivered-message queue (DLQ) on the function to capture events that weren't successfully processed. For more information, see Asynchronous invocation in the Amazon Lambda Developer Guide.

You can also create or configure the stack in the CloudFormation console. For more information, see Working with stacks, in the Amazon CloudFormation User Guide.

Creating a custom Lambda function

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.

Add permissions that allow your Lambda function to perform specified actions and access Amazon resources.
If you use the Lambda function provided by Amazon IoT Events, make sure that you choose the Python 3.7 runtime.

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')

For more information, see What is Amazon Lambda? in the Amazon Lambda Developer Guide.

CloudFormation template

Use the following CloudFormation template to create your Lambda function.


AWSTemplateFormatVersion: '2010-09-09'
Description: 'Notification Lambda for Alarm Model'
Resources:
  NotificationLambdaRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: sts:AssumeRole
      Path: "/"
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/AWSLambdaExecute'
      Policies:
        - PolicyName: "NotificationLambda"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: "Allow"
                Action:
                  - "ses:GetIdentityVerificationAttributes"
                  - "ses:SendEmail"
                  - "ses:VerifyEmailIdentity"
                Resource: "*"
              - Effect: "Allow"
                Action:
                  - "sns:Publish"
                  - "sns:OptInPhoneNumber"
                  - "sns:CheckIfPhoneNumberIsOptedOut"
                Resource: "*"
              - Effect: "Deny"
                Action:
                  - "sns:Publish"
                Resource: "arn:aws:sns:*:*:*"
  NotificationLambdaFunction:
    Type: AWS::Lambda::Function
    Properties:
      Role: !GetAtt NotificationLambdaRole.Arn
      Runtime: python3.7
      Handler: index.lambda_handler
      Timeout: 300
      MemorySize: 3008
      Code:
        ZipFile: |
          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')

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Responding to alarms

Using the Lambda function provided by Amazon IoT Events