alert.yml

AWSTemplateFormatVersion: 2010-09-09
Description: >-
  Stack for alerts via SNS.
Parameters:
  Email:
    Description: Email address that will receive alerts.
    Type: String
    Default: ''
Conditions:
  HasEmail: !Not [!Equals [!Ref Email, '']]
Resources:
  Topic:
    Type: AWS::SNS::Topic
    Properties: {}

  TopicPolicy:
    Type: AWS::SNS::TopicPolicy
    Properties:
      PolicyDocument:
        Id: id1
        Version: 2012-10-17
        Statement:
        - Sid: sid1
          Effect: Allow
          Principal:
            Service:
            - 'events.amazonaws.com' # Allow CloudWatch Events
            - 'budgets.amazonaws.com' # Allow Budget Notifications
          Action: 'sns:Publish'
          Resource: !Ref Topic
        - Sid: sid2
          Effect: Allow
          Principal:
            # Allow CloudWatch Alarms, ElastiCache Notifications,
            # Elastic Beanstalk Notifications, Auto Scaling Notification
            AWS: '*'
          Action: 'sns:Publish'
          Resource: !Ref Topic
          Condition:
            StringEquals:
              'AWS:SourceOwner': !Ref 'AWS::AccountId'
        - Sid: Sid3
          Effect: Allow
          Principal:
            Service: 'ses.amazonaws.com' # Allow SES Notifications & Events
          Action: 'sns:Publish'
          Resource: !Ref Topic
          Condition:
            StringEquals:
              'AWS:Referer': !Ref 'AWS::AccountId'
      Topics:
      - !Ref Topic

  EmailSubscription:
    Condition: HasEmail
    Type: AWS::SNS::Subscription
    Properties:
      Endpoint: !Ref Email
      Protocol: email
      TopicArn: !Ref Topic

Outputs:
  TopicArn:
    Description: The ARN of the alert topic.
    Value: !Ref Topic
    Export:
      Name: !Sub '${AWS::StackName}-TopicArn'