service.yml

AWSTemplateFormatVersion: "2010-09-09"

Transform: AWS::Serverless-2016-10-31

Description: "[CloudFormation] [Utility] Posting CloudWatch Events to Slack."

Parameters:

  Token:
    Type: String
    Description: |
      The Slack App access token the bot will use to post messages.

  Username:
    Type: String
    Description: |
      The username of the bot inside Slack. Messages will be posted under this
      username.

  Icon:
    Type: String
    ConstraintDescription: |
      Must be a slack compatible emoji, starting and ending with a colon.
    Description: |
      The Emoji Icon for the bot.

Globals:
  Function:
    Runtime: nodejs8.10
    Timeout: 10

Resources:

  EventTopic:
    Type: AWS::SNS::Topic

  EventFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: event.handler
      CodeUri: ./out
      Role: !GetAtt EventFunctionExecutionRole.Arn
      Environment:
        Variables:
          BOT_TOKEN: !Ref Token
          BOT_USERNAME: !Ref Username
          BOT_ICON: !Ref Icon

  EventFunctionLogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Sub "/aws/lambda/${EventFunction}"
      RetentionInDays: 3

  EventFunctionExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      Path: "/"
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Service:
                - !Sub "lambda.${AWS::URLSuffix}"
            Action: sts:AssumeRole

  EventFunctionExecutionPolicy:
    Type: AWS::IAM::Policy
    Properties:
      PolicyName: EventFunctionExecutionPolicy
      PolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Action:
              - logs:CreateLogGroup
              - logs:CreateLogStream
              - logs:PutLogEvents
            Resource:
              - !GetAtt EventFunctionLogGroup.Arn
      Roles:
        - !Ref EventFunctionExecutionRole

Outputs:

  EventFunction:
    Description: The name of the EventFunction to fire
    Value: !Ref EventFunction
    Export:
      Name: EventFunction

  EventFunctionArn:
    Description: The ARN of the EventFunction
    Value: !GetAtt EventFunction.Arn
    Export:
      Name: EventFunctionArn