template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  aws-bills-on-slack stdout AWS bills to Slack channel

Parameters:
  HeaderMessageText:
    Type: String
    Default: "Here's the daily bill on our AWS accounts:"
    Description: 'A short text that is prefixed to Slack message. See the screenshot example here - https://github.com/toricls/aws-bills-on-slack#readme.'
    MaxLength: 256
    MinLength: 0
  FooterMessageText:
    Type: String
    Default: ""
    Description: 'A short text that is suffixed to Slack message.'
    MaxLength: 256
    MinLength: 0
  OuId:
    Type: String
    Description: 'A Root ID or an OrganizationalUnit (OU) ID of your AWS Organization. aws-bills-on-slack fetchs the cost of AWS accounts under the specified Root or OU.'
    AllowedPattern: '^(r-[0-9a-z]{4,32})|(ou-[0-9a-z]{4,32}-[a-z0-9]{8,32})$'
  SlackIncomingWebhookUrl:
    Type: String
    Description: 'A url of Slack Incoming Webhook. See the doc to get your own - '
    AllowedPattern: '^https\:\/\/hooks\.slack\.com\/.*$'
  CronScheduleString:
    Type: String
    Description: "A cron string to run the script. The defualt value is 'cron(0 0 * * ? *)', which means the script would run at 0 AM UTC every day. See the expressions guide here - https://docs.aws.amazon.com/scheduler/latest/UserGuide/schedule-types.html#cron-based."
    Default: 'cron(0 0 * * ? *)'

Globals:
  Function:
    Timeout: 10

Resources:
  AwsBillsOnSlackFunc:
    Type: AWS::Serverless::Function # More info about Function Resource: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#awsserverlessfunction
    Properties:
      CodeUri: ./../../ # Points the root directory of the repository
      Handler: main
      Runtime: go1.x
      Architectures:
        - x86_64
      Environment: # More info about Env Vars: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#environment-object
        Variables:
          OU_ID: !Ref OuId
          SLACK_WEBHOOK: !Ref SlackIncomingWebhookUrl
          HEADER_TEXT: !Ref HeaderMessageText
          FOOTER_TEXT: !Ref FooterMessageText
      Policies:
        - Statement:
          - Sid: AllowListAccountsAndGetCosts
            Effect: Allow
            Action:
            - organizations:ListAccountsForParent
            - ce:GetCostAndUsage
            Resource: '*'
      Events:
        EveryDayWithTimeWindow:
          Type: ScheduleV2
          Properties:
            Description: Schedule with flexible time-window for Slack notification
            FlexibleTimeWindow:
              MaximumWindowInMinutes: 5
              Mode: FLEXIBLE
            State: ENABLED
            Name: aws-bills-on-slack-schedule
            ScheduleExpression: !Ref CronScheduleString

Outputs:
  AwsBillsOnSlackFuncArn:
    Description: "aws-bills-on-slack Lambda Function ARN"
    Value: !GetAtt AwsBillsOnSlackFunc.Arn