resource "aws_sns_topic_subscription" "billing_notify_slack" {
  provider  = "aws.billing"
  topic_arn = "${aws_sns_topic.budget_alerts.arn}"
  protocol  = "lambda"
  endpoint  = "${aws_lambda_function.notify_slack.arn}"
}

resource "aws_lambda_permission" "billing_notify_slack" {
  provider      = "aws.billing"
  statement_id  = "AllowExecutionFromBudgetSNS"
  action        = "lambda:InvokeFunction"
  function_name = "${aws_lambda_function.notify_slack.function_name}"
  principal     = "sns.amazonaws.com"
  source_arn    = "${aws_sns_topic.budget_alerts.arn}"
}