A script to use AWS CLI to create or update a CloudFormation stackset

create-or-update-stackset.sh

#!/usr/bin/env sh
# Adapted from https://gist.github.com/mdjnewman/b9d722188f4f9c6bb277a37619665e77

usage="Usage: $(basename "$0") stack-set-name template-file administration-role-name execution-role-name
where:
  stack-set-name - the stack set name
  template-file - the file path of the template
  administration-role-name - the name of the administration role
  execution-role-name - the name of the execution role
"

if [ "$1" = "-h" ] || [ "$1" = "--help" ] || [ "$1" = "help" ] || [ "$1" = "usage" ] ; then
  printf "$usage"
  exit 1
fi

if [ -z "$1" ] || [ -z "$2" ] || [ -z "$3" ] || [ -z "$4" ] ; then
  printf "$usage"
  exit 1
fi

account_id=$(aws sts get-caller-identity --query Account --output text)

printf "Checking if stack set exists ...\n"

if ! aws cloudformation describe-stack-set --stack-set-name $1 ; then

  printf "\nStack set does not exist, creating ...\n"
  aws cloudformation create-stack-set \
    --stack-set-name $1 \
    --template-body file://$2 \
    --administration-role-arn arn:aws:iam::$account_id:role/service-role/$3 \
    --execution-role-name $4

  printf "Stack set create command triggered, please verify it created successfully ...\n"

else

  printf "\nStack exists, attempting update ...\n"

  set +e
  update_output=$( aws cloudformation update-stack-set \
    --stack-set-name $1 \
    --template-body file://$2 \
    --administration-role-arn arn:aws:iam::$account_id:role/service-role/$3 \
    --execution-role-name $4 2>&1)
  status=$?
  set -e

  printf "$update_output"

  if [ $status -ne 0 ] ; then

    # Don't fail for no-op update
    if [[ $update_output == *"ValidationError"* && $update_output == *"No updates"* ]] ; then
      printf "\nFinished create/update - no updates to be performed\n"
      exit 0
    else
      exit $status
    fi

  fi

  printf "\nStack set update command triggered, please verify it created successfully ...\n"

fi