Painlessly create or update a CloudFormation stack in an idempotent way

When integrating CloudFormation into your CI/CD pipeline you are faced with the challenge of creating a CloudFormation stack on the first run of the pipeline, while you need to update the stack for all following pipeline runs. If you use the AWS CLI this is painful.

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You may also have your code and template in the same repository. Therefore code changes without the template. But the AWS CLI threats an update without changes to a stack as an error which is not the behavior that you need in your pipeline.

cfn-create-or-update can create or update a CloudFormation stack. If no updates are to be performed, no error is thrown. cfn-create-or-update behaves exactly as the AWS CLI regarding input values, output will be different.

Installation

To install the CLI tool cfn-create-or-update, run:

npm install -g cfn-create-or-update

To create or update a stack, run:

cfn-create-or-update --stack-name test --template-body file://template.yml

The first time you run this command, a stack will be created. The second time an update will be performed but only if the template has changes.

CLI parameters

cfn-create-or-update behaves exactly as the AWS CLI regarding input values. Supported parameters (as documented in the AWS CLI create-stack or update-stack):

cfn-create-or-update
--stack-name
--template-body
--template-url
--parameters
--capabilities 
--resource-types
--role-arn
--stack-policy-body
--stack-policy-url
--notification-arns
--tags

Global parameters (as documented in the AWS CLI

--profile
--region

Only used during create, otherwise ignored (as documented in the AWS CLI create-stack):

--disable-rollback | --no-disable-rollback
--timeout-in-minutes
--on-failure

Only used during update, otherwise ignored (as documented in the AWS CLI update-stack):

--use-previous-template | --no-use-previous-template]
--stack-policy-during-update-body
--stack-policy-during-update-url

Additional parameter, to wait for create complete / update complete.

---wait

cfn-create-or-update is available on GitHub for free (MIT license).

Other solutions to this problem:

• Use AWS CodePipeline
• Idempotent CloudFormation stack creation/update one-liner with Ansible