Fix missing `aws cloudformation ensure-stack`

I am missing

aws cloudformation ensure-stack --stack-name my-stack --local-template-file my-file.yaml

to just make the infrastructure as I described it.

Current aws cli requires awkward handling like this (pseudocode):

aws cloudformation list-stacks
if stack exists
    try
        aws cloudformation update-stack
    catch "nothing changed in your stack"
        ignore
    end
else
    aws cloudformation create-stack
end

I hope, AWS will extend awscli some day! In the mean time, to work around the pain of aws cli, since we are using ansible for orchestration anyway, I just reference the cloudformation template from an ansible playbook. Bonus: you can use some ansible, jinja2 logic or string interpolation for DRY, like e.g. using the stage name for both: template parameters and the name of the stack:

---
- name: Wrapper playbook for idempotent cloudformation stack handling
  gather_facts: false
  hosts: localhost
  vars:
    stage: None # please provide stage name
  tasks:
    - name: ensure a cloudformation stack as defined
      cloudformation:
        stack_name: "media-assets-{{ stage }}-stack"
        template: my-local-template-file.yaml
        region: eu-west-1
        template_parameters:
          topic: media
          stage: "{{ stage }}"

If you do not use ansible playbooks anyway, here are two other alternatives: