Cloud formation Nested Stacks best way to version control templates using TemplateURL - version-control

Question

We're creating a micro-services project to be deployed in multiple environments (dev,qa, stg, prd), we plan on making use of cloud formation templates using nested stacks for the shared resources between multiple services.
The thing is that when using nested stacks you need to specify the TemplateURL of the nested resource, and this is a static URL pointing an S3 Bucket that changes every time you do update the template (Upload a new template with some changes).
So the question is, what is the best way to use a version control tool like GIT to keep track of the changes made in a nested template that once it is upload to S3 would give you a new URL?

Answer 1

The cloudformation package command in the AWS Command Line Interface will upload local artifacts (including the TemplateURL property for the AWS::CloudFormation::Stack resource) to an S3 bucket, and output a transformed CloudFormation template referencing the uploaded artifact.
Using this command, the best way to track changes would be to commit both the base template and nested-stack templates to Git, then use cloudformation package as an intermediate processing step in your deploy script, e.g., with cloudformation deploy:
S3_BUCKET=my_s3_bucket
TEMPLATE=base_template.yml
OUTPUT_TEMPLATE=$(mktemp)
aws cloudformation package \
--template-file $TEMPLATE \
--s3-bucket $S3_BUCKET \
--output-template-file $OUTPUT_TEMPLATE
aws cloudformation deploy \
--template-file $OUTPUT_TEMPLATE \
--stack-name $STACK