I am trying to validate an AWS example CloudFormation template using a command like:
▶ aws cloudformation validate-template --template-body template.yml
This leads to the following error message:
An error occurred (ValidationError) when calling the ValidateTemplate operation:
Template format error: unsupported structure.
I tried this on many templates, including example templates from the AWS documentation. So I know the templates are okay.
What am I doing wrong?
Apparently, the very unhelpful error message comes as a result of improper formatting in the CLI command.
The --template-body argument must be specified as a file URI.
Thus, the correct, runnable form of the command above is:
▶ aws cloudformation validate-template --template-body file://template.yml
See this blog post for more information.