Add region_alias support for multiple aliases in a single region

[flyinbutrs]

Multiple region_aliases can now be in the same region, and with
the prepend_region_alias_to_stack_names flag set to true, the region_alias
will be part of the stack name for easier readability.

prepend_region_alias_to_stack_names: true
region_alias:
  - production: us-east-1
stacks:
  production:
    vpc:
      template: vpc.json

The config above would create a stack named "production-vpc"

It would also resolve parameters from:

parameters/vpc.json
parameters/us-east-1/vpc.json
parameters/production/vpc.json

[flyinbutrs]

FYI, I'm not entirely clear on the purpose of "additional_parameter_lookup_file_paths" vs as I did it below, explicitly resolving explicitly to the region_alias as I did below. I've preserved both, but I'm interested in the rationale behind additional_parameter_lookup_file_paths.

[stevehodgkiss]

Will this break how we currently define region aliases (as a hash)? It would be great if we could handle both to avoid having to upgrade previously written stack_master.yml files..

[flyinbutrs]

I think that was a typo in my example, but let me check. I can also rebase this now that s3 is merged in. And in the next week or so I should be able to work out the test failures.

[l-arjun-rao]

Hi @flyinbutrs and @stevehodgkiss
I chanced upon this pull-request, and this feature would really be useful to me too, as I need the ability to prefix the stack-names with prod/dev/test etc.
Just thought I'd touch base to ask if you were able to work out the test failures etc.

A big +1 from my side for this feature :-)

[et304383]

I'd honestly rather see a breaking change to just get rid of stack master using regions as keys or aliases.

I have never seen any project deal in terms of "regions" for separate stacks and I've always seen stacks separated in terms of environment (dev, staging, prod).

I highly suggest that stack master be overhauled to kill the region alias key in a major breaking release and move to using environments. Make region just an attribute of the stack so that an environment can be multi region if needed.

[patrobinson]

I highly suggest that stack master be overhauled to kill the region alias key in a major breaking release and move to using environments. Make region just an attribute of the stack so that an environment can be multi region if needed.

I agree, but I think we need to come up with a better way of handling "environments" before that can happy. Open to opinions!

[patrobinson]

This seems to have been super-seeded by #221

[patrobinson]

This PR is quite stale and has been superseeded. Closing for now but re-open when/if you're ready.