Nonscalar resolver and hook arguments

[sftrabbit]

YAML's tag syntax supports nonscalar tag arguments, such as lists or mappings (or even other tags). For example:

!sometag
  foo: bar
  baz: 123

However, Sceptre doesn't allow this for the arguments of resolvers and hooks. The resolver and hook constructors added to the YAML loader assume a scalar argument when calling loader.construct_scalar(node) (for both resolvers and hooks).

It would be useful to support nonscalar arguments for both resolvers and hooks for more configurable cases such as something like this:

!s3_upload
  path: some/file/path
  s3_bucket: !stack_output another_stack::BucketName
  s3_object_key: some_key

(Note the nested resolver! That's a bonus!)

There's a few ways to work around this at the moment, such as by passing things through sceptre_user_data or by passing strings that you parse into multiple arguments, but they typically result in some shenanigans involving using sceptre internals. Nonscalar arguments would be very neat and tidy!

PR incoming...

[cbosss]

@theseanything any thoughts on this feature? Anything I can help implement?

[ngfgrant]

Hi @sftrabbit - great issue and nice PR. Unfortunately, Sceptre has changed quite a bit. If this is still something you would like to see then you may need to redo the implementation of this 🙏

[ngfgrant]

Resolved by #473