As a specefic example, I have a group of subnets that are all used for the same thing, but are spread across multiple availabililty zones.
I'd like to be able to reference all of them as a list, so that I could do something like aws_subnet.myname[*].id to get all the subnet ids for that group of subnets.
Is there any way to do something like this?
There is no specialized feature for grouping resources, but you can do it yourself using a named local value:
locals {
subnets = flatten([aws_subnet.a, aws_subnet.b, aws_subnet.c])
}
The flatten call here is to normalize between resources with and without count set, since without count the resource expression returns just a single object while with count it is a sequence of instances.
Then elsewhere in the configuration in situations where you need all of these ids together, you can write local.subnets[*].id.