use count instead of for_each to support conditional enabling

[milesmatthias]

Addresses issues discovered in terraform-google-modules/terraform-google-memorystore#15

[morgante]

We specifically didn't do this because count causes issues with reordering APIs.

Could we combine count and for_each?

[milesmatthias]

No, TF doesn't allow combining count and for_each: https://www.terraform.io/docs/configuration/resources.html#for_each-multiple-resource-instances-defined-by-a-map-or-set-of-strings

[milesmatthias]

The other option here is to instruct users to use this module conditionally by passing in an empty list, something like this:

  activate_apis = var.enable_apis == "true" ? [
    "redis.googleapis.com",
  ] : []

[morgante]

Could we create a local which simply does that, then for_each over the local?

[milesmatthias]

I tried that approach, and it generates the same error.

[morgante]

Ok I'm going to try some possible solutions myself.

[morgante]

@milesmatthias PTAL at #303 and confirm it works for your module.