Use for_each instead of count

[gechr]

This is a pretty large change which uses Terraform 0.12.6's new resource-level for_each keyword instead of count to create >1 instances of the same resource. See hashicorp/terraform#21922 for implementation details.

It solves the general Terraform problem that, when count is used to create multiple resources, each resource is an element in a list, meaning if one is deleted/moved from the middle of the list (thus changing its numeric index), the entire list is reshuffled and a bunch of resources are destroyed/(re)created as a result. See hashicorp/terraform#14275 for the main bug report.

Fixes #38

[gechr]

The Integration tests are currently failing because the version of Terraform used for the tests is currently 0.12.3 and the changes require 0.12.6+

Error: Reserved argument name in resource block

  on ../../../organizations_iam.tf line 39, in resource "google_organization_iam_member" "organization_iam_additive":
  39:   for_each = {

The name "for_each" is reserved for use in a future version of Terraform.

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I've updated to 0.12.6 locally and run the integration tests again and they'll need to be updated before they'll pass. That said, I'd first like to understand whether this PR is likely to be accepted at all before I spend the time doing so. Thoughts?

[morgante]

Thanks for the contribution! I definitely think this is a preferable approach and we would like to go in this direction.

However, I would suggest holding on further work until we complete a planned refactor of moving each resource into a separate submodule.

[jason-huling]

Hey @morgante, is there an issue or PR tracking that refactor you mentioned?

[morgante]

Yes, see #43 to track the refactor.

[gechr]

Will revisit this once the refactor is complete.

Closing for now.