count doesn't iterate in subblocks under the resource

[cblecker]

Terraform Version

Terraform v0.7.11

Affected Resource(s)

• Tested with google_compute_backend_service, but may affect others

Terraform Configuration Files

resource "google_compute_backend_service" "backend-service" {
  name        = "backend-service"
  port_name   = "port${var.svc_port}"
  protocol    = "HTTP"
  timeout_sec = 10

  backend {
    count = "${length(var.instance_groups)}"
    group = "https://www.googleapis.com/compute/v1/projects/${var.project_name}/zones/${lookup(var.instance_groups_regions, "${var.instance_groups[count.index]}")}/instanceGroups/${var.instance_groups[count.index]}"
  }

  health_checks = ["${google_compute_http_health_check.http-health-check.self_link}"]
}

Expected Behavior

Terraform would have expanded and created multiple backend blocks inside the google_compute_backend_service resource.

Actual Behavior

* google_compute_backend_service.backend-service: backend.0: invalid or unknown key: count

Important Factoids

This may not be intended functionality, but does have useful possibilities for resources with multiple of a subblock.

[hydroxide]

Chiming in because I have already encountered several cases where this would prove useful.

• aws_instance - Conditionally declaring ebs_block_devices and ephemeral_block_devices depending on instance type
• aws_elb - Conditionally declare listeners based on environment (dev, stage, prod)

[davewalter]

We also encountered this when attempting to add a variable number of backends to a backend_service.

[zachgersh]

@jbardin - would love to actually implement this. Trying to figure out what level to implement this at and it would seem that it belongs in the schema package but I want to double check.

Other assumption, we would follow the same sort of API that count has on a resource. So, that you would get backend.0..backend.n.

[mitchellh]

Going to close this as a dup of #7034! Same idea.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

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