Conditional dynamic block in list of resource

Terraform
1

Hi everyone

Currently I’m using variable list of object to input some variable , then use the variable to create a list of resource (google_compute_instance) , but now I’m facing some issue that some of the instance didn’t need a attribute block named “alias_ip_range” , so I leave “” to the variable value , and try to use conditional dynamic block in the list of resource , if the value of alias_ip isn’t equal to “” then it will have the attribute block in the resource , if it have IP in CIDR format then will create the attribute block inside the resource and the attribute value will be the value of variable alias_ip , but It keep having a issue that in the list of variable , even some objects’s alias_ip is “” , it still create the attribute block inside the resource then cause error , does anyone know how to use conditional dynamic block with list of resource , or it’s unachievable?

Variable I declared :

variable "gce" {
  type = list(object({
    hostname         = string
    ip               = string
    alias_ip         = string
    subnet           = string
    zone             = string
    instance_type    = string
    image            = string
    disk_type        = string
    boot_disk_size   = string
    second_disk_size = string
    labels           = map(string)
    tag              = list(string)
    ssh_user         = string
    status           = string
  }))
}

And what I input to the variable list :

gce = [
    { ### server_1
      hostname         = "jason-test-1"
      ip               = "192.168.1.2"
      alias_ip         = "192.168.1.10/32"
      subnet           = module.VPC.subnet_1_id
      zone             = "asia-east1-a"
      instance_type    = "e2-small"
      image            = "projects/centos-cloud/global/images/centos-7-v20210512"
      disk_type        = "pd-balanced"
      boot_disk_size   = "20"
      second_disk_size = "0"
      labels = {
        "test" = "jason"
      }
      tag      = ["jason"]
      ssh_user = "jason.hsu"
      status   = "RUNNING"
    },
    { ### server_2
      hostname         = "jason-test-2"
      ip               = "192.168.1.3"
      alias_ip         = ""
      subnet           = module.VPC.subnet_1_id
      zone             = "asia-east1-c"
      instance_type    = "e2-small"
      image            = "projects/centos-cloud/global/images/centos-7-v20210512"
      disk_type        = "pd-balanced"
      boot_disk_size   = "20"
      second_disk_size = "0"
      labels = {
        "test" = "jason"
      }
      tag      = ["jason"]
      ssh_user = "jason.hsu"
      status   = "RUNNING"
    },
  ]

And here is my list of resource code :

resource "google_compute_instance" "gce" {
  for_each       = { for instance in var.gce : instance.hostname => instance }
  name           = each.value.hostname
  machine_type   = each.value.instance_type
  tags           = each.value.tag
  zone           = each.value.zone
  desired_status = var.gce_status

  network_interface {
    subnetwork = each.value.subnet
    access_config {
      network_tier = "PREMIUM"
    }

    dynamic "alias_ip_range" {
      for_each = {for instance in var.gce: instance.hostname=>instance if instance.alias_ip != "" }
      content {
        ip_cidr_range = each.value.alias_ip
      } 
    }

  }

  service_account {
    scopes = var.service_account_scope
  }

  boot_disk {
    source = google_compute_disk.disk0[each.key].name
  }
}

Does anyone know what’s wrong with my code ? Or it’s not possible to use conditional dynamic block inside list of resource?

Jason