Terraform Multilevel Maps with list throwing error - google-cloud-platform

Question

I am getting below error when I execute terraform plan. I don't see any error when I use a single volume name in volume_name, I am facing this error when I specify multiple volume names in volume_name= ["test-terraform-0", "test-terraform-1", "test-terraform-2"]. I request you to help me correct my issue or suggest an alternate idea/solution achieve my goal
terraform plan -var-file=customers/nike.tfvars
│ Error: Incorrect attribute value type
│
│ on gcp_compute_disk/gcp_compute_disk.tf line 4, in resource "google_compute_disk" "disk":
│ 4: name = each.value.volume_name
│ ├────────────────
│ │ each.value.volume_name is list of string with 3 elements
│
│ Inappropriate value for attribute "name": string required.
╵
│ Error: Incorrect attribute value type
│
│ on gcp_compute_disk/gcp_compute_disk.tf line 5, in resource "google_compute_disk" "disk":
│ 5: size = each.value.volume_size
│ ├────────────────
│ │ each.value.volume_size is list of number with 3 elements
│
│ Inappropriate value for attribute "size": number required.
╷
│ Error: Incorrect attribute value type
│
│ on gcp_compute_disk/gcp_compute_disk.tf line 6, in resource "google_compute_disk" "disk":
│ 6: type = each.value.volume_type
│ ├────────────────
│ │ each.value.volume_type is list of string with 3 elements
│
│ Inappropriate value for attribute "type": string required.
folder structure
├── gcp_compute_disk
│   ├── gcp_compute_disk.tf
│   └── variables.tf
├── gcp_instance
│   ├── gcp_instance.tf
│   └── variables.tf
├── main.tf
├── customers
│   └── nike.tfvars
└── variables.tf
vairable.tf
variable "instance_config" {
type = map(object({
name = string
image = string
type = string
tags = list(string)
deletion_protection = bool
startup_script = string
hostname = string
volume_name = list(string)
volume_size = list(number)
volume_type = list(string)
}))
default = {
test_vm = {
name = "test_vm"
image = "debian-cloud/debian-9"
type = "n1-standard-4"
tags = ["test_vm"]
deletion_protection = false
startup_script = "start-up.sh"
hostname = "test_vm"
volume_name = ["test-terraform-0", "test-terraform-1", "test-terraform-2"]
volume_size = [50, 50, 50]
volume_type = ["pd-standard", "pd-standard", "pd-standard", ]
}
}
}
.tfvars
instance_config = {
testvm1 = {
name = "solr"
image = "debian-cloud/debian-9"
type = "n1-standard-4"
tags = ["testvm1"]
deletion_protection = false
startup_script = "../scripts/start-up.sh"
hostname = "testvm1.terraform.test"
volume_name = ["testvm1-test-terraform-0", "testvm1-test-terraform-1", "testvm1-test-terraform-2"]
volume_size = [50, 50, 50]
volume_type = ["pd-standard", "pd-standard", "pd-standard", ]
},
testvm2 = {
name = "testvm2"
image = "debian-cloud/debian-9"
type = "f1-micro"
tags = ["testvm2"]
deletion_protection = false
startup_script = "../scripts/start-up.sh"
hostname = "testvm2.terraform.test"
volume_name = ["testvm2-test-terraform-0", "testvm2-test-terraform-1", "testvm2-test-terraform-2"]
volume_size = [50, 50, 50]
volume_type = ["pd-standard", "pd-standard", "pd-standard", ]
}
}
gcp_compute_disk.tf
resource "google_compute_disk" "disk" {
for_each = var.instance_config
name = each.value.volume_name
size = each.value.volume_size
type = each.value.volume_type
}
gcp_instance.tf
resource "google_compute_instance" "vm_instance" {
for_each = var.instance_config
name = each.value.name
machine_type = each.value.type
tags = each.value.tags
deletion_protection = each.value.deletion_protection
hostname = each.value.hostname
boot_disk {
initialize_params {
image = each.value.image
}
}
metadata_startup_script = file(each.value.startup_script)
attached_disk {
source = each.value.volume_name
}
network_interface {
network = var.gcp_network
}
}

Answer 1

You can check the following:
locals {
instance_volume_map = merge([for key, val in var.instance_config:
{
for idx in range(length(val.volume_size)):
"${key}-${idx}" => {
volume_name = val.volume_name[idx]
volume_size = val.volume_size[idx]
volume_type = val.volume_type[idx]
}
}
]...)
}
resource "google_compute_disk" "disk" {
for_each = local.instance_volume_map
name = each.value.volume_name
size = each.value.volume_size
type = each.value.volume_type
}
resource "google_compute_instance" "vm_instance" {
for_each = var.instance_config
name = each.value.name
machine_type = each.value.type
tags = each.value.tags
deletion_protection = each.value.deletion_protection
hostname = each.value.hostname
boot_disk {
initialize_params {
image = each.value.image
}
}
metadata_startup_script = file(each.value.startup_script)
dynamic "attached_disk" {
for_each = {for idx, val in range(length(each.value.volume_name)):
idx => val}
content {
source = local.instance_volume_map["${each.key}-${attached_disk.key}"].volume_name
}
}
network_interface {
network = var.gcp_network
}
}