main.tf

provider "google" {
  project = "..."
  region  = "us-central1"
  zone    = "us-central1-a"
}

locals {
  my_list_from_map = [for k, v in var.my_map : "${k}.${v}"]
}

resource "local_file" "my_file" {
  count = length(local.my_list_from_map)

  content  = local.my_list_from_map[count.index]
  filename = "${path.module}/abc_${count.index}.txt"
}

resource "local_file" "my_file_for_each" {
  for_each = { for x in var.my_list : x => x }

  content  = each.value
  filename = "${path.module}/${each.key}.txt"
}

data "template_file" "init" {
  template = "${file("${path.module}/init.tpl")}"
  vars = {
    name = "Luiz"
  }
}

resource "google_compute_instance" "default" {
  name         = "test"
  machine_type = "f1-micro"

  boot_disk {
    initialize_params {
      image = "debian-cloud/debian-9"
    }
  }

  dynamic "network_interface" {
    for_each = var.my_list

    content {
      network    = "default"
      subnetwork = network_interface.value
    }
  }
}

variable "subnet" {
  type = list(object({
    name          = string
    ip_cidr_range = string
    region        = string
  }))
}

output "subnet_ips" {
  value = var.subnet[*]["ip_cidr_range"]
}

# Variables.
# Primitives.
variable "my_string" {
  type = string
}

variable "my_number" {
  type = number
}

variable "my_bool" {
  type = bool
}

# Collections.
variable "my_list" {
  type = list(string)
}

variable "my_map" {
  type = map(string)
}

variable "my_set" {
  type = set(string)
}

# Structured.
variable "my_object" {
  type = object({
    id   = number
    name = string
  })
}

variable "my_tuple" {
  type = tuple([string, number, bool])
}

# Outputs.
output "my_string" {
  value = var.my_string
}

output "my_number" {
  value = var.my_number
}

output "my_bool" {
  value = var.my_bool
}

output "my_list" {
  value = var.my_list
}

output "my_map" {
  value = var.my_map
}

output "my_set" {
  value = var.my_set
}

output "my_object" {
  value = var.my_object
}

output "my_tuple" {
  value = var.my_tuple
}

terraform.tfvars

my_string = "abc"
my_number = 123
my_bool   = false

my_list = ["x", "y", "z"]
my_set  = ["b", "c", "d", "a"]
my_map = {
  k3 = "v3"
  k  = "v"
}

my_object = {
  id   = 123
  name = "abc"
}

my_tuple = ["abc", 123, false]


subnet = [
  {
    name          = "private"
    ip_cidr_range = "10.0.0.0/24"
    region        = "us-central1"
  },
  {
    name          = "public"
    ip_cidr_range = "192.168.0.0/24"
    region        = "us-central1"
  },
]