How to for_each through a list(objects) in Terraform 0.12
Seem's like I found what to do. If you pass not the maps of maps but the list of maps you can use such code
resource "google_compute_instance" "node" {
for_each = {for vm in var.vms: vm.hostname => vm}
name = "${each.value.hostname}"
machine_type = "custom-${each.value.cpu}-${each.value.ram*1024}"
zone = "${var.gcp_zone}"
boot_disk {
initialize_params {
image = "${var.image_name}"
size = "${each.value.hdd}"
}
}
network_interface {
network = "${var.network}"
}
metadata = {
env_id = "${var.env_id}"
service_types = "${join(",",each.value.service_types)}"
}
}
It will create actual number of instance and when you remove for example middle one of three(if you create three:)), terraform will remove what we asked.
From Terraform 0.12, you can use the for_each with modules like the following:
modules/google_compute_instance/variables.tf
variable "hosts" {
type = map(object({
hostname = string
cpu = number
ram = number
hdd = number
log_drive = number
template = string
service_types = list(string)
}))
}
modules/google_compute_instance/main.tf
resource "google_compute_instance" "gcp_instance" {
for_each = var.hosts
hostname = each.value.repository_name
cpu = each.value.cpu
ram = each.value.ram
hdd = each.value.hdd
log_drive = each.value.log_drive
template = each.value.template
service_types = each.value.service_types
}
servers.tf
module "gcp_instances" {
source = ./modules/google_compute_instance"
hosts = {
"test1-srfe" = {
hostname = "test1-srfe",
cpu = 1,
ram = 4,
hdd = 15,
log_drive = 300,
template = "Template-New",
service_types = ["sql", "db01", "db02"]
},
"test1-second" = {
hostname = "test1-second",
cpu = 1,
ram = 4,
hdd = 15,
log_drive = 300,
template = "APPs-Template",
service_types = ["configs"]
},
}
}
Of course, you can add as many variables as needed and use them in the module.
Using the for_each block is pretty new and there's not too much documentation. Some of the best info comes from their announcement blog post: https://www.hashicorp.com/blog/hashicorp-terraform-0-12-preview-for-and-for-each/
Also make sure to check out the Dynamic Blocks section of their documentation: https://www.terraform.io/docs/configuration/expressions.html#dynamic-blocks
From what your example looks like you need to have a set of values for each instance that is created so you'll have a map of maps:
Below is an example I created using Terraform 0.12.12:
variable "hostnames" {
default = {
"one" = {
"name" = "one",
"machine" = "n1-standard-1",
"os" = "projects/coreos-cloud/global/images/coreos-stable-2247-5-0-v20191016",
"zone" = "us-central1-a"
},
"two" = {
"name" = "two",
"machine" = "n1-standard-2",
"os" = "projects/centos-cloud/global/images/centos-8-v20191018",
"zone" = "us-central1-b"
}
}
}
resource "google_compute_instance" "default" {
for_each = var.hostnames
name = each.value.name
machine_type = each.value.machine
zone = each.value.zone
boot_disk {
initialize_params {
image = each.value.os
}
}
scratch_disk {
}
network_interface {
network = "default"
}
}
Terraform plan output:
Terraform will perform the following actions:
# google_compute_instance.default["one"] will be created
+ resource "google_compute_instance" "default" {
+ can_ip_forward = false
+ cpu_platform = (known after apply)
+ deletion_protection = false
+ guest_accelerator = (known after apply)
+ id = (known after apply)
+ instance_id = (known after apply)
+ label_fingerprint = (known after apply)
+ machine_type = "n1-standard-1"
+ metadata_fingerprint = (known after apply)
+ name = "one"
+ project = (known after apply)
+ self_link = (known after apply)
+ tags_fingerprint = (known after apply)
+ zone = "us-central1-a"
+ boot_disk {
+ auto_delete = true
+ device_name = (known after apply)
+ disk_encryption_key_sha256 = (known after apply)
+ kms_key_self_link = (known after apply)
+ mode = "READ_WRITE"
+ source = (known after apply)
+ initialize_params {
+ image = "projects/coreos-cloud/global/images/coreos-stable-2247-5-0-v20191016"
+ labels = (known after apply)
+ size = (known after apply)
+ type = (known after apply)
}
}
+ network_interface {
+ address = (known after apply)
+ name = (known after apply)
+ network = "default"
+ network_ip = (known after apply)
+ subnetwork = (known after apply)
+ subnetwork_project = (known after apply)
}
+ scheduling {
+ automatic_restart = (known after apply)
+ on_host_maintenance = (known after apply)
+ preemptible = (known after apply)
+ node_affinities {
+ key = (known after apply)
+ operator = (known after apply)
+ values = (known after apply)
}
}
+ scratch_disk {
+ interface = "SCSI"
}
}
# google_compute_instance.default["two"] will be created
+ resource "google_compute_instance" "default" {
+ can_ip_forward = false
+ cpu_platform = (known after apply)
+ deletion_protection = false
+ guest_accelerator = (known after apply)
+ id = (known after apply)
+ instance_id = (known after apply)
+ label_fingerprint = (known after apply)
+ machine_type = "n1-standard-2"
+ metadata_fingerprint = (known after apply)
+ name = "two"
+ project = (known after apply)
+ self_link = (known after apply)
+ tags_fingerprint = (known after apply)
+ zone = "us-central1-b"
+ boot_disk {
+ auto_delete = true
+ device_name = (known after apply)
+ disk_encryption_key_sha256 = (known after apply)
+ kms_key_self_link = (known after apply)
+ mode = "READ_WRITE"
+ source = (known after apply)
+ initialize_params {
+ image = "projects/centos-cloud/global/images/centos-8-v20191018"
+ labels = (known after apply)
+ size = (known after apply)
+ type = (known after apply)
}
}
+ network_interface {
+ address = (known after apply)
+ name = (known after apply)
+ network = "default"
+ network_ip = (known after apply)
+ subnetwork = (known after apply)
+ subnetwork_project = (known after apply)
}
+ scheduling {
+ automatic_restart = (known after apply)
+ on_host_maintenance = (known after apply)
+ preemptible = (known after apply)
+ node_affinities {
+ key = (known after apply)
+ operator = (known after apply)
+ values = (known after apply)
}
}
+ scratch_disk {
+ interface = "SCSI"
}
}
Plan: 2 to add, 0 to change, 0 to destroy.