What is the terraform syntax to encrypt the google_compute_disk using a custom managed KMS key in the google cloud platform.
Referring the documentation and using the KMS key self_link for disk_encryption_key.raw_key seems to not work. The resulting disk generated shows the disk is encrypted via google managed key.

Please let me know if I am using a wrong format.

**resource "google_compute_disk" "ext_disk" {
  name  = "testdisk"
  type  = "pd-ssd"
  zone = "${var.zone}"
  size = 16
  labels {
    environment = "${var.target_environment}"
  }
  disk_encryption_key {
    raw_key = "${google_kms_crypto_key.crypto_key.self_link}"
  }
}**