创建实例模板时，Terraform GCP，获取源图像的相对路径时出错

我在设置GCP实例模板时遇到了一个新问题。我假设terraform gcp提供程序上有更新。

resource "google_compute_instance_template" "backend-template" {
  name                    = "${var.platform_name}-backend-instance-template"
  description             = "Template used for backend instances"
  instance_description    = "backend Instance"
  machine_type            = "n1-standard-1"
  metadata_startup_script = "${lookup(var.startup_scripts,"backend-server")}"

disk {
  boot         = "true"
  source_image = "backend-packer-image"
}

metadata {
  APP_SETTINGS        = "${var.app_settings}"
  URL_STAGING         = "${var.url_staging}"
  API_URL_STAGING     = "${var.api_url_staging}"
  URL_PRODUCTION      = "${var.url_production}"
  API_URL_PRODUCTION  = "${var.api_url_production}"
  LOGIN_URL           = "${var.login_url}"
  API_URL             = "${var.api_url}"
  vault_server_IP     = "${lookup(var.static_ips, "vault-server")}"
  environment         = "${var.environment}"
}

network_interface {
  subnetwork = "${google_compute_subnetwork.private-fe-be.self_link}"
}

lifecycle {
  create_before_destroy = true
}

tags = ["no-ip", "backend-server"]

service_account {
  scopes = ["cloud-platform"]
}
}

这是运行脚本后的当前错误。但是，该图像backend-packer-image已经创建并存在于GCP上

* google_compute_instance_template.backend-template: 1 error(s) occurred:

* google_compute_instance_template.backend-template: error flattening disks: Error getting relative path for source image: String was not a self link: global/images/backend-packer-image