provider/google: provide assigned_nat_ip as well as nat_ip

builtin/providers/google/resource_compute_instance.go

@@ -136,9 +136,13 @@ func resourceComputeInstance() *schema.Resource {
 								Schema: map[string]*schema.Schema{
 									"nat_ip": &schema.Schema{
 										Type:     schema.TypeString,
-										Computed: true,
 										Optional: true,
 									},
+
+									"assigned_nat_ip": &schema.Schema{
+										Type:     schema.TypeString,
+										Computed: true,
+									},
 								},
 							},
 						},
@@ -629,9 +633,10 @@ func resourceComputeInstanceRead(d *schema.ResourceData, meta interface{}) error
 			var natIP string
 			accessConfigs := make(
 				[]map[string]interface{}, 0, len(iface.AccessConfigs))
-			for _, config := range iface.AccessConfigs {
+			for j, config := range iface.AccessConfigs {
 				accessConfigs = append(accessConfigs, map[string]interface{}{
-					"nat_ip": config.NatIP,
+					"nat_ip":          d.Get(fmt.Sprintf("network_interface.%d.access_config.%d.nat_ip", i, j)),
+					"assigned_nat_ip": config.NatIP,
 				})
 
 				if natIP == "" {

website/source/docs/providers/google/r/compute_instance.html.markdown

@@ -133,6 +133,10 @@ The `access_config` block supports:
 * `nat_ip` - (Optional) The IP address that will be 1:1 mapped to the instance's network ip.  If not
   given, one will be generated.
 
+* `assigned_nat_ip` - (Optional) The IP address that is assigned to the
+  instance. If `nat_ip` is filled, it will appear here. If `nat_ip` is left
+  blank, the ephemeral assigned IP will appear here.
+
 (DEPRECATED) The `network` block supports:
 
 * `source` - (Required) The name of the network to attach this interface to.

website/source/docs/providers/google/r/dns_record_set.markdown

@@ -40,7 +40,7 @@ resource "google_dns_record_set" "frontend" {
     name = "frontend.${google_dns_managed_zone.prod.dns_name}"
     type = "A"
     ttl = 300
-    rrdatas = ["${google_compute_instance.frontend.network_interface.0.access_config.0.nat_ip}"]
+    rrdatas = ["${google_compute_instance.frontend.network_interface.0.access_config.0.assigned_nat_ip}"]
 }
 ```