Add subnetwork_project field to allow for XPN in GCE instances

builtin/providers/google/resource_compute_instance.go

@@ -146,6 +146,12 @@ func resourceComputeInstance() *schema.Resource {
 							ForceNew: true,
 						},
 
+						"subnetwork_project": &schema.Schema{
+							Type:     schema.TypeString,
+							Optional: true,
+							ForceNew: true,
+						},
+
 						"name": &schema.Schema{
 							Type:     schema.TypeString,
 							Computed: true,
@@ -472,6 +478,7 @@ func resourceComputeInstanceCreate(d *schema.ResourceData, meta interface{}) err
 			// Load up the name of this network_interface
 			networkName := d.Get(prefix + ".network").(string)
 			subnetworkName := d.Get(prefix + ".subnetwork").(string)
+			subnetworkProject := d.Get(prefix + ".subnetwork_project").(string)
 			address := d.Get(prefix + ".address").(string)
 			var networkLink, subnetworkLink string
 
@@ -487,8 +494,11 @@ func resourceComputeInstanceCreate(d *schema.ResourceData, meta interface{}) err
 
 			} else {
 				region := getRegionFromZone(d.Get("zone").(string))
+				if subnetworkProject == "" {
+					subnetworkProject = project
+				}
 				subnetwork, err := config.clientCompute.Subnetworks.Get(
-					project, region, subnetworkName).Do()
+					subnetworkProject, region, subnetworkName).Do()
 				if err != nil {
 					return fmt.Errorf(
 						"Error referencing subnetwork '%s' in region '%s': %s",
@@ -711,6 +721,7 @@ func resourceComputeInstanceRead(d *schema.ResourceData, meta interface{}) error
 				"address":            iface.NetworkIP,
 				"network":            d.Get(fmt.Sprintf("network_interface.%d.network", i)),
 				"subnetwork":         d.Get(fmt.Sprintf("network_interface.%d.subnetwork", i)),
+				"subnetwork_project": d.Get(fmt.Sprintf("network_interface.%d.subnetwork_project", i)),
 				"access_config":      accessConfigs,
 			})
 		}

builtin/providers/google/resource_compute_instance_test.go

@@ -2,6 +2,7 @@ package google
 
 import (
 	"fmt"
+	"os"
 	"strings"
 	"testing"
 
@@ -417,6 +418,31 @@ func TestAccComputeInstance_subnet_custom(t *testing.T) {
 	})
 }
 
+func TestAccComputeInstance_subnet_xpn(t *testing.T) {
+	var instance compute.Instance
+	var instanceName = fmt.Sprintf("instance-test-%s", acctest.RandString(10))
+	var xpn_host = os.Getenv("GOOGLE_XPN_HOST_PROJECT")
+	if xpn_host == "" {
+		t.Fatal("GOOGLE_XPN_HOST_PROJECT must be set for TestAccComputeInstance_subnet_xpn test")
+	}
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckComputeInstanceDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: testAccComputeInstance_subnet_xpn(instanceName, xpn_host),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckComputeInstanceExists(
+						"google_compute_instance.foobar", &instance),
+					testAccCheckComputeInstanceHasSubnet(&instance),
+				),
+			},
+		},
+	})
+}
+
 func TestAccComputeInstance_address_auto(t *testing.T) {
 	var instance compute.Instance
 	var instanceName = fmt.Sprintf("instance-test-%s", acctest.RandString(10))
@@ -1039,6 +1065,40 @@ func testAccComputeInstance_subnet_custom(instance string) string {
 	}`, acctest.RandString(10), acctest.RandString(10), instance)
 }
 
+func testAccComputeInstance_subnet_xpn(instance string, xpn_host string) string {
+	return fmt.Sprintf(`
+	resource "google_compute_network" "inst-test-network" {
+		name = "inst-test-network-%s"
+		auto_create_subnetworks = false
+		project = "%s"
+	}
+
+	resource "google_compute_subnetwork" "inst-test-subnetwork" {
+		name = "inst-test-subnetwork-%s"
+		ip_cidr_range = "10.0.0.0/16"
+		region = "us-central1"
+		network = "${google_compute_network.inst-test-network.self_link}"
+		project = "%s"
+	}
+
+	resource "google_compute_instance" "foobar" {
+		name = "%s"
+		machine_type = "n1-standard-1"
+		zone = "us-central1-a"
+
+		disk {
+			image = "debian-8-jessie-v20160803"
+		}
+
+		network_interface {
+			subnetwork = "${google_compute_subnetwork.inst-test-subnetwork.name}"
+			subnetwork_project = "${google_compute_subnetwork.inst-test-subnetwork.project}"
+			access_config {	}
+		}
+
+	}`, acctest.RandString(10), xpn_host, acctest.RandString(10), xpn_host, instance)
+}
+
 func testAccComputeInstance_address_auto(instance string) string {
 	return fmt.Sprintf(`
 	resource "google_compute_network" "inst-test-network" {