Added internalIpv6Prefix attribute on Subnetwork resource

.changelog/8985.txt

@@ -0,0 +1,3 @@
+```release-note:enhancement
+compute: added output field `internal_ipv6_prefix` to `google_compute_subnetwork` resource
+```

google-beta/services/compute/resource_compute_subnetwork.go

@@ -292,6 +292,11 @@ If not specified IPV4_ONLY will be used. Possible values: ["IPV4_ONLY", "IPV4_IP
 				Description: `The gateway address for default routes to reach destination addresses
 outside this subnetwork.`,
 			},
+			"internal_ipv6_prefix": {
+				Type:        schema.TypeString,
+				Computed:    true,
+				Description: `The internal IPv6 address range that is assigned to this subnetwork.`,
+			},
 			"ipv6_cidr_range": {
 				Type:        schema.TypeString,
 				Computed:    true,
@@ -589,6 +594,9 @@ func resourceComputeSubnetworkRead(d *schema.ResourceData, meta interface{}) err
 	if err := d.Set("ipv6_cidr_range", flattenComputeSubnetworkIpv6CidrRange(res["ipv6CidrRange"], d, config)); err != nil {
 		return fmt.Errorf("Error reading Subnetwork: %s", err)
 	}
+	if err := d.Set("internal_ipv6_prefix", flattenComputeSubnetworkInternalIpv6Prefix(res["internalIpv6Prefix"], d, config)); err != nil {
+		return fmt.Errorf("Error reading Subnetwork: %s", err)
+	}
 	if err := d.Set("external_ipv6_prefix", flattenComputeSubnetworkExternalIpv6Prefix(res["externalIpv6Prefix"], d, config)); err != nil {
 		return fmt.Errorf("Error reading Subnetwork: %s", err)
 	}
@@ -1174,6 +1182,10 @@ func flattenComputeSubnetworkIpv6CidrRange(v interface{}, d *schema.ResourceData
 	return v
 }
 
+func flattenComputeSubnetworkInternalIpv6Prefix(v interface{}, d *schema.ResourceData, config *transport_tpg.Config) interface{} {
+	return v
+}
+
 func flattenComputeSubnetworkExternalIpv6Prefix(v interface{}, d *schema.ResourceData, config *transport_tpg.Config) interface{} {
 	return v
 }

google-beta/services/compute/resource_compute_subnetwork_test.go

@@ -366,6 +366,29 @@ func TestAccComputeSubnetwork_ipv6(t *testing.T) {
 	})
 }
 
+func TestAccComputeSubnetwork_internal_ipv6(t *testing.T) {
+	t.Parallel()
+
+	cnName := fmt.Sprintf("tf-test-%s", acctest.RandString(t, 10))
+	subnetworkName := fmt.Sprintf("tf-test-%s", acctest.RandString(t, 10))
+
+	acctest.VcrTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.AccTestPreCheck(t) },
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories(t),
+		CheckDestroy:             testAccCheckComputeSubnetworkDestroyProducer(t),
+		Steps: []resource.TestStep{
+			{
+				Config: testAccComputeSubnetwork_internal_ipv6(cnName, subnetworkName),
+			},
+			{
+				ResourceName:      "google_compute_subnetwork.subnetwork",
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
 func testAccCheckComputeSubnetworkExists(t *testing.T, n string, subnetwork *compute.Subnetwork) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		rs, ok := s.RootModule().Resources[n]
@@ -797,3 +820,22 @@ resource "google_compute_subnetwork" "subnetwork" {
 }
 `, cnName, subnetworkName)
 }
+
+func testAccComputeSubnetwork_internal_ipv6(cnName, subnetworkName string) string {
+	return fmt.Sprintf(`
+resource "google_compute_network" "custom-test" {
+  name                     = "%s"
+  auto_create_subnetworks  = false
+  enable_ula_internal_ipv6 = true
+}
+
+resource "google_compute_subnetwork" "subnetwork" {
+  name             = "%s"
+  ip_cidr_range    = "10.0.0.0/16"
+  region           = "us-central1"
+  network          = google_compute_network.custom-test.self_link
+  stack_type       = "IPV4_IPV6"
+  ipv6_access_type = "INTERNAL"
+}
+`, cnName, subnetworkName)
+}

website/docs/r/compute_subnetwork.html.markdown

@@ -360,6 +360,9 @@ In addition to the arguments listed above, the following computed attributes are
 * `ipv6_cidr_range` -
   The range of internal IPv6 addresses that are owned by this subnetwork.
 
+* `internal_ipv6_prefix` -
+  The internal IPv6 address range that is assigned to this subnetwork.
+
 * `external_ipv6_prefix` -
   The range of external IPv6 addresses that are owned by this subnetwork.
 * `self_link` - The URI of the created resource.