Add support for IPv6 addresses with the google_compute_external_vpn_…

…gateway terraform resource (GoogleCloudPlatform#11982)

mmv1/products/compute/ExternalVpnGateway.yaml

@@ -121,3 +121,12 @@ properties:
             Only IPv4 is supported. This IP address can be either from
             your on-premise gateway or another Cloud provider's VPN gateway,
             it cannot be an IP address from Google Compute Engine.
+        - name: 'ipv6Address'
+          type: String
+          description: |
+            IPv6 address of the interface in the external VPN gateway. This IPv6
+            address can be either from your on-premise gateway or another Cloud
+            provider's VPN gateway, it cannot be an IP address from Google Compute
+            Engine. Must specify an IPv6 address (not IPV4-mapped) using any format
+            described in RFC 4291 (e.g. 2001:db8:0:0:2d9:51:0:0). The output format
+            is RFC 5952 format (e.g. 2001:db8::2d9:51:0:0).

mmv1/third_party/terraform/services/compute/resource_compute_external_vpn_gateway_test.go

@@ -65,3 +65,42 @@ resource "google_compute_external_vpn_gateway" "external_gateway" {
 }
 `, suffix, key, value)
 }
+
+func TestAccComputeExternalVPNGateway_insertIpv6Address(t *testing.T) {
+	t.Parallel()
+
+	rnd := acctest.RandString(t, 10)
+	resourceName := "google_compute_external_vpn_gateway.external_gateway"
+
+	acctest.VcrTest(t, resource.TestCase{
+		PreCheck:                 func() { acctest.AccTestPreCheck(t) },
+		ProtoV5ProviderFactories: acctest.ProtoV5ProviderFactories(t),
+		Steps: []resource.TestStep{
+			{
+				Config: computeExternalVPNGatewayIpv6AddressConfig(rnd, "2001:db8:abcd:1234:5678:90ab:cdef:1234"),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(resourceName, "interface.0.ipv6_address", "2001:db8:abcd:1234:5678:90ab:cdef:1234"),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
+func computeExternalVPNGatewayIpv6AddressConfig(suffix, ipv6_address string) string {
+	return fmt.Sprintf(`
+resource "google_compute_external_vpn_gateway" "external_gateway" {
+  name            = "tf-test-external-gateway-%s"
+  redundancy_type = "SINGLE_IP_INTERNALLY_REDUNDANT"
+  description     = "An externally managed VPN gateway"
+  interface {
+    id           = 0
+    ipv6_address = "%s"
+  }
+}
+`, suffix, ipv6_address)
+}