[WIP] Bug Fix: azurerm_application_gateway - updatable gateway subn…

…et (#3437)

azurerm/resource_arm_application_gateway.go

@@ -302,6 +302,7 @@ func resourceArmApplicationGateway() *schema.Resource {
 			"gateway_ip_configuration": {
 				Type:     schema.TypeList,
 				Required: true,
+				MaxItems: 2,
 				Elem: &schema.Resource{
 					Schema: map[string]*schema.Schema{
 						"name": {
@@ -1094,7 +1095,7 @@ func resourceArmApplicationGatewayCreateUpdate(d *schema.ResourceData, meta inte
 	backendHTTPSettingsCollection := expandApplicationGatewayBackendHTTPSettings(d, gatewayID)
 	frontendIPConfigurations := expandApplicationGatewayFrontendIPConfigurations(d)
 	frontendPorts := expandApplicationGatewayFrontendPorts(d)
-	gatewayIPConfigurations := expandApplicationGatewayIPConfigurations(d)
+	gatewayIPConfigurations, stopApplicationGateway := expandApplicationGatewayIPConfigurations(d)
 	httpListeners := expandApplicationGatewayHTTPListeners(d, gatewayID)
 	probes := expandApplicationGatewayProbes(d)
 	sku := expandApplicationGatewaySku(d)
@@ -1175,6 +1176,17 @@ func resourceArmApplicationGatewayCreateUpdate(d *schema.ResourceData, meta inte
 		gateway.ApplicationGatewayPropertiesFormat.WebApplicationFirewallConfiguration = expandApplicationGatewayWafConfig(d)
 	}
 
+	if stopApplicationGateway {
+		future, err := client.Stop(ctx, resGroup, name)
+		if err != nil {
+			return fmt.Errorf("Error Stopping Application Gateway %q (Resource Group %q): %+v", name, resGroup, err)
+		}
+
+		if err = future.WaitForCompletionRef(ctx, client.Client); err != nil {
+			return fmt.Errorf("Error waiting for the Application Gateway %q (Resource Group %q) to stop: %+v", name, resGroup, err)
+		}
+	}
+
 	future, err := client.CreateOrUpdate(ctx, resGroup, name, gateway)
 	if err != nil {
 		return fmt.Errorf("Error Creating/Updating Application Gateway %q (Resource Group %q): %+v", name, resGroup, err)
@@ -1184,6 +1196,17 @@ func resourceArmApplicationGatewayCreateUpdate(d *schema.ResourceData, meta inte
 		return fmt.Errorf("Error waiting for the create/update of Application Gateway %q (Resource Group %q): %+v", name, resGroup, err)
 	}
 
+	if stopApplicationGateway {
+		future, err := client.Start(ctx, resGroup, name)
+		if err != nil {
+			return fmt.Errorf("Error Starting Application Gateway %q (Resource Group %q): %+v", name, resGroup, err)
+		}
+
+		if err = future.WaitForCompletionRef(ctx, client.Client); err != nil {
+			return fmt.Errorf("Error waiting for the Application Gateway %q (Resource Group %q) to start: %+v", name, resGroup, err)
+		}
+	}
+
 	read, err := client.Get(ctx, resGroup, name)
 	if err != nil {
 		return fmt.Errorf("Error retrieving Application Gateway %q (Resource Group %q): %+v", name, resGroup, err)
@@ -1839,9 +1862,10 @@ func flattenApplicationGatewayHTTPListeners(input *[]network.ApplicationGatewayH
 	return results, nil
 }
 
-func expandApplicationGatewayIPConfigurations(d *schema.ResourceData) *[]network.ApplicationGatewayIPConfiguration {
+func expandApplicationGatewayIPConfigurations(d *schema.ResourceData) (*[]network.ApplicationGatewayIPConfiguration, bool) {
 	vs := d.Get("gateway_ip_configuration").([]interface{})
 	results := make([]network.ApplicationGatewayIPConfiguration, 0)
+	stopApplicationGateway := false
 
 	for _, configRaw := range vs {
 		data := configRaw.(map[string]interface{})
@@ -1860,7 +1884,35 @@ func expandApplicationGatewayIPConfigurations(d *schema.ResourceData) *[]network
 		results = append(results, output)
 	}
 
-	return &results
+	if d.HasChange("gateway_ip_configuration") {
+		oldRaw, newRaw := d.GetChange("gateway_ip_configuration")
+		oldVS := oldRaw.([]interface{})
+		newVS := newRaw.([]interface{})
+
+		// If we're creating the application gateway return the current gateway ip configuration.
+		if len(oldVS) == 0 {
+			return &results, stopApplicationGateway
+		}
+
+		// The application gateway needs to be stopped if a gateway ip configuration is added or removed
+		if len(oldVS) != len(newVS) {
+			stopApplicationGateway = true
+		}
+
+		for i, configRaw := range newVS {
+			newData := configRaw.(map[string]interface{})
+			oldData := oldVS[i].(map[string]interface{})
+
+			newSubnetID := newData["subnet_id"].(string)
+			oldSubnetID := oldData["subnet_id"].(string)
+			// The application gateway needs to be shutdown if the subnet ids don't match
+			if newSubnetID != oldSubnetID {
+				stopApplicationGateway = true
+			}
+		}
+	}
+
+	return &results, stopApplicationGateway
 }
 
 func flattenApplicationGatewayIPConfigurations(input *[]network.ApplicationGatewayIPConfiguration) []interface{} {

azurerm/resource_arm_application_gateway_test.go

@@ -778,6 +778,41 @@ func TestAccAzureRMApplicationGateway_cookieAffinity(t *testing.T) {
 	})
 }
 
+func TestAccAzureRMApplicationGateway_gatewayIP(t *testing.T) {
+	resourceName := "azurerm_application_gateway.test"
+	ri := tf.AccRandTimeInt()
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testCheckAzureRMApplicationGatewayDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAzureRMApplicationGateway_basic(ri, testLocation()),
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMApplicationGatewayExists(resourceName),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+			{
+				Config: testAccAzureRMApplicationGateway_gatewayIPUpdated(ri, testLocation()),
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMApplicationGatewayExists(resourceName),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
 func testCheckAzureRMApplicationGatewayExists(resourceName string) resource.TestCheckFunc {
 	return func(s *terraform.State) error {
 		rs, ok := s.RootModule().Resources[resourceName]
@@ -3260,3 +3295,82 @@ resource "azurerm_application_gateway" "test" {
 }
 `, template, rInt)
 }
+
+func testAccAzureRMApplicationGateway_gatewayIPUpdated(rInt int, location string) string {
+	template := testAccAzureRMApplicationGateway_template(rInt, location)
+	return fmt.Sprintf(`
+%s
+
+resource "azurerm_subnet" "test1" {
+  name                 = "subnet1-%d"
+  resource_group_name  = "${azurerm_resource_group.test.name}"
+  virtual_network_name = "${azurerm_virtual_network.test.name}"
+  address_prefix       = "10.0.1.0/24"
+}
+
+
+# since these variables are re-used - a locals block makes this more maintainable
+locals {
+  backend_address_pool_name      = "${azurerm_virtual_network.test.name}-beap"
+  frontend_port_name             = "${azurerm_virtual_network.test.name}-feport"
+  frontend_ip_configuration_name = "${azurerm_virtual_network.test.name}-feip"
+  http_setting_name              = "${azurerm_virtual_network.test.name}-be-htst"
+  listener_name                  = "${azurerm_virtual_network.test.name}-httplstn"
+  request_routing_rule_name      = "${azurerm_virtual_network.test.name}-rqrt"
+}
+
+resource "azurerm_application_gateway" "test" {
+  name                = "acctestag-%d"
+  resource_group_name = "${azurerm_resource_group.test.name}"
+  location            = "${azurerm_resource_group.test.location}"
+
+  sku {
+    name     = "Standard_Small"
+    tier     = "Standard"
+    capacity = 2
+  }
+
+  gateway_ip_configuration {
+    name      = "my-gateway-ip-configuration"
+    subnet_id = "${azurerm_subnet.test1.id}"
+  }
+
+  frontend_port {
+    name = "${local.frontend_port_name}"
+    port = 80
+  }
+
+  frontend_ip_configuration {
+    name                 = "${local.frontend_ip_configuration_name}"
+    public_ip_address_id = "${azurerm_public_ip.test.id}"
+  }
+
+  backend_address_pool {
+    name = "${local.backend_address_pool_name}"
+  }
+
+  backend_http_settings {
+    name                  = "${local.http_setting_name}"
+    cookie_based_affinity = "Disabled"
+    port                  = 80
+    protocol              = "Http"
+    request_timeout       = 1
+  }
+
+  http_listener {
+    name                           = "${local.listener_name}"
+    frontend_ip_configuration_name = "${local.frontend_ip_configuration_name}"
+    frontend_port_name             = "${local.frontend_port_name}"
+    protocol                       = "Http"
+  }
+
+  request_routing_rule {
+    name                       = "${local.request_routing_rule_name}"
+    rule_type                  = "Basic"
+    http_listener_name         = "${local.listener_name}"
+    backend_address_pool_name  = "${local.backend_address_pool_name}"
+    backend_http_settings_name = "${local.http_setting_name}"
+  }
+}
+`, template, rInt, rInt)
+}