provider/azurerm: fix servicebus_topic updating values

builtin/providers/azurerm/resource_arm_servicebus_topic.go

@@ -80,17 +80,20 @@ func resourceArmServiceBusTopic() *schema.Resource {
 			"enable_partitioning": {
 				Type:     schema.TypeBool,
 				Optional: true,
+				ForceNew: true,
 			},
 
 			"max_size_in_megabytes": {
-				Type:     schema.TypeInt,
-				Optional: true,
-				Computed: true,
+				Type:         schema.TypeInt,
+				Optional:     true,
+				Computed:     true,
+				ValidateFunc: validateArmServiceBusTopicMaxSize,
 			},
 
 			"requires_duplicate_detection": {
 				Type:     schema.TypeBool,
 				Optional: true,
+				ForceNew: true,
 			},
 
 			"support_ordering": {
@@ -199,10 +202,18 @@ func resourceArmServiceBusTopicRead(d *schema.ResourceData, meta interface{}) er
 	d.Set("enable_express", props.EnableExpress)
 	d.Set("enable_filtering_messages_before_publishing", props.FilteringMessagesBeforePublishing)
 	d.Set("enable_partitioning", props.EnablePartitioning)
-	d.Set("max_size_in_megabytes", int(*props.MaxSizeInMegabytes))
 	d.Set("requires_duplicate_detection", props.RequiresDuplicateDetection)
 	d.Set("support_ordering", props.SupportOrdering)
 
+	// if partitioning is enabled then the max size returned by the API will be
+	// 16 times greater than the value set by the user
+	if *props.EnablePartitioning {
+		const partitionCount = 16
+		d.Set("max_size_in_megabytes", int(*props.MaxSizeInMegabytes/partitionCount))
+	} else {
+		d.Set("max_size_in_megabytes", int(*props.MaxSizeInMegabytes))
+	}
+
 	return nil
 }
 
@@ -221,3 +232,12 @@ func resourceArmServiceBusTopicDelete(d *schema.ResourceData, meta interface{})
 
 	return err
 }
+
+func validateArmServiceBusTopicMaxSize(i interface{}, k string) (s []string, es []error) {
+	v := i.(int)
+	if v%1024 != 0 || v < 0 || v > 10240 {
+		es = append(es, fmt.Errorf("%q must be a multiple of 1024 up to and including 10240", k))
+	}
+
+	return
+}

builtin/providers/azurerm/resource_arm_servicebus_topic_test.go

@@ -58,6 +58,63 @@ func TestAccAzureRMServiceBusTopic_update(t *testing.T) {
 	})
 }
 
+func TestAccAzureRMServiceBusTopic_enablePartitioning(t *testing.T) {
+	ri := acctest.RandInt()
+	preConfig := fmt.Sprintf(testAccAzureRMServiceBusTopic_basic, ri, ri, ri)
+	postConfig := fmt.Sprintf(testAccAzureRMServiceBusTopic_enablePartitioning, ri, ri, ri)
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testCheckAzureRMServiceBusTopicDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: preConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMServiceBusTopicExists("azurerm_servicebus_topic.test"),
+				),
+			},
+			resource.TestStep{
+				Config: postConfig,
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(
+						"azurerm_servicebus_topic.test", "enable_partitioning", "true"),
+					// Ensure size is read back in it's original value and not the x16 value returned by Azure
+					resource.TestCheckResourceAttr(
+						"azurerm_servicebus_topic.test", "max_size_in_megabytes", "10240"),
+				),
+			},
+		},
+	})
+}
+
+func TestAccAzureRMServiceBusTopic_enableDuplicateDetection(t *testing.T) {
+	ri := acctest.RandInt()
+	preConfig := fmt.Sprintf(testAccAzureRMServiceBusTopic_basic, ri, ri, ri)
+	postConfig := fmt.Sprintf(testAccAzureRMServiceBusTopic_enableDuplicateDetection, ri, ri, ri)
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testCheckAzureRMServiceBusTopicDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config: preConfig,
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMServiceBusTopicExists("azurerm_servicebus_topic.test"),
+				),
+			},
+			resource.TestStep{
+				Config: postConfig,
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(
+						"azurerm_servicebus_topic.test", "requires_duplicate_detection", "true"),
+				),
+			},
+		},
+	})
+}
+
 func testCheckAzureRMServiceBusTopicDestroy(s *terraform.State) error {
 	client := testAccProvider.Meta().(*ArmClient).serviceBusTopicsClient
 
@@ -159,3 +216,48 @@ resource "azurerm_servicebus_topic" "test" {
     enable_express = true
 }
 `
+
+var testAccAzureRMServiceBusTopic_enablePartitioning = `
+resource "azurerm_resource_group" "test" {
+    name = "acctestRG-%d"
+    location = "West US"
+}
+
+resource "azurerm_servicebus_namespace" "test" {
+    name = "acctestservicebusnamespace-%d"
+    location = "West US"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    sku = "standard"
+}
+
+resource "azurerm_servicebus_topic" "test" {
+    name = "acctestservicebustopic-%d"
+    location = "West US"
+    namespace_name = "${azurerm_servicebus_namespace.test.name}"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    enable_partitioning = true
+	max_size_in_megabytes = 10240
+}
+`
+
+var testAccAzureRMServiceBusTopic_enableDuplicateDetection = `
+resource "azurerm_resource_group" "test" {
+    name = "acctestRG-%d"
+    location = "West US"
+}
+
+resource "azurerm_servicebus_namespace" "test" {
+    name = "acctestservicebusnamespace-%d"
+    location = "West US"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    sku = "standard"
+}
+
+resource "azurerm_servicebus_topic" "test" {
+    name = "acctestservicebustopic-%d"
+    location = "West US"
+    namespace_name = "${azurerm_servicebus_namespace.test.name}"
+    resource_group_name = "${azurerm_resource_group.test.name}"
+    requires_duplicate_detection = true
+}
+`

website/source/docs/providers/azurerm/r/servicebus_topic.html.markdown

@@ -82,12 +82,16 @@ The following arguments are supported:
 
 * `enable_partitioning` - (Optional) Boolean flag which controls whether to enable
     the topic to be partitioned across multiple message brokers. Defaults to false.
+    Changing this forces a new resource to be created.
 
 * `max_size_in_megabytes` - (Optional) Integer value which controls the size of
-    memory allocated for the topic.
+    memory allocated for the topic. Supported values are multiples of 1024 up to
+    10240, if `enable_partitioning` is enabled then 16 partitions will be created
+    per GB, making the maximum possible topic size 163840 (10240 * 16).
 
 * `requires_duplicate_detection` - (Optional) Boolean flag which controls whether
-    the Topic requires duplicate detection. Defaults to false.
+    the Topic requires duplicate detection. Defaults to false. Changing this forces
+    a new resource to be created.
 
 * `support_ordering` - (Optional) Boolean flag which controls whether the Topic
     supports ordering. Defaults to false.