New Data Source: azurerm_notification_hub_namespace

```
$ acctests azurerm TestAccDataSourceAzureRMNotificationHubNamespace_free
=== RUN   TestAccDataSourceAzureRMNotificationHubNamespace_free
--- PASS: TestAccDataSourceAzureRMNotificationHubNamespace_free (130.03s)
PASS
ok  	github.com/terraform-providers/terraform-provider-azurerm/azurerm	130.081s
```

azurerm/data_source_notification_hub_namespace.go

@@ -0,0 +1,110 @@
+package azurerm
+
+import (
+	"fmt"
+
+	"github.com/Azure/azure-sdk-for-go/services/notificationhubs/mgmt/2017-04-01/notificationhubs"
+	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/terraform-providers/terraform-provider-azurerm/azurerm/utils"
+)
+
+func dataSourceNotificationHubNamespace() *schema.Resource {
+	return &schema.Resource{
+		Read: resourceArmDataSourceNotificationHubNamespaceRead,
+
+		Schema: map[string]*schema.Schema{
+			"name": {
+				Type:     schema.TypeString,
+				Required: true,
+				ForceNew: true,
+			},
+
+			"resource_group_name": resourceGroupNameForDataSourceSchema(),
+
+			"location": locationForDataSourceSchema(),
+
+			"sku": {
+				Type:     schema.TypeList,
+				Computed: true,
+				Elem: &schema.Resource{
+					Schema: map[string]*schema.Schema{
+						"name": {
+							Type:     schema.TypeString,
+							Computed: true,
+						},
+					},
+				},
+			},
+
+			"enabled": {
+				Type:     schema.TypeBool,
+				Computed: true,
+			},
+
+			"namespace_type": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+
+			// NOTE: skipping tags as there's a bug in the API where the Keys for Tags are returned in lower-case
+			// Azure Rest API Specs issue: https://github.com/Azure/azure-sdk-for-go/issues/2239
+			//"tags": tagsForDataSourceSchema(),
+
+			"servicebus_endpoint": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+		},
+	}
+}
+
+func resourceArmDataSourceNotificationHubNamespaceRead(d *schema.ResourceData, meta interface{}) error {
+	client := meta.(*ArmClient).notificationNamespacesClient
+	ctx := meta.(*ArmClient).StopContext
+
+	name := d.Get("name").(string)
+	resourceGroup := d.Get("resource_group_name").(string)
+
+	resp, err := client.Get(ctx, resourceGroup, name)
+	if err != nil {
+		if utils.ResponseWasNotFound(resp.Response) {
+			return fmt.Errorf("Notification Hub Namespace %q (Resource Group %q) was not found", name, resourceGroup)
+		}
+
+		return fmt.Errorf("Error making Read request on Notification Hub Namespace %q (Resource Group %q): %+v", name, resourceGroup, err)
+	}
+
+	d.SetId(*resp.ID)
+
+	d.Set("name", resp.Name)
+	d.Set("resource_group_name", resourceGroup)
+	if location := resp.Location; location != nil {
+		d.Set("location", azureRMNormalizeLocation(*location))
+	}
+
+	sku := flattenNotificationHubDataSourceNamespacesSku(resp.Sku)
+	if err := d.Set("sku", sku); err != nil {
+		return fmt.Errorf("Error setting `sku`: %+v", err)
+	}
+
+	if props := resp.NamespaceProperties; props != nil {
+		d.Set("enabled", props.Enabled)
+		d.Set("namespace_type", props.NamespaceType)
+		d.Set("servicebus_endpoint", props.ServiceBusEndpoint)
+	}
+
+	return nil
+}
+
+func flattenNotificationHubDataSourceNamespacesSku(input *notificationhubs.Sku) []interface{} {
+	outputs := make([]interface{}, 0)
+	if input == nil {
+		return outputs
+	}
+
+	output := map[string]interface{}{
+		"name": string(input.Name),
+	}
+	outputs = append(outputs, output)
+	return outputs
+}

azurerm/data_source_notification_hub_namespace_test.go

@@ -0,0 +1,43 @@
+package azurerm
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform-website/ext/terraform/helper/acctest"
+	"github.com/hashicorp/terraform/helper/resource"
+)
+
+func TestAccDataSourceAzureRMNotificationHubNamespace_free(t *testing.T) {
+	dataSourceName := "data.azurerm_notification_hub_namespace.test"
+	rInt := acctest.RandInt()
+	location := testLocation()
+	config := testAccDataSourceAzureRMNotificationHubNamespaceFree(rInt, location)
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testCheckAzureRMNotificationHubNamespaceDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: config,
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr(dataSourceName, "namespace_type", "NotificationHub"),
+					resource.TestCheckResourceAttr(dataSourceName, "sku.0.name", "Free"),
+				),
+			},
+		},
+	})
+}
+
+func testAccDataSourceAzureRMNotificationHubNamespaceFree(rInt int, location string) string {
+	resource := testAzureRMNotificationHubNamespace_free(rInt, location)
+	return fmt.Sprintf(`
+%s
+
+data "azurerm_notification_hub_namespace" "test" {
+  name                = "${azurerm_notification_hub_namespace.test.name}"
+  resource_group_name = "${azurerm_notification_hub_namespace.test.resource_group_name}"
+}
+`, resource)
+}

azurerm/provider.go

@@ -98,6 +98,7 @@ func Provider() terraform.ResourceProvider {
 			"azurerm_managed_disk":                          dataSourceArmManagedDisk(),
 			"azurerm_network_interface":                     dataSourceArmNetworkInterface(),
 			"azurerm_network_security_group":                dataSourceArmNetworkSecurityGroup(),
+			"azurerm_notification_hub_namespace":            dataSourceNotificationHubNamespace(),
 			"azurerm_platform_image":                        dataSourceArmPlatformImage(),
 			"azurerm_public_ip":                             dataSourceArmPublicIP(),
 			"azurerm_public_ips":                            dataSourceArmPublicIPs(),

website/azurerm.erb

@@ -59,7 +59,6 @@
                     <a href="/docs/providers/azurerm/d/cosmosdb_account.html">azurerm_cosmosdb_account</a>
                 </li>
 
-
                 <li<%= sidebar_current("docs-azurerm-datasource-dns-zone") %>>
                     <a href="/docs/providers/azurerm/d/dns_zone.html">azurerm_dns_zone</a>
                 </li>
@@ -108,6 +107,10 @@
                     <a href="/docs/providers/azurerm/d/network_security_group.html">azurerm_network_security_group</a>
                 </li>
 
+                <li<%= sidebar_current("docs-azurerm-datasource-notification-hub-namespace") %>>
+                    <a href="/docs/providers/azurerm/d/notification_hub_namespace.html">azurerm_notification_hub_namespace</a>
+                </li>
+
                 <li<%= sidebar_current("docs-azurerm-datasource-platform-image") %>>
                     <a href="/docs/providers/azurerm/d/platform_image.html">azurerm_platform_image</a>
                 </li>

website/docs/d/notification_hub_namespace.html.markdown

@@ -0,0 +1,48 @@
+---
+layout: "azurerm"
+page_title: "Azure Resource Manager: azurerm_notification_hub_namespace"
+sidebar_current: "docs-azurerm-datasource-notification-hub-namespace"
+description: |-
+  Gets information about the specified Notification Hub Namespace.
+---
+
+# Data Source: azurerm_notification_hub_namespace
+
+Gets information about the specified Notification Hub Namespace.
+
+## Example Usage
+
+```hcl
+data "azurerm_notification_hub_namespace" "test" {
+  name                = "${azurerm_network_security_group.test.name}"
+  resource_group_name = "${azurerm_resource_group.test.name}"
+}
+
+output "location" {
+  value = "${data.azurerm_notification_hub_namespace.test.servicebus_endpoint}"
+}
+```
+
+## Argument Reference
+
+* `name` - (Required) Specifies the Name of the Notification Hub Namespace.
+
+* `resource_group_name` - (Required) Specifies the Name of the Resource Group within which the Notification Hub exists.
+
+## Attributes Reference
+
+* `id` - The ID of the Notification Hub Namespace.
+
+* `location` - The Azure Region in which this Notification Hub Namespace exists.
+
+* `namespace_type` - The Type of Namespace, such as `Messaging` or `NotificationHub`.
+
+* `sku` - A `sku` block as defined below.
+
+* `enabled` - Is this Notification Hub Namespace enabled?
+
+---
+
+A `sku` block exports the following:
+
+* `name` - (Required) The name of the SKU to use for this Notification Hub Namespace. Possible values are `Free`, `Basic` or `Standard.`