[MS] provider/azurerm: Data Source for Azure Resource Group (#15022)

* Data Source support for Resource Group

* Better message for mismatching locations.

* Reuse existing read code

* Adds documentation

* Adds test

* Adds a function for composing ID strings

* Change location to computed.

builtin/providers/azurerm/data_source_arm_resource_group.go

@@ -0,0 +1,44 @@
+package azurerm
+
+import (
+	"github.com/hashicorp/terraform/helper/schema"
+)
+
+func dataSourceArmResourceGroup() *schema.Resource {
+	return &schema.Resource{
+		Read: dataSourceArmResourceGroupRead,
+
+		Schema: map[string]*schema.Schema{
+			"name": &schema.Schema{
+				Type:     schema.TypeString,
+				Required: true,
+			},
+
+			"location": locationForDataSourceSchema(),
+			"tags":     tagsForDataSourceSchema(),
+		},
+	}
+}
+
+func dataSourceArmResourceGroupRead(d *schema.ResourceData, meta interface{}) error {
+	armClient := meta.(*ArmClient)
+
+	resourceGroupName := d.Get("name").(string)
+	resourceId := &ResourceID{
+		SubscriptionID: armClient.subscriptionId,
+		ResourceGroup:  resourceGroupName,
+	}
+	resourceIdString, err := composeAzureResourceID(resourceId)
+
+	if err != nil {
+		return err
+	}
+
+	d.SetId(resourceIdString)
+
+	if err := resourceArmResourceGroupRead(d, meta); err != nil {
+		return err
+	}
+
+	return nil
+}

builtin/providers/azurerm/data_source_arm_resource_group_test.go

@@ -0,0 +1,46 @@
+package azurerm
+
+import (
+	"testing"
+
+	"fmt"
+
+	"github.com/hashicorp/terraform/helper/acctest"
+	"github.com/hashicorp/terraform/helper/resource"
+)
+
+func TestAccDataSourceAzureRMResourceGroup_basic(t *testing.T) {
+	ri := acctest.RandInt()
+	name := fmt.Sprintf("acctestRg_%d", ri)
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:  func() { testAccPreCheck(t) },
+		Providers: testAccProviders,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccDataSourceAzureRMResourceGroupBasic(name),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("data.azurerm_resource_group.test", "name", name),
+					resource.TestCheckResourceAttr("data.azurerm_resource_group.test", "location", "westus2"),
+					resource.TestCheckResourceAttr("data.azurerm_resource_group.test", "tags.%", "1"),
+					resource.TestCheckResourceAttr("data.azurerm_resource_group.test", "tags.env", "test"),
+				),
+			},
+		},
+	})
+}
+
+func testAccDataSourceAzureRMResourceGroupBasic(name string) string {
+	return fmt.Sprintf(`resource "azurerm_resource_group" "test" {
+		name     = "%s"
+		location = "West US 2"
+		tags {
+			env = "test"
+		}
+	}
+
+	data "azurerm_resource_group" "test" {
+		name = "${azurerm_resource_group.test.name}"
+	}
+	`, name)
+}

builtin/providers/azurerm/location.go

@@ -16,6 +16,13 @@ func locationSchema() *schema.Schema {
 	}
 }
 
+func locationForDataSourceSchema() *schema.Schema {
+	return &schema.Schema{
+		Type:     schema.TypeString,
+		Computed: true,
+	}
+}
+
 func deprecatedLocationSchema() *schema.Schema {
 	return &schema.Schema{
 		Type:             schema.TypeString,

builtin/providers/azurerm/provider.go

@@ -62,8 +62,9 @@ func Provider() terraform.ResourceProvider {
 		},
 
 		DataSourcesMap: map[string]*schema.Resource{
-			"azurerm_client_config": dataSourceArmClientConfig(),
-			"azurerm_public_ip":     dataSourceArmPublicIP(),
+			"azurerm_client_config":  dataSourceArmClientConfig(),
+			"azurerm_resource_group": dataSourceArmResourceGroup(),
+			"azurerm_public_ip":      dataSourceArmPublicIP(),
 		},
 
 		ResourcesMap: map[string]*schema.Resource{

builtin/providers/azurerm/resourceid.go

@@ -101,6 +101,31 @@ func parseAzureResourceID(id string) (*ResourceID, error) {
 	return idObj, nil
 }
 
+func composeAzureResourceID(idObj *ResourceID) (id string, err error) {
+	if idObj.SubscriptionID == "" || idObj.ResourceGroup == "" {
+		return "", fmt.Errorf("SubscriptionID and ResourceGroup cannot be empty")
+	}
+
+	id = fmt.Sprintf("/subscriptions/%s/resourceGroups/%s", idObj.SubscriptionID, idObj.ResourceGroup)
+
+	if idObj.Provider != "" {
+		if len(idObj.Path) < 1 {
+			return "", fmt.Errorf("ResourceID.Path should have at least one item when ResourceID.Provider is specified")
+		}
+
+		id += fmt.Sprintf("/providers/%s", idObj.Provider)
+
+		for k, v := range idObj.Path {
+			if k == "" || v == "" {
+				return "", fmt.Errorf("ResourceID.Path cannot contain empty strings")
+			}
+			id += fmt.Sprintf("/%s/%s", k, v)
+		}
+	}
+
+	return
+}
+
 func parseNetworkSecurityGroupName(networkSecurityGroupId string) (string, error) {
 	id, err := parseAzureResourceID(networkSecurityGroupId)
 	if err != nil {

builtin/providers/azurerm/resourceid_test.go

@@ -143,3 +143,88 @@ func TestParseAzureResourceID(t *testing.T) {
 		}
 	}
 }
+
+func TestComposeAzureResourceID(t *testing.T) {
+	testCases := []struct {
+		resourceID  *ResourceID
+		expectedID  string
+		expectError bool
+	}{
+		{
+			&ResourceID{
+				SubscriptionID: "00000000-0000-0000-0000-000000000000",
+				ResourceGroup:  "testGroup1",
+				Provider:       "foo.bar",
+				Path: map[string]string{
+					"k1": "v1",
+					"k2": "v2",
+					"k3": "v3",
+				},
+			},
+			"/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/testGroup1/providers/foo.bar/k1/v1/k2/v2/k3/v3",
+			false,
+		},
+		{
+			&ResourceID{
+				SubscriptionID: "00000000-0000-0000-0000-000000000000",
+				ResourceGroup:  "testGroup1",
+			},
+			"/subscriptions/00000000-0000-0000-0000-000000000000/resourceGroups/testGroup1",
+			false,
+		},
+		{
+			// If Provider is specified, there must be at least one element in Path.
+			&ResourceID{
+				SubscriptionID: "00000000-0000-0000-0000-000000000000",
+				ResourceGroup:  "testGroup1",
+				Provider:       "foo.bar",
+			},
+			"",
+			true,
+		},
+		{
+			// One of the keys in Path is an empty string.
+			&ResourceID{
+				SubscriptionID: "00000000-0000-0000-0000-000000000000",
+				ResourceGroup:  "testGroup1",
+				Provider:       "foo.bar",
+				Path: map[string]string{
+					"k2": "v2",
+					"":   "v1",
+				},
+			},
+			"",
+			true,
+		},
+		{
+			// One of the values in Path is an empty string.
+			&ResourceID{
+				SubscriptionID: "00000000-0000-0000-0000-000000000000",
+				ResourceGroup:  "testGroup1",
+				Provider:       "foo.bar",
+				Path: map[string]string{
+					"k1": "v1",
+					"k2": "",
+				},
+			},
+			"",
+			true,
+		},
+	}
+
+	for _, test := range testCases {
+		idString, err := composeAzureResourceID(test.resourceID)
+
+		if test.expectError && err != nil {
+			continue
+		}
+
+		if err != nil {
+			t.Fatalf("Unexpected error: %s", err)
+		}
+
+		if test.expectedID != idString {
+			t.Fatalf("Unexpected resource ID string:\nExpected: %s\nGot:      %s\n", test.expectedID, idString)
+		}
+	}
+}

builtin/providers/azurerm/tags.go

@@ -16,6 +16,13 @@ func tagsSchema() *schema.Schema {
 	}
 }
 
+func tagsForDataSourceSchema() *schema.Schema {
+	return &schema.Schema{
+		Type:     schema.TypeMap,
+		Computed: true,
+	}
+}
+
 func tagValueToString(v interface{}) (string, error) {
 	switch value := v.(type) {
 	case string:

website/source/docs/providers/azurerm/d/resource_group.html.markdown

@@ -0,0 +1,39 @@
+---
+layout: "azurerm"
+page_title: "Azure Resource Manager: azurerm_resource_group"
+sidebar_current: "docs-azurerm-datasource-resource-group"
+description: |-
+  Get information about the specified resource group.
+---
+
+# azurerm\_resource\_group
+
+Use this data source to access the properties of an Azure resource group.
+
+## Example Usage
+
+```hcl
+data "azurerm_resource_group" "test" {
+  name = "dsrg_test"
+}
+
+resource "azurerm_managed_disk" "test" {
+  name                 = "managed_disk_name"
+  location             = "${data.azurerm_resource_group.test.location}"
+  resource_group_name  = "${data.azurerm_resource_group.test.name}"
+  storage_account_type = "Standard_LRS"
+  create_option        = "Empty"
+  disk_size_gb         = "1"
+}
+```
+
+## Argument Reference
+
+* `name` - (Required) Specifies the name of the resource group.
+
+~> **NOTE:** If the specified location doesn't match the actual resource group location, an error message with the actual location value will be shown.
+
+## Attributes Reference
+
+* `location` - The location of the resource group.
+* `tags` - A mapping of tags assigned to the resource group.

website/source/layouts/azurerm.erb

@@ -17,6 +17,11 @@
                 <li<%= sidebar_current("docs-azurerm-datasource-client-config") %>>
                     <a href="/docs/providers/azurerm/d/client_config.html">azurerm_client_config</a>
                 </li>
+
+                <li<%= sidebar_current("docs-azurerm-datasource-resource-group") %>>
+                    <a href="/docs/providers/azurerm/d/resource_group.html">azurerm_resource_group</a>
+                </li>
+
                 <li<%= sidebar_current("docs-azurerm-datasource-public-ip") %>>
                     <a href="/docs/providers/azurerm/d/public_ip.html">azurerm_public_ip</a>
                 </li>