Add support for google_compute_project_metadata_item (#176)

* Add support for google_compute_project_metadata_item

This allows terraform users to manage single key/value items within the
project metadata map, rather than the entire map itself.

* Update CHANGELOG.md

* Add details about import

CHANGELOG.md

@@ -9,6 +9,7 @@ FEATURES:
 
 * **New Resource:** `google_bigtable_instance` [GH-177]
 * **New Resource:** `google_bigtable_table` [GH-177]
+* **New Resource:** `google_compute_project_metadata_item` - allows management of single key/value pairs within the project metadata map [GH-176]
 
 IMPROVEMENTS:
 

google/import_compute_project_metadata_item_test.go

@@ -0,0 +1,25 @@
+package google
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+)
+
+func TestAccComputeProjectMetadataItem_importBasic(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckProjectMetadataItemDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccProjectMetadataItem_basic("myKey", "myValue"),
+			},
+			{
+				ResourceName:      "google_compute_project_metadata_item.foobar",
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}

google/metadata.go

@@ -2,6 +2,7 @@ package google
 
 import (
 	"fmt"
+	"log"
 
 	"google.golang.org/api/compute/v1"
 )
@@ -71,3 +72,40 @@ func MetadataFormatSchema(curMDMap map[string]interface{}, md *compute.Metadata)
 
 	return newMD
 }
+
+// flattenComputeMetadata transforms a list of MetadataItems (as returned via the GCP client) into a simple map from key
+// to value.
+func flattenComputeMetadata(metadata []*compute.MetadataItems) map[string]string {
+	m := map[string]string{}
+
+	for _, item := range metadata {
+		// check for duplicates
+		if item.Value == nil {
+			continue
+		}
+		if val, ok := m[item.Key]; ok {
+			// warn loudly!
+			log.Printf("[WARN] Key '%s' already has value '%s' when flattening - ignoring incoming value '%s'",
+				item.Key,
+				val,
+				*item.Value)
+		}
+		m[item.Key] = *item.Value
+	}
+
+	return m
+}
+
+// expandComputeMetadata transforms a map representing computing metadata into a list of compute.MetadataItems suitable
+// for the GCP client.
+func expandComputeMetadata(m map[string]string) []*compute.MetadataItems {
+	metadata := make([]*compute.MetadataItems, len(m))
+
+	idx := 0
+	for key, value := range m {
+		metadata[idx] = &compute.MetadataItems{Key: key, Value: &value}
+		idx++
+	}
+
+	return metadata
+}

google/provider.go

@@ -86,6 +86,7 @@ func Provider() terraform.ResourceProvider {
 			"google_compute_instance_template":      resourceComputeInstanceTemplate(),
 			"google_compute_network":                resourceComputeNetwork(),
 			"google_compute_project_metadata":       resourceComputeProjectMetadata(),
+			"google_compute_project_metadata_item":  resourceComputeProjectMetadataItem(),
 			"google_compute_region_backend_service": resourceComputeRegionBackendService(),
 			"google_compute_route":                  resourceComputeRoute(),
 			"google_compute_router":                 resourceComputeRouter(),

google/resource_compute_project_metadata_item.go

@@ -0,0 +1,178 @@
+package google
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/hashicorp/terraform/helper/schema"
+	"google.golang.org/api/compute/v1"
+)
+
+func resourceComputeProjectMetadataItem() *schema.Resource {
+	return &schema.Resource{
+		Create: resourceComputeProjectMetadataItemCreate,
+		Read:   resourceComputeProjectMetadataItemRead,
+		Update: resourceComputeProjectMetadataItemUpdate,
+		Delete: resourceComputeProjectMetadataItemDelete,
+		Importer: &schema.ResourceImporter{
+			State: schema.ImportStatePassthrough,
+		},
+
+		Schema: map[string]*schema.Schema{
+			"key": {
+				Type:     schema.TypeString,
+				Required: true,
+				ForceNew: true,
+			},
+			"value": {
+				Type:     schema.TypeString,
+				Required: true,
+			},
+			"project": {
+				Type:     schema.TypeString,
+				Optional: true,
+				ForceNew: true,
+			},
+		},
+	}
+}
+
+func resourceComputeProjectMetadataItemCreate(d *schema.ResourceData, meta interface{}) error {
+	config := meta.(*Config)
+
+	projectID, err := getProject(d, config)
+	if err != nil {
+		return err
+	}
+
+	key := d.Get("key").(string)
+	val := d.Get("value").(string)
+
+	err = updateComputeCommonInstanceMetadata(config, projectID, key, &val)
+	if err != nil {
+		return err
+	}
+
+	d.SetId(key)
+
+	return nil
+}
+
+func resourceComputeProjectMetadataItemRead(d *schema.ResourceData, meta interface{}) error {
+	config := meta.(*Config)
+
+	projectID, err := getProject(d, config)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("[DEBUG] Loading project metadata: %s", projectID)
+	project, err := config.clientCompute.Projects.Get(projectID).Do()
+	if err != nil {
+		return fmt.Errorf("Error loading project '%s': %s", projectID, err)
+	}
+
+	md := flattenComputeMetadata(project.CommonInstanceMetadata.Items)
+	val, ok := md[d.Id()]
+	if !ok {
+		// Resource no longer exists
+		d.SetId("")
+		return nil
+	}
+
+	d.Set("key", d.Id())
+	d.Set("value", val)
+
+	return nil
+}
+
+func resourceComputeProjectMetadataItemUpdate(d *schema.ResourceData, meta interface{}) error {
+	config := meta.(*Config)
+
+	projectID, err := getProject(d, config)
+	if err != nil {
+		return err
+	}
+
+	if d.HasChange("value") {
+		key := d.Get("key").(string)
+		_, n := d.GetChange("value")
+		new := n.(string)
+
+		err = updateComputeCommonInstanceMetadata(config, projectID, key, &new)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func resourceComputeProjectMetadataItemDelete(d *schema.ResourceData, meta interface{}) error {
+	config := meta.(*Config)
+
+	projectID, err := getProject(d, config)
+	if err != nil {
+		return err
+	}
+
+	key := d.Get("key").(string)
+
+	err = updateComputeCommonInstanceMetadata(config, projectID, key, nil)
+	if err != nil {
+		return err
+	}
+
+	d.SetId("")
+	return nil
+}
+
+func updateComputeCommonInstanceMetadata(config *Config, projectID string, key string, afterVal *string) error {
+	updateMD := func() error {
+		log.Printf("[DEBUG] Loading project metadata: %s", projectID)
+		project, err := config.clientCompute.Projects.Get(projectID).Do()
+		if err != nil {
+			return fmt.Errorf("Error loading project '%s': %s", projectID, err)
+		}
+
+		md := flattenComputeMetadata(project.CommonInstanceMetadata.Items)
+
+		val, ok := md[key]
+
+		if !ok {
+			if afterVal == nil {
+				// Asked to set no value and we didn't find one - we're done
+				return nil
+			}
+		} else {
+			if afterVal != nil && *afterVal == val {
+				// Asked to set a value and it's already set - we're done.
+				return nil
+			}
+		}
+
+		if afterVal == nil {
+			delete(md, key)
+		} else {
+			md[key] = *afterVal
+		}
+
+		// Attempt to write the new value now
+		op, err := config.clientCompute.Projects.SetCommonInstanceMetadata(
+			projectID,
+			&compute.Metadata{
+				Fingerprint: project.CommonInstanceMetadata.Fingerprint,
+				Items:       expandComputeMetadata(md),
+			},
+		).Do()
+
+		if err != nil {
+			return err
+		}
+
+		log.Printf("[DEBUG] SetCommonInstanceMetadata: %d (%s)", op.Id, op.SelfLink)
+
+		return computeOperationWaitGlobal(config, op, project.Name, "SetCommonInstanceMetadata")
+	}
+
+	return MetadataRetryWrapper(updateMD)
+}

google/resource_compute_project_metadata_item_test.go

@@ -0,0 +1,118 @@
+package google
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform/helper/resource"
+	"github.com/hashicorp/terraform/terraform"
+)
+
+func TestAccComputeProjectMetadataItem_basic(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckProjectMetadataItemDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccProjectMetadataItem_basic("myKey", "myValue"),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckProjectMetadataItem_hasMetadata("myKey", "myValue"),
+				),
+			},
+		},
+	})
+}
+
+func TestAccComputeProjectMetadataItem_basicWithEmptyVal(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckProjectMetadataItemDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccProjectMetadataItem_basic("myKey", ""),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckProjectMetadataItem_hasMetadata("myKey", ""),
+				),
+			},
+		},
+	})
+}
+
+func TestAccComputeProjectMetadataItem_basicUpdate(t *testing.T) {
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckProjectMetadataItemDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccProjectMetadataItem_basic("myKey", "myValue"),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckProjectMetadataItem_hasMetadata("myKey", "myValue"),
+				),
+			},
+			{
+				Config: testAccProjectMetadataItem_basic("myKey", "myUpdatedValue"),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckProjectMetadataItem_hasMetadata("myKey", "myUpdatedValue"),
+				),
+			},
+		},
+	})
+}
+
+func testAccCheckProjectMetadataItem_hasMetadata(key, value string) resource.TestCheckFunc {
+	return func(s *terraform.State) error {
+		config := testAccProvider.Meta().(*Config)
+
+		project, err := config.clientCompute.Projects.Get(config.Project).Do()
+		if err != nil {
+			return err
+		}
+
+		metadata := flattenComputeMetadata(project.CommonInstanceMetadata.Items)
+
+		val, ok := metadata[key]
+		if !ok {
+			return fmt.Errorf("Unable to find a value for key '%s'", key)
+		}
+		if val != value {
+			return fmt.Errorf("Value for key '%s' does not match. Expected '%s' but found '%s'", key, value, val)
+		}
+		return nil
+	}
+}
+
+func testAccCheckProjectMetadataItemDestroy(s *terraform.State) error {
+	config := testAccProvider.Meta().(*Config)
+
+	project, err := config.clientCompute.Projects.Get(config.Project).Do()
+	if err != nil {
+		return err
+	}
+
+	metadata := flattenComputeMetadata(project.CommonInstanceMetadata.Items)
+
+	for _, rs := range s.RootModule().Resources {
+		if rs.Type != "google_compute_project_metadata_item" {
+			continue
+		}
+
+		_, ok := metadata[rs.Primary.ID]
+		if ok {
+			return fmt.Errorf("Metadata key/value '%s': '%s' still exist", rs.Primary.Attributes["key"], rs.Primary.Attributes["value"])
+		}
+	}
+
+	return nil
+}
+
+func testAccProjectMetadataItem_basic(key, val string) string {
+	return fmt.Sprintf(`
+resource "google_compute_project_metadata_item" "foobar" {
+  key   = "%s"
+  value = "%s"
+}
+`, key, val)
+}

website/docs/r/compute_project_metadata.html.markdown

@@ -8,7 +8,10 @@ description: |-
 
 # google\_compute\_project\_metadata
 
-Manages metadata common to all instances for a project in GCE.
+Manages metadata common to all instances for a project in GCE. If you
+want to manage only single key/value pairs within the project metadata
+rather than the entire set, then use
+[google_compute_project_metadata_item](compute_project_metadata_item.html).
 
 ## Example Usage
 

website/docs/r/compute_project_metadata_item.html.markdown

@@ -0,0 +1,48 @@
+---
+layout: "google"
+page_title: "Google: google_compute_project_metadata_item"
+sidebar_current: "docs-google-compute-project-metadata-item"
+description: |-
+  Manages a single key/value pair on common instance metadata
+---
+
+# google\_compute\_project\_metadata\_item
+
+Manages a single key/value pair on metadata common to all instances for
+a project in GCE. Using `google_compute_project_metadata_item` lets you
+manage a single key/value setting in Terraform rather than the entire
+project metadata map.
+
+## Example Usage
+
+```hcl
+resource "google_compute_project_metadata_item" "default" {
+  key = "my_metadata"
+  value = "my_value"
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `key` - (Required) The metadata key to set.
+
+* `value` - (Required) The value to set for the given metadata key.
+
+- - -
+
+* `project` - (Optional) The project in which the resource belongs. If it
+    is not provided, the provider project is used.
+
+## Attributes Reference
+
+Only the arguments listed above are exposed as attributes.
+
+## Import
+
+Project metadata items can be imported using the `key`, e.g.
+
+```
+$ terraform import google_compute_project_metadata_item.default my_metadata
+```

website/google.erb

@@ -153,6 +153,10 @@
       <a href="/docs/providers/google/r/compute_project_metadata.html">google_compute_project_metadata</a>
       </li>
 
+      <li<%= sidebar_current("docs-google-compute-project-metadata-item") %>>
+      <a href="/docs/providers/google/r/compute_project_metadata_item.html">google_compute_project_metadata_item</a>
+      </li>
+
       <li<%= sidebar_current("docs-google-compute-region-backend-service") %>>
       <a href="/docs/providers/google/r/compute_region_backend_service.html">google_compute_region_backend_service</a>
       </li>