prereqs for regional disks (#1753)

In testing an upcoming `google_compute_region_disk` resource, I had to make these changes. Checking them in separately so that when the magician runs, these changes will already be a part of TF.

google/disk_type.go

@@ -1,6 +1,7 @@
 package google
 
 import (
+	computeBeta "google.golang.org/api/compute/v0.beta"
 	"google.golang.org/api/compute/v1"
 )
 
@@ -13,3 +14,13 @@ func readDiskType(c *Config, zone *compute.Zone, project, name string) (*compute
 		return nil, err
 	}
 }
+
+// readRegionDiskType finds the disk type with the given name.
+func readRegionDiskType(c *Config, region *compute.Region, project, name string) (*computeBeta.DiskType, error) {
+	diskType, err := c.clientComputeBeta.RegionDiskTypes.Get(project, region.Name, name).Do()
+	if err == nil && diskType != nil && diskType.SelfLink != "" {
+		return diskType, nil
+	} else {
+		return nil, err
+	}
+}

google/field_helpers.go

@@ -46,6 +46,10 @@ func ParseDiskFieldValue(disk string, d TerraformResourceData, config *Config) (
 	return parseZonalFieldValue("disks", disk, "project", "zone", d, config, false)
 }
 
+func ParseRegionDiskFieldValue(disk string, d TerraformResourceData, config *Config) (*RegionalFieldValue, error) {
+	return parseRegionalFieldValue("disks", disk, "project", "region", "zone", d, config, false)
+}
+
 func ParseOrganizationCustomRoleName(role string) (*OrganizationFieldValue, error) {
 	return parseOrganizationFieldValue("roles", role, false)
 }

google/resource_compute_instance.go

@@ -251,7 +251,7 @@ func resourceComputeInstance() *schema.Resource {
 						"source": &schema.Schema{
 							Type:             schema.TypeString,
 							Required:         true,
-							DiffSuppressFunc: linkDiffSuppress,
+							DiffSuppressFunc: compareSelfLinkOrResourceName,
 						},
 
 						"device_name": &schema.Schema{
@@ -863,11 +863,22 @@ func resourceComputeInstanceRead(d *schema.ResourceData, meta interface{}) error
 			continue
 		}
 		disk := v.(map[string]interface{})
-		source, err := ParseDiskFieldValue(disk["source"].(string), d, config)
+		s := disk["source"].(string)
-		if err != nil {
+		var sourceLink string
-			return err
+		if strings.Contains(s, "regions/") {
+			source, err := ParseRegionDiskFieldValue(disk["source"].(string), d, config)
+			if err != nil {
+				return err
+			}
+			sourceLink = source.RelativeLink()
+		} else {
+			source, err := ParseDiskFieldValue(disk["source"].(string), d, config)
+			if err != nil {
+				return err
+			}
+			sourceLink = source.RelativeLink()
 		}
-		attachedDiskSources[source.RelativeLink()] = i
+		attachedDiskSources[sourceLink] = i
 	}
 
 	attachedDisks := make([]map[string]interface{}, d.Get("attached_disk.#").(int))
@@ -878,11 +889,21 @@ func resourceComputeInstanceRead(d *schema.ResourceData, meta interface{}) error
 		} else if disk.Type == "SCRATCH" {
 			scratchDisks = append(scratchDisks, flattenScratchDisk(disk))
 		} else {
-			source, err := ParseDiskFieldValue(disk.Source, d, config)
+			var sourceLink string
-			if err != nil {
+			if strings.Contains(disk.Source, "regions/") {
-				return err
+				source, err := ParseRegionDiskFieldValue(disk.Source, d, config)
+				if err != nil {
+					return err
+				}
+				sourceLink = source.RelativeLink()
+			} else {
+				source, err := ParseDiskFieldValue(disk.Source, d, config)
+				if err != nil {
+					return err
+				}
+				sourceLink = source.RelativeLink()
 			}
-			adIndex, inConfig := attachedDiskSources[source.RelativeLink()]
+			adIndex, inConfig := attachedDiskSources[sourceLink]
 			di := map[string]interface{}{
 				"source":      ConvertSelfLinkToV1(disk.Source),
 				"device_name": disk.DeviceName,
@@ -1408,13 +1429,24 @@ func resourceComputeInstanceUpdate(d *schema.ResourceData, meta interface{}) err
 func expandAttachedDisk(diskConfig map[string]interface{}, d *schema.ResourceData, meta interface{}) (*computeBeta.AttachedDisk, error) {
 	config := meta.(*Config)
 
-	source, err := ParseDiskFieldValue(diskConfig["source"].(string), d, config)
+	s := diskConfig["source"].(string)
-	if err != nil {
+	var sourceLink string
-		return nil, err
+	if strings.Contains(s, "regions/") {
+		source, err := ParseRegionDiskFieldValue(s, d, config)
+		if err != nil {
+			return nil, err
+		}
+		sourceLink = source.RelativeLink()
+	} else {
+		source, err := ParseDiskFieldValue(s, d, config)
+		if err != nil {
+			return nil, err
+		}
+		sourceLink = source.RelativeLink()
 	}
 
 	disk := &computeBeta.AttachedDisk{
-		Source: source.RelativeLink(),
+		Source: sourceLink,
 	}
 
 	if v, ok := diskConfig["mode"]; ok {

website/docs/r/compute_instance_template.html.markdown

@@ -206,7 +206,8 @@ The `disk` block supports:
     read-write mode.
 
 * `source` - (Required if source_image not set) The name of the disk (such as
-    those managed by `google_compute_disk`) to attach.
+    those managed by `google_compute_disk`) to attach. This cannot be a regional
+    disk.
 
 * `disk_type` - (Optional) The GCE disk type. Can be either `"pd-ssd"`,
     `"local-ssd"`, or `"pd-standard"`.