Don't try to dedupe guest accelerator expansion code

The API calls to Google to create guest accelerators take different values
for instances and instance templates. Instance templates don't have a zone
and can thus *only* be passed a guest accelerator name.

google/field_helpers.go

@@ -46,6 +46,10 @@ func ParseOrganizationCustomRoleName(role string) (*OrganizationFieldValue, erro
 	return parseOrganizationFieldValue("roles", role, false)
 }
 
+func ParseAcceleratorFieldValue(accelerator string, d TerraformResourceData, config *Config) (*ZonalFieldValue, error) {
+	return parseZonalFieldValue("acceleratorTypes", accelerator, "project", "zone", d, config, false)
+}
+
 // ------------------------------------------------------------
 // Base helpers used to create helpers for specific fields.
 // ------------------------------------------------------------

google/resource_compute_instance.go

@@ -638,6 +638,11 @@ func resourceComputeInstanceCreate(d *schema.ResourceData, meta interface{}) err
 		return fmt.Errorf("Error creating network interfaces: %s", err)
 	}
 
+	accels, err := expandInstanceGuestAccelerators(d, config)
+	if err != nil {
+		return fmt.Errorf("Error creating guest accelerators: %s", err)
+	}
+
 	// Create the instance information
 	instance := &compute.Instance{
 		CanIpForward:      d.Get("can_ip_forward").(bool),
@@ -650,7 +655,7 @@ func resourceComputeInstanceCreate(d *schema.ResourceData, meta interface{}) err
 		Tags:              resourceInstanceTags(d),
 		Labels:            expandLabels(d),
 		ServiceAccounts:   expandServiceAccounts(d.Get("service_account").([]interface{})),
-		GuestAccelerators: expandGuestAccelerators(zone.Name, d.Get("guest_accelerator").([]interface{})),
+		GuestAccelerators: accels,
 		MinCpuPlatform:    d.Get("min_cpu_platform").(string),
 		Scheduling:        scheduling,
 	}
@@ -1123,6 +1128,30 @@ func expandAttachedDisk(diskConfig map[string]interface{}, d *schema.ResourceDat
 	return disk, nil
 }
 
+// See comment on expandInstanceTemplateGuestAccelerators regarding why this
+// code is duplicated.
+func expandInstanceGuestAccelerators(d TerraformResourceData, config *Config) ([]*compute.AcceleratorConfig, error) {
+	configs, ok := d.GetOk("guest_accelerator")
+	if !ok {
+		return nil, nil
+	}
+	accels := configs.([]interface{})
+	guestAccelerators := make([]*compute.AcceleratorConfig, len(accels))
+	for i, raw := range accels {
+		data := raw.(map[string]interface{})
+		at, err := ParseAcceleratorFieldValue(data["type"].(string), d, config)
+		if err != nil {
+			return nil, fmt.Errorf("cannot parse accelerator type: %v", err)
+		}
+		guestAccelerators[i] = &compute.AcceleratorConfig{
+			AcceleratorCount: int64(data["count"].(int)),
+			AcceleratorType:  at.RelativeLink(),
+		}
+	}
+
+	return guestAccelerators, nil
+}
+
 func resourceComputeInstanceDelete(d *schema.ResourceData, meta interface{}) error {
 	config := meta.(*Config)
 

google/resource_compute_instance_template.go

@@ -478,6 +478,35 @@ func buildDisks(d *schema.ResourceData, config *Config) ([]*compute.AttachedDisk
 	return disks, nil
 }
 
+// We don't share this code with compute instances because instances want a
+// partial URL, but instance templates want the bare accelerator name (despite
+// the docs saying otherwise).
+//
+// Using a partial URL on an instance template results in:
+// Invalid value for field 'resource.properties.guestAccelerators[0].acceleratorType':
+// 'zones/us-east1-b/acceleratorTypes/nvidia-tesla-k80'.
+// Accelerator type 'zones/us-east1-b/acceleratorTypes/nvidia-tesla-k80'
+// must be a valid resource name (not an url).
+func expandInstanceTemplateGuestAccelerators(d TerraformResourceData, config *Config) []*compute.AcceleratorConfig {
+	configs, ok := d.GetOk("guest_accelerator")
+	if !ok {
+		return nil
+	}
+	accels := configs.([]interface{})
+	guestAccelerators := make([]*compute.AcceleratorConfig, len(accels))
+	for i, raw := range accels {
+		data := raw.(map[string]interface{})
+		guestAccelerators[i] = &compute.AcceleratorConfig{
+			AcceleratorCount: int64(data["count"].(int)),
+			// We can't use ParseAcceleratorFieldValue here because an instance
+			// template does not have a zone we can use.
+			AcceleratorType: data["type"].(string),
+		}
+	}
+
+	return guestAccelerators
+}
+
 func resourceComputeInstanceTemplateCreate(d *schema.ResourceData, meta interface{}) error {
 	config := meta.(*Config)
 
@@ -545,7 +574,7 @@ func resourceComputeInstanceTemplateCreate(d *schema.ResourceData, meta interfac
 
 	instanceProperties.ServiceAccounts = expandServiceAccounts(d.Get("service_account").([]interface{}))
 
-	instanceProperties.GuestAccelerators = expandGuestAccelerators("", d.Get("guest_accelerator").([]interface{}))
+	instanceProperties.GuestAccelerators = expandInstanceTemplateGuestAccelerators(d, config)
 
 	instanceProperties.Tags = resourceInstanceTags(d)
 	if _, ok := d.GetOk("labels"); ok {

google/utils.go

@@ -596,19 +596,6 @@ func expandServiceAccounts(configs []interface{}) []*compute.ServiceAccount {
 	return accounts
 }
 
-func expandGuestAccelerators(zone string, configs []interface{}) []*compute.AcceleratorConfig {
-	guestAccelerators := make([]*compute.AcceleratorConfig, len(configs))
-	for i, raw := range configs {
-		data := raw.(map[string]interface{})
-		guestAccelerators[i] = &compute.AcceleratorConfig{
-			AcceleratorCount: int64(data["count"].(int)),
-			AcceleratorType:  acceleratorRef(zone, data["type"].(string)),
-		}
-	}
-
-	return guestAccelerators
-}
-
 func flattenGuestAccelerators(accelerators []*compute.AcceleratorConfig) []map[string]interface{} {
 	acceleratorsSchema := make([]map[string]interface{}, len(accelerators))
 	for i, accelerator := range accelerators {
@@ -619,18 +606,3 @@ func flattenGuestAccelerators(accelerators []*compute.AcceleratorConfig) []map[s
 	}
 	return acceleratorsSchema
 }
-
-// Instances want a partial URL, but instance templates want the bare
-// accelerator name without zone (despite the docs saying otherwise).
-//
-// Using a partial URL on an instance template results in:
-// Invalid value for field 'resource.properties.guestAccelerators[0].acceleratorType':
-// 'zones/us-east1-b/acceleratorTypes/nvidia-tesla-k80'.
-// Accelerator type 'zones/us-east1-b/acceleratorTypes/nvidia-tesla-k80'
-// must be a valid resource name (not an url).
-func acceleratorRef(zone, accelerator string) string {
-	if strings.HasPrefix(accelerator, "zones/") || zone == "" {
-		return accelerator
-	}
-	return fmt.Sprintf("zones/%s/acceleratorTypes/%s", zone, accelerator)
-}