allow empty metadata.startup-script

google/metadata.go

@@ -3,6 +3,7 @@ package google
 import (
 	"errors"
 	"fmt"
+
 	computeBeta "google.golang.org/api/compute/v0.beta"
 	"google.golang.org/api/compute/v1"
 )
@@ -135,7 +136,7 @@ func resourceInstanceMetadata(d TerraformResourceData) (*computeBeta.Metadata, e
 	m := &computeBeta.Metadata{}
 	mdMap := d.Get("metadata").(map[string]interface{})
 	if v, ok := d.GetOk("metadata_startup_script"); ok && v.(string) != "" {
-		if ss, ok := mdMap["startup-script"]; ok && ss != "" {
+		if _, ok := mdMap["startup-script"]; ok {
 			return nil, errors.New("Cannot provide both metadata_startup_script and metadata.startup-script.")
 		}
 		mdMap["startup-script"] = v

google/resource_compute_instance.go

@@ -787,7 +787,7 @@ func resourceComputeInstanceRead(d *schema.ResourceData, meta interface{}) error
 	// If the existing config specifies "metadata.startup-script" instead of "metadata_startup_script",
 	// we shouldn't move the remote metadata.startup-script to metadata_startup_script.  Otherwise,
 	// we should.
-	if ss, ok := existingMetadata["startup-script"]; !ok || ss == "" {
+	if _, ok := existingMetadata["startup-script"]; !ok {
 		d.Set("metadata_startup_script", md["startup-script"])
 		// Note that here we delete startup-script from our metadata list. This is to prevent storing the startup-script
 		// as a value in the metadata since the config specifically tracks it under 'metadata_startup_script'

google/resource_compute_instance_from_template_test.go

@@ -168,6 +168,29 @@ func TestAccComputeInstanceFromTemplate_012_removableFields(t *testing.T) {
 	})
 }
 
+func TestAccComputeInstanceFromTemplate_overrideMetadataDotStartupScript(t *testing.T) {
+	var instance compute.Instance
+	instanceName := fmt.Sprintf("terraform-test-%s", acctest.RandString(10))
+	templateName := fmt.Sprintf("terraform-test-%s", acctest.RandString(10))
+	resourceName := "google_compute_instance_from_template.inst"
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckComputeInstanceFromTemplateDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccComputeInstanceFromTemplate_overrideMetadataDotStartupScript(instanceName, templateName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckComputeInstanceExists(resourceName, &instance),
+					resource.TestCheckResourceAttr(resourceName, "metadata.startup-script", ""),
+				),
+			},
+		},
+	})
+
+}
+
 func testAccCheckComputeInstanceFromTemplateDestroy(s *terraform.State) error {
 	config := testAccProvider.Meta().(*Config)
 
@@ -511,3 +534,45 @@ resource "google_compute_instance_from_template" "inst" {
 }
 `, instance)
 }
+
+func testAccComputeInstanceFromTemplate_overrideMetadataDotStartupScript(instance, template string) string {
+	return fmt.Sprintf(`
+data "google_compute_image" "my_image" {
+	family  = "debian-9"
+	project = "debian-cloud"
+}
+
+resource "google_compute_instance_template" "foobar" {
+	name = "%s"
+	machine_type = "n1-standard-1"
+
+	disk {
+		source_image = "${data.google_compute_image.my_image.self_link}"
+		auto_delete = true
+		boot = true
+	}
+
+	network_interface {
+		network = "default"
+	}
+
+	metadata = {
+		startup-script = "#!/bin/bash\necho Hello"
+	}
+
+	can_ip_forward = true
+}
+
+resource "google_compute_instance_from_template" "inst" {
+	name = "%s"
+	zone = "us-central1-a"
+
+	source_instance_template = "${google_compute_instance_template.foobar.self_link}"
+
+	// Overrides
+	metadata = {
+		startup-script = ""
+	}
+}
+`, template, instance)
+}