builder/googlecompute: Support provisioning VM without external IP address

This change adds an `omit_external_ip` configuration property that, when true,
will cause no external IP address to be associated with the Google Compute
Engine VM provisioned to create an image. When using `omit_external_ip`, you
must also set the `use_internal_ip` configuration property to true.

Addresses #3296

builder/googlecompute/config.go

@@ -37,6 +37,7 @@ type Config struct {
 	MachineType          string            `mapstructure:"machine_type"`
 	Metadata             map[string]string `mapstructure:"metadata"`
 	Network              string            `mapstructure:"network"`
+	OmitExternalIP       bool              `mapstructure:"omit_external_ip"`
 	Preemptible          bool              `mapstructure:"preemptible"`
 	RawStateTimeout      string            `mapstructure:"state_timeout"`
 	Region               string            `mapstructure:"region"`
@@ -169,6 +170,14 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		}
 	}
 
+	if c.OmitExternalIP && c.Address != "" {
+		errs = packer.MultiErrorAppend(fmt.Errorf("you can not specify an external address when 'omit_external_ip' is true"))
+	}
+
+	if c.OmitExternalIP && !c.UseInternalIP {
+		errs = packer.MultiErrorAppend(fmt.Errorf("'use_internal_ip' must be true if 'omit_external_ip' is true"))
+	}
+
 	// Check for any errors.
 	if errs != nil && len(errs.Errors) > 0 {
 		return nil, nil, errs

builder/googlecompute/driver.go

@@ -53,6 +53,7 @@ type InstanceConfig struct {
 	Metadata            map[string]string
 	Name                string
 	Network             string
+	OmitExternalIP      bool
 	Preemptible         bool
 	Region              string
 	ServiceAccountEmail string

builder/googlecompute/driver_gce.go

@@ -256,21 +256,24 @@ func (d *driverGCE) RunInstance(c *InstanceConfig) (<-chan error, error) {
 		subnetworkSelfLink = subnetwork.SelfLink
 	}
 
-	// If given a regional ip, get it
-	accessconfig := compute.AccessConfig{
-		Name: "AccessConfig created by Packer",
-		Type: "ONE_TO_ONE_NAT",
-	}
-
-	if c.Address != "" {
-		d.ui.Message(fmt.Sprintf("Looking up address: %s", c.Address))
-		region_url := strings.Split(zone.Region, "/")
-		region := region_url[len(region_url)-1]
-		address, err := d.service.Addresses.Get(d.projectId, region, c.Address).Do()
-		if err != nil {
-			return nil, err
+	var accessconfig *compute.AccessConfig
+	// Use external IP if OmitExternalIP isn't set
+	if !c.OmitExternalIP {
+		accessconfig = &compute.AccessConfig{
+			Name: "AccessConfig created by Packer",
+			Type: "ONE_TO_ONE_NAT",
+		}
+
+		// If given a static IP, use it
+		if c.Address != "" {
+			region_url := strings.Split(zone.Region, "/")
+			region := region_url[len(region_url)-1]
+			address, err := d.service.Addresses.Get(d.projectId, region, c.Address).Do()
+			if err != nil {
+				return nil, err
+			}
+			accessconfig.NatIP = address.Address
 		}
-		accessconfig.NatIP = address.Address
 	}
 
 	// Build up the metadata
@@ -307,11 +310,9 @@ func (d *driverGCE) RunInstance(c *InstanceConfig) (<-chan error, error) {
 		Name: c.Name,
 		NetworkInterfaces: []*compute.NetworkInterface{
 			&compute.NetworkInterface{
-				AccessConfigs: []*compute.AccessConfig{
-					&accessconfig,
-				},
-				Network:    network.SelfLink,
-				Subnetwork: subnetworkSelfLink,
+				AccessConfigs: []*compute.AccessConfig{accessconfig},
+				Network:       network.SelfLink,
+				Subnetwork:    subnetworkSelfLink,
 			},
 		},
 		Scheduling: &compute.Scheduling{

builder/googlecompute/step_create_instance.go

@@ -25,7 +25,7 @@ func (config *Config) getImage() Image {
 
 func (config *Config) getInstanceMetadata(sshPublicKey string) (map[string]string, error) {
 	instanceMetadata := make(map[string]string)
-  var err error
+	var err error
 
 	// Copy metadata from config.
 	for k, v := range config.Metadata {
@@ -77,6 +77,7 @@ func (s *StepCreateInstance) Run(state multistep.StateBag) multistep.StepAction
 		Metadata:            metadata,
 		Name:                name,
 		Network:             config.Network,
+		OmitExternalIP:      config.OmitExternalIP,
 		Preemptible:         config.Preemptible,
 		Region:              config.Region,
 		ServiceAccountEmail: config.account.ClientEmail,

website/source/docs/builders/googlecompute.html.md

@@ -146,6 +146,9 @@ builder.
 -   `network` (string) - The Google Compute network to use for the
     launched instance. Defaults to `"default"`.
 
+-   `omit_external_ip` (boolean) - If true, the instance will not have an external IP.
+    `use_internal_ip` must be true if this property is true.
+
 -   `preemptible` (boolean) - If true, launch a preembtible instance.
 
 -   `region` (string) - The region in which to launch the instance. Defaults to