Convert `ena_support` to a pointer

This means it now has three states, `true`, `false`, & `nil`. The
default state is now `nil` which does nothing instead of `false` which
now will explicitly disable ENA support instead of just not enabling it.

builder/amazon/chroot/step_register_ami.go

@@ -14,7 +14,7 @@ import (
 // StepRegisterAMI creates the AMI.
 type StepRegisterAMI struct {
 	RootVolumeSize           int64
-	EnableAMIENASupport      bool
+	EnableAMIENASupport      *bool
 	EnableAMISriovNetSupport bool
 }
 
@@ -83,7 +83,7 @@ func (s *StepRegisterAMI) Run(ctx context.Context, state multistep.StateBag) mul
 		// As of February 2017, this applies to C3, C4, D2, I2, R3, and M4 (excluding m4.16xlarge)
 		registerOpts.SriovNetSupport = aws.String("simple")
 	}
-	if s.EnableAMIENASupport {
+	if s.EnableAMIENASupport != nil && *s.EnableAMIENASupport {
 		// Set EnaSupport to true
 		// As of February 2017, this applies to C5, I3, P2, R4, X1, and m4.16xlarge
 		registerOpts.EnaSupport = aws.Bool(true)

builder/amazon/common/ami_config.go

@@ -19,7 +19,7 @@ type AMIConfig struct {
 	AMIRegions              []string          `mapstructure:"ami_regions"`
 	AMISkipRegionValidation bool              `mapstructure:"skip_region_validation"`
 	AMITags                 TagMap            `mapstructure:"tags"`
-	AMIENASupport           bool              `mapstructure:"ena_support"`
+	AMIENASupport           *bool             `mapstructure:"ena_support"`
 	AMISriovNetSupport      bool              `mapstructure:"sriov_support"`
 	AMIForceDeregister      bool              `mapstructure:"force_deregister"`
 	AMIForceDeleteSnapshot  bool              `mapstructure:"force_delete_snapshot"`

builder/amazon/common/step_modify_ebs_instance.go

@@ -12,7 +12,7 @@ import (
 )
 
 type StepModifyEBSBackedInstance struct {
-	EnableAMIENASupport      bool
+	EnableAMIENASupport      *bool
 	EnableAMISriovNetSupport bool
 }
 
@@ -40,22 +40,24 @@ func (s *StepModifyEBSBackedInstance) Run(_ context.Context, state multistep.Sta
 
 	// Handle EnaSupport flag.
 	// As of February 2017, this applies to C5, I3, P2, R4, X1, and m4.16xlarge
-	var prefix string
-	if s.EnableAMIENASupport {
-		prefix = "En"
-	} else {
-		prefix = "Dis"
-	}
-	ui.Say(fmt.Sprintf("%sabling Enhanced Networking (ENA)...", prefix))
-	_, err := ec2conn.ModifyInstanceAttribute(&ec2.ModifyInstanceAttributeInput{
-		InstanceId: instance.InstanceId,
-		EnaSupport: &ec2.AttributeBooleanValue{Value: aws.Bool(s.EnableAMIENASupport)},
-	})
-	if err != nil {
-		err := fmt.Errorf("Error %sabling Enhanced Networking (ENA) on %s: %s", strings.ToLower(prefix), *instance.InstanceId, err)
-		state.Put("error", err)
-		ui.Error(err.Error())
-		return multistep.ActionHalt
+	if s.EnableAMIENASupport != nil {
+		var prefix string
+		if *s.EnableAMIENASupport {
+			prefix = "En"
+		} else {
+			prefix = "Dis"
+		}
+		ui.Say(fmt.Sprintf("%sabling Enhanced Networking (ENA)...", prefix))
+		_, err := ec2conn.ModifyInstanceAttribute(&ec2.ModifyInstanceAttributeInput{
+			InstanceId: instance.InstanceId,
+			EnaSupport: &ec2.AttributeBooleanValue{Value: aws.Bool(*s.EnableAMIENASupport)},
+		})
+		if err != nil {
+			err := fmt.Errorf("Error %sabling Enhanced Networking (ENA) on %s: %s", strings.ToLower(prefix), *instance.InstanceId, err)
+			state.Put("error", err)
+			ui.Error(err.Error())
+			return multistep.ActionHalt
+		}
 	}
 
 	return multistep.ActionContinue

builder/amazon/common/step_source_ami_info.go

@@ -20,7 +20,7 @@ import (
 type StepSourceAMIInfo struct {
 	SourceAmi                string
 	EnableAMISriovNetSupport bool
-	EnableAMIENASupport      bool
+	EnableAMIENASupport      *bool
 	AMIVirtType              string
 	AmiFilters               AmiFilterOptions
 }
@@ -106,7 +106,7 @@ func (s *StepSourceAMIInfo) Run(_ context.Context, state multistep.StateBag) mul
 
 	// Enhanced Networking can only be enabled on HVM AMIs.
 	// See http://goo.gl/icuXh5
-	if s.EnableAMIENASupport || s.EnableAMISriovNetSupport {
+	if (s.EnableAMIENASupport != nil && *s.EnableAMIENASupport) || s.EnableAMISriovNetSupport {
 		err = s.canEnableEnhancedNetworking(image)
 		if err != nil {
 			state.Put("error", err)

builder/amazon/ebs/builder.go

@@ -70,7 +70,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 	errs = packer.MultiErrorAppend(errs, b.config.BlockDevices.Prepare(&b.config.ctx)...)
 	errs = packer.MultiErrorAppend(errs, b.config.RunConfig.Prepare(&b.config.ctx)...)
 
-	if b.config.IsSpotInstance() && (b.config.AMIENASupport || b.config.AMISriovNetSupport) {
+	if b.config.IsSpotInstance() && ((b.config.AMIENASupport != nil && *b.config.AMIENASupport) || b.config.AMISriovNetSupport) {
 		errs = packer.MultiErrorAppend(errs,
 			fmt.Errorf("Spot instances do not support modification, which is required "+
 				"when either `ena_support` or `sriov_support` are set. Please ensure "+

builder/amazon/ebssurrogate/builder.go

@@ -85,7 +85,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 		errs = packer.MultiErrorAppend(errs, fmt.Errorf("no volume with name '%s' is found", b.config.RootDevice.SourceDeviceName))
 	}
 
-	if b.config.IsSpotInstance() && (b.config.AMIENASupport || b.config.AMISriovNetSupport) {
+	if b.config.IsSpotInstance() && ((b.config.AMIENASupport != nil && *b.config.AMIENASupport) || b.config.AMISriovNetSupport) {
 		errs = packer.MultiErrorAppend(errs,
 			fmt.Errorf("Spot instances do not support modification, which is required "+
 				"when either `ena_support` or `sriov_support` are set. Please ensure "+

builder/amazon/ebssurrogate/step_register_ami.go

@@ -16,7 +16,7 @@ type StepRegisterAMI struct {
 	RootDevice               RootBlockDevice
 	AMIDevices               []*ec2.BlockDeviceMapping
 	LaunchDevices            []*ec2.BlockDeviceMapping
-	EnableAMIENASupport      bool
+	EnableAMIENASupport      *bool
 	EnableAMISriovNetSupport bool
 	image                    *ec2.Image
 }
@@ -44,7 +44,7 @@ func (s *StepRegisterAMI) Run(ctx context.Context, state multistep.StateBag) mul
 		// As of February 2017, this applies to C3, C4, D2, I2, R3, and M4 (excluding m4.16xlarge)
 		registerOpts.SriovNetSupport = aws.String("simple")
 	}
-	if s.EnableAMIENASupport {
+	if s.EnableAMIENASupport != nil && *s.EnableAMIENASupport {
 		// Set EnaSupport to true
 		// As of February 2017, this applies to C5, I3, P2, R4, X1, and m4.16xlarge
 		registerOpts.EnaSupport = aws.Bool(true)

builder/amazon/ebsvolume/builder.go

@@ -24,7 +24,7 @@ type Config struct {
 	awscommon.RunConfig    `mapstructure:",squash"`
 
 	VolumeMappings     []BlockDevice `mapstructure:"ebs_volumes"`
-	AMIENASupport      bool          `mapstructure:"ena_support"`
+	AMIENASupport      *bool         `mapstructure:"ena_support"`
 	AMISriovNetSupport bool          `mapstructure:"sriov_support"`
 
 	launchBlockDevices awscommon.BlockDevices
@@ -70,7 +70,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 		errs = packer.MultiErrorAppend(errs, err)
 	}
 
-	if b.config.IsSpotInstance() && (b.config.AMIENASupport || b.config.AMISriovNetSupport) {
+	if b.config.IsSpotInstance() && ((b.config.AMIENASupport != nil && *b.config.AMIENASupport) || b.config.AMISriovNetSupport) {
 		errs = packer.MultiErrorAppend(errs,
 			fmt.Errorf("Spot instances do not support modification, which is required "+
 				"when either `ena_support` or `sriov_support` are set. Please ensure "+

builder/amazon/instance/builder.go

@@ -156,7 +156,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 			errs, fmt.Errorf("x509_key_path points to bad file: %s", err))
 	}
 
-	if b.config.IsSpotInstance() && (b.config.AMIENASupport || b.config.AMISriovNetSupport) {
+	if b.config.IsSpotInstance() && ((b.config.AMIENASupport != nil && *b.config.AMIENASupport) || b.config.AMISriovNetSupport) {
 		errs = packer.MultiErrorAppend(errs,
 			fmt.Errorf("Spot instances do not support modification, which is required "+
 				"when either `ena_support` or `sriov_support` are set. Please ensure "+

builder/amazon/instance/step_register_ami.go

@@ -12,7 +12,7 @@ import (
 )
 
 type StepRegisterAMI struct {
-	EnableAMIENASupport      bool
+	EnableAMIENASupport      *bool
 	EnableAMISriovNetSupport bool
 }
 
@@ -38,7 +38,7 @@ func (s *StepRegisterAMI) Run(ctx context.Context, state multistep.StateBag) mul
 		// As of February 2017, this applies to C3, C4, D2, I2, R3, and M4 (excluding m4.16xlarge)
 		registerOpts.SriovNetSupport = aws.String("simple")
 	}
-	if s.EnableAMIENASupport {
+	if s.EnableAMIENASupport != nil && *s.EnableAMIENASupport {
 		// Set EnaSupport to true
 		// As of February 2017, this applies to C5, I3, P2, R4, X1, and m4.16xlarge
 		registerOpts.EnaSupport = aws.Bool(true)