Add StepMountExtra

builder/amazon/chroot/builder.go

@@ -400,7 +400,9 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 		&StepPostMountCommands{
 			Commands: b.config.PostMountCommands,
 		},
-		&StepMountExtra{},
+		&StepMountExtra{
+			ChrootMounts: b.config.ChrootMounts,
+		},
 		&StepCopyFiles{},
 		&StepChrootProvision{},
 		&StepEarlyCleanup{},

builder/amazon/chroot/step_mount_extra.go

@@ -17,19 +17,19 @@ import (
 // Produces:
 //   mount_extra_cleanup CleanupFunc - To perform early cleanup
 type StepMountExtra struct {
-	mounts []string
+	ChrootMounts [][]string
+	mounts       []string
 }
 
 func (s *StepMountExtra) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
-	config := state.Get("config").(*Config)
 	mountPath := state.Get("mount_path").(string)
 	ui := state.Get("ui").(packer.Ui)
 	wrappedCommand := state.Get("wrappedCommand").(CommandWrapper)
 
-	s.mounts = make([]string, 0, len(config.ChrootMounts))
+	s.mounts = make([]string, 0, len(s.ChrootMounts))
 
 	ui.Say("Mounting additional paths within the chroot...")
-	for _, mountInfo := range config.ChrootMounts {
+	for _, mountInfo := range s.ChrootMounts {
 		innerPath := mountPath + mountInfo[2]
 
 		if err := os.MkdirAll(innerPath, 0755); err != nil {

builder/azure/chroot/builder.go

@@ -23,12 +23,13 @@ type Config struct {
 
 	FromScratch bool `mapstructure:"from_scratch"`
 
-	CommandWrapper    string   `mapstructure:"command_wrapper"`
-	MountOptions      []string `mapstructure:"mount_options"`
-	MountPartition    string   `mapstructure:"mount_partition"`
-	MountPath         string   `mapstructure:"mount_path"`
-	PreMountCommands  []string `mapstructure:"pre_mount_commands"`
-	PostMountCommands []string `mapstructure:"post_mount_commands"`
+	CommandWrapper    string     `mapstructure:"command_wrapper"`
+	PreMountCommands  []string   `mapstructure:"pre_mount_commands"`
+	MountOptions      []string   `mapstructure:"mount_options"`
+	MountPartition    string     `mapstructure:"mount_partition"`
+	MountPath         string     `mapstructure:"mount_path"`
+	PostMountCommands []string   `mapstructure:"post_mount_commands"`
+	ChrootMounts      [][]string `mapstructure:"chroot_mounts"`
 
 	OSDiskSizeGB             int32  `mapstructure:"osdisk_size_gb"`
 	OSDiskStorageAccountType string `mapstructure:"osdisk_storageaccounttype"`
@@ -48,7 +49,12 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 		InterpolateContext: &b.config.ctx,
 		InterpolateFilter: &interpolate.RenderFilter{
 			Exclude: []string{
-				// fields to exclude from interpolation
+				// these fields are interpolated in the steps,
+				// when more information is available
+				"command_wrapper",
+				"post_mount_commands",
+				"pre_mount_commands",
+				"mount_path",
 			},
 		},
 	}, raws...)
@@ -65,11 +71,11 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 	if b.config.FromScratch {
 		if b.config.OSDiskSizeGB == 0 {
 			errs = packer.MultiErrorAppend(
-				errs, errors.New("osdisk_size_gb is required with from_scratch."))
+				errs, errors.New("osdisk_size_gb is required with from_scratch"))
 		}
 		if len(b.config.PreMountCommands) == 0 {
 			errs = packer.MultiErrorAppend(
-				errs, errors.New("pre_mount_commands is required with from_scratch."))
+				errs, errors.New("pre_mount_commands is required with from_scratch"))
 		}
 	}
 
@@ -81,7 +87,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 
 func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (packer.Artifact, error) {
 	if runtime.GOOS != "linux" {
-		return nil, errors.New("The azure-chroot builder only works on Linux environments.")
+		return nil, errors.New("the azure-chroot builder only works on Linux environments")
 	}
 
 	var azcli client.AzureClientSet
@@ -151,6 +157,9 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 		&chroot.StepPostMountCommands{
 			Commands: b.config.PostMountCommands,
 		},
+		&chroot.StepMountExtra{
+			ChrootMounts: b.config.ChrootMounts,
+		},
 	)
 
 	// Run!