Merge pull request #545 from dwc0011/add-manual-mount-command-option

Add manual mount command option

Author: tanmay-hc

.web-docs/components/builder/chroot/README.md

@@ -122,6 +122,10 @@ information.
   a command with sudo or so on. This is a configuration template where the `.Command` variable
   is replaced with the command to be run. Defaults to `{{.Command}}`.
 
+- `manual_mount_command` (string) - Manual Mount Command that is executed to manually mount the
+  root device and before the post mount commands. The device and
+  mount path are provided by `{{.Device}}` and `{{.MountPath}}`.
+
 - `pre_mount_commands` ([]string) - A series of commands to execute after attaching the root volume and before mounting the chroot.
   This is not required unless using `from_scratch`. If so, this should include any partitioning
   and filesystem creation commands. The path to the device is provided by `{{.Device}}`.

builder/azure/chroot/builder.go

@@ -61,6 +61,10 @@ type Config struct {
 	// a command with sudo or so on. This is a configuration template where the `.Command` variable
 	// is replaced with the command to be run. Defaults to `{{.Command}}`.
 	CommandWrapper string `mapstructure:"command_wrapper"`
+	// Manual Mount Command that is executed to manually mount the
+	// root device and before the post mount commands. The device and
+	// mount path are provided by `{{.Device}}` and `{{.MountPath}}`.
+	ManualMountCommand string `mapstructure:"manual_mount_command" required:"false"`
 	// A series of commands to execute after attaching the root volume and before mounting the chroot.
 	// This is not required unless using `from_scratch`. If so, this should include any partitioning
 	// and filesystem creation commands. The path to the device is provided by `{{.Device}}`.
@@ -169,6 +173,7 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, []string, error) {
 				"command_wrapper",
 				"post_mount_commands",
 				"pre_mount_commands",
+				"manual_mount_command",
 				"mount_path",
 			},
 		},
@@ -613,6 +618,7 @@ func buildsteps(
 		},
 		&StepMountDevice{
 			MountOptions:   config.MountOptions,
+			Command:        config.ManualMountCommand,
 			MountPartition: config.MountPartition,
 			MountPath:      config.MountPath,
 		},

builder/azure/chroot/builder.hcl2spec.go

@@ -10,6 +10,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -25,19 +26,20 @@ import (
 var _ multistep.Step = &StepMountDevice{}
 
 type StepMountDevice struct {
+	Command        string
 	MountOptions   []string
 	MountPartition string
 	MountPath      string
 
-	mountPath string
+	mountPath     string
+	isManualMount bool
 }
 
 func (s *StepMountDevice) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
 	ui := state.Get("ui").(packersdk.Ui)
 	device := state.Get("device").(string)
 	config := state.Get("config").(*Config)
-	wrappedCommand := state.Get("wrappedCommand").(common.CommandWrapper)
-
+	isManualMount := s.Command != ""
 	ictx := config.ctx
 
 	ictx.Data = &struct{ Device string }{Device: filepath.Base(device)}
@@ -59,12 +61,13 @@ func (s *StepMountDevice) Run(ctx context.Context, state multistep.StateBag) mul
 	}
 
 	log.Printf("Mount path: %s", mountPath)
-
-	if err := os.MkdirAll(mountPath, 0755); err != nil {
-		err := fmt.Errorf("error creating mount directory: %s", err)
-		state.Put("error", err)
-		ui.Error(err.Error())
-		return multistep.ActionHalt
+	if !isManualMount {
+		if err := os.MkdirAll(mountPath, 0755); err != nil {
+			err := fmt.Errorf("error creating mount directory: %s", err)
+			state.Put("error", err)
+			ui.Error(err.Error())
+			return multistep.ActionHalt
+		}
 	}
 
 	var deviceMount string
@@ -79,23 +82,31 @@ func (s *StepMountDevice) Run(ctx context.Context, state multistep.StateBag) mul
 
 	ui.Say("Mounting the root device...")
 	stderr := new(bytes.Buffer)
-
-	// build mount options from mount_options config, useful for nouuid options
-	// or other specific device type settings for mount
-	opts := ""
-	if len(s.MountOptions) > 0 {
-		opts = "-o " + strings.Join(s.MountOptions, " -o ")
-	}
-	mountCommand, err := wrappedCommand(
-		fmt.Sprintf("mount %s %s %s", opts, deviceMount, mountPath))
-	if err != nil {
-		err := fmt.Errorf("error creating mount command: %s", err)
-		state.Put("error", err)
-		ui.Error(err.Error())
-		return multistep.ActionHalt
+	var cmd *exec.Cmd
+	if !isManualMount {
+		// build mount options from mount_options config, useful for nouuid options
+		// or other specific device type settings for mount
+		opts := ""
+		if len(s.MountOptions) > 0 {
+			opts = "-o " + strings.Join(s.MountOptions, " -o ")
+		}
+		wrappedCommand := state.Get("wrappedCommand").(common.CommandWrapper)
+		mountCommand, err := wrappedCommand(
+			fmt.Sprintf("mount %s %s %s", opts, deviceMount, mountPath))
+		if err != nil {
+			err := fmt.Errorf("error creating mount command: %s", err)
+			state.Put("error", err)
+			ui.Error(err.Error())
+			return multistep.ActionHalt
+		}
+		log.Printf("[DEBUG] (step mount) mount command is %s", mountCommand)
+		cmd = common.ShellCommand(mountCommand)
+
+	} else {
+		log.Printf("[DEBUG] (step mount) mount command is %s", s.Command)
+		cmd = common.ShellCommand(fmt.Sprintf("%s %s", s.Command, mountPath))
 	}
-	log.Printf("[DEBUG] (step mount) mount command is %s", mountCommand)
-	cmd := common.ShellCommand(mountCommand)
+
 	cmd.Stderr = stderr
 	if err := cmd.Run(); err != nil {
 		err := fmt.Errorf(
@@ -107,6 +118,7 @@ func (s *StepMountDevice) Run(ctx context.Context, state multistep.StateBag) mul
 
 	// Set the mount path so we remember to unmount it later
 	s.mountPath = mountPath
+	s.isManualMount = isManualMount
 	state.Put("mount_path", s.mountPath)
 	state.Put("mount_device_cleanup", s)
 
@@ -126,19 +138,22 @@ func (s *StepMountDevice) CleanupFunc(state multistep.StateBag) error {
 	}
 
 	ui := state.Get("ui").(packersdk.Ui)
-	wrappedCommand := state.Get("wrappedCommand").(common.CommandWrapper)
-
-	ui.Say("Unmounting the root device...")
-	unmountCommand, err := wrappedCommand(fmt.Sprintf("umount -R %s", s.mountPath))
-	if err != nil {
-		return fmt.Errorf("error creating unmount command: %s", err)
+	if !s.isManualMount {
+		wrappedCommand := state.Get("wrappedCommand").(common.CommandWrapper)
+
+		ui.Say("Unmounting the root device...")
+		unmountCommand, err := wrappedCommand(fmt.Sprintf("umount -R %s", s.mountPath))
+		if err != nil {
+			return fmt.Errorf("error creating unmount command: %s", err)
+		}
+
+		cmd := common.ShellCommand(unmountCommand)
+		if err := cmd.Run(); err != nil {
+			return fmt.Errorf("error unmounting root device: %s", err)
+		}
+	} else {
+		ui.Say("Skipping Unmounting the root device, it is manually unmounted via manual mount command script...")
 	}
-
-	cmd := common.ShellCommand(unmountCommand)
-	if err := cmd.Run(); err != nil {
-		return fmt.Errorf("error unmounting root device: %s", err)
-	}
-
 	s.mountPath = ""
 	return nil
 }

builder/azure/chroot/step_mount_device.go

@@ -6,6 +6,10 @@
   a command with sudo or so on. This is a configuration template where the `.Command` variable
   is replaced with the command to be run. Defaults to `{{.Command}}`.
 
+- `manual_mount_command` (string) - Manual Mount Command that is executed to manually mount the
+  root device and before the post mount commands. The device and
+  mount path are provided by `{{.Device}}` and `{{.MountPath}}`.
+
 - `pre_mount_commands` ([]string) - A series of commands to execute after attaching the root volume and before mounting the chroot.
   This is not required unless using `from_scratch`. If so, this should include any partitioning
   and filesystem creation commands. The path to the device is provided by `{{.Device}}`.