Option to mount image for booting host machine (#172)

commands/list.go

@@ -42,7 +42,7 @@ func NewListCommand(cmdF *CmdFactory) *cobra.Command {
 	}
 
 	storageF = cmdF.AddStorageFlags(cmd)
-	filterF = cmdF.AddFilterFlags(cmd, []string{config.BuildTypeImage, config.BuildTypeMount, config.BuildTypeVM})
+	filterF = cmdF.AddFilterFlags(cmd, []string{config.BuildTypeImage, config.BuildTypeMount, config.BuildTypeBoot, config.BuildTypeVM})
 	formatF = cmdF.AddFormatFlags(cmd)
 	return cmd
 }

commands/mount.go

@@ -41,6 +41,7 @@ func NewMountCommand(cmdF *CmdFactory) *cobra.Command {
 	}
 	storageF = cmdF.AddStorageFlags(cmd)
 	formatF = cmdF.AddFormatFlags(cmd)
+	cmd.Flags().BoolVar(&mountF.Boot, "boot", false, "Create mount used to boot host machine")
 	cmd.Flags().StringVar(&mountF.LibvirtAddr, "libvirt-addr", "unix:///var/run/libvirt/libvirt-sock", "Address libvirt listens on")
 	cmd.Flags().StringVar(&mountF.XMLDir, "xml-dir", must.String(os.UserHomeDir())+"/osman", "Directory where VM definition is taken from if vm-file argument is not provided")
 	cmd.Flags().StringVar(&mountF.VMFile, "vm", "", "Defines VM for mounted image in Libvirt using provided file. If flag is provided without value or value is `auto` then file is derived as <xml-dir>/<image-name>.xml")

config/filter.go

@@ -15,13 +15,17 @@ const (
 	// BuildTypeMount represents mount build
 	BuildTypeMount = "mount"
 
+	// BuildTypeBoot represents boot build
+	BuildTypeBoot = "boot"
+
 	// BuildTypeVM represents vm build
 	BuildTypeVM = "vm"
 )
 
 var typeMapping = map[string]types.BuildType{
 	BuildTypeImage: types.BuildTypeImage,
 	BuildTypeMount: types.BuildTypeMount,
+	BuildTypeBoot:  types.BuildTypeBoot,
 	BuildTypeVM:    types.BuildTypeVM,
 }
 

config/mount.go

@@ -9,6 +9,9 @@ import (
 
 // MountFactory collects data for mount config
 type MountFactory struct {
+	// Boot means that the mount is created for booting host machine
+	Boot bool
+
 	// XMLDir is a directory where VM definition is taken from if xml file is not provided explicitly
 	XMLDir string
 
@@ -26,7 +29,13 @@ func (f *MountFactory) Config(args Args) Mount {
 		LibvirtAddr: f.LibvirtAddr,
 		Type:        types.BuildTypeMount,
 	}
+	if f.Boot {
+		config.Type = types.BuildTypeBoot
+	}
 	if f.VMFile != "" {
+		if f.Boot {
+			panic(errors.New("can't mount as boot and vm at the same time"))
+		}
 		config.Type = types.BuildTypeVM
 		if f.VMFile != "auto" {
 			config.VMFile = f.VMFile

functions.go

@@ -314,13 +314,16 @@ func vmName(doc *etree.Document) string {
 
 func cloneForMount(ctx context.Context, image types.BuildInfo, buildKey types.BuildKey, imageType types.BuildType, s storage.Driver) (retInfo types.BuildInfo, retErr error) {
 	buildID := types.NewBuildID(imageType)
-	if _, _, err := s.Clone(ctx, image.BuildID, buildKey.Name, buildID); err != nil {
+	finalizeFn, _, err := s.Clone(ctx, image.BuildID, buildKey.Name, buildID)
+	if err != nil {
 		return types.BuildInfo{}, err
 	}
 	defer func() {
 		if retErr != nil {
 			_ = s.Drop(ctx, buildID)
+			return
 		}
+		retErr = finalizeFn()
 	}()
 
 	if err := s.StoreManifest(ctx, types.ImageManifest{

infra/storage/zfs.go

@@ -71,7 +71,7 @@ func (d *zfsDriver) Info(ctx context.Context, buildID types.BuildID) (types.Buil
 	}
 
 	mounted := ""
-	if buildID.Type().Properties().Mountable {
+	if buildID.Type().Properties().Mountable && filesystem.Info.Mountpoint != "none" {
 		mounted = filesystem.Info.Mountpoint
 	}
 	buildInfo.Mounted = mounted
@@ -131,8 +131,15 @@ func (d *zfsDriver) Clone(ctx context.Context, srcBuildID types.BuildID, dstImag
 		return nil, "", err
 	}
 
+	properties := dstBuildID.Type().Properties()
+
+	mountpoint := "none"
+	if properties.AutoMount {
+		mountpoint = "/" + d.config.Root + "/" + string(dstBuildID) + "/root"
+	}
+
 	filesystem, err := snapshot.Clone(ctx, d.config.Root+"/"+string(dstBuildID), zfs.CloneOptions{Properties: map[string]string{
-		"mountpoint": "/" + d.config.Root + "/" + string(dstBuildID) + "/root",
+		"mountpoint": mountpoint,
 		propertyName: string(must.Bytes(json.Marshal(types.BuildInfo{
 			BuildID:   dstBuildID,
 			BasedOn:   srcBuildID,
@@ -144,16 +151,23 @@ func (d *zfsDriver) Clone(ctx context.Context, srcBuildID types.BuildID, dstImag
 		return nil, "", err
 	}
 	return func() error {
-		properties := dstBuildID.Type().Properties()
-		if !properties.Mountable {
-			if err := filesystem.Unmount(ctx); err != nil {
+		if !properties.Mountable || !properties.AutoMount {
+			value, _, err := filesystem.GetProperty(ctx, "mounted")
+			if err != nil {
 				return err
 			}
+			if value == "yes" {
+				if err := filesystem.Unmount(ctx); err != nil {
+					return err
+				}
+			}
+		}
+		if !properties.Mountable {
 			if err := filesystem.SetProperty(ctx, "canmount", "off"); err != nil {
 				return err
 			}
 		}
-		if properties.Cloneable {
+		if properties.Cloneable || properties.Revertable {
 			if _, err := filesystem.Snapshot(ctx, "image"); err != nil {
 				return err
 			}

infra/types/types.go

@@ -86,9 +86,15 @@ type BuildTypeProperties struct {
 	// Cloneable means image may be cloned
 	Cloneable bool
 
-	// Mountable means image stays mounted
+	// Revertable means image might be reverted to original state
+	Revertable bool
+
+	// Mountable means image can't be mounted
 	Mountable bool
 
+	// AutoMount means image is automatically mounted
+	AutoMount bool
+
 	// VM means vm in libvirt is defined for this image
 	VM bool
 }
@@ -100,16 +106,25 @@ const (
 	// BuildTypeMount is the mount build type
 	BuildTypeMount BuildType = "mid"
 
+	// BuildTypeBoot is the boot build type
+	BuildTypeBoot BuildType = "bid"
+
 	// BuildTypeVM is the vm build type
 	BuildTypeVM BuildType = "vid"
 )
 
 var buildTypes = map[BuildType]BuildTypeProperties{
 	BuildTypeImage: {
-		Cloneable: true,
+		Cloneable:  true,
+		Revertable: true,
 	},
 	BuildTypeMount: {
 		Mountable: true,
+		AutoMount: true,
+	},
+	BuildTypeBoot: {
+		Mountable:  true,
+		Revertable: true,
 	},
 	BuildTypeVM: {
 		Mountable: true,