feat: vgchange and pointer returns

args.go

@@ -33,7 +33,9 @@ const (
 	ArgsTypePVs      ArgsType = "pvs"
 	ArgsTypeVGs      ArgsType = "vgs"
 	ArgsTypeLVCreate ArgsType = "lvcreate"
+	ArgsTypeLVChange ArgsType = "lvchange"
 	ArgsTypeVGCreate ArgsType = "vgcreate"
+	ArgsTypeVGChange ArgsType = "vgchange"
 	ArgsTypeLVRename ArgsType = "lvrename"
 )
 

client.go

@@ -2,6 +2,12 @@ package lvm2go
 
 import (
 	"context"
+	"errors"
+)
+
+var (
+	ErrVolumeGroupNotFound   = errors.New("volume group not found")
+	ErrLogicalVolumeNotFound = errors.New("logical volume not found")
 )
 
 type client struct{}
@@ -41,14 +47,23 @@ type MetaClient interface {
 
 // VolumeGroupClient is a client that provides operations on lvm2 volume groups.
 type VolumeGroupClient interface {
+	// VG returns a volume group that matches the given options.
+	//
+	// If no VolumeGroupName is defined, ErrVolumeGroupNameRequired is returned.
+	// If no volume group is found, ErrVolumeGroupNotFound is returned.
+	//
+	// It is equivalent to calling VGs with the same options and returning the first volume group in the list.
+	// see VGs for more information.
+	VG(ctx context.Context, opts ...VGsOption) (*VolumeGroup, error)
+
 	// VGs return a list of volume groups that match the given options.
 	//
 	// If no volume groups are found, an empty slice is returned.
 	// If options limit the number of volume groups returned,
 	// the slice may be shorter than the total number of volume groups.
 	//
 	// See man lvm vgs for more information.
-	VGs(ctx context.Context, opts ...VGsOption) ([]VolumeGroup, error)
+	VGs(ctx context.Context, opts ...VGsOption) ([]*VolumeGroup, error)
 
 	// VGCreate creates a new volume group with the given options.
 	//
@@ -83,14 +98,24 @@ type VolumeGroupClient interface {
 
 // LogicalVolumeClient is a client that provides operations on lvm2 logical volumes.
 type LogicalVolumeClient interface {
+	// LV returns a logical volume that matches the given options.
+	//
+	// If no LogicalVolumeName is defined, ErrLogicalVolumeNameRequired is returned.
+	// If no VolumeGroupName is defined, ErrVolumeGroupNameRequired is returned.
+	// If no logical volume is found in the volume group, ErrLogicalVolumeNotFound is returned.
+	//
+	// It is equivalent to calling LVs with the same options and returning the first logical volume in the list.
+	// see LVs for more information.
+	LV(ctx context.Context, opts ...LVsOption) (*LogicalVolume, error)
+
 	// LVs return a list of logical volumes that match the given options.
 	//
 	// If no logical volumes are found, an empty slice is returned.
 	// If options limit the number of volume groups returned,
 	// the slice may be shorter than the total number of logical volumes.
 	//
 	// See man lvm lvs for more information.
-	LVs(ctx context.Context, opts ...LVsOption) ([]LogicalVolume, error)
+	LVs(ctx context.Context, opts ...LVsOption) ([]*LogicalVolume, error)
 
 	// LVCreate creates a new logical volume with the given options.
 	//
@@ -137,7 +162,7 @@ type PhysicalVolumeClient interface {
 	// the slice may be shorter than the total number of physical volumes.
 	//
 	// See man lvm pvs for more information.
-	PVs(ctx context.Context, opts ...PVsOption) ([]PhysicalVolume, error)
+	PVs(ctx context.Context, opts ...PVsOption) ([]*PhysicalVolume, error)
 
 	// PVCreate creates a new physical volume with the given options.
 	//

client_test.go

@@ -74,10 +74,6 @@ func TestLVs(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			if len(lvs) != len(tc.Volumes) {
-				t.Fatalf("Expected %d logical volumes, got %d", len(tc.Volumes), len(lvs))
-			}
-
 			for _, expected := range infra.lvs {
 				found := false
 				for _, lv := range lvs {
@@ -97,14 +93,10 @@ func TestLVs(t *testing.T) {
 				}
 			}
 
-			vgs, err := clnt.VGs(ctx, infra.volumeGroup.Name)
+			vg, err := clnt.VG(ctx, infra.volumeGroup.Name)
 			if err != nil {
 				t.Fatal(err)
 			}
-			if len(vgs) != 1 {
-				t.Fatalf("Expected 1 volume group, got %d", len(vgs))
-			}
-			vg := vgs[0]
 
 			if vg.Name != infra.volumeGroup.Name {
 				t.Fatalf("Expected volume group %s, got %s", infra.volumeGroup.Name, vg.Name)

config_test.go

@@ -9,6 +9,7 @@ import (
 )
 
 func Test_RawConfig(t *testing.T) {
+	t.Parallel()
 	FailTestIfNotRoot(t)
 	slog.SetDefault(slog.New(NewContextPropagatingSlogHandler(NewTestingHandler(t))))
 	slog.SetLogLoggerLevel(slog.LevelDebug)

json_convert_helper.go

@@ -17,7 +17,9 @@ func unmarshalAndConvertToStrings(raw map[string]json.RawMessage, key string, fi
 		return err
 	}
 
-	*fieldPtr = strings.Split(str, ",")
+	if len(str) > 0 {
+		*fieldPtr = strings.Split(str, ",")
+	}
 
 	return nil
 }

logical_volume.go

@@ -18,7 +18,7 @@ type LogicalVolume struct {
 	Major int64  `json:"lv_kernel_major"`
 	Minor int64  `json:"lv_kernel_minor"`
 
-	Tags string       `json:"lv_tags"`
+	Tags Tags         `json:"lv_tags"`
 	Attr LVAttributes `json:"lv_attr"`
 	Size Size         `json:"lv_size"`
 
@@ -43,7 +43,6 @@ func (lv *LogicalVolume) UnmarshalJSON(data []byte) error {
 		"lv_name":      (*string)(&lv.Name),
 		"lv_full_name": &lv.FullName,
 		"lv_path":      &lv.Path,
-		"lv_tags":      &lv.Tags,
 		"origin":       &lv.Origin,
 		"pool_lv":      &lv.PoolLogicalVolume,
 		"vg_name":      (*string)(&lv.VolumeGroupName),
@@ -55,6 +54,14 @@ func (lv *LogicalVolume) UnmarshalJSON(data []byte) error {
 		}
 	}
 
+	for key, fieldPtr := range map[string]*Tags{
+		"lv_tags": &lv.Tags,
+	} {
+		if err := unmarshalAndConvertToStrings(raw, key, (*[]string)(fieldPtr)); err != nil {
+			return err
+		}
+	}
+
 	for key, fieldPtr := range map[string]*int64{
 		"lv_kernel_major": &lv.Major,
 		"lv_kernel_minor": &lv.Minor,
@@ -119,6 +126,10 @@ func (opt LogicalVolumeName) ApplyToLVChangeOptions(opts *LVChangeOptions) {
 	opts.LogicalVolumeName = opt
 }
 
+func (opt LogicalVolumeName) ApplyToLVsOptions(opts *LVsOptions) {
+	opts.LogicalVolumeName = opt
+}
+
 type FQLogicalVolumeName struct {
 	VolumeGroupName
 	LogicalVolumeName
@@ -147,11 +158,16 @@ func (opt *FQLogicalVolumeName) ApplyToLVResizeOptions(opts *LVResizeOptions) {
 func (opt *FQLogicalVolumeName) ApplyToLVReduceOptions(opts *LVReduceOptions) {
 	opts.VolumeGroupName, opts.LogicalVolumeName = opt.VolumeGroupName, opt.LogicalVolumeName
 }
+
 func (opt *FQLogicalVolumeName) ApplyToLVRenameOptions(opts *LVRenameOptions) {
 	opts.VolumeGroupName = opt.VolumeGroupName
 	opts.SetOldOrNew(opt.LogicalVolumeName)
 }
 
+func (opt *FQLogicalVolumeName) ApplyToLVsOptions(opts *LVsOptions) {
+	opts.VolumeGroupName, opts.LogicalVolumeName = opt.VolumeGroupName, opt.LogicalVolumeName
+}
+
 func (opt *FQLogicalVolumeName) Split() (VolumeGroupName, LogicalVolumeName) {
 	return opt.VolumeGroupName, opt.LogicalVolumeName
 }

lv_attr_test.go

@@ -8,6 +8,7 @@ import (
 )
 
 func TestLVAttributes(t *testing.T) {
+	t.Parallel()
 	type args struct {
 		raw string
 	}

lvchange.go

@@ -52,7 +52,7 @@ func (c *client) LVChange(ctx context.Context, opts ...LVChangeOption) error {
 }
 
 func (list LVChangeOptionsList) AsArgs() (Arguments, error) {
-	args := NewArgs(ArgsTypeGeneric)
+	args := NewArgs(ArgsTypeLVChange)
 	options := LVChangeOptions{}
 	for _, opt := range list {
 		opt.ApplyToLVChangeOptions(&options)

lvextend_test.go

@@ -8,6 +8,7 @@ import (
 )
 
 func TestLVExtend(t *testing.T) {
+	t.Parallel()
 	FailTestIfNotRoot(t)
 
 	clnt := NewClient()

lvmdevices_test.go

@@ -12,6 +12,7 @@ import (
 )
 
 func TestLVMDevices(t *testing.T) {
+	t.Parallel()
 	FailTestIfNotRoot(t)
 
 	_, err := exec.LookPath("lvmdevices")

lvrename_test.go

@@ -9,6 +9,7 @@ import (
 )
 
 func TestLVRename(t *testing.T) {
+	t.Parallel()
 	FailTestIfNotRoot(t)
 
 	clnt := NewClient()

lvs.go

@@ -7,6 +7,7 @@ import (
 type (
 	LVsOptions struct {
 		VolumeGroupName
+		LogicalVolumeName
 		Tags
 		Select
 
@@ -27,10 +28,10 @@ var (
 // LVs returns a list of logical volumes that match the given options.
 // If no logical volumes are found, nil is returned.
 // It is really just a wrapper around the `lvs --reportformat json` command.
-func (c *client) LVs(ctx context.Context, opts ...LVsOption) ([]LogicalVolume, error) {
+func (c *client) LVs(ctx context.Context, opts ...LVsOption) ([]*LogicalVolume, error) {
 	type lvReport struct {
 		Report []struct {
-			LV []LogicalVolume `json:"lv"`
+			LV []*LogicalVolume `json:"lv"`
 		} `json:"report"`
 	}
 
@@ -67,6 +68,39 @@ func (c *client) LVs(ctx context.Context, opts ...LVsOption) ([]LogicalVolume, e
 	return lvs, nil
 }
 
+func (c *client) LV(ctx context.Context, opts ...LVsOption) (*LogicalVolume, error) {
+	foundVG := false
+	foundLV := false
+	for _, opt := range opts {
+		if _, ok := opt.(VolumeGroupName); ok {
+			foundVG = true
+		}
+		if _, ok := opt.(LogicalVolumeName); ok {
+			foundLV = true
+		}
+		if foundVG && foundLV {
+			break
+		}
+	}
+	if !foundVG {
+		return nil, ErrVolumeGroupNameRequired
+	}
+	if !foundLV {
+		return nil, ErrLogicalVolumeNameRequired
+	}
+
+	lvs, err := c.LVs(ctx, opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(lvs) == 0 {
+		return nil, ErrLogicalVolumeNotFound
+	}
+
+	return lvs[0], nil
+}
+
 func (opts *LVsOptions) ApplyToArgs(args Arguments) error {
 	for _, arg := range []Argument{
 		opts.VolumeGroupName,

physical_volume.go

@@ -2,8 +2,11 @@ package lvm2go
 
 import (
 	"encoding/json"
+	"errors"
 )
 
+var ErrPhysicalVolumeNameRequired = errors.New("PhysicalVolumeName is required for a fully qualified physical volume")
+
 type PhysicalVolume struct {
 	UUID         string             `json:"pv_uuid"`
 	Name         PhysicalVolumeName `json:"pv_name"`

pvs.go

@@ -27,10 +27,10 @@ var (
 // PVs returns a list of logical volumes that match the given options.
 // If no logical volumes are found, nil is returned.
 // It is really just a wrapper around the `lvs --reportformat json` command.
-func (c *client) PVs(ctx context.Context, opts ...PVsOption) ([]PhysicalVolume, error) {
+func (c *client) PVs(ctx context.Context, opts ...PVsOption) ([]*PhysicalVolume, error) {
 	type lvReport struct {
 		Report []struct {
-			PV []PhysicalVolume `json:"pv"`
+			PV []*PhysicalVolume `json:"pv"`
 		} `json:"report"`
 	}
 
@@ -68,16 +68,16 @@ func (c *client) PVs(ctx context.Context, opts ...PVsOption) ([]PhysicalVolume,
 }
 
 func (opts *PVsOptions) ApplyToArgs(args Arguments) error {
-	if err := opts.VolumeGroupName.ApplyToArgs(args); err != nil {
-		return err
-	}
-
-	if err := opts.CommonOptions.ApplyToArgs(args); err != nil {
-		return err
-	}
 
-	if err := opts.ColumnOptions.ApplyToArgs(args); err != nil {
-		return err
+	for _, arg := range []Argument{
+		opts.VolumeGroupName,
+		opts.Tags,
+		opts.CommonOptions,
+		opts.ColumnOptions,
+	} {
+		if err := arg.ApplyToArgs(args); err != nil {
+			return err
+		}
 	}
 
 	return nil

size_test.go

@@ -86,6 +86,7 @@ func init() {
 }
 
 func Test_Size(t *testing.T) {
+	t.Parallel()
 	for _, tc := range DefaultSizeTestCases {
 		t.Run(tc.InputToParse, func(t *testing.T) {
 			actual, err := ParseSize(tc.InputToParse)

tags.go

@@ -19,6 +19,9 @@ func (opt Tags) ApplyToLVCreateOptions(opts *LVCreateOptions) {
 func (opt Tags) ApplyToVGRemoveOptions(opts *VGRemoveOptions) {
 	opts.Tags = opt
 }
+func (opt Tags) ApplyToVGChangeOptions(opts *VGChangeOptions) {
+	opts.Tags = opt
+}
 func (opt Tags) ApplyToLVRemoveOptions(opts *LVRemoveOptions) {
 	opts.Tags = opt
 }
@@ -29,6 +32,10 @@ func (opt Tags) ApplyToArgs(args Arguments) error {
 	}
 
 	switch args.GetType() {
+	case ArgsTypeLVChange:
+		fallthrough
+	case ArgsTypeVGChange:
+		fallthrough
 	case ArgsTypeVGCreate:
 		fallthrough
 	case ArgsTypeLVCreate:

util_test.go

@@ -102,8 +102,15 @@ func (t LoopbackDevices) PhysicalVolumeNames() PhysicalVolumeNames {
 
 }
 
+// testLoopbackCreationSync is a mutex to synchronize the creation of loopback devices in tests
+// so that they don't interfere with each other by requesting the same free loopback device
+var testLoopbackCreationSync = sync.Mutex{}
+
 func MakeTestLoopbackDevice(t *testing.T, size Size) LoopbackDevice {
+	t.Helper()
 	ctx := context.Background()
+	testLoopbackCreationSync.Lock()
+	defer testLoopbackCreationSync.Unlock()
 
 	backingFilePath := filepath.Join(t.TempDir(), fmt.Sprintf("%s.img", NewNonDeterministicTestID(t)))
 
@@ -132,7 +139,6 @@ func MakeTestLoopbackDevice(t *testing.T, size Size) LoopbackDevice {
 	}
 	logger = logger.With("loop", loop)
 	logger.DebugContext(ctx, "created test loopback device successfully")
-
 	t.Cleanup(func() {
 		logger.DebugContext(ctx, "cleaning up test loopback device")
 		if err := loop.Close(); err != nil {