[#13] Add info FrostFS backend cmd

Signed-off-by: Aleksey Kravchenko <al.kravchenko@yadro.com>

backend/frostfs/frostfs.go

@@ -16,6 +16,8 @@ import (
 	"time"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/ape"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/api/refs"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/checksum"
 	sdkClient "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container"
 	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
@@ -40,6 +42,7 @@ func init() {
 		Name:        "frostfs",
 		Description: "Distributed, decentralized object storage FrostFS",
 		NewFs:       NewFs,
+		CommandHelp: commandHelp,
 		Options: []fs.Option{
 			{
 				Name:     "endpoint",
@@ -155,6 +158,59 @@ func init() {
 	})
 }
 
+var commandHelp = []fs.CommandHelp{
+	{
+		Name:  "info",
+		Short: "Show information about the FrostFS objects and containers",
+		Long: `This command can be used to get information about the FrostFS objects and containers.
+
+Usage Examples:
+
+    rclone backend info frostfs:container/path/to/dir
+    rclone backend info frostfs:container/path/to/dir path/to/file/in/dir.txt
+    rclone backend info frostfs:container/path/to/dir path/to/file/in/dir.txt -o "format={cid}:{oid}"
+
+The optional "format" flag overrides the information output. In this example, if an object is stored in
+a container with the identifier "9mvN7hsUcYoGoHjxpRWtqmDipnmaeRmGVDqRxxPyy2n1" and 
+its own identifier is "4VPCNFsZ2SQt1GNfYw2uTBNnz5bLgC7i4k4ovtuXKyJP", the output of this command will be
+"9mvN7hsucoGoHjxPqrWmDipnMaemGVDqrxxPyynn1:4VpcNFsZqsQt1Gnfw2utBnzn5Blgc7i4kvtuXyKyJp".
+
+The default output format is the same as that of the frostfs-cli utility, 
+with the "container get" and "object head" options. Here is an example of output:
+
+ --- Container info ---
+CID: 9mvN7hsUcYoGoHjxpRWtqmDipnmaeRmGVDqRxxPyy2n1
+Owner ID: NQL7q6PvPaisWNwdWfoR1LsEsAyje8P3jX
+Created: 2025-02-17 15:07:51 +0300 MSK
+Attributes:
+  Timestamp=1739794071
+  Name=test
+  __SYSTEM__NAME=test
+  __SYSTEM__ZONE=container
+  __SYSTEM__DISABLE_HOMOMORPHIC_HASHING=true
+Placement policy:
+REP 3
+
+ --- Object info ---
+ID: 4VPCNFsZ2SQt1GNfYw2uTBNnz5bLgC7i4k4ovtuXKyJP
+CID: 9mvN7hsUcYoGoHjxpRWtqmDipnmaeRmGVDqRxxPyy2n1
+Owner: NQL7q6PvPaisWNwdWfoR1LsEsAyje8P3jX
+CreatedAt: 559
+Size: 402905
+HomoHash: <empty>
+Checksum: 2a068fe24c53bc8bf7d6bbb997414f7938b080305dc45f9fd3ff684bc11fbb7b
+Type: REGULAR
+Attributes:
+  FileName=cat.png
+  FilePath=dir1/dir2/dir3/cat.png
+  Timestamp=1733410524 (2024-12-05 17:55:24 +0300 MSK)
+ID signature:
+  public key: 026b7c7a7a16225eb13a5a733495a1bcdd1f016dfa9193498821379b0de2ba6870
+  signature: 049f6712c8378d323269b605a282bcacd7565ce2eefe1f10a9739c48945f739d95102c478b9cb1d429cd3330b4b5262e725392e322de3bbfa4ce18a9c842289219
+`,
+	},
+}
+
 // Options defines the configuration for this backend
 type Options struct {
 	FrostfsEndpoint              string      `config:"endpoint"`
@@ -210,6 +266,272 @@ type Object struct {
 	timestamp   time.Time
 }
 
+// Command the backend to run a named command
+//
+// The command run is name
+// args may be used to read arguments from
+// opts may be used to read optional arguments from
+func (f *Fs) Command(ctx context.Context, name string, arg []string, opt map[string]string) (out interface{}, err error) {
+	switch name {
+	case "info":
+		return f.infoCmd(ctx, arg, opt)
+	default:
+		return nil, fs.ErrorCommandNotFound
+	}
+}
+
+func (f *Fs) containerInfo(ctx context.Context, cnrID cid.ID) (container.Container, error) {
+	prm := pool.PrmContainerGet{
+		ContainerID: cnrID,
+	}
+	var cnr container.Container
+	cnr, err := f.pool.GetContainer(ctx, prm)
+	if err != nil {
+		return container.Container{}, fmt.Errorf("couldn't get container '%s': %w", cnrID, err)
+	}
+	return cnr, err
+}
+
+func (f *Fs) getObjectsHead(ctx context.Context, cnrID cid.ID, objIDs []oid.ID) ([]object.Object, error) {
+	var res []object.Object
+	for _, objID := range objIDs {
+		var prmHead pool.PrmObjectHead
+		prmHead.SetAddress(newAddress(cnrID, objID))
+
+		obj, err := f.pool.HeadObject(ctx, prmHead)
+		if err != nil {
+			return nil, err
+		}
+		res = append(res, obj)
+	}
+
+	return res, nil
+}
+
+type printer struct {
+	w   io.Writer
+	err error
+}
+
+func newPrinter(w io.Writer) *printer {
+	return &printer{w: w}
+}
+
+func (p *printer) printf(format string, a ...interface{}) {
+	if p.err != nil {
+		return
+	}
+	if _, err := fmt.Fprintf(p.w, format, a...); err != nil {
+		p.err = err
+	}
+}
+
+func (p *printer) lastError() error {
+	return p.err
+}
+
+func (p *printer) printContainerInfo(cnrID cid.ID, cnr container.Container) {
+	p.printf("CID: %v\nOwner ID: %v", cnrID, cnr.Owner())
+	var timestamp time.Time
+	var attrs []string
+	cnr.IterateAttributes(func(key string, value string) {
+		attrs = append(attrs, fmt.Sprintf("  %v=%v", key, value))
+		if key == object.AttributeTimestamp {
+			val, err := strconv.ParseInt(value, 10, 64)
+			if err == nil {
+				timestamp = time.Unix(val, 0)
+			}
+		}
+	})
+	if !timestamp.IsZero() {
+		p.printf("\nCreated: %v", timestamp)
+	}
+	if len(attrs) > 0 {
+		p.printf("\nAttributes:\n%s", strings.Join(attrs, "\n"))
+	}
+
+	s := bytes.NewBufferString("")
+	if err := cnr.PlacementPolicy().WriteStringTo(s); err != nil {
+		return
+	}
+
+	p.printf("\nPlacement policy:\n%s", s.String())
+}
+
+func (p *printer) printChecksum(name string, recv func() (checksum.Checksum, bool)) {
+	var strVal string
+
+	cs, csSet := recv()
+	if csSet {
+		strVal = hex.EncodeToString(cs.Value())
+	} else {
+		strVal = "<empty>"
+	}
+
+	p.printf("\n%s: %s", name, strVal)
+}
+
+func (p *printer) printObject(obj *object.Object) {
+	objIDStr := "<empty>"
+	cnrIDStr := objIDStr
+	if objID, ok := obj.ID(); ok {
+		objIDStr = objID.String()
+	}
+	if cnrID, ok := obj.ContainerID(); ok {
+		cnrIDStr = cnrID.String()
+	}
+	p.printf("\nID: %v", objIDStr)
+	p.printf("\nCID: %v", cnrIDStr)
+	p.printf("\nOwner: %s", obj.OwnerID())
+	p.printf("\nCreatedAt: %d", obj.CreationEpoch())
+	p.printf("\nSize: %d", obj.PayloadSize())
+	p.printChecksum("HomoHash", obj.PayloadHomomorphicHash)
+	p.printChecksum("Checksum", obj.PayloadChecksum)
+	p.printf("\nType: %s", obj.Type())
+
+	p.printf("\nAttributes:")
+	for _, attr := range obj.Attributes() {
+		if attr.Key() == object.AttributeTimestamp {
+			var strVal string
+			val, err := strconv.ParseInt(attr.Value(), 10, 64)
+			if err == nil {
+				strVal = time.Unix(val, 0).String()
+			} else {
+				strVal = "malformed"
+			}
+			p.printf("\n  %s=%s (%s)",
+				attr.Key(),
+				attr.Value(),
+				strVal)
+			continue
+		}
+		p.printf("\n  %s=%s", attr.Key(), attr.Value())
+	}
+
+	if signature := obj.Signature(); signature != nil {
+		p.printf("\nID signature:")
+
+		var sigV2 refs.Signature
+		signature.WriteToV2(&sigV2)
+
+		p.printf("\n  public key: %s", hex.EncodeToString(sigV2.GetKey()))
+		p.printf("\n  signature: %s", hex.EncodeToString(sigV2.GetSign()))
+	}
+
+	if ecHeader := obj.ECHeader(); ecHeader != nil {
+		p.printf("\nEC header:")
+
+		p.printf("\n  parent object ID: %s", ecHeader.Parent().EncodeToString())
+		p.printf("\n  index: %d", ecHeader.Index())
+		p.printf("\n  total: %d", ecHeader.Total())
+		p.printf("\n  header length: %d", ecHeader.HeaderLength())
+	}
+
+	p.printSplitHeader(obj)
+}
+
+func (p *printer) printSplitHeader(obj *object.Object) {
+	if splitID := obj.SplitID(); splitID != nil {
+		p.printf("Split ID: %s\n", splitID)
+	}
+
+	if objID, ok := obj.ParentID(); ok {
+		p.printf("Split ParentID: %s\n", objID)
+	}
+
+	if prev, ok := obj.PreviousID(); ok {
+		p.printf("\nSplit PreviousID: %s", prev)
+	}
+
+	for _, child := range obj.Children() {
+		p.printf("\nSplit ChildID: %s", child.String())
+	}
+
+	parent := obj.Parent()
+	if parent != nil {
+		p.printf("\n\nSplit Parent Header:")
+
+		p.printObject(parent)
+	}
+
+}
+
+func formattedInfoOutput(format string, cnrID cid.ID, objHeads []object.Object) (string, error) {
+	format = strings.ReplaceAll(format, "{cid}", cnrID.String())
+	objIDStr := "<empty>"
+	if len(objHeads) > 0 {
+		objID, ok := objHeads[0].ID()
+		if ok {
+			objIDStr = objID.String()
+		}
+	}
+
+	return strings.ReplaceAll(format, "{oid}", objIDStr), nil
+}
+
+func (f *Fs) infoCmd(ctx context.Context, arg []string, opt map[string]string) (out interface{}, err error) {
+	var cnrID cid.ID
+
+	if cnrID, err = f.resolveContainerID(ctx, f.rootContainer); err != nil {
+		return nil, err
+	}
+
+	var format string
+	for k, v := range opt {
+		switch k {
+		case "format":
+			format = v
+		default:
+			return nil, fmt.Errorf("unknown option \"%s\"", k)
+		}
+	}
+
+	var objIDs []oid.ID
+	var filePath string
+	if len(arg) > 0 {
+		filePath = strings.TrimPrefix(arg[0], "/")
+		if f.rootDirectory != "" {
+			filePath = f.rootDirectory + "/" + filePath
+		}
+
+		if objIDs, err = f.findObjectsFilePath(ctx, cnrID, filePath); err != nil {
+			return
+		}
+	}
+
+	cnr, err := f.containerInfo(ctx, cnrID)
+	if err != nil {
+		return
+	}
+	var objHeads []object.Object
+	if objHeads, err = f.getObjectsHead(ctx, cnrID, objIDs); err != nil {
+		return
+	}
+
+	if format != "" {
+		return formattedInfoOutput(format, cnrID, objHeads)
+	}
+
+	w := bytes.NewBufferString("")
+	p := newPrinter(w)
+	p.printf(" --- Container info ---\n")
+	p.printContainerInfo(cnrID, cnr)
+
+	if len(arg) > 0 {
+		p.printf("\n\n --- Object info ---")
+		if len(objHeads) > 0 {
+			// Print info about the first object only
+			p.printObject(&objHeads[0])
+		} else {
+			p.printf("\nNo object with \"%s\" file path was found", filePath)
+		}
+	}
+	if err := p.lastError(); err != nil {
+		return nil, err
+	}
+	return w.String(), nil
+}
+
 // Shutdown the backend, closing any background tasks and any
 // cached connections.
 func (f *Fs) Shutdown(_ context.Context) error {