s3: add backend restore command to restore objects from GLACIER

See: https://forum.rclone.org/t/rclone-settier-fails-with-scaleway-entitytoolarge/17384

backend/s3/s3.go

@@ -52,6 +52,7 @@ import (
 	"github.com/rclone/rclone/fs/fserrors"
 	"github.com/rclone/rclone/fs/fshttp"
 	"github.com/rclone/rclone/fs/hash"
+	"github.com/rclone/rclone/fs/operations"
 	"github.com/rclone/rclone/fs/walk"
 	"github.com/rclone/rclone/lib/atexit"
 	"github.com/rclone/rclone/lib/bucket"
@@ -70,6 +71,7 @@ func init() {
 		Name:        "s3",
 		Description: "Amazon S3 Compliant Storage Provider (AWS, Alibaba, Ceph, Digital Ocean, Dreamhost, IBM COS, Minio, etc)",
 		NewFs:       NewFs,
+		CommandHelp: commandHelp,
 		Options: []fs.Option{{
 			Name: fs.ConfigProvider,
 			Help: "Choose your S3 provider.",
@@ -2040,6 +2042,126 @@ func (f *Fs) PublicLink(ctx context.Context, remote string, expire fs.Duration,
 	return httpReq.Presign(time.Duration(expire))
 }
 
+var commandHelp = []fs.CommandHelp{{
+	Name:  "restore",
+	Short: "Restore objects from GLACIER to normal storage",
+	Long: `This command can be used to restore one or more objects from GLACIER
+to normal storage.
+
+Usage Examples:
+
+    rclone backend restore s3:bucket/path/to/object [-o priority=PRIORITY] [-o lifetime=DAYS]
+    rclone backend restore s3:bucket/path/to/directory [-o priority=PRIORITY] [-o lifetime=DAYS]
+    rclone backend restore s3:bucket [-o priority=PRIORITY] [-o lifetime=DAYS]
+
+This flag also obeys the filters. Test first with -i/--interactive or --dry-run flags
+
+    rclone -i backend restore --include "*.txt" s3:bucket/path -o priority=Standard
+
+All the objects shown will be marked for restore, then
+
+    rclone backend restore --include "*.txt" s3:bucket/path -o priority=Standard
+
+It returns a list of status dictionaries with Remote and Status
+keys. The Status will be OK if it was successfull or an error message
+if not.
+
+    [
+        {
+            "Status": "OK",
+            "Path": "test.txt"
+        },
+        {
+            "Status": "OK",
+            "Path": "test/file4.txt"
+        }
+    ]
+
+`,
+	Opts: map[string]string{
+		"priority":    "Priority of restore: Standard|Expedited|Bulk",
+		"lifetime":    "Lifetime of the active copy in days",
+		"description": "The optional description for the job.",
+	},
+}}
+
+// 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
+//
+// The result should be capable of being JSON encoded
+// If it is a string or a []string it will be shown to the user
+// otherwise it will be JSON encoded and shown to the user like that
+func (f *Fs) Command(ctx context.Context, name string, arg []string, opt map[string]string) (out interface{}, err error) {
+	switch name {
+	case "restore":
+		req := s3.RestoreObjectInput{
+			//Bucket:         &f.rootBucket,
+			//Key:            &encodedDirectory,
+			RestoreRequest: &s3.RestoreRequest{},
+		}
+		if lifetime := opt["lifetime"]; lifetime != "" {
+			ilifetime, err := strconv.ParseInt(lifetime, 10, 64)
+			if err != nil {
+				return nil, errors.Wrap(err, "bad lifetime")
+			}
+			req.RestoreRequest.Days = &ilifetime
+		}
+		if priority := opt["priority"]; priority != "" {
+			req.RestoreRequest.GlacierJobParameters = &s3.GlacierJobParameters{
+				Tier: &priority,
+			}
+		}
+		if description := opt["description"]; description != "" {
+			req.RestoreRequest.Description = &description
+		}
+		type status struct {
+			Status string
+			Remote string
+		}
+		var (
+			outMu sync.Mutex
+			out   = []status{}
+		)
+		err = operations.ListFn(ctx, f, func(obj fs.Object) {
+			// Remember this is run --checkers times concurrently
+			o, ok := obj.(*Object)
+			st := status{Status: "OK", Remote: obj.Remote()}
+			defer func() {
+				outMu.Lock()
+				out = append(out, st)
+				outMu.Unlock()
+			}()
+			if operations.SkipDestructive(ctx, obj, "restore") {
+				return
+			}
+			if !ok {
+				st.Status = "Not an S3 object"
+				return
+			}
+			bucket, bucketPath := o.split()
+			reqCopy := req
+			reqCopy.Bucket = &bucket
+			reqCopy.Key = &bucketPath
+			err = f.pacer.Call(func() (bool, error) {
+				_, err = f.c.RestoreObject(&reqCopy)
+				return f.shouldRetry(err)
+			})
+			if err != nil {
+				st.Status = err.Error()
+			}
+		})
+		if err != nil {
+			return out, err
+		}
+		return out, nil
+	default:
+		return nil, fs.ErrorCommandNotFound
+	}
+}
+
 // ------------------------------------------------------------
 
 // Fs returns the parent Fs
@@ -2657,6 +2779,7 @@ var (
 	_ fs.Copier      = &Fs{}
 	_ fs.PutStreamer = &Fs{}
 	_ fs.ListRer     = &Fs{}
+	_ fs.Commander   = &Fs{}
 	_ fs.Object      = &Object{}
 	_ fs.MimeTyper   = &Object{}
 	_ fs.GetTierer   = &Object{}