Streaming Transfers (#153)

server/backup/backup_local.go

@@ -66,7 +66,7 @@ func (b *LocalBackup) Generate(ctx context.Context, basePath, ignore string) (*A
 	}
 
 	b.log().WithField("path", b.Path()).Info("creating backup for server")
-	if err := a.Create(b.Path()); err != nil {
+	if err := a.Create(ctx, b.Path()); err != nil {
 		return nil, err
 	}
 	b.log().Info("created backup successfully")

server/backup/backup_s3.go

@@ -57,7 +57,7 @@ func (s *S3Backup) Generate(ctx context.Context, basePath, ignore string) (*Arch
 	}
 
 	s.log().WithField("path", s.Path()).Info("creating backup for server")
-	if err := a.Create(s.Path()); err != nil {
+	if err := a.Create(ctx, s.Path()); err != nil {
 		return nil, err
 	}
 	s.log().Info("created backup successfully")

server/events.go

@@ -5,8 +5,7 @@ import (
 	"github.com/pterodactyl/wings/system"
 )
 
-// Defines all of the possible output events for a server.
-// noinspection GoNameStartsWithPackageName
+// Defines all the possible output events for a server.
 const (
 	DaemonMessageEvent          = "daemon message"
 	InstallOutputEvent          = "install output"
@@ -19,6 +18,7 @@ const (
 	BackupCompletedEvent        = "backup completed"
 	TransferLogsEvent           = "transfer logs"
 	TransferStatusEvent         = "transfer status"
+	DeletedEvent                = "deleted"
 )
 
 // Events returns the server's emitter instance.

server/filesystem/archive.go

@@ -2,13 +2,13 @@ package filesystem
 
 import (
 	"archive/tar"
+	"context"
 	"io"
 	"io/fs"
 	"os"
 	"path/filepath"
 	"strings"
 	"sync"
-	"sync/atomic"
 
 	"emperror.dev/errors"
 	"github.com/apex/log"
@@ -18,7 +18,7 @@ import (
 	ignore "github.com/sabhiram/go-gitignore"
 
 	"github.com/pterodactyl/wings/config"
-	"github.com/pterodactyl/wings/system"
+	"github.com/pterodactyl/wings/internal/progress"
 )
 
 const memory = 4 * 1024
@@ -33,13 +33,13 @@ var pool = sync.Pool{
 // TarProgress .
 type TarProgress struct {
 	*tar.Writer
-	p *Progress
+	p *progress.Progress
 }
 
 // NewTarProgress .
-func NewTarProgress(w *tar.Writer, p *Progress) *TarProgress {
+func NewTarProgress(w *tar.Writer, p *progress.Progress) *TarProgress {
 	if p != nil {
-		p.w = w
+		p.Writer = w
 	}
 	return &TarProgress{
 		Writer: w,
@@ -47,6 +47,7 @@ func NewTarProgress(w *tar.Writer, p *Progress) *TarProgress {
 	}
 }
 
+// Write .
 func (p *TarProgress) Write(v []byte) (int, error) {
 	if p.p == nil {
 		return p.Writer.Write(v)
@@ -54,84 +55,6 @@ func (p *TarProgress) Write(v []byte) (int, error) {
 	return p.p.Write(v)
 }
 
-// Progress is used to track the progress of any I/O operation that are being
-// performed.
-type Progress struct {
-	// written is the total size of the files that have been written to the writer.
-	written int64
-	// Total is the total size of the archive in bytes.
-	total int64
-	// w .
-	w io.Writer
-}
-
-// NewProgress .
-func NewProgress(total int64) *Progress {
-	return &Progress{total: total}
-}
-
-// SetWriter sets the writer progress will forward writes to.
-// NOTE: This function is not thread safe.
-func (p *Progress) SetWriter(w io.Writer) {
-	p.w = w
-}
-
-// Written returns the total number of bytes written.
-// This function should be used when the progress is tracking data being written.
-func (p *Progress) Written() int64 {
-	return atomic.LoadInt64(&p.written)
-}
-
-// Total returns the total size in bytes.
-func (p *Progress) Total() int64 {
-	return atomic.LoadInt64(&p.total)
-}
-
-// Write totals the number of bytes that have been written to the writer.
-func (p *Progress) Write(v []byte) (int, error) {
-	n := len(v)
-	atomic.AddInt64(&p.written, int64(n))
-	if p.w != nil {
-		return p.w.Write(v)
-	}
-	return n, nil
-}
-
-// Progress returns a formatted progress string for the current progress.
-func (p *Progress) Progress(width int) string {
-	// current = 100 (Progress, dynamic)
-	// total = 1000 (Content-Length, dynamic)
-	// width = 25 (Number of ticks to display, static)
-	// widthPercentage = 100 / width (What percentage does each tick represent, static)
-	//
-	// percentageDecimal = current / total = 0.1
-	// percentage = percentageDecimal * 100 = 10%
-	// ticks = percentage / widthPercentage = 2.5
-	//
-	// ticks is a float64, so we cast it to an int which rounds it down to 2.
-
-	// Values are cast to floats to prevent integer division.
-	current := p.Written()
-	total := p.Total()
-	// width := is passed as a parameter
-	widthPercentage := float64(100) / float64(width)
-	percentageDecimal := float64(current) / float64(total)
-	percentage := percentageDecimal * 100
-	ticks := int(percentage / widthPercentage)
-
-	// Ensure that we never get a negative number of ticks, this will prevent strings#Repeat
-	// from panicking.  A negative number of ticks is likely to happen when the total size is
-	// inaccurate, such as when we are going off of rough disk usage calculation.
-	if ticks < 0 {
-		ticks = 0
-	} else if ticks > width {
-		ticks = width
-	}
-
-	bar := strings.Repeat("=", ticks) + strings.Repeat(" ", width-ticks)
-	return "[" + bar + "] " + system.FormatBytes(current) + " / " + system.FormatBytes(total)
-}
-
 type Archive struct {
 	// BasePath is the absolute path to create the archive from where Files and Ignore are
 	// relative to.
@@ -146,12 +69,12 @@ type Archive struct {
 	Files []string
 
 	// Progress wraps the writer of the archive to pass through the progress tracker.
-	Progress *Progress
+	Progress *progress.Progress
 }
 
 // Create creates an archive at dst with all the files defined in the
 // included Files array.
-func (a *Archive) Create(dst string) error {
+func (a *Archive) Create(ctx context.Context, dst string) error {
 	f, err := os.OpenFile(dst, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0o600)
 	if err != nil {
 		return err
@@ -169,6 +92,11 @@ func (a *Archive) Create(dst string) error {
 		writer = f
 	}
 
+	return a.Stream(ctx, writer)
+}
+
+// Stream .
+func (a *Archive) Stream(ctx context.Context, w io.Writer) error {
 	// Choose which compression level to use based on the compression_level configuration option
 	var compressionLevel int
 	switch config.Get().System.Backups.CompressionLevel {
@@ -183,7 +111,7 @@ func (a *Archive) Create(dst string) error {
 	}
 
 	// Create a new gzip writer around the file.
-	gw, _ := pgzip.NewWriterLevel(writer, compressionLevel)
+	gw, _ := pgzip.NewWriterLevel(w, compressionLevel)
 	_ = gw.SetConcurrency(1<<20, 1)
 	defer gw.Close()
 
@@ -197,16 +125,16 @@ func (a *Archive) Create(dst string) error {
 	options := &godirwalk.Options{
 		FollowSymbolicLinks: false,
 		Unsorted:            true,
-		Callback:            a.callback(pw),
 	}
 
 	// If we're specifically looking for only certain files, or have requested
 	// that certain files be ignored we'll update the callback function to reflect
 	// that request.
+	var callback godirwalk.WalkFunc
 	if len(a.Files) == 0 && len(a.Ignore) > 0 {
 		i := ignore.CompileIgnoreLines(strings.Split(a.Ignore, "\n")...)
 
-		options.Callback = a.callback(pw, func(_ string, rp string) error {
+		callback = a.callback(pw, func(_ string, rp string) error {
 			if i.MatchesPath(rp) {
 				return godirwalk.SkipThis
 			}
@@ -214,7 +142,19 @@ func (a *Archive) Create(dst string) error {
 			return nil
 		})
 	} else if len(a.Files) > 0 {
-		options.Callback = a.withFilesCallback(pw)
+		callback = a.withFilesCallback(pw)
+	} else {
+		callback = a.callback(pw)
+	}
+
+	// Set the callback function, wrapped with support for context cancellation.
+	options.Callback = func(path string, de *godirwalk.Dirent) error {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+			return callback(path, de)
+		}
 	}
 
 	// Recursively walk the path we are archiving.

server/filesystem/archive_test.go

@@ -1,48 +0,0 @@
-package filesystem
-
-import (
-	"bytes"
-	"testing"
-
-	. "github.com/franela/goblin"
-)
-
-func TestProgress(t *testing.T) {
-	g := Goblin(t)
-
-	g.Describe("Progress", func() {
-		g.It("properly initializes", func() {
-			total := int64(1000)
-			p := NewProgress(total)
-			g.Assert(p).IsNotNil()
-			g.Assert(p.Total()).Equal(total)
-			g.Assert(p.Written()).Equal(int64(0))
-		})
-
-		g.It("increments written when Write is called", func() {
-			v := []byte("hello")
-			p := NewProgress(1000)
-			_, err := p.Write(v)
-			g.Assert(err).IsNil()
-			g.Assert(p.Written()).Equal(int64(len(v)))
-		})
-
-		g.It("renders a progress bar", func() {
-			v := bytes.Repeat([]byte{' '}, 100)
-			p := NewProgress(1000)
-			_, err := p.Write(v)
-			g.Assert(err).IsNil()
-			g.Assert(p.Written()).Equal(int64(len(v)))
-			g.Assert(p.Progress(25)).Equal("[==                       ] 100 B / 1000 B")
-		})
-
-		g.It("renders a progress bar when written exceeds total", func() {
-			v := bytes.Repeat([]byte{' '}, 1001)
-			p := NewProgress(1000)
-			_, err := p.Write(v)
-			g.Assert(err).IsNil()
-			g.Assert(p.Written()).Equal(int64(len(v)))
-			g.Assert(p.Progress(25)).Equal("[=========================] 1001 B / 1000 B")
-		})
-	})
-}

server/filesystem/compress.go

@@ -6,6 +6,7 @@ import (
 	"compress/gzip"
 	"context"
 	"fmt"
+	"io"
 	iofs "io/fs"
 	"os"
 	"path"
@@ -21,7 +22,7 @@ import (
 	"github.com/mholt/archiver/v4"
 )
 
-// CompressFiles compresses all of the files matching the given paths in the
+// CompressFiles compresses all the files matching the given paths in the
 // specified directory. This function also supports passing nested paths to only
 // compress certain files and folders when working in a larger directory. This
 // effectively creates a local backup, but rather than ignoring specific files
@@ -36,7 +37,7 @@ func (fs *Filesystem) CompressFiles(dir string, paths []string) (os.FileInfo, er
 		return nil, err
 	}
 
-	// Take all of the paths passed in and merge them together with the root directory we've gotten.
+	// Take all the paths passed in and merge them together with the root directory we've gotten.
 	for i, p := range paths {
 		paths[i] = filepath.Join(cleanedRootDir, p)
 	}
@@ -52,7 +53,7 @@ func (fs *Filesystem) CompressFiles(dir string, paths []string) (os.FileInfo, er
 		fmt.Sprintf("archive-%s.tar.gz", strings.ReplaceAll(time.Now().Format(time.RFC3339), ":", "")),
 	)
 
-	if err := a.Create(d); err != nil {
+	if err := a.Create(context.Background(), d); err != nil {
 		return nil, err
 	}
 
@@ -147,6 +148,7 @@ func (fs *Filesystem) DecompressFileUnsafe(ctx context.Context, dir string, file
 	if err != nil {
 		return err
 	}
+	// TODO: defer file close?
 
 	// Identify the type of archive we are dealing with.
 	format, input, err := archiver.Identify(filepath.Base(file), f)
@@ -157,13 +159,49 @@ func (fs *Filesystem) DecompressFileUnsafe(ctx context.Context, dir string, file
 		return err
 	}
 
+	return fs.extractStream(ctx, extractStreamOptions{
+		Directory: dir,
+		Format:    format,
+		Reader:    input,
+	})
+}
+
+// ExtractStreamUnsafe .
+func (fs *Filesystem) ExtractStreamUnsafe(ctx context.Context, dir string, r io.Reader) error {
+	format, input, err := archiver.Identify("archive.tar.gz", r)
+	if err != nil {
+		if errors.Is(err, archiver.ErrNoMatch) {
+			return newFilesystemError(ErrCodeUnknownArchive, err)
+		}
+		return err
+	}
+
+	return fs.extractStream(ctx, extractStreamOptions{
+		Directory: dir,
+		Format:    format,
+		Reader:    input,
+	})
+}
+
+type extractStreamOptions struct {
+	// The directory to extract the archive to.
+	Directory string
+	// File name of the archive.
+	FileName string
+	// Format of the archive.
+	Format archiver.Format
+	// Reader for the archive.
+	Reader io.Reader
+}
+
+func (fs *Filesystem) extractStream(ctx context.Context, opts extractStreamOptions) error {
 	// Decompress and extract archive
-	if ex, ok := format.(archiver.Extractor); ok {
-		return ex.Extract(ctx, input, nil, func(ctx context.Context, f archiver.File) error {
+	if ex, ok := opts.Format.(archiver.Extractor); ok {
+		return ex.Extract(ctx, opts.Reader, nil, func(ctx context.Context, f archiver.File) error {
 			if f.IsDir() {
 				return nil
 			}
-			p := filepath.Join(dir, ExtractNameFromArchive(f))
+			p := filepath.Join(opts.Directory, ExtractNameFromArchive(f))
 			// If it is ignored, just don't do anything with the file and skip over it.
 			if err := fs.IsIgnored(p); err != nil {
 				return nil
@@ -174,20 +212,19 @@ func (fs *Filesystem) DecompressFileUnsafe(ctx context.Context, dir string, file
 			}
 			defer r.Close()
 			if err := fs.Writefile(p, r); err != nil {
-				return wrapError(err, file)
+				return wrapError(err, opts.FileName)
 			}
 			// Update the file permissions to the one set in the archive.
 			if err := fs.Chmod(p, f.Mode()); err != nil {
-				return wrapError(err, file)
+				return wrapError(err, opts.FileName)
 			}
 			// Update the file modification time to the one set in the archive.
 			if err := fs.Chtimes(p, f.ModTime(), f.ModTime()); err != nil {
-				return wrapError(err, file)
+				return wrapError(err, opts.FileName)
 			}
 			return nil
 		})
 	}
-
 	return nil
 }
 

server/installer/errors.go

@@ -0,0 +1,19 @@
+package installer
+
+type validationError struct {
+	msg string
+}
+
+func (e *validationError) Error() string {
+	return e.msg
+}
+
+func IsValidationError(err error) bool {
+	_, ok := err.(*validationError)
+
+	return ok
+}
+
+func NewValidationError(msg string) error {
+	return &validationError{msg: msg}
+}

server/installer/installer.go

@@ -0,0 +1,52 @@
+package installer
+
+import (
+	"context"
+
+	"emperror.dev/errors"
+	"github.com/asaskevich/govalidator"
+
+	"github.com/pterodactyl/wings/remote"
+	"github.com/pterodactyl/wings/server"
+)
+
+type Installer struct {
+	server            *server.Server
+	StartOnCompletion bool
+}
+
+type ServerDetails struct {
+	UUID              string `json:"uuid"`
+	StartOnCompletion bool   `json:"start_on_completion"`
+}
+
+// New validates the received data to ensure that all the required fields
+// have been passed along in the request. This should be manually run before
+// calling Execute().
+func New(ctx context.Context, manager *server.Manager, details ServerDetails) (*Installer, error) {
+	if !govalidator.IsUUIDv4(details.UUID) {
+		return nil, NewValidationError("uuid provided was not in a valid format")
+	}
+
+	c, err := manager.Client().GetServerConfiguration(ctx, details.UUID)
+	if err != nil {
+		if !remote.IsRequestError(err) {
+			return nil, errors.WithStackIf(err)
+		}
+		return nil, errors.WrapIf(err, "installer: could not get server configuration from remote API")
+	}
+
+	// Create a new server instance using the configuration we wrote to the disk
+	// so that everything gets instantiated correctly on the struct.
+	s, err := manager.InitServer(c)
+	if err != nil {
+		return nil, errors.WrapIf(err, "installer: could not init server instance")
+	}
+	i := Installer{server: s, StartOnCompletion: details.StartOnCompletion}
+	return &i, nil
+}
+
+// Server returns the server instance.
+func (i *Installer) Server() *server.Server {
+	return i.server
+}

server/transfer/archive.go

@@ -0,0 +1,52 @@
+package transfer
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"github.com/pterodactyl/wings/internal/progress"
+	"github.com/pterodactyl/wings/server/filesystem"
+)
+
+// Archive returns an archive that can be used to stream the contents of the
+// contents of a server.
+func (t *Transfer) Archive() (*Archive, error) {
+	if t.archive == nil {
+		// Get the disk usage of the server (used to calculate the progress of the archive process)
+		rawSize, err := t.Server.Filesystem().DiskUsage(true)
+		if err != nil {
+			return nil, fmt.Errorf("transfer: failed to get server disk usage: %w", err)
+		}
+
+		// Create a new archive instance and assign it to the transfer.
+		t.archive = NewArchive(t, uint64(rawSize))
+	}
+
+	return t.archive, nil
+}
+
+// Archive represents an archive used to transfer the contents of a server.
+type Archive struct {
+	archive *filesystem.Archive
+}
+
+// NewArchive returns a new archive associated with the given transfer.
+func NewArchive(t *Transfer, size uint64) *Archive {
+	return &Archive{
+		archive: &filesystem.Archive{
+			BasePath: t.Server.Filesystem().Path(),
+			Progress: progress.NewProgress(size),
+		},
+	}
+}
+
+// Stream returns a reader that can be used to stream the contents of the archive.
+func (a *Archive) Stream(ctx context.Context, w io.Writer) error {
+	return a.archive.Stream(ctx, w)
+}
+
+// Progress returns the current progress of the archive.
+func (a *Archive) Progress() *progress.Progress {
+	return a.archive.Progress
+}

server/transfer/doc.go

@@ -0,0 +1,4 @@
+// Package transfer handles all logic related to transferring servers between
+// two nodes. This includes the logic for archiving a server on the source node
+// and logic for importing a server from the source node into the target node.
+package transfer

server/transfer/manager.go

@@ -0,0 +1,57 @@
+package transfer
+
+import (
+	"sync"
+)
+
+var (
+	incomingTransfers = NewManager()
+	outgoingTransfers = NewManager()
+)
+
+// Incoming returns a transfer manager for incoming transfers.
+func Incoming() *Manager {
+	return incomingTransfers
+}
+
+// Outgoing returns a transfer manager for outgoing transfers.
+func Outgoing() *Manager {
+	return outgoingTransfers
+}
+
+// Manager manages transfers.
+type Manager struct {
+	mu        sync.RWMutex
+	transfers map[string]*Transfer
+}
+
+// NewManager returns a new transfer manager.
+func NewManager() *Manager {
+	return &Manager{
+		transfers: make(map[string]*Transfer),
+	}
+}
+
+// Add adds a transfer to the manager.
+func (m *Manager) Add(transfer *Transfer) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.transfers[transfer.Server.ID()] = transfer
+}
+
+// Remove removes a transfer from the manager.
+func (m *Manager) Remove(transfer *Transfer) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	delete(m.transfers, transfer.Server.ID())
+}
+
+// Get gets a transfer from the manager using a server ID.
+func (m *Manager) Get(id string) *Transfer {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	return m.transfers[id]
+}

server/transfer/source.go

@@ -0,0 +1,159 @@
+package transfer
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"time"
+
+	"github.com/pterodactyl/wings/internal/progress"
+)
+
+// PushArchiveToTarget POSTs the archive to the target node and returns the
+// response body.
+func (t *Transfer) PushArchiveToTarget(url, token string) ([]byte, error) {
+	ctx, cancel := context.WithCancel(t.ctx)
+	defer cancel()
+
+	t.SendMessage("Preparing to stream server data to destination...")
+	t.SetStatus(StatusProcessing)
+
+	a, err := t.Archive()
+	if err != nil {
+		t.Error(err, "Failed to get archive for transfer.")
+		return nil, errors.New("failed to get archive for transfer")
+	}
+
+	t.SendMessage("Streaming archive to destination...")
+
+	// Send the upload progress to the websocket every 5 seconds.
+	ctx2, cancel2 := context.WithCancel(ctx)
+	defer cancel2()
+	go func(ctx context.Context, p *progress.Progress, tc *time.Ticker) {
+		defer tc.Stop()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-tc.C:
+				t.SendMessage("Uploading " + p.Progress(25))
+			}
+		}
+	}(ctx2, a.Progress(), time.NewTicker(5*time.Second))
+
+	// Create a new request using the pipe as the body.
+	body, writer := io.Pipe()
+	defer body.Close()
+	defer writer.Close()
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, body)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Authorization", token)
+
+	// Create a new multipart writer that writes the archive to the pipe.
+	mp := multipart.NewWriter(writer)
+	defer mp.Close()
+	req.Header.Set("Content-Type", mp.FormDataContentType())
+
+	// Create a new goroutine to write the archive to the pipe used by the
+	// multipart writer.
+	errChan := make(chan error)
+	go func() {
+		defer close(errChan)
+		defer writer.Close()
+		defer mp.Close()
+
+		src, pw := io.Pipe()
+		defer src.Close()
+		defer pw.Close()
+
+		h := sha256.New()
+		tee := io.TeeReader(src, h)
+
+		dest, err := mp.CreateFormFile("archive", "archive.tar.gz")
+		if err != nil {
+			errChan <- errors.New("failed to create form file")
+			return
+		}
+
+		ch := make(chan error)
+		go func() {
+			defer close(ch)
+
+			if _, err := io.Copy(dest, tee); err != nil {
+				ch <- fmt.Errorf("failed to stream archive to destination: %w", err)
+				return
+			}
+
+			t.Log().Debug("finished copying dest to tee")
+		}()
+
+		if err := a.Stream(ctx, pw); err != nil {
+			errChan <- errors.New("failed to stream archive to pipe")
+			return
+		}
+		t.Log().Debug("finished streaming archive to pipe")
+
+		// Close the pipe writer early to release resources and ensure that the data gets flushed.
+		_ = pw.Close()
+
+		// Wait for the copy to finish before we continue.
+		t.Log().Debug("waiting on copy to finish")
+		if err := <-ch; err != nil {
+			errChan <- err
+			return
+		}
+
+		if err := mp.WriteField("checksum", hex.EncodeToString(h.Sum(nil))); err != nil {
+			errChan <- errors.New("failed to stream checksum")
+			return
+		}
+
+		cancel2()
+		t.SendMessage("Finished streaming archive to destination.")
+
+		if err := mp.Close(); err != nil {
+			t.Log().WithError(err).Error("error while closing multipart writer")
+		}
+		t.Log().Debug("closed multipart writer")
+	}()
+
+	t.Log().Debug("sending archive to destination")
+	client := http.Client{Timeout: 0}
+	res, err := client.Do(req)
+	t.Log().Debug("waiting for stream to complete")
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case err2 := <-errChan:
+		t.Log().Debug("stream completed")
+		if err != nil || err2 != nil {
+			if err == context.Canceled {
+				return nil, err
+			}
+
+			t.Log().WithError(err).Debug("failed to send archive to destination")
+			return nil, fmt.Errorf("http error: %w, multipart error: %v", err, err2)
+		}
+		defer res.Body.Close()
+		t.Log().Debug("received response from destination")
+
+		v, err := io.ReadAll(res.Body)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read response body: %w", err)
+		}
+
+		if res.StatusCode != http.StatusOK {
+			return nil, errors.New(string(v))
+		}
+
+		return v, nil
+	}
+}

server/transfer/transfer.go

@@ -0,0 +1,128 @@
+package transfer
+
+import (
+	"context"
+	"time"
+
+	"github.com/apex/log"
+	"github.com/mitchellh/colorstring"
+
+	"github.com/pterodactyl/wings/server"
+	"github.com/pterodactyl/wings/system"
+)
+
+// Status represents the current status of a transfer.
+type Status string
+
+// String satisfies the fmt.Stringer interface.
+func (s Status) String() string {
+	return string(s)
+}
+
+const (
+	// StatusPending is the status of a transfer when it is first created.
+	StatusPending Status = "pending"
+	// StatusProcessing is the status of a transfer when it is currently in
+	// progress, such as when the archive is being streamed to the target node.
+	StatusProcessing Status = "processing"
+
+	// StatusCancelling is the status of a transfer when it is in the process of
+	// being cancelled.
+	StatusCancelling Status = "cancelling"
+
+	// StatusCancelled is the final status of a transfer when it has been
+	// cancelled.
+	StatusCancelled Status = "cancelled"
+	// StatusFailed is the final status of a transfer when it has failed.
+	StatusFailed Status = "failed"
+	// StatusCompleted is the final status of a transfer when it has completed.
+	StatusCompleted Status = "completed"
+)
+
+// Transfer represents a transfer of a server from one node to another.
+type Transfer struct {
+	// ctx is the context for the transfer.
+	ctx context.Context
+	// cancel is used to cancel all ongoing transfer operations for the server.
+	cancel *context.CancelFunc
+
+	// Server associated with the transfer.
+	Server *server.Server
+	// status of the transfer.
+	status *system.Atomic[Status]
+
+	// archive is the archive that is being created for the transfer.
+	archive *Archive
+}
+
+// New returns a new transfer instance for the given server.
+func New(ctx context.Context, s *server.Server) *Transfer {
+	ctx, cancel := context.WithCancel(ctx)
+
+	return &Transfer{
+		ctx:    ctx,
+		cancel: &cancel,
+
+		Server: s,
+		status: system.NewAtomic(StatusPending),
+	}
+}
+
+// Context returns the context for the transfer.
+func (t *Transfer) Context() context.Context {
+	return t.ctx
+}
+
+// Cancel cancels the transfer.
+func (t *Transfer) Cancel() {
+	status := t.Status()
+	if status == StatusCancelling ||
+		status == StatusCancelled ||
+		status == StatusCompleted ||
+		status == StatusFailed {
+		return
+	}
+
+	if t.cancel == nil {
+		return
+	}
+
+	t.SetStatus(StatusCancelling)
+	(*t.cancel)()
+}
+
+// Status returns the current status of the transfer.
+func (t *Transfer) Status() Status {
+	return t.status.Load()
+}
+
+// SetStatus sets the status of the transfer.
+func (t *Transfer) SetStatus(s Status) {
+	// TODO: prevent certain status changes from happening.
+	// If we are cancelling, then we can't go back to processing.
+	t.status.Store(s)
+
+	t.Server.Events().Publish(server.TransferStatusEvent, s)
+}
+
+// SendMessage sends a message to the server's console.
+func (t *Transfer) SendMessage(v string) {
+	t.Server.Events().Publish(
+		server.TransferLogsEvent,
+		colorstring.Color("[yellow][bold]"+time.Now().Format(time.RFC1123)+" [Transfer System] [Source Node]:[default] "+v),
+	)
+}
+
+// Error logs an error that occurred on the source node.
+func (t *Transfer) Error(err error, v string) {
+	t.Log().WithError(err).Error(v)
+	t.SendMessage(v)
+}
+
+// Log returns a logger for the transfer.
+func (t *Transfer) Log() *log.Entry {
+	if t.Server == nil {
+		return log.WithField("subsystem", "transfer")
+	}
+	return t.Server.Log().WithField("subsystem", "transfer")
+}