Streaming Transfers (#153)

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
+	}
+}