Simplify GCloud upload code

Author: csweichel

components/content-service/pkg/storage/gcloud.go

@@ -15,7 +15,6 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
-	"sync"
 	"time"
 
 	gcpstorage "cloud.google.com/go/storage"
@@ -366,39 +365,29 @@ func (rs *DirectGCPStorage) Upload(ctx context.Context, source string, name stri
 		firstBackup = true
 	}
 
-	var wg sync.WaitGroup
 	var written int64
 
-	wg.Add(1)
+	wc := obj.NewWriter(ctx)
+	wc.Metadata = options.Annotations
+	wc.ContentType = options.ContentType
+	// Increase chunk size for faster uploading
+	wc.ChunkSize = googleapi.DefaultUploadChunkSize * 4
 
-	go func() {
-		defer wg.Done()
-
-		wc := obj.NewWriter(ctx)
-		wc.Metadata = options.Annotations
-		wc.ContentType = options.ContentType
-		// Increase chunk size for faster uploading
-		wc.ChunkSize = googleapi.DefaultUploadChunkSize * 4
-
-		written, err = io.Copy(wc, sfn)
-		if err != nil {
-			log.WithError(err).WithField("name", name).Error("Error while uploading file")
-			return
-		}
-
-		// persist changes in GCS
-		err = wc.Close()
-		if err != nil {
-			log.WithError(err).WithField("name", name).Error("Error while uploading file")
-			return
-		}
-	}()
+	written, err = io.Copy(wc, sfn)
+	if err != nil {
+		log.WithError(err).WithField("name", name).Error("Error while uploading file")
+		return "", "", err
+	}
 
-	wg.Wait()
+	// persist changes in GCS
+	err = wc.Close()
+	if err != nil {
+		log.WithError(err).WithField("name", name).Error("Error while uploading file")
+		return "", "", err
+	}
 
 	if written != totalSize {
-		err = xerrors.Errorf("Wrote fewer bytes than it should have, %d instead of %d", written, totalSize)
-		return
+		return "", "", xerrors.Errorf("Wrote fewer bytes than it should have, %d instead of %d", written, totalSize)
 	}
 
 	// maintain backup trail if we're asked to - we do this prior to overwriting the regular backup file