storage/minio: add workaround for unspecified size in Save when multipart is disabled

modules/storage/minio.go

@@ -5,6 +5,7 @@
 package storage
 
 import (
+	"bytes"
 	"context"
 	"io"
 	"net/url"
@@ -141,6 +142,22 @@ func (m *MinioStorage) Save(path string, r io.Reader, size int64) (int64, error)
 		disableSignature, disableMultipart = m.config.DisableSignature, m.config.DisableMultipart
 	}
 
+	if disableMultipart && size < 0 {
+		// Attempts to read everything from the source into memory. This can take a big toll on memory, and it can become a potential DoS source
+		// but since we have disabled multipart upload this mean we can't really stream write anymore...
+		// well, unless we have a better way to estimate the stream size, this would be a workaround
+
+		buf := &bytes.Buffer{}
+		if n, err := io.Copy(buf, r); err != nil {
+			// I guess this would likely be EOF or OOM...?
+			return -1, err
+		} else {
+			// Since we read all the data from the source, it might not be usable again,
+			// so we should swap the reader location to our memory buffer
+			r, size = buf, n
+		}
+	}
+
 	uploadInfo, err := m.client.PutObject(
 		m.ctx,
 		m.bucket,