add info for connection reset by peer for dl piece stage

internal/stage_dl_piece.go

@@ -5,6 +5,7 @@ import (
  "math/rand"
  "os"
  "path"
+ "strings"
 
  tester_utils "github.com/codecrafters-io/tester-utils"
 )
@@ -90,6 +91,15 @@ func testDownloadPiece(stageHarness *tester_utils.StageHarness) error {
 
  logger.Infof("Running ./your_bittorrent.sh download_piece -o %s %s %d", downloadedFilePath, torrentFilePath, t.pieceIndex)
  result, err := executable.Run("download_piece", "-o", downloadedFilePath, torrentFilePath, fmt.Sprintf("%d", t.pieceIndex))
+ resultStr := string(result.Stdout)
+
+ if strings.Contains(resultStr, "Connection reset by peer") || strings.Contains(resultStr, "EOF") {
+ logger.Infoln("Connection reset by peer or EOF type of errors can be transient issues (try again), but they can also happen when peers receive unexpected messages (sending a REQUEST message with an incorrect offset/length, block size larger than 16 kb etc.)")
+ if t.pieceLength != 262144 {
+ logger.Infof("Last piece of the file can be less than piece length specified in torrent metadata. For instance, the length of this piece is %d", t.pieceLength)
+ }
+ }
+
  if err != nil {
  return err
  }