errdefs: add timeout case for NeedsRetryWithHTTP

For some registry servers whose gateway has https on port 443 but
does not forward the request to the registry server, an io timeout
error occurs and we may need to fallback to http as well.

Signed-off-by: Yan Song <[email protected]>

Author: imeoer

pkg/errdefs/errors.go

@@ -21,7 +21,7 @@ var (
 	ErrSameTag          = errors.New("ERR_SAME_TAG")
 )
 
-// IsErrHTTPResponseToHTTPSClient returns whether err is
+// isErrHTTPResponseToHTTPSClient returns whether err is
 // "http: server gave HTTP response to HTTPS client"
 func isErrHTTPResponseToHTTPSClient(err error) bool {
 	// The error string is unexposed as of Go 1.16, so we can't use `errors.Is`.
@@ -30,15 +30,21 @@ func isErrHTTPResponseToHTTPSClient(err error) bool {
 	return strings.Contains(err.Error(), unexposed)
 }
 
-// IsErrConnectionRefused return whether err is
+// isErrConnectionRefused return whether err is
 // "connect: connection refused"
 func isErrConnectionRefused(err error) bool {
 	const errMessage = "connect: connection refused"
 	return strings.Contains(err.Error(), errMessage)
 }
 
+// isErrTimeout return whether err is "timeout"
+func isErrTimeout(err error) bool {
+	const errMessage = "timeout"
+	return strings.Contains(err.Error(), errMessage)
+}
+
 func NeedsRetryWithHTTP(err error) bool {
-	return err != nil && (isErrHTTPResponseToHTTPSClient(err) || isErrConnectionRefused(err))
+	return err != nil && (isErrHTTPResponseToHTTPSClient(err) || isErrConnectionRefused(err) || isErrTimeout(err))
 }
 
 func isErrInconsistentNydusLayer(err error) bool {