probelabs/goreplay · error

error writing packet header: %v

Error message

error writing packet header: %v

What it means

Writer.WritePacket wraps the underlying writer failure that occurred while writing the 16-byte pcap record header (disk full, closed writer, I/O error), reporting the capture info for context.

Source

Thrown at internal/capture/dump.go:122

	usecs := t.Nanosecond() / w.tsScaler
	binary.LittleEndian.PutUint32(w.buf[0:4], uint32(secs))
	binary.LittleEndian.PutUint32(w.buf[4:8], uint32(usecs))
	binary.LittleEndian.PutUint32(w.buf[8:12], uint32(ci.CaptureLength))
	binary.LittleEndian.PutUint32(w.buf[12:16], uint32(ci.Length))
	_, err := w.w.Write(w.buf[:])
	return err
}

// WritePacket writes the given packet data out to the file.
func (w *Writer) WritePacket(ci gopacket.CaptureInfo, data []byte) error {
	if ci.CaptureLength != len(data) {
		return fmt.Errorf("capture length %d does not match data length %d", ci.CaptureLength, len(data))
	}
	if ci.CaptureLength > ci.Length {
		return fmt.Errorf("invalid capture info %+v:  capture length > length", ci)
	}
	if err := w.writePacketHeader(ci); err != nil {
		return fmt.Errorf("error writing packet header: %v", err)
	}
	_, err := w.w.Write(data)
	return err
}

View on GitHub (pinned to 251e45abd2)

Solutions

1. Check disk space and write permissions for the output capture file
2. Verify the output writer wasn't closed concurrently
3. Inspect the wrapped %v error for the OS-level I/O cause

When it happens

Trigger: Thrown at internal/capture/dump.go:122 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of probelabs/goreplay@251e45abd2 (2026-09-02). Data as JSON: /api/errors/f275969668539f98. Report an issue: GitHub.