HELPER-MUX(8) User Contributed Perl Documentation HELPER-MUX(8)

helper-mux - Concurrency protocol multiplexer for Squid helpers

helper-mux helper-path [helper-options ...]

helper-mux purpose is to relieve some of the burden squid has when dealing with slow helpers. It does so by acting as a middleman between squid and the actual helpers, talking to squid via the multiplexed variant of the helper protocol and to the helpers via the non-multiplexed variant.

Helpers are started on demand, and in theory the muxer can handle up to 1k helpers per instance. It is up to squid to decide how many helpers to start.

The helper can be controlled using various signals: - SIGHUP: dump the state of all helpers to STDERR

Path to the helper being multiplexed.
Command line options for the helper being multiplexed.

helper-mux knows nothing about the actual messages being passed around, and as such cannot yet compensate for broken helpers.

It is not yet able to manage dying helpers.

* Copyright (C) 1996-2022 The Squid Software Foundation and contributors
* Squid software is distributed under GPLv2+ license and includes
* contributions from numerous individuals and organizations.
* Please see the COPYING and CONTRIBUTORS files for details.
  Copyright (C) Francesco Chemolli <>
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  GNU General Public License for more details.
  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
2022-12-12 perl v5.36.0