..
.. NB:  This file is machine generated, DO NOT EDIT!
..
.. Edit ./vmod_purge.vcc and run make instead
..


:tocdepth: 1


.. _vmod_purge(3):

=================================
VMOD purge - Varnish Purge Module
=================================

SYNOPSIS
========

.. parsed-literal::

  import purge [as name] [from "path"]
  
  :ref:`purge.hard()`
   
  :ref:`purge.soft()`
   
DESCRIPTION
===========

*vmod_purge* contains functions that offer a finer-grained control
than ``return(purge)`` from ``vcl_recv{}``. The functions can only be
called from ``vcl_hit{}`` or ``vcl_miss{}`` and they should in general
be used in both to ensure that all variants of a same object are taken
care of.

EXAMPLE
=======

::

    sub vcl_recv {
	if (req.method == "PURGE") {
	    if (client.ip !~ purge_acl) {
		return (synth(405));
	    }
	    return (hash);
	}
    }

    sub my_purge {
	set req.http.purged = purge.hard();
	if (req.http.purged == "0") {
	    return (synth(404));
	}
	else {
	    return (synth(200));
	}
    }

    sub vcl_hit {
	if (req.method == "PURGE") {
	    call my_purge;
	}
    }

    sub vcl_miss {
	if (req.method == "PURGE") {
	    call my_purge;
	}
    }

    sub vcl_synth {
	if (req.method == "PURGE") {
	    if (req.http.purged) {
		set resp.http.purged = req.http.purged;
	    }
	    return (deliver);
	}
    }

.. _purge.hard():

INT hard()
----------

This is equivalent to ``return(purge)`` but explicitly called from
``vcl_hit{}`` and ``vcl_miss{}``. It returns the number of purged
objects.

Example::

	set req.http.purged = purge.hard();

Restricted to: ``vcl_hit``, ``vcl_miss``.



.. _purge.soft():

INT soft(DURATION ttl, DURATION grace, DURATION keep)
-----------------------------------------------------

::

   INT soft(DURATION ttl=0, DURATION grace=-1, DURATION keep=-1)

Sets the *ttl*, *grace* and *keep*. By default, *ttl* is set to ``0`` with
*grace* and *keep* periods left untouched. Setting *grace* or *keep* to a
negative value or to something higher than the objects current value leaves them
untouched. Setting all three parameters to ``0`` is equivalent to a hard purge.
Returns the number of soft-purged objects.

A soft-purge can only decrease the lifetime of an object. Let's consider an
object in cache created with *ttl*, *grace*, and *keep* of 60 seconds each:

``purge.soft(ttl = 0s, grace = -1s, keep = -1s);``

* If the object is **fresh**, the *ttl* is reduced to 0 seconds and the object
  expires after 120 seconds.
* If the object is **stale**, the expiry time is not changed.

``purge.soft(ttl = 0s, grace = 10s, keep = 10s);``

* If the object is **fresh**, the *ttl* is reduced to 0 seconds, *grace* and
  *keep* are reduced to 10 seconds. The object expires after 20 seconds.
* If the object has been **stale** for 5 seconds, *grace* is reduced to 5
  seconds and *keep* is reduced to 10 seconds. The object expires after 15
  seconds.
* If the object has been **stale** for 15 seconds, *grace* is reduced to 0
  seconds and *keep* is reduced to 5 seconds. The object expires after 5
  seconds.
* If the object has been **stale** for 20 seconds or more, the object
  immediately expires.

``purge.soft(ttl = 10s, grace = -1s, keep = -1s);``

* If the object has been **fresh** for 5 seconds, the *ttl* is reduced to 10
  seconds. The object expires after 130 seconds.
* If the object has been **fresh** for 55 seconds, the *ttl* is not changed. The
  object expires after 125 seconds.
* If the object is **stale**, the expiry time is not changed.

When the expiry time of an object is reduced due to a softpurge, an
``EXP_Reduce`` entry is logged under the ``ExpKill`` VSL tag. If a softpurge
does not reduce the expiry time of an object, an ``EXP_Unchanged`` entry is
logged instead.

Restricted to: ``vcl_hit``, ``vcl_miss``.

SEE ALSO
========

* :ref:`vcl(7)`

COPYRIGHT
=========

::

  Copyright (c) 2017 Varnish Software AS
  All rights reserved.
 
  Author: Dridi Boukelmoune <dridi.boukelmoune@gmail.com>
 
  SPDX-License-Identifier: BSD-2-Clause
 
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions
  are met:
  1. Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
  2. Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
 
  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  SUCH DAMAGE.
