https://github.com/mnutt/libvmod-cachehits

Varnish vmod for notifying backend of previous cache hit rate for stale objects
https://github.com/mnutt/libvmod-cachehits

Last synced: about 2 months ago
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Varnish vmod for notifying backend of previous cache hit rate for stale objects

• Host: GitHub
• URL: https://github.com/mnutt/libvmod-cachehits
• Owner: mnutt
• License: unlicense
• Created: 2021-12-25T21:38:30.000Z (about 3 years ago)
• Default Branch: master
• Last Pushed: 2024-08-26T20:42:27.000Z (4 months ago)
• Last Synced: 2024-08-26T23:08:30.148Z (4 months ago)
• Language: M4
• Size: 105 KB
• Stars: 0
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst
  • Changelog: CHANGES.rst
  • License: COPYING

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README

        
============

vmod-cachehits

============

SYNOPSIS

========

import cachehits;

DESCRIPTION

===========

Varnish vmod to enable hinting to the backend the number of previous cache hits.

The intended usage is for the backend to notice that an object has a high cache hit rate and run additional optimizations. (for example, higher png compression level)

FUNCTIONS

=========

Prototype

        ::

                count()

Return value

       INT

Description

       Returns number of cache hits for stale object

CacheHits

        ::

                set bereq.http.Cache-Hits = cachehits.count();

INSTALLATION

============

The source tree is based on autotools to configure the building, and

does also have the necessary bits in place to do functional unit tests

using the ``varnishtest`` tool.

Building requires the Varnish header files and uses pkg-config to find

the necessary paths.

Usage::

 ./autogen.sh

 ./configure

If you have installed Varnish to a non-standard directory, call

``autogen.sh`` and ``configure`` with ``PKG_CONFIG_PATH`` pointing to

the appropriate path. For instance, when varnishd configure was called

with ``--prefix=$PREFIX``, use

::

 export PKG_CONFIG_PATH=${PREFIX}/lib/pkgconfig

 export ACLOCAL_PATH=${PREFIX}/share/aclocal

The module will inherit its prefix from Varnish, unless you specify a

different ``--prefix`` when running the ``configure`` script for this

module.

Make targets:

* make - builds the vmod.

* make install - installs your vmod.

* make check - runs the unit tests in ``src/tests/*.vtc``.

* make distcheck - run check and prepare a tarball of the vmod.

If you build a dist tarball, you don't need any of the autotools or

pkg-config. You can build the module simply by running::

 ./configure

 make

Installation directories

------------------------

By default, the vmod ``configure`` script installs the built vmod in the

directory relevant to the prefix. The vmod installation directory can be

overridden by passing the ``vmoddir`` variable to ``make install``.

USAGE

=====

In your VCL you could then use this vmod along the following lines::

        import cachehits;

        sub vcl_backend_fetch {

                set bereq.http.Cache-Hits = cachehits.count();

        }

COMMON PROBLEMS

===============

* configure: error: Need varnish.m4 -- see README.rst

  Check whether ``PKG_CONFIG_PATH`` and ``ACLOCAL_PATH`` were set correctly

  before calling ``autogen.sh`` and ``configure``

* Incompatibilities with different Varnish Cache versions

  Make sure you build this vmod against its correspondent Varnish Cache version.

  For instance, to build against Varnish Cache 4.1, this vmod must be built from

  branch 4.1.