MEMCACHED

Andrei Dragus

   OpenSIPS

Edited by

Andrei Dragus

   Copyright  2009 Voice System

   Copyright  2009 Andrei Dragus
   Revision History
   Revision $Revision: 5901 $ $Date: 2009-07-21 10:45:05 +0300
                              (Tue, 21 Jul 2009) $
     __________________________________________________________

   Table of Contents

   1. Admin Guide

        1.1. Overview
        1.2. Advantages
        1.3. Limitations
        1.4. Dependencies

              1.4.1. OpenSIPS Modules
              1.4.2. External Libraries or Applications

        1.5. Exported Parameters

              1.5.1. server (string)
              1.5.2. Exported Functions

   List of Examples

   1.1. Set server parameter
   1.2. Use memcached servers

Chapter 1. Admin Guide

1.1. Overview

   This module is an implementation of a cache system designed to
   work with a memcached server. It uses libmemcached client
   library to connect to several memcached servers that store
   data. It registers the three functions for storing, fetching
   and removing a value to the core memcache management interface.

1.2. Advantages

     * memory costs are no longer on the server
     * many servers may be used so the memory is virtually
       unlimited
     * the cache is persistent so a restart of the server will not
       affect the cache
     * memcached is an open-source project so it can be used to
       exchange data with various other applicationsr
     * servers may be grouped together (e.g. for security purposes
       : some can be inside a private network, some can be in a
       public one)

1.3. Limitations

     * keys (in key:value pairs) may not contain spaces or control
       characters

1.4. Dependencies

1.4.1. OpenSIPS Modules

   None.

1.4.2. External Libraries or Applications

   The following libraries or applications must be installed
   before running OpenSIPS with this module loaded:
     * libmemcached:
       libmemcached can be downloaded from:
       http://tangent.org/552/libmemcached.html. Download the
       archive, extract sources, run ./configure, make,sudo make
       install.
       ...
       wget http://download.tangent.org/libmemcached-0.31.tar.gz
       tar -xzvf libmemcached-0.31.tar.gz
       cd libmemcached-0.31
       ./configure
       make
       sudo make install
       ...

1.5. Exported Parameters

1.5.1. server (string)

   The names of the servers to connect to. It can be set more than
   one time. Each value represents a group of servers to connect
   to. Each group of servers may be accessed using
   "memcached_$(GROUP_NAME)" as the first parameter of the
   cache_fetch, cache_store, cache_remove script functions. Each
   group contains a list of comma separated url:[port]. If port is
   missing the default value is used(11211).

   Example 1.1. Set server parameter
...
modparam("memcached", "server","group1 = localhost:9999,127.0.0.1" );
modparam("memcached", "server","y = random_url:8888" );
...

   Example 1.2. Use memcached servers
...
cache_store("memcached_group1","key","$ru value");
cache_fetch("memcached_y","key",$avp(i:10));
cache_remove("memcached_group1","key");
...

1.5.2. Exported Functions

   The module does not export functions to be used in
   configuration script.
