MEMCACHED

Andrei Dragus

OpenSIPS

Edited by

Andrei Dragus

Revision History
Revision $Revision: 5901 $$Date: 2009-07-21 09:45:05 +0200 (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.