mqueue Module

Elena-Ramona Modroiu

Edited by

Elena-Ramona Modroiu

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. mqueue (string)
4. Functions
4.1. mq_add(queue, key, value)
4.2. mq_fetch(queue)
4.3. mq_pv_free(queue)

List of Examples

1.1. Set mqueue parameter
1.2. mq_add usage
1.3. mq_fetch usage
1.4. mq_pv_free usage

Chapter 1. Admin Guide

1. Overview

This module offers generic message queue system in shared memory for inter-process communication via config file. One example of usage is to send time consuming operations to a timer process that consumes items in the queue, without affecting SIP message handling.

There can be defined many queues, access to values being done via pseudo variables.

2. Dependencies

2.1. Kamailio Modules

The following modules must be loaded before this module:

  • None.

2.2. External Libraries or Applications

The following libraries or applications must be installed before running Kamailio with this module loaded:

  • None.

3. Parameters

3.1. mqueue (string)

Definition of memory queue

Default value is none.

Value must be a list of parameters: attr=value;... The attribute 'name' is mandatory, defining the name of the queue. Optional attribute 'size' specifies the maximum number of items in queue, if it is execeeded the oldest one is removed.

The parameter can be set many time, each holding the definition of one queue.

Example 1.1. Set mqueue parameter

modparam("mqueue", "mqueue", "name=myq;size=20;")
modparam("mqueue", "mqueue", "name=qaz")

4. Functions

4.1.  mq_add(queue, key, value)

Add a new item (key, value) in the queue. If max size of queue is exceeded, the oldest one is removed.

Example 1.2. mq_add usage

mq_add("myq", "$rU", "call from $fU");

4.2.  mq_fetch(queue)

Take oldest item from queue and fill $mqk(queue) and $mqv(queue) pseudo variables.

Return: true on success (1); false on failure (-1) or no item fetched (-2).

Example 1.3. mq_fetch usage

   xlog("$mqk(myq) - $mqv(myq)\n");

4.3.  mq_pv_free(queue)

Free the item fetched in pseudo-variables. It is optional, a new fetch frees the old values.

Example 1.4. mq_pv_free usage