Distributed Message Queue Module

Marius Ovidiu Bucur

Edited by

Marius Ovidiu Bucur

Copyright © 2011 Marius Bucur

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. dmq_server_address(str)
3.2. dmq_notification_address(str)
2. Developer Guide
1. dmq_load_api(dmq_api_t* api)

List of Examples

1.1. Set dmq_server_address parameter
1.2. Set dmq_notification_address parameter
2.1. dmq_api_t structure

Chapter 1. Admin Guide

Table of Contents

1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. dmq_server_address(str)
3.2. dmq_notification_address(str)

1. Overview

The DMQ module implements a distributed message passing system on top of Kamailio. The DMQ nodes within the system are grouped in a logical entity called DMQ bus and are able to communicate with each others by sending/receiving messages (either by broadcast or sending a DMQ message to a specific node). The system transparently deals with node discovery, node consistency within the DMQ bus, retransmissions, etc.

2. Dependencies

2.1. Kamailio Modules

The following modules must be loaded before this module:

  • sl.

  • tm.

2.2. External Libraries or Applications

  • Each peer needs to use its own serialization mechanism. Some examples are libtpl, protobuf. .

3. Parameters

3.1. dmq_server_address(str)

The local server address.

The modules needs it to know on which interface the DMQ engine should send and receive messages.

Default value is “NULL”.

Example 1.1. Set dmq_server_address parameter 

...
modparam("dmq", "dmq_server_address", "mysql://kamailio:kamailiorw@localhost/kamailio")
...

3.2. dmq_notification_address(str)

The address of the DMQ node from which the local node should retrieve initial information.

Default value is “NULL”.

Example 1.2. Set dmq_notification_address parameter 

...
modparam("dmq", "dmq_notification_address", "mysql://kamailio:kamailiorw@localhost/kamailio")
...

Chapter 2. Developer Guide

Table of Contents

1. dmq_load_api(dmq_api_t* api)

The module provides the following functions that can be used in other Kamailio modules.

1.  dmq_load_api(dmq_api_t* api)

This function binds the dmq modules and fills the structure with the exported functions -> register_dmq_peer - registers an entity as a DMQ peer which permits receiving/sending messages between nodes which support the same peer, -> bcast_message - broadcast a DMQ message to all peers available in the DMQ bus, -> send_message - sends a DMQ message to a specific peer in the local DMQ bus.

Example 2.1. dmq_api_t structure 

...
typedef struct dmq_api {
	register_dmq_peer_t register_dmq_peer;
	bcast_message_t bcast_message;
	send_message_t send_message;
} dmq_api_t;
...