The configuration database module - cfg_db

Tomas Mandys

Table of Contents

1. Admin Guide
1. Overview
2. Dependencies
3. Parameters
3.1. db_url (string)
3.2. transl_tbl (string) := "cfg_transl"
3.3. custom_tbl (string) := "cfg_custom"
4. Examples

List of Examples

1.1. Example db_url
1.2. Content of tables

Chapter 1. Admin Guide

1. Overview

The module implements a database driver for the configuration parameters API. When configuration parameters are being declared (typically when starting) API then driver is notified and has chance to set value (of any parameter) based on value taken from database. It's primarily targeted for interfacing with 3rd party software which is aware of the Kamailio configuration.

A parameter is uniquely identified by a group_name plus a name, which is used by the driver to check if a value can be found. Because configuration parameters may be spread in many tables, a translation table is used to indicate where to start searching. Multiple look-up tables may be defined for single parameter, tables are searched in the first round by exact match until parameter is found, all tables listed with wildcard (asterisk) in group name are searched in the second round. If a parameter is not found then its value is left unchanged.

Configuration parameters are normally declared in C code and this module additionally supports also declaring custom parameters in extra table. Such parameters may be used typically in script only. All parameters listed in the table are declared in the first step, values are initialized in the second step using the same procedure as C-code parameters.

The module does not reflect changes made in parameters when Kamailio is running. It just declares variables and assigns values when Kamailio is starting. That's all.

2. Dependencies

A loaded database module.

3. Parameters

3.1. db_url (string)

Default database URL.

The format is:

		db_url = database

Example 1.1. Example db_url

modparam("cfg_db", "db_url", "mysql://SER:123@");

3.2. transl_tbl (string) := "cfg_transl"

Name of table used for pointing group_name+name into configuration table. If empty/null field values are found then default values will be used. The default values are declared in record having group_name called <default>. The C-code "absolutely" default values ("cfg_var", "group_name", "name", "value"). The other keyword is asterisk * which matches all parameters and will be used if parameter is not explicitely mentioned.

3.3. custom_tbl (string) := "cfg_custom"

Name of table used for extra param declaration (group_name, name, type, min/max value, description).

4. Examples

Example 1.2. Content of tables

	cfg_transl table:
	my|route_addr|cfg_my|my_group_name|my_name|my_value	; overrides <default> values
	*|*||||	; matches all param ids, points to tables defined in row <default>
	<default>||cfg_var|group_name|name|value  ; default cfg_table* values
	cfg_custom table:
	my|route_addr|S|||Routing address
	my|use_rtp_proxy|I|0|1|Use RTP proxy
	cfg_var table:
	cfg_my table:
	cfg_dns table: