1. cfg_db module

Tomas Mandys

Iptel.org

Revision History
Revision $Revision$	$Date$

1.1. Overview

1.2. Dependencies

1.3. Parameters

1.3.1. db_url (string)
1.3.2. transl_tbl (string) := "cfg_transl"
1.3.3. custom_tbl (string) := "cfg_custom"

1.4. Functions

1.5. Examples

1.1. Overview

The module implements driver for config params API. When config parameters are being declared (typically when is starting) API then driver is notified and has chance 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 configuration.

Parameter is uniquely identified by group_name plus name. Hence the driver checks a value can be found regarding particular parameter. Because configuration parameters may be spread in many tables, translation table telling where parameters will be sniffed, is used first. More look-up tables may be defined for single parameter, tables are sniffed in the first round by exact match until parameter is found, all tables listed with wildcard (asterisk) in group name are sniffed in the second round. If parameter is not found then its value is left unchanged.

Config 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 params.

The module does not reflect changes made in parameters when ser is running. It just declares variable and assings value when ser is starting. That's all.

1.2. Dependencies

A loaded database module.

1.3. Parameters

1.3.1. `db_url` (string)

Default database URL.

The format is:

			db_url = database

Example 1. Example db_url

	loadmodule("mysql.so");
	loadmodule("cfg_db.so");
	...
	modparam("cfg_db", "db_url", "mysql://ser:123@127.0.0.1:12345/ser");
	...

1.3.2. `transl_tbl` (string) := "cfg_transl"

Name of table used for pointing group_name+name into config 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.

1.3.3. `custom_tbl` (string) := "cfg_custom"

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

1.4. Functions

None.

1.5. Examples

Example 2. Content of tables

	cfg_transl table:
	group_name|name|cfg_table|cfg_table_group_name_field|cfg_table_name_field|cfg_table_value_field
	core|use_dst_blacklist|cfg_dns|||
	core|dst_blacklist_mem|cfg_dns|||
	core|dst_blacklist_expire|||
	my|route_addr|cfg_my|my_group_name|my_name|my_value	; overrides <default> values
	my|use_rtp_proxy|cfg_my|my_group_name|my_name|my_value
	*|*||||	; 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:
	group_name|name|value_type|min_value|max_value|description
	my|route_addr|S|||Routing address
	my|use_rtp_proxy|I|0|1|Use RTP proxy
	
	cfg_var table:
	group_name|my_name|value
	core|debug|4
	
	cfg_my table:
	my_group_name|my_name|my_value
	my|route_addr|127.0.0.1
	my|use_rtp_proxy|1
	
	cfg_dns table:
	group_name|name|value
	dns|use_dst_blacklist|1
	dns|dst_blacklist_mem|1024
	dns|dst_blacklist_expire|60