The configuration database module - cfg_db

Tomas Mandys

   Iptel.org

   Copyright © 2008 Tomas Mandys
     __________________________________________________________________

   List of Examples

   1. Example db_url
   2. Content of tables

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 SER is
   running. It just declares variables and assigns values when SER is
   starting. That's all.

2. Dependencies

   A loaded database module.

3. Parameters

   3.1. db_url (string)
   3.2. transl_tbl (string) := "cfg_transl"
   3.3. custom_tbl (string) := "cfg_custom"

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");
...

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 2. Content of tables
        cfg_transl table:
        group_name|name|cfg_table|cfg_table_group_name_field|cfg_table_name_fiel
d|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 <def
ault> values
        my|use_rtp_proxy|cfg_my|my_group_name|my_name|my_value
        *|*|||| ; matches all param ids, points to tables defined in row <defaul
t>
        <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
