Page 298 - Asterisk™: The Future of Telephony

var_name
The option on the left side of the equals sign (i.e., disallow is the var_name in
disallow=all).
var_val
The value to an option on the right side of the equals sign (i.e., all is the var_val
in disallow=all).
commented
Any value other than 0 will evaluate as if it were prefixed with a semicolon in the
flat file (commented out).

A Word About Metrics

The metrics in static realtime are used to control the order that objects are read into
memory. Think of the cat_metric and var_metric as the original line numbers in the
flat file. A higher cat_metric is processed first (because Asterisk matches categories from
bottom to top―this is why the order of users and peers can matter in sip.conf or
iax.conf). A lower var_metric is processed first within the category because Asterisk will
process the order of options top-down within the category (e.g., disallow=all should
be set to a value lower than the allow’s value within the category to make sure it is
processed first).

A simple file we can load from static realtime is the musiconhold.conf file. Let’s start by
moving this file to a temporary location:
# cd /etc/asterisk
# mv musiconhold.conf musiconhold.conf.old
In order for the classes to be removed from memory, we need to restart Asterisk. Then
we can verify our classes are blank by running moh show classes:
*CLI> restart now
*CLI> moh show classes
*CLI>
So let’s put the [default] class back into Asterisk, but now we’ll load it from the data-
base. Connect to PostgreSQL and execute the following INSERT statements:
INSERT INTO ast_config (filename,category,var_name,var_val)
VALUES ('musiconhold.conf','general','mode','files');
INSERT INTO ast_config (filename,category,var_name,var_val)
VALUES ('musiconhold.conf','general','directory','/var/lib/asterisk/moh');
You can verify your values have made it into the database by running a SELECT state-
ment:
asterisk=# select filename,category,var_name,var_val from ast_config;
filename | category | var_name | var_val
------------------+----------------+--------------+------------------------
musiconhold.conf | general | mode | files

270 | Chapter 12: Relational Database Integration