Failover for SQL lookup expansions?

[Phil Mayers]

On 10/03/11 14:21, Brian Candler wrote:
> With freeradius 2.1.10 I can configure failover for SQL lookups like this:
>
> 	# in policy.conf
>          sql_foo {
>              redundant {
>                  sql_foo_local
>                  sql_foo_remote
>              }
>          }
>
>
> 	# in sites-available/foo
>          authorize {
>              sql_foo
>          }
>
>
> However, it looks like I can't use this redundant module inside a string
> expansion:
>
>      authorize {
>          update request {
>              Huntgroup-Name = "%{sql_foo:SELECT groupname FROM radhuntgroup where nasipaddress='%{NAS-IP-Address}' limit 1}"
>          }
>      }

Correct. Virtual modules (e.g. "redundant") do not implement the "xlat" 
function.


> How could I get the same level of redundancy for string expansions? Could I
> do the expansion multiple times inside a redundant section? I am thinking of
> perhaps:

Unfortunately the "xlat" functions in FR don't return error/success 
codes. They return "length of result string", and 0 for any failure 
condition, which means it's impossible to distinguish a failure from an 
empty result, and also that you can't use "if (ok)" constructs.

You will probably need something like this:

update request {
   Attrib := "%{sql1:select ...}"
}
if (!Attrib) {
   update request {
     Attrib := "%{sql2:select ...}"
   }
}

...and you will obviously need to ensure that a working SQL module never 
returns an empty string for your query, else you'll just double the work up.