5.1.10 filters statement

The filters statement configures user-defined external filters. See section 11.1 Filters, for the detailed discussion of external filters.

Syntax

filters { filter ident { exec-path path ; error-log filename ; common bool [max-wait]; auth { input-format fmt ; wait-reply bool ; }; acct { input-format fmt ; wait-reply bool ; }; }; ... };

Each filter directive defines a new filter. The ident argument declares the name of the filter. This string must be used in Exec-Program-Wait or Acct-Ext-Program attributes to trigger invocation of this filter (see section 14.3.7 Exec-Program-Wait).

Usage

exec-path path

Absolute path to the filter program.

error-log filename

Redirect error output from the filter program to filename. If the filename does not start with a slash, it is taken relative to the current logging directory (see section log-dir).

auth

acct

These compound statements define authentication and accounting parts of this filter. Any one of them may be missing. The two statements allowed within auth and acct blocks are:

input-format fmt

Format of the input line for this filter. Usually this string uses %C{} notations (see section 5.14 Macro Substitution).

You can also use the return value from a rewrite function as input line to the filter. To do so, declare:

input-format "=my_func()";

where my_func is the name of the rewrite function to invoke. The function must return string value.

wait-reply bool

If the filter prints a single line of output for each input line, set this to yes. Otherwise, if the filter produces no output, use wait-reply no.