From: Hans Fugal <fugalh@...>
Date: 2005-03-26T03:29:50+09:00
Subject: loading "plugins"

I am writing a log analyzer (hans.fugal.net/src/clog) that uses a sort 
of plugin (I call them agents) which is basically a class that gets 
instantiated and then called to do work. I want to include various 
agents with the distribution.

Where should the files end up? How should I discover the agents?

The sysadmin will be able to specify a directory (or directories) that 
contain his own agents, in addition to the included agents. I can scan 
that directory for .rb files and load them. That part works. But I don't 
want to make the sysadmin specify where the standard agents are in the 
config file - that should be implied. "require 'clog/agents/*'" would 
express what I want to do, although that isn't valid. I don't want to 
hardcode a path to /usr/local/lib/site_ruby/whatever, either.

Ultimately, the sysadmin should refer to the agents with a simple 
one-word name, e.g. Postfix or Bogofilter.

I don't know if my question makes sense, but I'm wondering what you all 
would do because there is no obvious best way to do this to me at the 
moment.

(and yes, I know IoC or DI would fit here but I don't want to put the 
burden of figuring out what the heck those are on the poor sysadmin who 
just needs to specify what agent to use)