From: Patrick Hurley <phurley@...>
Date: 2005-03-26T03:46:01+09:00
Subject: Re: loading "plugins"

On Sat, 26 Mar 2005 03:29:50 +0900, Hans Fugal <fugalh@xmission.com> wrote:
> 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)
> 
> 

What is wrong with something like:

base = "."
Dir.glob("#{base}/*.rb").each { |plugin|
  require plugin
}

where you can obviously set base to anything you want.

Patrick