gem to deal with config file / program options

[Shadowfirebird]

Hi all,

Short version: What gems do people use to deal with program options in a YAML file and taken from the command line? I seem to have too much choice to make a sensible decision as to which to use.


Long version:

I mostly write command-line ruby programs and I've getting fed up with dealing with program options. You know the sort of thing: my program collects command line options using optparse; saved options from a YAML file; and implicitly knows good defaults for these. The idea being that these three all end up in a hash that the gubbins of my program can refer to.

I've decided that rather than dealing with this in a half-arsed manner I want to get it right this time. I don't mind rolling my own, but obviously if there's a gem that does it for me, I'll use that. The problem is that there are hundreds of gems called config-something, and half of them look as if they might do the job -- if there was any documentation...

(The real trick I'd like to pull is to specify the YAML filename on the command line, but still have the command line options override those in the YAML file.)

What does everyone else use?

Ta,
Shadowfirebird.

 

[Chris Kottom]

[Note: parts of this message were removed to make it a legal post.]

For command line arguments, Ruby's OptionParser is a part of the standard
library.
http://www.ruby-doc.org/stdlib/libdoc/optparse/rdoc/classes/OptionParser.html

<http://www.ruby-doc.org/stdlib/libdoc/optparse/rdoc/classes/OptionParser.html>For
YAML configuration files, I've never needed anything so complex that I
couldn't get there with a combination of YAML::load_file and Hash#merge
using Ryan Bates'
Railscast<http://railscasts.com/episodes/85-yaml-configuration-file>on
YAML configuration files as a sort of loose template. Are you looking
for something more sophisticated than that?

 

[Shadowfirebird]

I've never needed anything so complex that I

couldn't get there with a combination of YAML::load_file and Hash#merge
using Ryan Bates'
Railscast<http://railscasts.com/episodes/85-yaml-configuration-file>on
YAML configuration files as a sort of loose template. Are you looking
for something more sophisticated than that?

A little more, yes.

I've done as you did until I reached the point where the program I was writing needed the ability to specify the config file on the command line -- but still have command line options override those in the config file.

Sure, I can see to code my own way out of this: one hash for default options, one hash made up of command line options, and one hash for the config file; then merge. But if some kind person has written an elegant gem that gives me all I could want in this department (much as optparse does so well for the command line), and if everyone but me was already using it, then I should be, too.

Plus, some of the descriptions for gems hint at cleverer stuff: objects that inherently know what their configuration options are, for example. But I can't find any documentation on how this works out in practice.