Strategies for writing Ruby applications to be easily distri

Ruby
1

Hello,

This is mostly a repost of ruby-talk[229723] with some clarifications
and an appeal for ideas.

I have recently attempted to write a RubyGem for the Saikuro project.
Unfortunately, I have learned that there is a mismatch between how I
wrote Saikuro and how RubyGems expects executables to work.

I would like to know is are there any better or commonly followed ways
of writing executables that work with RubyGems and other installation
programs such as setup.rb ?

Below are the differences between how I wrote Saikuro and what
RubyGems does.

Saikuro uses the “if FILE == $0” check before doing the
“application work”. When RubyGems creates a new gemified saikuro
wrapper to call the real saikuro bin “$0” is the gemified saikuro and
not the real one. Thus, by default nothing happens.

For fun I cheated and commented out the “if FILE” check and
replaced it with “if true”. Saikuro will work with this change, but I
then ran “saikuro -?” to get a usage message and found the next
problem:

I was reading through the Programming Ruby book and found a part that
showed how to use rdoc to create usage messages. I figured this might
be better than my normal technique so I used it in Saikuro. This has
caused a number of problems actually.

  • With the above cheat I get the gem message:
    –
    /usr/bin/saikuro: invalid option – ?
    This file was generated by RubyGems.

The application ‘Saikuro’ is installed as part of a gem, and this file
is here to facilitate running it.

Which is not the usage message I wanted.

My original goal was to keep Saikuro simple so that as a single file
nothing complicated was needed. But now I suppose that should change.

I am planning to move all logic above and “if FILE == $0” block
into a separate library file. Then add a require to this newly made
file and remove the “if FILE” check logic to make the insides of
the block automatically run.

Next I will stop using rdoc usage and simply put the usage message in
a method that outputs a String.

Does this sound like a good strategy?

Thanks,
Zev

2

On Dec 18, 2006, at 22:34, Zev B. wrote:

This is mostly a repost of ruby-talk[229723] with some clarifications
and an appeal for ideas.

I have recently attempted to write a RubyGem for the Saikuro project.
Unfortunately, I have learned that there is a mismatch between how I
wrote Saikuro and how RubyGems expects executables to work.

I would like to know is are there any better or commonly followed ways
of writing executables that work with RubyGems and other installation
programs such as setup.rb ?

My executables typically consist of three lines:

#!/usr/local/bin/ruby -w
require ‘some_file’
SomeFile.run

Where SomeFile::run is something like:

class SomeFile
def self.run(args = ARGV)
options = process_args args
new(option[:foo]).run
end
end

I was reading through the Programming Ruby book and found a part that
showed how to use rdoc to create usage messages. I figured this might
be better than my normal technique so I used it in Saikuro. This has
caused a number of problems actually.

What does this technique look like? I’m not familiar with it.

My original goal was to keep Saikuro simple so that as a single file
nothing complicated was needed. But now I suppose that should change.

I am planning to move all logic above and “if FILE == $0” block
into a separate library file. Then add a require to this newly made
file and remove the “if FILE” check logic to make the insides of
the block automatically run.

I keep these together, but put the logic that would normally go in
“if FILE == $0” into its own method or methods. That keeps the
executable as simple as possible.

–
Eric H. - [email protected] - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!