We are using Ruby on some projects and really wanted to give Apache Buildr a try. The problem with buildr is that it plugs ifself into the maven dependency management. Downgrading dependencies back to maven was not an option, so we needed a way to use Ivy with Buildr.

ivy4r to the rescue

To integrate ivy into buildr ivy4r was created. Ivy4r is a wrapper around Ivy using antwrap and provides a pure ruby interface to ivy. The interface provides all Ant tasks that can be useful. On top of this two extensions are provided one for buildr one for rake. By requiring the appropriate extension ivy can be integrated seamless into the build process using the standard way buildr extensions are configured.

For more information check out the ivy4r documentation on github or rubyforge:

• http://github.com/klaas1979/ivy4r/tree/master
• http://hamburgrb.rubyforge.org/ivy4r/

First I tried to use only hoe but did not get a gemspec file out of it. So I added jeweler to get a gemspec via the rake target gemspec but did not want to configure hoe and jeweler separate. So I used the hoe generated gemspec object to initialize jeweler and thought that it was a good solution.

But then I stumbled upon the best solution, hoe supports the generation of gemspecs only the target name is a bit akward. Just call rake with the command rake debug_gem as recommended on github.

The previous solution combining hoe and jeweler

The rake file:

require 'rubygems'
require 'hoe'
require 'yourgem'

hoe = Hoe.spec 'yourgem' do |p|
  # self.rubyforge_name = 'yourgemx' # if different than 'yourgem'
  p.developer('Yourname', 'yourmail@example.com')
  p.remote_rdoc_dir = '' # Release to root only one project
  p.extra_deps << yourdeps
  File.open(File.join(File.dirname(__FILE__), 'VERSION'), 'w') do |file|
    file.puts Yourgem::VERSION
  end
end

begin
  require 'jeweler'
  Jeweler::Tasks.new(hoe.spec)
rescue LoadError
  puts "Jeweler not available. Install it with: sudo gem install technicalpickles-jeweler -s http://gems.github.com"
end

How to write RDoc comments

• RDoc Homepage The homepage links
• Ruby Standard Lib documentation links from the standard library documentation
• rdoc.info allows you to generate RDoc on the fly for Github projects and browse it as well

How to browse RDoc for installed gems

• bdoc very nice browsing for documentation should be used with the better hanna rdoc template
• sinatra-rubygems reimplementation of gem server to use apache not webrick
• Gembox sinatra based application to browse the locally installed gems
• docs.github.com for github based projects that use rdoc.info

One problem is to provide ruby callback functions for the C library. I am trying to figure out how to extend sqlite3-ruby to work with jruby. Sqlite3-ruby uses swig to create a native binding to the sqlite3 library. Within driver.rb some callbacks are registered for the C code like:

API.sqlite3_busy_handler( db, API::Sqlite3_ruby_busy_handler, cb )

API::Sqlite3_ruby_busy_handler is a callback implemented in the native extension. FFI does not provide any support for callbacks. To support C APIs that use callbacks a workaround must be found.