Converting GEM to RPM

GEM2RPM

#!/usr/bin/env ruby                                                                                                     
                                                                                                                        
require 'fpm'                                                                                                           
                                                                                                                        
# FIXME: set these from the command line                                                                                
target = 'system'                                                                                                       
iteration = 1                                                                                                           
src_dir = '/var/tmp/gems/cache';                                                                                        
                                                                                                                        
dst_lib_dir = {                                                                                                         
  'puppet' => '/opt/puppet/lib/ruby/gems/1.9.1',                                                                        
  'system' => '/usr/lib64/ruby/gems/1.9.1'                                                                              
}                                                                                                                       
rpm_rubygem_prefix = {                                                                                                  
  'puppet' => 'pe-',                                                                                                    
  'system' => ''                                                                                                        
}                                                                                                                       
                                                                                                                        
def gem2rpm(opts)                                                                                                       
  package = FPM::Package::Gem.new                                                                                       
  package.input(opts['src_gem'])                                                                                        
  # get the dependencies from the gem                                                                                   
  dependencies = package.dependencies                                                                                   
  # clear dependencies and provides from the gem                                                                        
  package.dependencies = []                                                                                             
  package.provides = []                                                                                                 
  # convert the ruby deps to rpm deps (using code copied from fpm)                                                      
  fixed_deps = []                                                                                                       
  dependencies.each do |dep|                                                                                            
    dep.gsub!(/rubygem-/, "#{opts['prefix']}rubygem-")                                                                  
    name, op, version = dep.split(/\s+/)                                                                                
    if op == "~>"                                                                                                       
      # ~> x.y means: > x.y and < (x+1).0                                                                               
      fixed_deps << "#{name} >= #{version}"                                                                             
      fixed_deps << "#{name} < #{version.to_i + 1}.0.0"                                                                 
    else                                                                                                                
      fixed_deps << dep                                                                                                 
    end                                                                                                                 
  end                                                                                                                   
  # Add in ruby and rubygems deps (with appropriate prefix)                                                             
  fixed_deps << "#{opts['prefix']}ruby"                                                                                 
  fixed_deps << "#{opts['prefix']}rubygems"                                                                             
  rpm = package.convert(FPM::Package::RPM)                                                                              
  rpm.iteration = opts['iteration']                                                                                     
  rpm.name = opts['rpm_name']                                                                                           
  rpm.attributes[:prefix] = opts['dst_lib_dir']                                                                         
  # set the rpm deps                                                                                                    
  rpm.dependencies = fixed_deps                                                                                         
  begin                                                                                                                 
    output = "NAME-VERSION.ARCH.rpm"                                                                                    
    rpm.output(rpm.to_s(output))                                                                                        
  ensure                                                                                                                
    rpm.cleanup                                                                                                         
  end                                                                                                                   
end                                                                                                                     
                                                                                                                        
gemlist = Dir.glob("#{src_dir}/*.gem")
                                                                                                                        
gemlist.each{ |gem|                                                                                                     
  # strip the path                                                                                                      
  gem_file = File.basename(gem)                                                                                         
  # get the name of the gem, ie. strip the version and .gem                                                             
  if gem_file =~ /(.*)-(?:[0-9]+\.)+[0-9]+\.gem/                                                                        
    gem_name = $1                                                                                                       
    # add the RPM name prefix                                                                                           
    rpm_name = "#{rpm_rubygem_prefix[target]}rubygem-#{gem_name}"                                                       
    # convert the gem to RPM                                                                                            
    gem2rpm({                                                                                                           
      'src_gem'     => gem,                                                                                             
      'rpm_name'    => rpm_name,                                                                                        
      'dst_lib_dir' => dst_lib_dir[target],                                                                             
      'iteration'   => iteration,                                                                                       
      'prefix'      => rpm_rubygem_prefix[target]                                                                       
    })                                                                                                                  
  else                                                                                                                  
    puts "Couldn't extract gem name from: #{gem_file}"                                                                  
  end                                                                                                                   
}