script to convert gems to RPMs

gistfile1.rb

#!/usr/bin/env ruby

require 'trollop'
require 'fpm'

# used to ensure versions extracted from gems are converted to
# semantic versioning-compliant strings before being used
# in RPM requires
require 'semverly'

class Converter

  def initialize(logger = Logger.new(STDOUT))
    @logger = logger
  end

  # extra RPM dependencies required by individual packages
  # keyed on gem name, each entry is an array
  EXTRA_DEPS = {
    'nokogiri' => ['libxslt'],
    'gpgme'    => ['gpgme'],
  }

  # Sometimes we need to require a pre-existing ruby gem that is not
  # installed with a "*rubygem-*" name. An example of this is hiera
  # which is installed as pe-hiera on PE, rather than pe-rubygem-hiera
  # This hash is used to convert one requirement to another
  TRANSLATE_DEPS = {
    'rubygem-hiera' => {
      'name' => 'hiera',
      'epoch' => '',
    }
  }

  # library prefix for the target packages
  DST_LIB_DIR = {
    'puppet' => '/opt/puppet/lib/ruby/gems/1.9.1',
    'system' => '/usr/lib64/ruby/gems/1.9.1',
  }

  # name prefix for the target packages
  RPM_RUBYGEM_PREFIX = {
    'puppet' => 'pe-',
    'system' => '',
  }

  # location of the gem binary to use
  GEM_BIN = {
    'puppet' => '/opt/puppet/bin/gem',
    'system' => '/usr/bin/gem'
  }

  def convert(
    src_gem,
    target,
    iteration,
    epoch
  )
    # get just the filename from the supplied full-path
    gem_file = File.basename(src_gem)
    # get the name of the gem, ie. strip the version and .gem
    if gem_file =~ /(.*)-(?:[0-9]+\.)+[0-9]+\.gem/
      gem_name = $1
      @logger.debug "gem name: #{gem_name}"
    else
      @logger.warn "Couldn't extract gem name from: #{src_gem}"
      return
    end
    dst_lib_dir = DST_LIB_DIR[target]
    prefix      = RPM_RUBYGEM_PREFIX[target]
    extra_deps  = EXTRA_DEPS[gem_name] || []
    rpm_name    = "#{prefix}rubygem-#{gem_name}"
    @logger.debug "rpm name: #{rpm_name}"

    # this is needed to prevent the stupid nokogiri stupid build process
    # from stupidly building & bundling the entire libxslt and libxml2
    # libraries
    ENV['NOKOGIRI_USE_SYSTEM_LIBRARIES'] = "1"
    # And the same thing here for gpgme
    ENV['RUBY_GPGME_USE_SYSTEM_LIBRARIES'] = "1"

    package = FPM::Package::Gem.new
    package.input(src_gem)
    # get the dependencies from the gem
    dependencies = package.dependencies
    @logger.debug "gem dependencies: #{dependencies}"
    # clear dependencies and provides from the gem
    package.dependencies = []
    package.provides = []
    # make sure we use the correct gem bin
    package.attributes[:gem_gem] = GEM_BIN[target]
    @logger.debug "using gem binary from #{GEM_BIN[target]}"
    # convert the ruby deps to rpm deps (using code copied from fpm)
    # but modified to include epoch
    fixed_deps = []
    dependencies.each do |dep|
      @logger.debug "Processing dependency: #{dep}"
      name, op, version = dep.split(/\s+/)
      @logger.debug "name: [#{name}] op: [#{op}] version: [#{version}]"
      sem_ver = SemVer.parse(version)
      @logger.debug "semantic version: [#{sem_ver}]"
      if TRANSLATE_DEPS.key?(name)
        h = TRANSLATE_DEPS[name]
        name = h['name']
        if h.key?('epoch')
          epoch = h['epoch']
        end
      end
      epoch_str = epoch ? "%s:" % epoch : ''
      @logger.debug "Using epoch: #{epoch_str}"
      name = "#{prefix}#{name}"
      @logger.debug "Using package name: #{name}"
      if op == "~>"
        # ~> x.y   means: > x.y and < (x+1).0
        # ~> x.y.z means: > x.y.z and < x.(y+1).0
        case version.split('.').size
        when 1
          upper_ver = false
        when 2
          upper_ver = SemVer.new(sem_ver.major + 1, 0, 0)
        when 3
          upper_ver = SemVer.new(sem_ver.major, sem_ver.minor + 1, 0)
        else
          raise Exception.new "Don't know how to deal with ~> #{version}"
        end
        fixed_deps << "#{name} >= #{epoch_str}#{sem_ver}"
        fixed_deps << "#{name} < #{epoch_str}#{upper_ver}" if upper_ver
      else
        fixed_deps << "#{name} #{op} #{epoch_str}#{sem_ver}"
      end
    end 
    # Add in ruby and rubygems deps (with appropriate prefix)
    fixed_deps << "#{prefix}ruby"
    fixed_deps << "#{prefix}rubygems"
    extra_deps.each do |dep|
      fixed_deps << dep
    end
    @logger.debug "RPM dependencies: #{fixed_deps}"
    rpm = package.convert(FPM::Package::RPM)
    rpm.iteration = iteration
    rpm.epoch = epoch
    rpm.name = rpm_name
    rpm.attributes[:prefix] = dst_lib_dir
    # set the rpm deps
    rpm.dependencies = fixed_deps
    
    begin
      output = "NAME-VERSION-ITERATION.ARCH.rpm"
      rpm.output(rpm.to_s(output))
    ensure
      rpm.cleanup
    end
  end

end
  
opts = Trollop::options do
  banner <<-EOS
Convert ruby gems to RPMs

The target specifies which ruby to use:
 * system - install to /usr/lib64/ruby/gems, prefix: rubygem-
 * puppet - install to /opt/puppet/lib/ruby/gems, prefix: pe-rubygem-

Usage:
       convert_gems_to_rpms.rb [options] <filenames>+

where [options] are:

EOS

  opt :epoch,   'RPM epoch to use. Defaults to 2 to trump EPEL.', :default => "2"
  opt :release, 'RPM release to create', :default => "1"
  opt :target,  'which ruby to use - system or puppet', :default => 'system'
  opt :verbose, 'Show info-level logging'
  opt :debug,   'Show debug-level logging'
end

# Make sure we have a sane umask
File.umask(0022)

logger = Cabin::Channel.get
logger.subscribe(STDOUT)

if opts[:debug]
  logger.level = :debug
elsif opts[:verbose]
  logger.level = :info
else
  logger.level = :warn
end

ARGV.each{ |src_gem|
  Converter.new(logger).convert(src_gem, opts[:target], opts[:release], opts[:epoch])
}