List all runtime dependencies for the given gem

all_runtime_dependencies.rb

#!/usr/bin/env ruby

target = ARGV.shift.strip

class App
  def initialize
    @deps = []
  end

  def resolve(gem)
    if @deps.include? gem or gem.strip.empty? then
      return
    end

    # puts "resolving: " + gem

    @deps << gem

    # cmd = "gem dependency " + gem + " | egrep -v ^Gem | egrep -v 'development\\)$' | awk '{print $1}'"
    # gems = `#{cmd}`
    # gems.strip.split(/\n/).each { |g| resolve(g) }

    specs = Gem::Dependency.new(gem).matching_specs
    return if !specs or specs.empty?

    specs.first.dependencies.each do |d|
      next if d.type == :development
      resolve(d.name)
    end

    return @deps
  end
end

puts "listing all runtime dependencies for #{target}"
puts App.new.resolve(target).sort