analyse gem disk usage

gem-disk-usage.rb

def gems(group = nil)
  require 'bundler'

  groups = Bundler.load.current_dependencies.map {|d| d.groups }.uniq.flatten.uniq.sort
  return groups if group.nil?

  raise "unsupported gem group: #{group}" if !groups.include?(group.to_sym)

  Bundler.load.current_dependencies.select{ |dep| dep.groups.include?(group.to_sym) }
end

def parse(line)
  disk_size_in_kb, gem_name = line.split("\t")
  name, _delimiter, version = gem_name.rpartition('-') # good enough

  require 'filesize' # https://rubygems.org/gems/filesize

  {
    'name' => name,
    'version' => version,
    'full_name' => gem_name,
    'disk_size_in_kb' => disk_size_in_kb.to_i,
    'disk_size_in_human' => Filesize.from("#{disk_size_in_kb} K").pretty
  }
end

def get_gem_details(default_only: true)
  default_gems = gems(:default).map {|gem| gem.name}.sort.to_set
  all_gems = `cd #{Gem.dir}/gems && du -s * | sort -hr`.split("\n").map {|line| parse(line) }
  all_gems = all_gems.select {|detail| default_gems.include?(detail['name'])} if default_only

  disk_size_sum_in_kb = all_gems.pluck('disk_size_in_kb').sum
  result = all_gems.map do |gem_detail|
    percentage = (gem_detail['disk_size_in_kb'].to_f/disk_size_sum_in_kb)*100
    gem_detail.merge('percentage' => percentage.round(2))
  end

  result
end

# core ext
class Array
  def pluck(*keys)
    if keys.count > 1
      map { |element| keys.map { |key| element[key] } }
    else
      key = keys.first
      map { |element| element[key] }
    end
  end
end

get_gem_details(default_only: true)
get_gem_details(default_only: true).first(10).pluck('name','percentage','disk_size_in_human')
get_gem_details(default_only: true).first(100).pluck('name','percentage','disk_size_in_human')