Get dependencies list of a Ruby project by reading its Gemfile and Gemfile.lock

list_dependencies.rb

#!/usr/bin/env ruby

# frozen_string_literal: true

# USAGE:
#   $ ./list_dependencies.rb
#   $ ./list_dependencies.rb /path/to/project
#
# @see: https://stackoverflow.com/questions/44681231/how-to-list-ruby-production-only-dependencies-using-gemfile-lock-and-lockfilepar

require "bundler"

project_path      = File.expand_path(ARGV[0] || ".", __dir__)
gemfile_path      = File.expand_path("./Gemfile", project_path)
gemfile_lock_path = File.expand_path("./Gemfile.lock", project_path)

class DependecyTree
  def initialize(gemfile_path, gemfile_lock_path)
    @definition = Bundler::Definition.build(gemfile_path, gemfile_lock_path, nil)
  end

  def all_dependencies
    return @all_dependencies if @all_dependencies

    collect_dependencies
  end

  def lock_file
    @definition.locked_gems
  end

  def groupify(dep)
    dep.groups.map do |g|
      a = [{ group: g, name: dep.name, dep: dep }]
      begin
        a << runtime_dependencies(g, dep.to_spec)
      rescue Gem::LoadError => _e
        a[-1] = { group: g, name: dep.name, dep: dep, error: "NOT INSTALLED" }
      end
    end
  end

  def collect_dependencies
    @all_dependencies = @definition.dependencies.map do |dep|
      groupify(dep)
    end.flatten

    group_missing(@all_dependencies)

    @all_dependencies.uniq!
  end

  def runtime_dependencies(group, spec)
    spec.dependencies.select { |dep| dep.type == :runtime }.map do |dep|
      a = { group: group, name: dep.name, dep: dep }
      dep.to_spec.dependencies.empty? ? a : [a] << runtime_dependencies(group, dep.to_spec)
    end
  end

  def group_missing(dependencies)
    all_locks.cycle(2) do |a|
      deep_dep = dependencies.find_all { |h| a.include?(h[:name]) }.uniq

      a.each do |k|
        deep_dep.each do |h|
          dependencies << { group: h[:group], name: k, error: "NOT INSTALLED" }
        end
      end
    end
  end

  def all_locks
    lock_file.specs.map do |spec|
      spec.to_lock.split("\n").map do |s|
        s.slice(/[\w\-]+/)
      end
    end
  end
end

# Print

$stdout.puts "Ruby\t#{RUBY_VERSION}\tRuby is a dynamic, interpreted, reflective, object-oriented, general-purpose programming language.\tGPLv2 or 2-clause BSD license\thttps://www.ruby-lang.org"

$stdout.puts ""
$stdout.puts "Name\tVersion\tDescription\tLicense(s)\tWebsite"

DependecyTree.new(gemfile_path, gemfile_lock_path).all_dependencies.uniq { |s| s[:name] }.sort{ |a, b| a[:name] <=> b[:name] }.each do |desc|
  gemspec = desc[:dep].to_spec

  $stdout.puts "#{gemspec.name}\t#{gemspec.version}\t#{gemspec.summary}\t#{gemspec.licenses.join(", ")}\t#{gemspec.homepage}"

rescue Gem::MissingSpecError => _e
end