CODEWITHSUNDEEP
ruby
shevy
shevy

Reputation: 1010

Ruby - How to find out all dependencies of a given Gem in a .rb file?

How can I find out all dependencies of a given Gem in a .rb file without having to rely on system() or similar external calls?

Consider this project:

https://rubygems.org/gems/diamond_shell

It has about 20 - 25 dependencies.

I need to traverse all dependencies, on all the linked dependencies too, and populate an array with all of them.

Edit: Thanks for the answers.

Upvotes: 2

Views: 1006

Answers (2)

Max
Max

Reputation: 22375

You can yank the code out of lib/rubygems/commands/dependency_command.rb. Here's a simple method I made.

require 'rubygems/commands/dependency_command'

def get_dependencies name, local = true
  cmd = Gem::Commands::DependencyCommand.new

  dependency = cmd.gem_dependency name, nil, nil

  specs =
  if local
    dependency.matching_specs.uniq.sort
  else
    cmd.fetch_remote_specs(dependency).uniq.sort
  end

  dependencies = []
  specs.each do |spec|
    dependencies.concat spec.dependencies.sort_by { |dep| dep.name }.map { |dep| [dep.name, dep.requirement] }
  end
  dependencies
end

puts get_dependencies('diamond_shell', false)

Upvotes: 3

changingrainbows
changingrainbows

Reputation: 2711

If you happen to be using Bundler for ruby gem management (http://bundler.io), the bundle install run generates a Gemfile.lock manifest file with all project gems and their dependencies. An example is below:

sunspot (2.0.0)
  pr_geohash (~> 1.0)
  rsolr (~> 1.0.7)
sunspot_rails (2.0.0)
  nokogiri
  sunspot (= 2.0.0)
teaspoon (0.7.8)
  phantomjs (>= 1.8.1.1)
  railties (>= 3.2.5, < 5)

This file can be easily parsed to get your dependency tree.

Upvotes: 2

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