Gemfile to Bundle

Transcript

1. From Gemfile to Bundle Samuel Giddins
2. Samuel Giddins Realm CocoaPods Bundler RestKit
3. how does bundler work, anyway?
4. @indirect gave this talk: http://andre.arko.net/2015/04/28/how-does-bundler-work-anyway/
5. But today, we’ll focus on what bundler does to transform your Gemfile into a full-on runtime environment
6. So, let’s start with our humble Gemfile
7. source "https://rubygems.org" ruby "2.2.2" gem "rails", "4.2.1" gem "devise" gem "fastly-rails" gem "http" gem "jquery-rails" gem "nokogiri" gem "nilify_blanks" gem "pg" gem "premailer-rails" gem "puma", "~> 2.11", ">= 2.11.2" group :development do gem "guard-livereload", "~> 2.4", require: false gem "guard-rails" gem "guard-rspec" end group :development, :test do gem "dotenv-rails", "~> 2.0" gem "pry-rails" gem "rspec-rails" end group :production do gem "rails_12factor" end group :test do gem "webmock" gem "vcr" end
8. We now run bundle install
9. RubyGems picks the appropriate bundler version to run
10. bundler's CLI will dispatch to the Install command class, passing in any command line options we used
11. we translate those options into settings that bundler will use for the lifetime of the process
12. now starts the fun part
13. now starts the fun part => Bundler.definition
14. the Definition encapsulates the Gemfile & the Gemfile.lock
15. it's what the user defines to be a part of the Environment
16. Dsl.evaluate(gemfile, lockfile) => Dsl.new.instance_eval(File.read gemfile)
17. Dsl class defines the following methods: —gemspec —gem —source —git_source —path —git —github —group
18. We now perform dependency resolution with those gems, plus those in the lockfile
19. Molinillo https://stripe.com/video/open-source-retreat
20. definition.resolve => definition.specs
21. Now it's Installer time
22. Installer.install(Bundler.root, definition, options)
23. ensure every one of definition.specs is installed
24. either in parallel or sequentially
25. spec.source.install(spec, install_options)
26. Installation depends on the source that spec comes from
27. Sources: —RubyGems —Path —Git
28. aside: Sources define both how we fetch specs for resolution & how we install them
29. aside: Sources have caused some security issues in the past
30. So, we've installed all our gems. bundle install is done
31. Next, we run bundle exec
32. Next, we run bundle exec since we need our code to actually run
33. SharedHelpers.set_bundle_environment
34. which foo
35. If not => Bundler.load.setup_environment
36. Runtime.new(root, definition)
37. Our Runtime represents....
38. ENV["BUNDLE_BIN_PATH"] = && ENV["BUNDLE_GEMFILE"] = && SharedHelpers.set_bundle_environment
39. Kernel.exec(@cmd, *args)
40. This only works because we have -rbundler/setup in RUBYOPT
41. Bundler.setup
42. And now we just manipulate RubyGems & $LOAD_PATH
43. Phew.
44. Concepually simple.
45. Unimaginable edge cases.
46. Bundler
47. Available now on Speaker Deck. https://speakerdeck.com/segiddins/gemfile-to-bundle
48. self .meetup .audience .each .lazy .flat_map(&:questions) .map(&:answer)
49. Samuel Giddins Realm @segiddins