1. 相依性管理
以Ruby開發為例
大貓 (@miaout17)

2. About Me
• 大貓 (YC Ling, @miaout17)
• 2004年因為奇妙的機緣開始學習Ruby
– RPG Maker XP
– Rails? 能吃嗎?

3. About Me
• 大貓 (YC Ling, @miaout17)
• 業餘Ruby遊戲開發者(2004~2007)
• C++/Lua/ActionScript遊戲開發者(2007~2010)
• Java/Ruby Web開發者(2010~now)
• 業餘Functional Programming愛好者
• Github: https://github.com/miaout17

4. 這場分享
• 不是來傳Ruby教的
• 沒什麼Ruby程式碼，不會Ruby也能聽懂
• 分享我對「高階語言相依性管理」的想法
– Ruby開發流程很方便
– 自Ruby開發流程抽取與語言無關的概念

5. Top 10 Programmer Excuses
Google: 2011 COSCUP Lightning Talk 嵌入式開發的故事

6. Top 10 Programmer WTF

7. 相依性！

8. 高階語言開發的相依性
Applications
How can we make
Libraries
it more smooth?
Virtual Machine/Interpreter/Compiler
Abstraction!
Native Code / Libraries
Write once, debug
run anywhere OS
Hardware

9. High-Level Languages Development
in 2012 should…
1. 容易安裝、切換執行環境
2. 容易安裝函式庫
3. 確保所有開發者、部署環境使用相同版本
的函式庫
4. 使用版本控制系統，程式化地管理相依性
5. 函式庫應使用一致的版號規則描述相容性

10. “Getting Started” Scenario
Install environment
Clone the project
Install project
dependencies
Run the program Execute unit test
TDD

11. 安裝 Ruby Rubies
Install environment
$ apt-get install ruby
$ yum –y install ruby Clone the project
Install project
• Not always up-to-date dependencies
• Always not up-to-date
• Multiple Rubies: MRI Execute unit test
1.8.7, 1.9.2, 1.9.3, REE, JRuby, Ru TDD
binius, IronRuby, MacRuby, …

12. RVM (Ruby Version Manager)
安裝RVM Install environment
$ curl -L get.rvm.io | bash -s stable
Clone the project
安裝Rubies
$ rvm install 1.8.7
Install project
$ rvm install 1.9.3-p125 dependencies
$ rvm install jruby
切換不同Rubies Execute unit test
$ rvm use 1.8.7
$ rvm use 1.9.3 --default TDD
See Also: PerlBrew, PythonBrew, PHPBrew…

13. .rvmrc
提醒您使用正確的Ruby環境

14. 安裝環境
$ rvm install 1.9.3 Install environment
Clone the project
Install project
dependencies
Execute unit test
TDD

15. 下載專案源始碼
Install environment
$ git clone git://github.com/rails/rails.git Clone the project
Install project
dependencies
Execute unit test
TDD

16. Library Management in Ruby
• 主流工具： Install environment
– RubyGems: 管理Ruby套件
– Bundler: 管理Application與Gem的 Clone the project
相依性
Install project
dependencies
Execute unit test
TDD

17. RubyGems
安裝gem及其相依的gems
$ gem install rails
$ gem install rails –v=2.3.5
更新gems
$ gem update
發佈gems
$ gem push foo-1.0.0.gem
Yes. A lot of languages can do this.
See Also: pip, cpan, pear, onion, cabal, npm, maven, ivy…

18. Gemspec

19. Gem 相依性
固定版本
Devise
s.add_dependency ’devise', ‘1.5.0' 2.0.0
最小版本 Broken!
Devise
s.add_dependency ’devise', ‘>= 1.5.0' 1.6.0
版本範圍
Library Devise
s.add_dependency ’devise', ‘>= 1.5’, ‘< 2.0’ Foobar 1.5.0
“Twiddle Wakka”
s.add_dependency ’devise', ‘~> 1.5’ # ‘>= 1.5’, ‘< 2.0’
s.add_dependency ’devise', ‘~> 1.5.1’ # ‘>=1.5.1’, ‘< 1.6’
Just a shortcut?

20. Semantic Versioning
• Authored by Tom Preston-Werner, inventor of
Gravatars and cofounder of GitHub
• 一致的版號規則: Major.Minor.Patch
• Rails 3.1.10
– Major version: 3
– Minor version: 1
– Patch version: 10

21. Semantic Versioning
• Major version change
– 不向下相容
– Ex. Rails 2.3.7 -> 3.0.0
• Minor version change
– 向下相容，增加新功能
– Ex. Rails 3.0.10 -> 3.1.0
• Patch version change
– 向下相容，只修正bug
– Ex. Rails 3.1.0 -> 3.1.1

22. Semantic Versioning
• 例外: Major version 0為早期開發
– 0.0.1, 0.0.2, 0.9.4 什麼都可能不相容
• 更多細節請見 http://semver.org/
– Pre-release
– Tag name
– Semantic versioning v2.0.0-rc1
• See also: Apache APR Version Numbering

23. Semantic Versioning
• Semantic Version + Twiddle Wakka
– 使用一致的版號規則描述相容性
– 簡潔地指定「相容的版本區間」
s.add_dependency ’devise', ‘~> 1.5’ # ‘>= 1.5’, ‘< 2.0’
s.add_dependency ’devise', ‘~> 1.5.0’ # ‘>=1.5.0’, ‘< 1.6’
• Encouraged by the Ruby community
– http://robots.thoughtbot.com/post/2508037841/twiddle-wakka
– http://www.slideshare.net/copiousfreetime/gemology
– 許多專案Follow此規則

24. 為什麼需要Bundler?
Installed Gems
Rails
Broken!
3.0.0
Execute with Rails Sqlite3
Execute with
2.3.7 1.3.3
Bundler Bundler
Project Project
Alala Devise Wahaha
2.0.0
JSON
1.2.1

25. Gem v.s. Bundler
• Gem
– 安裝/反安裝/發佈gem
– Gemspec管理gem與gem的相依性
• Bundler
– 管理application與gem的相依性
• 幫你把application需要的gem一次全部裝好
• 確保所有開發者及部署使用相同版本的gem
– 題外話：bundler也能拿來開發gem

26. Bundler
在Gemfile中設定相依性
See Also: gradle, maven, ivy, sbt, virtualenv, carton

27. Bundler
bundle install
執行`bundle install`:
1. 計算並安裝所需要的gem
2. 產生 “Gemfile.lock”

28. Gemfile.lock

29. Bundler
Ensure you are using right gems
在Shell中執行：
$ bunlde exec ruby your_app.rb
或是在程式啟始點：
require "rubygems"
require "bundler/setup"
建議：所有的Ruby專案都可以使用Bundler

30. Bundler with git
修改Gemfile
$ vim Gemfile
$ bundle install # or bundle update
$ git add Gemfile Gemfile.lock; git commit
更新Gems
$ bundle update
$ git add Gemfile.lock; git commit

31. 安裝相依之函式庫
Install environment
Clone the project
Install project
$ bundle install dependencies
Execute unit test
TDD

32. 執行單元測試…
使用正確版本的函式庫
Install environment
Clone the project
Install project
dependencies
$ bundle exec rake test Execute unit test
TDD

33. Wrapping up
$ rvm install 1.9.3-p125 Install environment
$ git clone git://github.com/rails/rails.git Clone the project
$ cd rails Install project
dependencies
$ bundle install
$ bundle exec rake test Execute unit test
TDD

34. 結論

35. High-Level Languages Development
in 2012 should…
1. 容易安裝、切換執行環境
2. 容易安裝函式庫
3. 確保所有開發者、部署環境使用相同版本
的函式庫
4. 使用版本控制系統，程式化地管理相依性
5. 函式庫應使用一致的版號規則描述相容性

36. 這些概念與語言無關

37. PHPBrew, Onion
https://github.com/c9s/phpbrew
Brew & manage PHP versions in pure
PHP at HOME
https://github.com/c9s/Onion
Onion, The fast approach to
build/bundle PEAR packages for PHP.

38. Carton
Carton is a new command to manage Perl
module dependencies for your applications.
Like gem bundler for Ruby, Carton solves the
issue of "upgrading CPAN modules broke my
code" by allowing you to lock and freeze
dependencies. Carton makes it easy to
manage and reproduce module installations
on any environments.

41. 不要走開，接下來是iHower大大精彩的分享
「那些Functional Programming教我的事」
Any Question?