A brief overview of caching technics using Rails

1. Caching with Rails Vincent Spehner Twitter: @vzmind Blog: vzmind.tumblr.com Janvier 2011

2. Vzmind aka Ruby on Rails creator

3. Why caching ? Culture Pub Almost 20 000 Vidéos 2 000 000 pages viewed https://github.com/thinkdry/blank-application

5. Rails cachingkeyworld:

6. Pages

7. Action

8. Fragment

9. Sweepersconfig.action_controller.perform_caching = true app/config/environments/production.rb Proxy (Squid, Varnish) Web Server (Apache, Nginx) Rails Stack (Rack, App) DB (PostgreSQL, MySQL) Browser Cache as earlier as youcan

11. Easy to implement but monotlithic and limited

12. Storedinside the File System onlyconfig.action_controller.page_cache_directory = RAILS_ROOT + “/…” config/environment.rb class Articles < ContentController # Add cache on articles index page caches_page :index app/controllers/articles_controller.rb Proxy Web Server Rails Stack DB Browser public/cache/articles.html

14. Easy to implement

15. Carefulwithfilters (Action cachingis an aroundfilteritself)

16. Carefulwith cache path

17. Chooseyour Cache Storeconfig.action_controller.cache_store = :file_store, RAILS_ROOT + /public/cache“ config/environment.rb class Articles < ContentController caches_action :show, :cache_path => Proc.new{ |controller| if controller.request.mobile_device? controller.params.merge(:mobile=>controller.request.mobile_device?) else controller.params end} app/controllers/articles_controller.rb expire_action :action => :show App/sweepers/article_sweeper.rb Proxy Web Server Rails Stack DB Browser public/cache/articles.html

19. Atomiccaching (result/string/object)

20. Chooseyour Cache Store- cache(:action => ‘list', :action_suffix => 'all_articles’) do = All articles: -@articles.each do |article| = article.title app/views/articles/index.haml.html expire_fragment(:controller => ‘articles', :action => ‘list', :action_suffix => 'all_articles') app/sweepers/article_sweeper.rb Proxy Web Server Rails Stack DB Browser public/cache/articles.html

22. Default memory storage

23. Store everything (even object)

24. Not thread safe

25. ActiveSupport::Cache::FileStore

26. Just for my HTML output

27. Old school

28. Simple

29. ActiveSupport::Cache::MemCacheStore

30. Most popularmemory cache store

31. Multi servers

33. Maintaining a cache iscostly and addcomplexity

34. Time basedflushing if usingmemcachedclass ArticleSweeper < ActionController::Caching::Sweeper # This sweeper observe articles model and delete cache on save observe :article def after_save(article) clear_article_cache(article) end def clear_article_cache(article) expire_pageindex_path, client end End app/sweepers/article_sweeper.rb

36. Nginx/apache rewrite rules

37. Hack for subdomainif any# Check index CACHE set $requested_page $request_uri; # Initialize variables set $cache_path "/cache/views/$http_host/static/"; if ($request_uri ~ ^/$){ set $requested_page "index"; } # Check if the page is in the cache. if (-f $document_root/$cache_path/$requested_page.html) { rewrite (.*) $cache_path/$requested_page.html break; }

39. UsingMemcached ?

40. UsingRack::Cache ?

42. :expire_in > 30.minutes

43. Intelligent keys- cache(“#{article.id}-#{article.update_at.to_i}” -data) do = My heavy stuffs to cache # => /cache/3-1234567-data #Or just writing - cache(article) do = My heavy stuffs to cache # => /cache/articles/3-1234567 #And if related to a specific user - cache([article,user]) do = My heavy stuffs to cache # => /cache/articles/3-1234567/users/23-12345678

44. Thanks you folks !!