Sutures

Multi-db tips for ruby on rails

Transcript

1. Sutures Strategies for dealing with multiple databases in Ruby applications
2. Why? • The one database only stores a fraction of the complete data model. • You need features from a second database. • Your trying to migrate away from one database. • You want to run intensive queries on a reporting mirror.
3. How? • Secondbase • Sequel • Ruby Object Mapper
4. Secondbase Karle wrote this
5. Secondbase • Gives you the most “Rails like” integration • CustomInk uses this • Only works with two databases
6. Installing Secondbase # in your Gemfile gem 'secondbase' # in config/database.yml# development: adapter: sqlite database: myapp_development test: adapter: sqlite database: myapp_test # SecondBase configurations: secondbase: development: adapter: mysql database: myapp_development test: adapter: mysql database: myapp_test
7. Using Secondbase • Migrations go in db/secondbase/migrate • Models inherit from Secondbase::Base • Regular rails rake tasks work as normal
8. Using Secondbase # somewhere in config/initializers/*.rb Delayed::Backend::ActiveRecord::Job.extend SecondBase::Forced ActiveRecord::SessionStore::Session.extend SecondBase::Forced class ApplicationController < ActionController::Base around_filter :cache_other_db_connections private def cache_other_db_connections SecondBase::Base.connection.cache { yield } end end
9. Secondbase’s Caveats • Two databases only
10. Sequel CustomInk uses this too!
11. Sequel • Maintained by Jeremy Evans • Provides a query DSL and an active record model • Lightweight • Provides most of its features via plugins
12. Using Sequel # in your Gemfile gem 'sequel' # somewhere in config/initializers/*.rb DB_ONE = Sequel.connect('postgres://user:password@localhost/ db_one') DB_TWO = Sequel.connect('postgres://user:password@localhost/ db_two') # raw db query DB_TWO[:posts].where(:category => 'Ruby Loco') # in your models class Post < Sequel::Model end Post.db = DB_TWO
13. Migrating Sequel • Write the rake tasks using Sequel::Migrator • sequel -m /migrations/dir <connection details>
14. Sequel’s Caveats • Everything is a plugin • Sequel model close, but not exactly ActiveRecord • Does not play nice with spring
15. Closing Thoughts • Yes, you can do this • Command Query Responsibility Segregation really helps • Remember to breathe