FreshConnection
FreshConnection supports to connect with Mysql slave servers via Load Balancers. All connections will be disconnected every time at the end of the action.
Installation
For Rails3 and 4
Add this line to your application's Gemfile:
gem "fresh_connection"
And then execute:
$ bundle
Or install it yourself as:
$ gem install fresh_connection
Config
config/database.yml
production:
adapter: mysql2
encoding: utf8
reconnect: true
database: kaeru
pool: 5
username: master
password: master
host: localhost
socket: /var/run/mysqld/mysqld.sock
slave:
username: slave
password: slave
host: slave
slave
is config to connect to slave servers.
Others will use the master setting. If you want to change, write in the slave.
use multiple slave servers group
If you may want to user multiple slave group, write multiple slave group to config/database.yml.
production:
adapter: mysql2
encoding: utf8
reconnect: true
database: kaeru
pool: 5
username: master
password: master
host: localhost
socket: /var/run/mysqld/mysqld.sock
slave:
username: slave
password: slave
host: slave
admin_slave:
username: slave
password: slave
host: admin_slaves
And call establish_fresh_connection method in model that access to admin_slave
slave group.
class AdminUser < ActiveRecord::Base
establish_fresh_connection :admin_slave
end
The children is access to same slave group of parent.
class Parent < ActiveRecord::Base
establish_fresh_connection :admin_slave
end
class AdminUser < Parent
end
class Benefit < Parent
end
AdminUser and Benefit access to admin_slave
slave group.
Declare model that doesn't use slave db
class SomethingModel < ActiveRecord::Base
master_db_only!
end
If model that always access to master servers is exist, You may want to write master_db_only!
in model.
The model that master_db_only model's child is always access to master db.
Slave Connection Manager
Default slave connection manager is FreshConnection::ConnectionManager. If you would like to change slave connection manager, assign yourself slave connection manager.
config/initializers/fresh_connection.rb
FreshConnection.connection_manager = MySlaveConnection
Yourself Slave Connection Manager should be inherited FreshConnection::AbstractConnectionManager
class MySlaveConnection < FreshConnection::AbstractConnectionManager
def slave_connection
# must return object of ActiveRecord::ConnectionAdapters::Mysql2Adapter
end
def put_aside!
# called when end of Rails controller action
end
def recovery(failure_connection, exception)
# called when raise exception to access slave server
end
end
Usage
Read query will be access to slave server.
Article.where(:id => 1)
If you want to access to master saver, use readonly(false).
Article.where(:id => 1).readonly(false)
In transaction, Always will be access to master server.
Article.transaction do
Article.where(:id => 1)
end
Contributing
- Fork it
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create new Pull Request
Test
I'm glad that you would do test! To run the test suite, you need mysql installed. How to setup your test environment.
bundle install --path bundle
GEM_HOME=bundle/ruby/(your ruby version) gem install bundler --pre
bundle exec appraisal install
This command run the spec suite for all rails versions supported.
bundle exec appraisal rake spec