feature: added main slaver logic

.gitignore

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+/.bundle/
+/.yardoc
+/Gemfile.lock
+/_yardoc/
+/coverage/
+/doc/
+/pkg/
+/spec/reports/
+/tmp/
+gemfiles/
+spec/internal/config/database.yml
+spec/internal/test_other
+spec/internal/test

.rspec

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+--format documentation
+--color

Appraisals

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+appraise 'rails3.1' do
+  gem 'rails', '~> 3.1.0'
+end
+
+appraise 'rails3.2' do
+  gem 'rails', '~> 3.2.0'
+end

Gemfile

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+source 'https://rubygems.org'
+
+gemspec

LICENSE.txt

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+The MIT License (MIT)
+
+Copyright (c) 2015 Denis Korobitcin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

Makefile

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+BUNDLE = bundle
+BUNDLE_OPTIONS = -j 3
+RSPEC = ${APPRAISAL} rspec
+APPRAISAL = ${BUNDLE} exec appraisal
+
+all: test
+
+test: configs bundler appraisal
+	${RSPEC} 2>&1
+
+define DATABASE_YML
+test:
+  adapter: sqlite3
+  database: test
+test_other:
+  adapter: sqlite3
+  database: test_other
+endef
+export DATABASE_YML
+
+configs:
+	echo "$${DATABASE_YML}" > spec/internal/config/database.yml
+
+bundler:
+	if ! gem list bundler -i > /dev/null; then \
+	  gem install bundler; \
+	fi
+	${BUNDLE} install ${BUNDLE_OPTIONS}
+
+appraisal:
+	${APPRAISAL} install

README.md

@@ -1 +1,119 @@
-# slaver
+[![Dolly](http://dolly.railsc.ru/badges/abak-press/slaver/master)](http://dolly.railsc.ru/projects/129/builds/latest/?ref=master)
+
+# Slaver
+
+Welcome to slaver!
+
+It's a simple gem for rails application within multi-database environment.
+It allows you to change your current connection to other database configuration.
+Some ideas was inspired by [octopus](https://github.com/tchandy/octopus).
+
+## WARNING
+
+It was tested only on `rails 3` and `ruby 1.9.3`. Other configurations may work or may not:)
+
+## Installation
+
+Add this line to your application's Gemfile:
+
+```ruby
+gem 'slaver'
+```
+
+And then execute:
+
+    $ bundle
+
+Or install it yourself as:
+
+    $ gem install slaver
+
+## Usage
+
+### Config
+You must have other connection on your database.yml file. For example:
+
+```yml
+production:
+  adapter: pg
+  host: master
+  database: master
+  post: 11111
+
+production_slave:
+  adapter: sqlite3
+  host: slave
+  database: slave
+  post: 11113
+
+production_mysql:
+  adapter: mysql
+  user: me
+  host: somewhere_else
+  post: 11112
+  database: mysql
+```
+
+### Chain with AR
+
+Only works with class/scope methods. Connection changed until query is perfomed. After that it'll swiched back to default connection.
+
+```ruby
+  SomeModel.on(:production_mysql).where(name: 'me').first
+
+
+  # or, if you name starting with you Rails.env it can be skipped
+  SomeModel.on(:mysql).where(name: 'me').to_a
+```
+
+### Execute block on other connection
+
+Connection will be switched only for required class.
+
+```ruby
+  SomeModel.within(:slave) do
+    SomeModel.where(name: 'me')
+  end
+
+  # It also can be combined with "on" method
+
+  SomeModel.within(:mysql) do
+    me = SomeModel.find_by_name('me')
+    SomeModel.on(:slave).find_by_name('me').update_attributes(me.attributes)
+  end
+
+  # ACTUNG!!
+  Somemodel.within(:slave) do
+    #!!! Will be executed on default connection for OtherModel
+    OtherModel.where(name: 'me').first
+  end
+```
+### ACTUNG!!!!
+
+If you connection does not exists, behavior may change dependent of you current Rails environment:
+ - `Rails.env == production`: It'll raise `ArgumentError`
+ - otherwise: It'll try to switch to default connection - `Rails.env`
+
+### Missing features
+
+1. 'on' with assosiations
+2. Transaction safety
+3. `on` method on instance
+
+## Development
+
+To run test on local machine use `make` command. For more info please reffer to Makefile.
+
+## Contributing
+
+1. Fork it ( https://github.com/abak-press/slaver/fork )
+2. Create your feature branch (git checkout -b my-new-feature)
+3. Commit your changes (git commit -am 'Add some feature')
+4. Push to the branch (git push origin my-new-feature)
+5. Create new Pull Request
+
+
+
+## License
+
+The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).

Rakefile

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+require "bundler/gem_tasks"
+require "rspec/core/rake_task"
+
+RSpec::Core::RakeTask.new(:spec)
+
+task :default => :spec

config.ru

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+require 'rubygems'
+require 'bundler'
+
+Bundler.require :default, :development
+
+Combustion.initialize! :all
+run Combustion::Application

lib/slaver.rb

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+require 'rails'
+require 'slaver/version'
+require 'slaver/proxy'
+require 'slaver/proxy_methods'
+require 'slaver/connection'
+require 'slaver/railtie'
+
+module Slaver
+end

lib/slaver/connection.rb

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+module Slaver
+  module Connection
+    extend ActiveSupport::Concern
+
+    included do
+      include ProxyMethods
+    end
+
+    module ClassMethods
+      # TODO: Make it work with associations
+      # Public: Change database connection for next query
+      # WARNING: It'll change current DB connection until
+      # insert, select or execute methods call
+      #
+      # config_name  - String or Symbol, name of config_section
+      #
+      # NOTE:
+      #  if config was not found:
+      #  1) On production
+      #    throws ArgumentError
+      #  2) Uses default configuration for current environment
+      #
+      # Exception safety:
+      #  throws ArgumentError if no configuration was found
+      #
+      # Examples
+      #
+      # SomeModel.on(:slave).create(...)
+      # SomeModel.on(:slave).where(...).first
+      #
+      # It also can be chained with other 'on' methods
+      # SomeModel.on(:slave).on(:other).find_by(...)
+      #
+      # Returns self
+      def on(config_name)
+        @saved_config ||= @current_config
+        @saved_block ||= @block
+        @block = false
+
+        @current_config = prepare(config_name)
+
+        initialize_pool(@current_config) unless pools[@current_config]
+
+        self
+      end
+
+      # Public: Changes model's connection to database temporarily to execute block.
+      #
+      # config_name - String or Symbol, name of config_section
+      #
+      # NOTE:
+      #  if config was not found:
+      #  1) On production
+      #    throws ArgumentError
+      #  2) Uses default configuration for current environment
+      #
+      # Exception safety:
+      #  throws ArgumentError if no configuration was found
+      #
+      # Examples
+      #
+      #   SomeModel.within :test_slave do
+      #     # do some computations here
+      #   end
+      #   => will execute given block with different db_connection
+      #
+      #   It is also possible to nest database connection code
+      #
+      #   SomeModel.within :slave do
+      #     do some computations here
+      #     SomeModel.within :slave2 do
+      #       # some other computations go here
+      #     end
+      #   end
+      #   => will execute given block with different db_connection
+      #
+      # Returns noting
+      def within(config_name)
+        config_name = prepare(config_name)
+
+        initialize_pool(config_name) unless pools[config_name]
+
+        with_config(config_name) do
+          keep_block do
+            yield
+          end
+        end
+      end
+
+      def clear_config
+        @block = @saved_block if @saved_block
+        @saved_block = nil
+        @current_config = @block && @saved_config
+        @saved_config = nil
+      end
+
+      def pools
+        @pools ||= {}
+      end
+
+      def within_block?
+        !!@block
+      end
+
+      private
+
+      def with_config(config_name)
+        last_config = @current_config
+        @current_config = config_name
+
+        begin
+          yield
+        ensure
+          @current_config = last_config
+        end
+      end
+
+      def keep_block
+        last_block = @block
+        @block = true
+
+        begin
+          yield
+        ensure
+          @block = last_block
+        end
+      end
+
+      def initialize_pool(config_name)
+        if config_name == default_config
+          pools[config_name] = connection_pool_without_proxy
+        else
+          pools[config_name] = create_connection_pool(config_name)
+        end
+      end
+
+      def prepare(config_name)
+        config_name = config_name.to_s
+
+        return config_name if ::ActiveRecord::Base.configurations[config_name].present?
+
+        config_name = "#{Rails.env}_#{config_name}"
+
+        if (::ActiveRecord::Base.configurations[config_name]).blank?
+          if Rails.env.production?
+            raise ArgumentError, "Can't find #{config_name} on database configurations"
+          else
+            config_name = default_config
+          end
+        end
+
+        config_name
+      end
+
+      def default_config
+        Rails.env
+      end
+
+      def create_connection_pool(config_name)
+        config = ::ActiveRecord::Base.configurations[config_name]
+        config.symbolize_keys!
+        arg = ActiveRecord::Base::ConnectionSpecification.new(config, "#{config[:adapter]}_connection")
+
+        ActiveRecord::ConnectionAdapters::ConnectionPool.new(arg)
+      end
+    end
+  end
+end