Module: ActiveRecordShards::DefaultSlavePatches

Included in:
ActiveRecord::Base
Defined in:
lib/active_record_shards/default_slave_patches.rb

Defined Under Namespace

Modules: ActiveRelationPatches, HasAndBelongsToManyPreloaderPatches, Rails41HasAndBelongsToManyBuilderExtension

Constant Summary collapse

CLASS_SLAVE_METHODS = 
[ :find_by_sql, :count_by_sql,  :calculate, :find_one, :find_some, :find_every, :exists?, :table_exists? ]

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.extended(base) ⇒ Object 



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# File 'lib/active_record_shards/default_slave_patches.rb', line 29

def self.extended(base)
  CLASS_SLAVE_METHODS.each { |m| ActiveRecordShards::DefaultSlavePatches.wrap_method_in_on_slave(true, base, m) }

  base.class_eval do
    # fix ActiveRecord to do the right thing, and use our aliased quote_value
    def quote_value(*args, &block)
      self.class.quote_value(*args, &block)
    end

    def reload_with_slave_off(*args, &block)
      self.class.on_master { reload_without_slave_off(*args, &block) }
    end
    alias_method :reload_without_slave_off, :reload
    alias_method :reload, :reload_with_slave_off

    class << self
      def columns_with_default_slave(*args, &block)
        read_columns_from = if on_slave_by_default? && !Thread.current[:_active_record_shards_slave_off]
          :slave
        else
          :master
        end

        on_cx_switch_block(read_columns_from, :construct_ro_scope => false) { columns_without_default_slave(*args, &block) }
      end
      alias_method :columns_without_default_slave, :columns
      alias_method :columns, :columns_with_default_slave
    end

    class << self
      def transaction_with_slave_off(*args, &block)
        if on_slave_by_default?
          old_val = Thread.current[:_active_record_shards_slave_off]
          Thread.current[:_active_record_shards_slave_off] = true
        end

        transaction_without_slave_off(*args, &block)
      ensure
        if on_slave_by_default?
          Thread.current[:_active_record_shards_slave_off] = old_val
        end
      end

      alias_method :transaction_without_slave_off, :transaction
      alias_method :transaction, :transaction_with_slave_off
    end
  end
  if ActiveRecord::Associations.const_defined?(:HasAndBelongsToManyAssociation)
    ActiveRecordShards::DefaultSlavePatches.wrap_method_in_on_slave(false, ActiveRecord::Associations::HasAndBelongsToManyAssociation, :construct_sql)
    ActiveRecordShards::DefaultSlavePatches.wrap_method_in_on_slave(false, ActiveRecord::Associations::HasAndBelongsToManyAssociation, :construct_find_options!)
  end
end

.wrap_method_in_on_slave(class_method, base, method) ⇒ Object 



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# File 'lib/active_record_shards/default_slave_patches.rb', line 4

def self.wrap_method_in_on_slave(class_method, base, method)
  base_methods = if class_method
    base.methods + base.private_methods
  else
    base.instance_methods + base.private_instance_methods
  end

  return unless base_methods.include?(method)
  _, method, punctuation = method.to_s.match(/^(.*?)([\?\!]?)$/).to_a
  base.class_eval <<-RUBY, __FILE__, __LINE__ + 1
    #{class_method ? "class << self" : ""}
      def #{method}_with_default_slave#{punctuation}(*args, &block)
        on_slave_unless_tx do
          #{method}_without_default_slave#{punctuation}(*args, &block)
        end
      end

      alias_method :#{method}_without_default_slave#{punctuation}, :#{method}#{punctuation}
      alias_method :#{method}#{punctuation}, :#{method}_with_default_slave#{punctuation}
    #{class_method ? "end" : ""}
  RUBY
end

Instance Method Details

#on_slave_unless_tx(&block) ⇒ Object 



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# File 'lib/active_record_shards/default_slave_patches.rb', line 82

def on_slave_unless_tx(&block)
  if on_slave_by_default? && !Thread.current[:_active_record_shards_slave_off]
    on_slave { yield }
  else
    yield
  end
end