Module: Redis::Objects::Locks::ClassMethods

Defined in:
lib/redis/objects/locks.rb

Overview

Class methods that appear in your class when you include Redis::Objects.

Instance Method Summary collapse

Instance Method Details

#clear_lock(name, id) ⇒ Object

Clear the lock. Use with care - usually only in an Admin page to clear stale locks (a stale lock should only happen if a server crashes.)



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# File 'lib/redis/objects/locks.rb', line 54

def clear_lock(name, id)
  verify_lock_defined!(name)
  redis.del(redis_field_key("#{name}_lock", id))
end

#lock(name, options = {}) ⇒ Object

Define a new lock. It will function like a model attribute, so it can be used alongside ActiveRecord/DataMapper, etc.



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# File 'lib/redis/objects/locks.rb', line 17

def lock(name, options={})
  options[:timeout] ||= 5  # seconds
  lock_name = "#{name}_lock"
  @redis_objects[lock_name.to_sym] = options.merge(:type => :lock)
  klass_name = '::' + self.name
  if options[:global]
    instance_eval <<-EndMethods
      def #{lock_name}(&block)
        @#{lock_name} ||= Redis::Lock.new(redis_field_key(:#{lock_name}), #{klass_name}.redis, #{klass_name}.redis_objects[:#{lock_name}])
      end
    EndMethods
    class_eval <<-EndMethods
      def #{lock_name}(&block)
        self.class.#{lock_name}(block)
      end
    EndMethods
  else
    class_eval <<-EndMethods
      def #{lock_name}(&block)
        @#{lock_name} ||= Redis::Lock.new(redis_field_key(:#{lock_name}), #{klass_name}.redis, #{klass_name}.redis_objects[:#{lock_name}])
      end
    EndMethods
  end
end

#obtain_lock(name, id, &block) ⇒ Object

Obtain a lock, and execute the block synchronously. Any other code (on any server) will spin waiting for the lock up to the :timeout that was specified when the lock was defined.

Raises:

  • (ArgumentError) 


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# File 'lib/redis/objects/locks.rb', line 45

def obtain_lock(name, id, &block)
  verify_lock_defined!(name)
  raise ArgumentError, "Missing block to #{self.name}.obtain_lock" unless block_given?
  lock_name = "#{name}_lock"
  Redis::Lock.new(redis_field_key(lock_name, id), redis, @redis_objects[lock_name.to_sym]).lock(&block)
end