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 52

def clear_lock(name, id)
  verify_lock_defined!(name)
  lock_name = field_key("#{name}_lock", id)
  redis.del(lock_name)
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
  @redis_objects[name] = options.merge(:type => :lock)
  if options[:global]
    instance_eval <<-EndMethods
      def #{name}_lock(&block)
        @#{name} ||= Redis::Lock.new(field_key(:#{name}_lock, ''), redis, @redis_objects[:#{name}])
      end
    EndMethods
    class_eval <<-EndMethods
      def #{name}_lock(&block)
        self.class.#{name}(block)
      end
    EndMethods
  else
    class_eval <<-EndMethods
      def #{name}_lock(&block)
        @#{name} ||= Redis::Lock.new(field_key(:#{name}_lock), redis, self.class.redis_objects[:#{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 43

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