module Redis::Objects::Locks::ClassMethods
Class methods that appear in your class when you include Redis::Objects
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Public Instance Methods
clear_lock(name, id)
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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.)
# File lib/redis/objects/locks.rb, line 58 def clear_lock(name, id) verify_lock_defined!(name) redis.del(redis_field_key("#{name}_lock", id)) end
lock(name, options={})
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Define a new lock. It will function like a model attribute, so it can be used alongside ActiveRecord/DataMapper, etc.
# 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) ivar_name = :"@#{lock_name}" mod = Module.new do define_method(lock_name) do |&block| instance_variable_get(ivar_name) or instance_variable_set(ivar_name, Redis::Lock.new( redis_field_key(lock_name), redis_field_redis(lock_name), redis_objects[lock_name.to_sym] ) ) end end if options[:global] extend mod # dispatch to class methods define_method(lock_name) do |&block| self.class.public_send(lock_name, &block) end else include mod end end
obtain_lock(name, id, &block)
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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.
# File lib/redis/objects/locks.rb, line 49 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_field_redis(lock_name), redis_objects[lock_name.to_sym]).lock(&block) end
Private Instance Methods
verify_lock_defined!(name)
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# File lib/redis/objects/locks.rb, line 65 def verify_lock_defined!(name) unless redis_objects.has_key?("#{name}_lock".to_sym) raise Redis::Objects::UndefinedLock, "Undefined lock :#{name} for class #{self.name}" end end