我的用户模型有一个讨厌的方法,不应该同时为同一记录的两个实例调用.我需要连续执行两个http请求,同时确保任何其他线程不会同时为同一记录执行相同的方法.
class User
...
def nasty_long_running_method
// something nasty will happen if this method is called simultaneously
// for two instances of the same record and the later one finishes http_request_1
// before the first one finishes http_request_2.
http_request_1 // Takes 1-3 seconds.
http_request_2 // Takes 1-3 seconds.
update_model
end
end
例如,这会破坏一切：
user = User.first
Thread.new { user.nasty_long_running_method }
Thread.new { user.nasty_long_running_method }
但这没关系,应该允许：
user1 = User.find(1)
user2 = User.find(2)
Thread.new { user1.nasty_long_running_method }
Thread.new { user2.nasty_long_running_method }