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active-hash / active_hash

A readonly ActiveRecord-esque base class that lets you use a hash, a Yaml file or a custom file as the datasource
MIT License
1.2k stars 179 forks source link

Add thread safety to ActiveFile #229

Closed dmitriy-kiriyenko closed 2 years ago

dmitriy-kiriyenko commented 3 years ago

ActiveFile is not thread-safe, which results in the following: if the very first request to ActiveFile goes simultaneously from even two threads, the first one is going to return as if the data was empty. The second request will immediately fix that, but that unlucky thread will receive a bad value. It may store it in the database or memoize it, which will result in further problem escalation.

We can't just synchronise it, because we check the variable very far from reload. While we must synchronise, it's not enough. We have to flag it as 'done' only after it's loaded.

Another problem is that we touch all in process of reloading, which will check data_loaded flag and try to reload again. To counter that, I come out with a method that won't trigger reload, to use it in methods that work during reload.

Resolves #159.

dmitriy-kiriyenko commented 3 years ago

@zilkey any chance?

ghost commented 2 years ago

@zilkey If you have the time, Please see a bit little 🙏

yujideveloper commented 2 years ago

@adampal @kbrock I believe we should merge this pr. Could you review this?

adampal commented 2 years ago

Thanks @dmitriy-kiriyenko I tested locally and confirmed this definitely fixes the issue @drmnick saw in #159