Prevent re-entrant callbacks

[sjtrny]

JITCache is designed specifically for this purpose. Re-entrant callbacks can be blocked and the computation only run once.

Preventing Wasteful Parallel Callbacks When Running Multiple Processes and Caching

In my app multiple callbacks depend on a shared result. Calculating this shared result once is slow enough, but having multiple processes (or threads) repeatedly doing the calculation is even slower. I think I am looking for a cache-like solution that when the cache returns a miss, the requesting callbacks will simply wait until the first callback is finished and then grab the same result. I have tried using Flask-Caching but in my tests it seems like if there is a cache miss then all workers/t…