Reminds me of my work in the blockchain space. I built a Decentralized Exchange which gets all of its inputs from blockchain data. Since all the inputs are deterministic (and it's all based in block time instead of real time), I can replay any scenario any number of times... But it goes one step further than what is mentioned in the article because I can replay any bug which ever happens, exactly as it happened, IN PRODUCTION.
The output is also deterministic so all operations are idempotent; they can be replayed any number of times, going as far back in the past as you want and end up with exactly the same state.
But, ironically, the DEX hasn't had any bug since it started operating 3 years ago... It makes debugging so easy, I was able to resolve every possible issue I could imagine before the launch.
I think I haven't updated the code in a year but I've been running it this whole time and it's been processing trades.
Another unusual feature is that you could technically trade between 2 blockchains while the DEX is offline... Even if the DEX is only restarted 1 year or decades later, it will resolve the trades as though the DEX had been online the entire time. Only difference is that the disbursement of funds will be in the future after the DEX is restarted.
The output is also deterministic so all operations are idempotent; they can be replayed any number of times, going as far back in the past as you want and end up with exactly the same state.
But, ironically, the DEX hasn't had any bug since it started operating 3 years ago... It makes debugging so easy, I was able to resolve every possible issue I could imagine before the launch.
I think I haven't updated the code in a year but I've been running it this whole time and it's been processing trades.
Another unusual feature is that you could technically trade between 2 blockchains while the DEX is offline... Even if the DEX is only restarted 1 year or decades later, it will resolve the trades as though the DEX had been online the entire time. Only difference is that the disbursement of funds will be in the future after the DEX is restarted.