The Watchdog Hydra
Ammar checked, and sure enough, his code was sending hundreds of thousands of requests per second. It didn’t take him long to figure out why: requests from the watchdog were failing with a 500 error, so it called the login method. The login method had been succeeding, so another watchdog got scheduled. Thirty seconds later, that failed, as did all the previously scheduled watchdogs, which all called login again. Which, on success, scheduled a fresh round of watchdogs. Every thirty seconds, the number of scheduled calls doubled. Before long, Ammar’s code was DoSing the API.