Polly

Polly makes a comeback along with the microservices: retry, timeout, and circuit breaker in our services all live through it. Policies are described declaratively and attached to HttpClient via DI — what I hand-crafted in 2017 for the ERP integration is now a few lines of configuration.

Three forks of the same system integrate with one and the same ERP, and we need to tell a fight over a resource apart from the ERP itself being down. Instead of mutexes I put together a solution on Polly: retry policies plus automatic circuit breaking when the ERP is genuinely dead.

Back then I didn't know this "breaker" had a name and a whole textbook pattern behind it — to me it was just common sense, conveniently packaged into a library.