Cracking Polly
Introduction Polly is a .NET resilience and transient-fault-handling library. It lets you express strategies like retry, circuit breaker, timeout, rate limiting, hedging, and fallback around any piece of code, so a flaky downstream dependency doesn’t automatically become an outage in your own service. If you used Polly a few years ago and haven’t looked at it since, the library you remember is gone. Polly v8 was a ground-up rewrite, built in collaboration with Microsoft, and it changes both the API and the mental model. This post is a practical, current tour of what Polly looks like today: pipelines instead of policies, the built-in HTTP resilience handlers, hedging, chaos engineering support, and the one thing that’s changed about the license terms that maintainers of paid products should know about. ...