Refactor lib for better readability

**Feature request**
It would be great to have retry for controllers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_retry` with default `false`.

No file or test is named. Start by locating controller handling and configuration parsing, then trace how controller failures are surfaced. Confirm the retry behavior and configuration semantics before implementing; done means controllers retry when enable_retry is true and retain current behavior by default.

Written by the indexing model from the issue text.