7. Living With Failure — Retry, Circuit Breakers, Resources

Coming soon

This chapter is an outline. The full draft ships in a follow-up PR.

What this chapter will cover

Production code spends most of its time either failing or recovering from something that failed a moment ago. This chapter covers the three Uni primitives that let you write that gracefully: Retry, CircuitBreaker, and Resource.

Concepts introduced:

• Retry policies: exponential backoff, jitter, and which errors are safe to retry (and which are dangerous to).
• Circuit breakers: when a backend is clearly down, stop making it worse. The state machine (closed → open → half-open) and how Uni models it.
• Idempotency as a precondition for retry — and how to tell whether your call is idempotent.
• Resource for scoped resource lifetimes that compose with Design sessions.
• Combining the three: the canonical "HTTP call with retry, circuit breaker, and a bounded connection pool" pattern.

Reference you can read now

• Control Flow — Overview
• Retry
• Circuit Breaker
• Resource

← 6. Rx, the Composable Stream | Next → 8. HTTP Clients and Servers