Module renew 

When to renew, and what a renewal that keeps failing looks like from the outside.

Everything in this module is pure: no network, no clock of its own — the caller always supplies now. That is deliberate. “Renew well ahead of expiry” and “a renewal that has been failing for days must not first become visible as a total outage” are both decisions this module can get wrong without ever touching a CA, so they are tested that way.

Structs

RenewalPolicy

When renewal is attempted, and how often a failing attempt retries.

RenewalTracker

Tracks renewal attempts against one certificate’s expiry, so that a caller can ask two questions without touching the network: is a renewal due right now, and how loudly should its recent history be surfaced.

Enums

AlertLevel

How urgently a failing renewal should be surfaced.

Constants

CRITICAL_WINDOW 🔒

How close to expiry AlertLevel::Critical starts, regardless of how many attempts have failed. An expired wildcard is a total outage, so this floor does not wait for a retry count.

WARNING_FAILURE_THRESHOLD 🔒

How many consecutive failures, once renewal is due, promote Ok to Warning. One is deliberately not enough — a single failed attempt an hour after the last success is exactly what the retry interval exists to absorb quietly; a pattern is what earns attention.