When DNSWATCHER_TARGETS is empty or unset (the default), dnswatcher now
exits with a clear error message instead of silently starting with
nothing to monitor.
Added ErrNoTargets sentinel error returned from config.New when both
domains and hostnames lists are empty after target classification. This
causes the fx application to fail to start, preventing silent
misconfiguration.
Also extracted classifyAndValidateTargets and parseDurationOrDefault
helper functions to keep buildConfig within the funlen limit.
Closes#69
Replace DNSWATCHER_DOMAINS and DNSWATCHER_HOSTNAMES with a single
DNSWATCHER_TARGETS env var. Names are automatically classified as apex
domains or hostnames using the Public Suffix List
(golang.org/x/net/publicsuffix).
- ClassifyDNSName() uses EffectiveTLDPlusOne to determine type
- Public suffixes themselves (e.g. co.uk) are rejected with an error
- Old DOMAINS/HOSTNAMES vars removed entirely (pre-1.0, no compat needed)
- README updated with pre-1.0 warning
Closes#10
Full project structure following upaas conventions: uber/fx DI, go-chi
routing, slog logging, Viper config. State persisted as JSON file with
per-nameserver record tracking for inconsistency detection. Stub
implementations for resolver, portcheck, tlscheck, and watcher.
