When a watched name's nameservers answer with a CNAME and no address,
the DNS check asks ResolveIPAddresses for the name, which looks it up
again and follows the chain, and saves the addresses at its end in the
hostname state as cnameAddresses. The port and TLS checks use them.
Before, a CNAME into another zone got no port or TLS checks. A change
in those addresses is notified as a CNAME address change. When
following fails, or none of the name's nameservers answered, the
addresses the last check saved are kept. The domain check now runs the
hostname check for the apex instead of a copy of it.
Model: opus-5-5
Each domain check now looks up the addresses every nameserver's name
resolves to, with the resolver's ResolveIPAddresses, and saves them
sorted in the domain's state. A nameserver that stays in the
delegation and resolves to different addresses sends one NS Address
Change notification naming the domain, the nameserver and the old and
new addresses. Added or removed nameservers get only the NS change
notification. A failed or empty lookup keeps the previous addresses,
because the resolver returns no address without an error when every
server it asks times out. State files without the field load, and the
next check fills it in silently. Watcher tests that run domain checks
use example.com, which has two nameservers, to stay within the
per-attempt limit.
Model: opus-5-5
The runtime image runs as uid 10001, which owns /var/lib/dnswatcher. The
working directory is /, so config loading finds no .env or dnswatcher
config file there; the binary lives in /usr/local/bin. A Docker
HEALTHCHECK probes /.well-known/healthcheck every 10 seconds with busybox
wget, well inside the 60 seconds upaas waits.
Startup now fails with an error naming the data directory when it cannot
be written, instead of running with every save failing. The check creates
the directory if needed and writes and removes the temp file Save uses;
tests cover the create and the write failing.
README gains "Running under upaas": the prod branch, host directory
setup, network and port, environment and health check.
Model: opus-5-5
## Summary
Port state keys are `ip:port` with a single `hostname` field. When multiple hostnames resolve to the same IP (shared hosting, CDN), only one hostname was associated. This caused orphaned port state when that hostname removed the IP from DNS while the IP remained valid for other hostnames.
## Changes
### State (`internal/state/state.go`)
- `PortState.Hostname` (string) → `PortState.Hostnames` ([]string)
- Custom `UnmarshalJSON` for backward compatibility: reads old single `hostname` field and migrates to a single-element `hostnames` slice
- Added `DeletePortState` and `GetAllPortKeys` methods for cleanup
### Watcher (`internal/watcher/watcher.go`)
- Refactored `checkAllPorts` into three phases:
1. Build IP:port → hostname associations from current DNS data
2. Check each unique IP:port once with all associated hostnames
3. Clean up stale port state entries with no hostname references
- Port change notifications now list all associated hostnames (`Hosts:` instead of `Host:`)
- Added `buildPortAssociations`, `parsePortKey`, and `cleanupStalePorts` helper functions
### README
- Updated state file format example: `hostname` → `hostnames` (array)
- Updated notification description to reflect multiple hostnames
## Backward Compatibility
Existing state files with the old single `hostname` string are handled gracefully via custom JSON unmarshaling — they are read as single-element `hostnames` slices.
Closes #55
Co-authored-by: clawbot <clawbot@noreply.eeqj.de>
Reviewed-on: #65
Co-authored-by: clawbot <clawbot@noreply.example.org>
Co-committed-by: clawbot <clawbot@noreply.example.org>
State.Save() was using RLock but mutating s.snapshot.LastUpdated,
which is a write operation. This created a data race since other
goroutines could also hold a read lock and observe a partially
written timestamp. Changed to full Lock to ensure exclusive access
during the mutation.
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.
sneak
clawbot
