The console could not see local zones at all. `blocklist.local_zones` compiled
a store that nothing read back: there was no API for a zone, its records, its
delegations or the file a record came from, and no way to change one without
editing YAML and reloading. The Domains page is the blocklist's inline rules,
not local data, so nothing in the console covered the half of the server that
answers authoritatively from disk. There is now a Zones page and the endpoints
behind it: `GET /api/zones`, `POST`/`PUT`/`DELETE /api/zones/records`,
`POST`/`DELETE /api/zones/delegations` and `DELETE /api/zones?zone=`.
**The console owns one directory and nothing else.** `blocklist.managed_zones`
holds one `<apex>.zone` per zone, with that zone's SOA, apex NS set and the
records added there, and it is compiled by the same `localzone.Load` as the
operator's files — so a record added from the console is served on the next
query, with no reload and no restart. Files in `blocklist.local_zones` are
listed and shown read-only and are never rewritten; the key defaults to empty,
so a deployment that never sets it gets a zone browser and no zone writes.
Which file a record came from is now part of the store (`zone.files`, keyed by
the index the store already uses), so the snapshot can say "console" or "your
file" per record; the query path does not read it.
**The writer proves its own output.** A record is validated by the project's own
master-file parser, so `www` means `www.<zone>` and a bare CNAME target is
completed exactly as it would be in a zone file; the file is rendered, and the
rendering is re-parsed and compared with the records it meant to write before
the file is renamed into place. A writer bug that dropped a record would
otherwise present as a zone that silently stopped answering. A zone that cannot
answer is refused rather than created: no SOA means no NXDOMAIN or NODATA
authority, and no apex NS means nothing is delegated and no server is named. The
SOA's primary follows the apex NS set — a zone whose SOA names a server outside
its own NS set hands out a referral no resolver can follow — and the serial
moves on every write.
**A delegation takes the names under it, so a record below a cut is refused.**
The store answers those names as delegated without reading the zone file, which
would make the record data that looks alive and never answers. `DELETE
/api/zones?zone=` exists for the same reason from the other side: a zone the
console created is a real zone, so it says NXDOMAIN for what it does not hold,
and deleting a record is not what gives a name back to upstream. It is
refused for a zone that also has records outside the managed directory, because
removing that file would remove none of the zone.
**Two bugs the work turned up.** `engine.applyConfig` published local-record
metrics only when `blocklist.local_zones` was non-empty, so a zone the console
created was served but never counted; the gate is now the store's own record
count. And the record-value renderer fell back to `RR.String()` for every type
it did not know, which is the whole line rather than the RDATA — it wrote a
name and a TTL into the value column for DHCID, LOC, SSHFP and SVCB, and would
have fed that back as a record value on the next edit.
Every write recompiles the store and flushes the cache. Which names changed is
not knowable from the API, and a cached upstream answer for a name the zone now
answers is simply wrong, so the flush is blunt on purpose.
The wire shapes are type aliases in `internal/api` rather than copies, so there
is one set of json tags, and `TestZoneEndpointKeySets` pins the key set at every
level with a record and a delegation actually present — an empty list only
proves the envelope. `TestZoneWritesNeedAManagedDirectory` pins the read-only
default, and `TestZoneConsoleRoundTrip` walks the whole thing: a record added
through the API is answered authoritatively on the next query, a cut stops the
parent answering below it, and deleting the zone hands the name back.
Verified against a running instance built from this tree: records and
wildcards answer with `aa`, relative names are qualified, a record below a cut
is refused with a message that says why, and the file on disk is a zone file
an operator can read. The console page is typechecked and built; the browser was
not available in this round, so it has not been looked at.
Local zones were only editable as mounted files, so operators could not manage DNS entries from the console. Add a Local zones editor backed by a shared Kubernetes ConfigMap, validate master files before saving, scope the pod service account to that ConfigMap, and reload changed zones on every replica while flushing stale cache entries.
internal/engine, internal/config and internal/metrics had no test file at all,
and writing them turned up five real bugs.
internal/engine (23 tests, new harness_test.go): a wired engine over a fake
upstream on loopback, a local zone, a blocklist, a cache, a query log and an
injectable clock. It pins the pipeline order end to end -- ACL deny before the
local zone, local zone before blocklist, blocklist before cache, drop sends
nothing, the concurrency and rate-limit refusals, serve-stale served with TTL 1
and refreshed once per key, truncation against a 512-byte client, and exactly
one metrics record and one query-log entry per query.
Five fixes:
- config.ParseSize ignored the unit multiplier, so 512MiB parsed as 512 bytes
and the whole memory envelope was inert for anyone who wrote a unit.
- finalize (EDNS0 and the UDP size) ran only on the cache-hit path, so a large
uncached answer left oversized for a 512-byte client. It now runs on the
upstream, local-zone and blocklist paths too.
- The upstream UDP client read buffer was hard-coded to 1232 while we advertise
dns.max_udp_size, so with a larger buffer configured every answer above 1232
bytes was read truncated and became SERVFAIL. The pool takes the size now.
- LRU.prefetchGate was a 64-slot global cap, not the single flight its comment
promised: a burst of stale hits launched up to 64 duplicate refreshes of one
name. It is a per-key latch now; distinct names still refresh in parallel.
- metrics.RecordMiss and RecordStaleHit moved only the Prometheus collector, so
the Cache page's misses and stale hits read 0 for the life of the process.
AGENTS.md gains the trap that cost the most time: this version of miekg/dns
reports a character-string over 255 bytes as zero length, so such a message
silently fails to pack, and the write failure looks like a client timeout.
A cgroup OOM kill is the worst outcome available to a resolver: an outage
rather than a cache miss, with no chance to serve stale on the way out. So:
- memory.limit / memory.reserve / memory.cache_max_bytes, a new config section.
limit becomes a GOMEMLIMIT through debug.SetMemoryLimit, reduced by the
reserve. The reserve exists because the Go heap does not account for
goroutine stacks, runtime metadata, or the bbolt mmap backing the cache
snapshot and the query log — handing the runtime the full cgroup limit is how
you get killed by a mechanism that believed it had headroom.
- config.Size, so a budget reads as "512MiB" rather than a byte count converted
by hand. Strict about junk: "512MiBx" is an error.
- The cache byte budget is now actually fed to the LRU. It already enforced
maxBytes per shard on insert, but had no setter and nothing ever called one,
so the footprint of cache.size was unbounded: one cached ANY or TXT answer
can be tens of kilobytes, so 500k entries is anywhere from 150MB to several GB
depending on what the traffic asked for.
- api.pprof mounts net/http/pprof on the admin listener. The pprof handlers sit
on the app-level mux, not inside the API's own handler, so they would bypass
the auth middleware entirely; the option is therefore refused unless every
admin address is loopback. Profiling means port-forwarding, so this is safe
by construction rather than by policy, and cmdline cannot leak an argument
that happens to be a key.
- serveUDP was calling net.ResolveUDPAddr per packet. The peer already is a
*net.UDPAddr; that call builds a string, re-parses the port and allocates on
the busiest path in the process.
Also fixes a flaky test: TestParallelPolicyAnswersFromTheFastestUpstream
asserted the slow upstreams were hit, but the fan-out cancels on the first
answer, so whether they were dispatched before cancellation is a real race. It
now asserts the answer came from the fast upstream and that nothing waited.
mats
developer