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.
The cache snapshot never loaded, so every restart was a cold cache. Snapshot
packed the whole key while Load decoded the record header out of the key's
remainder instead of the value, so every entry was skipped. The two sides are
now an explicit encodeRecord/decodeRecord pair with a version byte and a CRC-32C
trailer, so a future format change is detected instead of silently misparsed.
Load also drops entries that are already past ExpiresAt and rewrites the TTL to
the time actually left, so a served TTL never jumps back up across a restart.
Blocklist, all six gaps the failing tests were pointing at: a leading UTF-8 BOM
is stripped, "!allow example.com" works, SourceMeta exists for a source that
only ever contributed a rule, Pattern() reports the bare name again (the new
WireName() produces the wildcard form for the API), an RPZ record with no
explicit TTL inherits the zone default instead of whatever the reader left in
the RR, a hosts line with no address in the first field says so, and the
adblock parser handles CRLF and adblock-flavoured lines pasted into a plain
list. TestHolderSwapIsAtomic was asserting the wrong invariant — the swap was
always atomic, a name blocked by the old set is legitimately unblocked by the
new one.
Tests added for acl and resolver, both of which turned up real bugs:
- a PTR suffix matched across label boundaries, so a group scoped to
example.com. also swallowed ample.com. and notexample.com. — a client could
land in a group it does not belong to;
- the "*" catch-all was dropped from the rendered domain patterns, so the
engine's per-query recompile lost the "everything" case;
- Upstream.Success never closed an open breaker, so a recovered upstream stayed
excluded for the full cooldown;
- Exchange fanned out in parallel even under policy: failover.
Deploy set: go.mod requires Go 1.27.1 but CI pinned 1.23 and the Dockerfile
pinned golang:1.23-alpine, so neither could have built. The Dockerfile also
copied the source tree after the console bundle, which clobbered it.
The k8s set asked for hostNetwork with two replicas, but the server never sets
SO_REUSEPORT, so the second pod could not bind :53 and would crash-loop. It now
runs without hostNetwork behind a LoadBalancer Service, with a separate
ClusterIP Service for the Ingress (a headless Service cannot back one), a
ServiceAccount, an API-key Secret, per-pod PVCs, and a kustomization. The HPA
is gone: it cannot drive a StatefulSet. To let the API key come from that
Secret, config.Load now expands ${VAR} / ${VAR:-default} / ${NAME-default} and
fails to start on an unset variable with no default, so a missing secret is a
crash loop rather than an unauthenticated console. Expansion skips YAML
comments, so documenting ${VAR} in the ConfigMap does not break the file.
Verified: gofmt, go build, go vet clean; go test -race ./internal/... green
(acl, app, blocklist, cache, config, resolver, zonefile).
- cache.Entry.Hits and LRU.perShard become atomics; SetCapacity now evicts
down to the new budget; packKey fully qualifies names before packing
- resolver.Pool rewritten copy-on-write (atomic.Pointer to an immutable
state); Upstream is immutable with shared *upstreamStats, so health
survives a Rebind and the query path stops racing the config hook
- Pool.Exchange no longer marks a dead upstream healthy: Success was
called before the error check, so the breaker never tripped
- qlog live ring publishes through atomic pointers
- blocklist.Holder.Get nil-safe; Builder lists each source once
- web: fix toast(string) misuse that rendered empty mutation toasts
- add unit tests for cache (with benchmarks) and zonefile
- STATUS.md: green -race integration suite, remaining failures and the
broken bbolt snapshot round trip documented
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