The Deployment runs two replicas, but WebSocket subscribers live only in
each process's in-memory hub. Every replica races to read the same
global unpublished outbox rows, and publishing succeeded even when the
winning replica held no matching local subscriber -- that replica then
set the single global published_at. A client connected to the other
replica never received the event, and delivery degraded further with
each replica added. REST recovery eventually converged, but short-lived
proposal transitions could be observed late or not at all.
Publish committed events through PostgreSQL LISTEN/NOTIFY so the replica
that owns the subscriber's connection delivers it, regardless of which
replica drained the row. The listener holds its own pgx connection --
LISTEN is session state, so a pooled database/sql connection cannot
carry it -- and reconnects with backoff, since losing it would silently
downgrade that replica's subscribers to REST-only recovery.
The fan-out is optional: without EventFanout configured, behaviour is
unchanged local-hub publication, which stays correct for a single
replica and for tests. Only outbox-sourced events are routed through it;
the in-request-path publishes remain local, as those are a latency
optimisation for the caller's own connection.
Fan-out needs a wire shape of its own because ControlPlaneEvent hides
PlayerID from clients, and the recipient is exactly what a peer replica
needs to route on.
banned_until and ban_reason have been in the schema since 0001, but no
production query ever read them -- grepping the tree found no reference
outside the migration itself. The only ban check was an in-memory map on
domain.TicketVerifier used by domain tests. Once real Steam login is
wired, a banned identity would keep full access through every existing
session until expiry and could obtain new ones.
Make the ban part of the durable authentication transaction rather than
a policy each login adapter must remember to re-implement:
- Session issuance inserts only when the identity exists and has no
active ban, so a banned player cannot mint a session.
- Authentication joins the identity and rejects an active ban on every
request, so a ban takes effect immediately on every replica rather
than at session expiry.
- ApplyIdentityBan sets the ban and revokes that identity's sessions in
one serializable transaction, closing the window where the ban is
durable but another replica still accepts an issued session.
Bans are time-bounded and clearing one does not resurrect sessions the
ban revoked.
Tests cover enforcement across two independently constructed stores
standing in for two replicas, expiry/unban semantics, and -- separately,
because revocation would otherwise mask it -- that a ban applied without
revoking anything still blocks the next request.
Both playlists shared one hash and sorted set, causing two independent
failures.
Starvation: Snapshot performed an unbounded ZRANGEBYSCORE and HMGET,
decoded the whole queue, and the matcher then truncated to its candidate
limit *before* filtering by playlist. A large casual prefix could
therefore leave the ranked worker with zero candidates indefinitely even
while ranked tickets were queued further down the set.
Mutual erasure: each matcher captured only its own playlist as the
durable source, but Rebuild replaced the shared keys, so a casual repair
wiped ranked projections and vice versa.
Namespace the keys per playlist, push the limit into Redis (LIMIT 0 N)
so reads no longer scale with total queue depth, and scope Rebuild to
one namespace. Rebuild now rejects a candidate whose playlist does not
match the namespace, which would reintroduce the starvation. Upsert
derives the namespace from the candidate; Remove takes the playlist,
since a ticket ID alone no longer identifies its namespace.
Add tests for a 300-deep casual backlog not starving ranked, for neither
playlist's rebuild erasing the other, and for the limit being applied
without losing enqueue ordering.
The candidate projection selected only from queue_tickets and its scan
never set Candidate.Rating, so every PostgreSQL-sourced ranked candidate
arrived with Go's zero value. Rating tolerance, selection scoring and
team partitioning all read that field, so ranked matchmaking treated a
900-rated player as identical to a 2100-rated one. Unit tests missed it
because they construct candidates with ratings already populated.
Join the ratings table, defaulting to domain.GlickoInitialRating for a
player with no ratings row yet -- a genuinely new profile, matching the
column default.
Fix the same defect on the Redis path too, which is reached differently:
the projection is seeded from the candidate CreateQueueTicket builds,
not from the candidate query, and that candidate also left Rating unset.
Resolve the rating inside the enqueue transaction so both projections
agree on one authoritative value. The rating is never client-supplied.
Add a store-backed test with deliberately distant ratings (900 vs 2100)
plus an unrated player, asserting both projections and that the spread
survives. Verified it fails without the fix.
ApplyInitialConnectPlan wrote a payload of {match_id,state,action},
omitting event, revision, resource_id, occurred_at and player_ids --
every field deliverStateOutboxEvent requires. Delivery rejected the row,
dispatch returned on the first error so it was never acknowledged, and
because reads are ordered oldest-first it was retried ahead of every
later state_changed event on every 100ms poll. One initial-connect
transition therefore blocked lifecycle delivery for all matches, not
just its own.
Two independent fixes, since either alone leaves the system fragile:
Build envelopes through one validating helper (MarshalOutboxEnvelope)
and convert all five writers to it. A writer that omits a required
field now fails its own transaction instead of committing a row that
can only ever poison the queue. The helper takes revision as int64 so
the -1 "nothing matched" sentinel some CTEs return surfaces as an error
rather than wrapping to a huge uint64.
Make dispatch resilient regardless: a delivery failure is now counted
against that row and the batch continues, with the row dead-lettered
after MaxOutboxDeliveryAttempts so a poison event degrades to one lost
notification instead of a stalled queue. Ordering within an aggregate
is still honoured -- later events of a failed match are deferred, so no
client observes that match's newer state before its older state. An ack
failure still stops the batch, being a database rather than a payload
problem.
Initial-connect events now address every participant, not just the
connected ones: a no-show needs to learn their ticket was failed and a
penalty applied.
test_contracts.py required operation ID `recordPlayerConnected`, but
openapi.json names that endpoint `claimPlayerConnection` — the accurate
name, since POST /servers/{id}/connect claims a connection lease and
returns a generation. Align the test on the document and assert the set
difference, so a future mismatch names the missing operation instead of
reporting "False is not true".
test_observability_manifests.py copied only two of the four files the
checker reads, so it died on a missing kustomization.yaml before ever
reaching the mutated namespace. Copy the full fixture, split the
namespace and scrape-path mutations into separate cases so either
defect produces its own diagnostic, and add an unmutated-copy case so a
broken fixture can't make the mutation cases pass vacuously.
Neither suite was invoked by any Make target or workflow, which is why
both could sit red. Add them, plus test_threat_model.py, to
verify_multiplayer_local.sh.
Closes §8.43's 'version-mismatch-specific client messaging' gap. Per
the user's explicit go-ahead to design new server behavior for this
(rather than only wiring up something that already existed, the
pattern every other fix this session followed): before this, there
was no server-side protocol rejection at all. queue_create accepted
any protocol_version >= 1 unconditionally, so an outdated client could
only ever discover a mismatch by waiting in the queue forever
unmatched -- the matcher's own compatibility check requires every
formed player to share an identical protocol_version -- with no error
and no explanation given to the player.
Server: Service.MinProtocolVersion (opt-in, zero by default so every
existing caller keeps accepting protocol_version 1 unconditionally)
rejects a below-floor queue_create with 426 Upgrade Required /
client_outdated before the request ever reaches the candidate
provider. Wired via cmd/control-plane's new --min-protocol-version
flag (validated non-negative at startup).
Client: ControlPlaneClient recognises HTTPClient.RESPONSE_UPGRADE_REQUIRED
on queue_create specifically and sets a distinct 'Your client is out
of date -- please update to continue searching' message instead of
the server's raw generic error string, and clears _last_queue_create
so can_retry_queue_create() never offers 'Retry Search' for a failure
that retrying with the same build can never fix.
Verified: go build/vet/test -race clean across every server package.
TestQueueCreateEnforcesMinProtocolVersion covers below-floor rejection
(candidate provider never reached), exactly-at-floor acceptance, and
the error body naming client_outdated; TestQueueCreateMinProtocolVersionZeroIsDisabled
proves the opt-in default doesn't change behavior for every existing
caller. Godot: test_outdated_client_receives_a_distinct_message_and_no_retry_offer
proves the distinct message and suppressed retry offer. Full Godot
suite (217/217, 0 failed, no crash), full make verify-multiplayer-local
gate, zero new crash reports.
Closes part of the 'live Redis failover' gap in §8.46, found by
reproducing a genuine Redis outage (not just an empty/partial cache)
against CandidateProjection.Snapshot with a killed miniredis instance.
CandidateProjection.Snapshot funnelled two different situations into
the same code path: the index erroring outright (Redis unreachable)
and the index coming back empty (ambiguous — a genuinely empty queue,
or a lost keyspace). Both went through Repair, which itself calls
Index.Rebuild — a second Redis round-trip that fails for exactly the
same reason the first one did. The result: a real Redis outage, or
the window during a failover, made Snapshot fail outright even though
PostgreSQL — the documented authoritative source everywhere
(RedisCandidateIndex's own comment, cmd/matcher, cmd/control-plane's
--redis-addr help text all call it a rebuildable/optional
acceleration layer) — was completely healthy. Matchmaking would stop
entirely on a Redis outage despite the architecture explicitly not
requiring that.
Snapshot now falls back to serving Source (PostgreSQL) directly
whenever the index errors OR comes back empty, and only best-effort
attempts to repopulate Redis afterward — that attempt's outcome is
deliberately ignored, since a caller must never be denied service
just because the opportunistic rebuild also hit the same down Redis.
Snapshot still fails when Source itself is unavailable; the fallback
is not unconditional.
Verified: reproduced the bug first (killed-miniredis Snapshot call
failed even though Source was healthy), then fixed it. go build/vet
clean; all pre-existing store-package tests pass unmodified,
including the two live-redis:7-alpine-container tests
(TestRealRedisCandidateIndexUpsertSnapshotRemove,
TestRealRedisCandidateProjectionRepairsAfterFlush, run against a real
container and torn down after). Two new tests cover the fallback
directly (killed miniredis, Source still served, exactly one Source
call) and that the fallback is not unconditional (both Redis and
Source down still fails). Full go test ./... -race clean across
every server package.
Remaining: live matcher-worker-under-load-during-failover integration,
i.e. running the actual matcher process against a real Redis that
goes down mid-run under concurrent load, not just this unit-level
reproduction.
Closes the 'innocent-ticket restoration' gap noted in §8.20 and found
by re-examining §8.16's matcher worker. domain.FormFromQueue's anchor
is always the single oldest candidate, deterministically. If
domain.PrepareProposal then rejected that exact formation for a
reason specific to those particular players — mismatched protocol,
incomplete ranked identity metadata, a duplicate-SteamID pair, ranked
admission generally — RunOnce returned immediately and the next
matcher interval reproduced the identical formation and failed again.
Forever: nothing in the queue ever changes, so the same doomed anchor
group would be retried every single pass, permanently head-of-line-
blocking every other waiting player behind it too, not just the
players actually at fault. This is worse than the already-fixed
no-common-region crash-loop (§8.16) — that one killed the process;
this one fails silently and just never matches anyone again.
Two changes, both required together:
1. RunOnce now excludes a failed formation's players and retries
with the remaining candidate pool, bounded to 8 attempts per pass.
A batch with no viable formation at all (the pre-existing
no-common-region case) still returns immediately, since retrying
that can't help.
2. That fix was inert without a second one: RunOnce was asking
Source for exactly w.Size candidates, so after excluding one
failed formation's players there was nothing left to retry
against. domain.SelectCandidates was always designed to search a
larger pool (anchor plus an arbitrary remainder, widening through
it) — the call site just never gave it one. RunOnce now requests
up to 10x w.Size, capped at 200.
Verified: go build/vet/test -race clean across every server package.
Three new matcher tests cover the exclusion retry (an 8-candidate
batch whose permanently-doomed oldest 4 still lets the remaining 4
form and claim, correctly excluding the doomed players from the
claimed ticket set), that exhausting every attempt surfaces the last
real error rather than a silent false/nil, and that Source is
actually asked for more than w.Size candidates — a regression guard
for exactly the companion bug above. All six pre-existing worker
tests still pass unmodified, confirming the fix preserves every prior
guarantee (mixed-playlist/duplicate-identity rejection, incomplete
batch handling, durable claim failure propagation, Run's existing
per-pass-error survival).
Closes the 'concurrent proposal-recovery expiry races' gap noted in
§8.46. GetProposal (read-side recovery) and RespondToProposal both
run the identical expiry-advance SQL in their own transaction, so any
number of them can observe the same past-expiry proposal at once —
this had never been exercised concurrently, only sequentially (the
existing late-response test drives one call at a time).
TestPostgreSQLConcurrentProposalExpiryRecoveryAppliesCooldownsExactlyOnce
races 8 concurrent GetProposal/RespondToProposal calls, each with a
distinct 'now' past the proposal window, against one proposal and
asserts: EXPIRED lands on the proposal and both tickets exactly once,
a PROPOSAL_TIMEOUT penalty lands exactly once per offending player
(not once per racing transaction), and no idempotency row survives a
closed-proposal response. The design already defends against this —
ProposalParticipantExpireSQL only ever flips a still-PENDING row
once, so a losing racer's 'now' can't match
recordProposalTimeoutCooldowns' responded_at filter — this test is
what actually proves that holds under real concurrent load rather
than by inspection.
Verified: real postgres:17-alpine container, go test -tags
integration ./store/... -run
TestPostgreSQLConcurrentProposalExpiryRecoveryAppliesCooldownsExactlyOnce
-race -count=3 clean; full -tags integration ./store/... -race run
clean; full non-integration go build/vet/test -race clean across
every server package; container removed after the run.
Closes the 'live duplicate/conflict alerting also remains' gap noted
in §8.10: a durable domain.ErrConflict/ErrResultConflict rejection on
/v1/servers/{id}/{register,connect,disconnect,shutdown,result} was
already logged as a structured 'conflict' stage event, but had no
Prometheus signal distinct from the generic 4xx-class counter, which
also catches ordinary client noise (malformed bodies, expired
tokens). A real duplicate registration, raced reconnect, or replayed
result would have been invisible to alerting until someone went
looking through logs.
observability.Metrics gains ObserveServerConflict(kind), a bounded
counter keyed to serverMutation's own five routes (an unrecognized
kind folds into "other", so a caller mistake can't grow the label
set), exported as cosmic_clash_api_server_conflicts_total. Wired at
each of serverMutation's four conflict branches in server/api/service.go.
deploy/observability/prometheus-rules.yaml adds
CosmicClashControlPlaneServerConflicts, mirroring the existing
allocator quota-denial alert shape, firing on >3 conflicts of one
kind in 15 minutes.
Verified: go build/vet/test -race clean across every server package;
new unit tests cover per-kind counting, the bounded 'other' fallback,
the counter's absence until first observed, and a nil-receiver no-op;
a service-level test proves a real register conflict is exported
through the live /metrics endpoint. scripts/verify_observability_manifests.py
passes against the edited rules file.
Remaining, and explicitly out of scope here: this alert has only been
validated statically, never against a live Prometheus/Alertmanager
firing on real traffic — that requires the same live cluster this
sandbox has never had.
Josh Creek