feat: wire API queue projection to Redis

server/api/service.go

@@ -34,6 +34,13 @@ type QueueBackend interface {
 	Get(context.Context, string, string, time.Time) (domain.QueueTicket, error)
 }
 
+// CandidateIndex is a transient projection of durable queue ownership. Index
+// failures must never change the result of an already successful mutation.
+type CandidateIndex interface {
+	Upsert(context.Context, domain.Candidate) error
+	Remove(context.Context, string) error
+}
+
 type SessionBackend interface {
 	Authenticate(context.Context, string, string, time.Time) (domain.Session, error)
 }
@@ -77,6 +84,7 @@ type Service struct {
 	Candidate       CandidateProvider
 	CandidateV2     CandidateProviderV2
 	QueueBackend    QueueBackend
+	CandidateIndex  CandidateIndex
 	Probe           ProbeProvider
 	Assignment      AssignmentProvider
 	Now             func() time.Time
@@ -220,6 +228,7 @@ func (s *Service) queueCreate(w http.ResponseWriter, r *http.Request) {
 			writeDomainError(w, err)
 			return
 		}
+		s.projectCandidate(r.Context(), ticket)
 		s.publishTicketEvent(ticket, now)
 		writeJSON(w, http.StatusCreated, toQueueResponse(ticket))
 		return
@@ -249,10 +258,23 @@ func (s *Service) queueCreate(w http.ResponseWriter, r *http.Request) {
 		writeDomainError(w, err)
 		return
 	}
+	s.projectCandidate(r.Context(), ticket)
 	s.publishTicketEvent(ticket, now)
 	writeJSON(w, http.StatusCreated, toQueueResponse(ticket))
 }
 
+func (s *Service) projectCandidate(ctx context.Context, ticket domain.QueueTicket) {
+	if s.CandidateIndex != nil {
+		_ = s.CandidateIndex.Upsert(ctx, ticket.Candidate)
+	}
+}
+
+func (s *Service) removeCandidate(ctx context.Context, ticketID string) {
+	if s.CandidateIndex != nil {
+		_ = s.CandidateIndex.Remove(ctx, ticketID)
+	}
+}
+
 func (s *Service) contractQueueCreate(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodPost {
 		s.queueCreate(w, r)
@@ -391,6 +413,11 @@ func (s *Service) queueMutation(w http.ResponseWriter, r *http.Request) {
 		writeDomainError(w, err)
 		return
 	}
+	if ticket.State == domain.Cancelled {
+		s.removeCandidate(r.Context(), ticket.TicketID)
+	} else {
+		s.projectCandidate(r.Context(), ticket)
+	}
 	s.publishTicketEvent(ticket, now)
 	if r.Header.Get("X-Contract-Delete") == "1" {
 		w.WriteHeader(http.StatusNoContent)