refactor once again

grpc_server.go

@@ -9,6 +9,7 @@ import (
 
 	messages "git.tornberg.me/go-cart-actor/proto"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/reflection"
 )
 
@@ -198,8 +199,11 @@ func (s *cartActorGRPCServer) GetState(ctx context.Context, req *messages.StateR
 
 // ControlPlane: Ping
 func (s *cartActorGRPCServer) Ping(ctx context.Context, _ *messages.Empty) (*messages.PingReply, error) {
+	// Expose cart owner cookie (first-touch owner = this host) for HTTP gateways translating gRPC metadata.
+	// Gateways that propagate Set-Cookie can help establish sticky sessions at the edge.
+	_ = grpc.SendHeader(ctx, metadata.Pairs("set-cookie", fmt.Sprintf("cartowner=%s; Path=/; HttpOnly", s.syncedPool.Hostname())))
 	return &messages.PingReply{
-		Host:     s.syncedPool.Hostname,
+		Host:     s.syncedPool.Hostname(),
 		UnixTime: time.Now().Unix(),
 	}, nil
 }
@@ -214,7 +218,7 @@ func (s *cartActorGRPCServer) Negotiate(ctx context.Context, req *messages.Negot
 		}
 	}
 	// This host
-	hostSet[s.syncedPool.Hostname] = struct{}{}
+	hostSet[s.syncedPool.Hostname()] = struct{}{}
 	// Known remotes
 	s.syncedPool.mu.RLock()
 	for h := range s.syncedPool.remoteHosts {