rpcperms: add ctx and cancel to InterceptorChain

lnd.go

@@ -322,7 +322,7 @@ func Main(cfg *Config, lisCfg ListenerCfg, implCfg *ImplementationCfg,
 	interceptorChain := rpcperms.NewInterceptorChain(
 		rpcsLog, cfg.NoMacaroons, cfg.RPCMiddleware.Mandatory,
 	)
-	if err := interceptorChain.Start(); err != nil {
+	if err := interceptorChain.Start(ctx); err != nil {
 		return mkErr("error starting interceptor chain: %v", err)
 	}
 	defer func() {

rpcperms/interceptor.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/btcsuite/btclog/v2"
 	grpc_middleware "github.com/grpc-ecosystem/go-grpc-middleware"
+	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/macaroons"
 	"github.com/lightningnetwork/lnd/monitoring"
@@ -189,7 +190,7 @@ type InterceptorChain struct {
 	// middleware crashes.
 	mandatoryMiddleware []string
 
-	quit chan struct{}
+	cancel fn.Option[context.CancelFunc]
 	sync.RWMutex
 }
 
@@ -209,15 +210,17 @@ func NewInterceptorChain(log btclog.Logger, noMacaroons bool,
 		rpcsLog:                   log,
 		registeredMiddlewareNames: make(map[string]int),
 		mandatoryMiddleware:       mandatoryMiddleware,
-		quit:                      make(chan struct{}),
 	}
 }
 
 // Start starts the InterceptorChain, which is needed to start the state
 // subscription server it powers.
-func (r *InterceptorChain) Start() error {
+func (r *InterceptorChain) Start(ctx context.Context) error {
 	var err error
 	r.started.Do(func() {
+		_, cancel := context.WithCancel(ctx)
+		r.cancel = fn.Some(cancel)
+
 		err = r.ntfnServer.Start()
 	})
 
@@ -228,7 +231,7 @@ func (r *InterceptorChain) Start() error {
 func (r *InterceptorChain) Stop() error {
 	var err error
 	r.stopped.Do(func() {
-		close(r.quit)
+		r.cancel.WhenSome(func(fn context.CancelFunc) { fn() })
 		err = r.ntfnServer.Stop()
 	})
 
@@ -368,9 +371,6 @@ func (r *InterceptorChain) SubscribeState(_ *lnrpc.SubscribeStateRequest,
 				return nil
 			}
 			return stream.Context().Err()
-
-		case <-r.quit:
-			return fmt.Errorf("server exiting")
 		}
 	}
 }