lit: use db.Store interface instead of raw DB pointer

Give the sessionRpcServer access to the session store via the
session.Store interface instead of the raw DB pointer. This will make it
possible to swop out the implementation (which is currently bbolt) with
something else such as a SQL implementation. We move the responsibility
of closing the DB to the main LiT server.

Author: ellemouton

session_rpcserver.go

@@ -58,7 +58,7 @@ type sessionRpcServer struct {
 // sessionRpcServerConfig holds the values used to configure the
 // sessionRpcServer.
 type sessionRpcServerConfig struct {
-	db                      *session.BoltStore
+	db                      session.Store
 	basicAuth               string
 	grpcOptions             []grpc.ServerOption
 	registerGrpcServers     func(server *grpc.Server)
@@ -175,10 +175,6 @@ func (s *sessionRpcServer) start(ctx context.Context) error {
 func (s *sessionRpcServer) stop() error {
 	var returnErr error
 	s.stopOnce.Do(func() {
-		if err := s.cfg.db.Close(); err != nil {
-			log.Errorf("Error closing session DB: %v", err)
-			returnErr = err
-		}
 		s.sessionServer.Stop()
 
 		close(s.quit)

terminal.go

@@ -1457,6 +1457,13 @@ func (g *LightningTerminal) shutdownSubServers() error {
 		}
 	}
 
+	if g.sessionDB != nil {
+		if err := g.sessionDB.Close(); err != nil {
+			log.Errorf("Error closing session DB: %v", err)
+			returnErr = err
+		}
+	}
+
 	if g.lndClient != nil {
 		g.lndClient.Close()
 	}