cln+lnd: liveness check on swapout

This change causes the liquid daemon to be monitored
for dead or alive at the start of the swapout execution.
Previously, at the start of a swapout,
it would succeed even if the liquid daemon was not running,
If a subsequent process required the liquid daemon,
 an error would occur.

In addition, cross-checking by interceptors and hooks
 has been discontinued.
This is because hooks by glightning are unstable and currently only
 swapout needs to be monitored for life and death.

clightning/clightning.go

@@ -131,7 +131,6 @@ func NewClightningClient(ctx context.Context) (*ClightningClient, <-chan interfa
 	cl.Plugin = glightning.NewPlugin(cl.onInit)
 	err := cl.Plugin.RegisterHooks(&glightning.Hooks{
 		CustomMsgReceived: cl.OnCustomMsg,
-		RpcCommand:        cl.OnRPCCommand,
 	})
 	if err != nil {
 		return nil, nil, err
@@ -413,25 +412,6 @@ type Message struct {
 	Message string `json:"message"`
 }
 
-func (cl *ClightningClient) OnRPCCommand(event *glightning.RpcCommandEvent) (*glightning.RpcCommandResponse, error) {
-	if cl.gbitcoin != nil {
-		ok, err := cl.gbitcoin.Ping()
-		if err != nil || !ok {
-			log.Infof("trying to send command %s, but failed to connect: %v", event.Cmd.MethodName, err)
-			return event.ReturnError("bitcoin_unavailable", -1)
-		}
-	}
-
-	if cl.liquidWallet != nil {
-		ok, err := cl.liquidWallet.Ping()
-		if err != nil || !ok {
-			log.Infof("trying to send command %s, but failed to connect: %v", event.Cmd.MethodName, err)
-			return event.ReturnError("liquid_unavailable", -1)
-		}
-	}
-	return event.Continue(), nil
-}
-
 // AddMessageHandler adds a listener for incoming peermessages
 func (cl *ClightningClient) AddMessageHandler(f func(peerId string, msgType string, payload []byte) error) {
 	cl.msgHandlers = append(cl.msgHandlers, f)

clightning/clightning_commands.go

@@ -247,6 +247,9 @@ func (l *SwapOut) Call() (jrpc2.Result, error) {
 		if !l.cl.swaps.LiquidEnabled {
 			return nil, errors.New("liquid swaps are not enabled")
 		}
+		if ok, perr := l.cl.liquidWallet.Ping(); perr != nil || !ok {
+			return nil, fmt.Errorf("liquid wallet not reachable: %v", perr)
+		}
 
 	} else if strings.Compare(l.Asset, "btc") == 0 {
 		if !l.cl.swaps.BitcoinEnabled {

cmd/peerswaplnd/peerswapd/main.go

@@ -397,9 +397,7 @@ func run() error {
 	}
 	defer lis.Close()
 
-	grpcSrv := grpc.NewServer(
-		grpc.UnaryInterceptor(livenessCheckInterceptor(liquidRpcWallet)),
-	)
+	grpcSrv := grpc.NewServer()
 
 	peerswaprpc.RegisterPeerSwapServer(grpcSrv, peerswaprpcServer)
 
@@ -441,23 +439,6 @@ func run() error {
 	return nil
 }
 
-func livenessCheckInterceptor(liquidWallet wallet.Wallet) grpc.UnaryServerInterceptor {
-	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
-		if liquidWallet != nil {
-			ok, err := liquidWallet.Ping()
-			if err != nil {
-				log.Infof("trying to send command %s, but failed to connect: %v", info.FullMethod, err)
-				return nil, fmt.Errorf("liquid backend not reachable: %v", err)
-			}
-			if !ok {
-				log.Infof("trying to send command %s, but failed to connect", info.FullMethod)
-				return nil, errors.New("liquid backend not reachable")
-			}
-		}
-		return handler(ctx, req)
-	}
-}
-
 func getBitcoinChain(ctx context.Context, li lnrpc.LightningClient) (*chaincfg.Params, error) {
 	gi, err := li.GetInfo(ctx, &lnrpc.GetInfoRequest{})
 	if err != nil {

peerswaprpc/server.go

@@ -114,6 +114,9 @@ func (p *PeerswapServer) SwapOut(ctx context.Context, request *SwapOutRequest) (
 		if !p.swaps.LiquidEnabled {
 			return nil, errors.New("liquid swaps are not enabled")
 		}
+		if ok, perr := p.liquidWallet.Ping(); perr != nil || !ok {
+			return nil, fmt.Errorf("liquid wallet not reachable: %v", perr)
+		}
 
 	} else if strings.Compare(request.Asset, "btc") == 0 {
 		if !p.swaps.BitcoinEnabled {