multi: make remote signer RPC timeout configurable

config.go

@@ -579,7 +579,9 @@ func DefaultConfig() Config {
 		ChannelCommitInterval:   defaultChannelCommitInterval,
 		ChannelCommitBatchSize:  defaultChannelCommitBatchSize,
 		CoinSelectionStrategy:   defaultCoinSelectionStrategy,
-		RemoteSigner:            &lncfg.RemoteSigner{},
+		RemoteSigner: &lncfg.RemoteSigner{
+			Timeout: lncfg.DefaultRemoteSignerRPCTimeout,
+		},
 	}
 }
 
@@ -1554,6 +1556,7 @@ func ValidateConfig(cfg Config, interceptor signal.Interceptor, fileParser,
 		cfg.Cluster,
 		cfg.HealthChecks,
 		cfg.RPCMiddleware,
+		cfg.RemoteSigner,
 	)
 	if err != nil {
 		return nil, err

config_builder.go

@@ -688,7 +688,6 @@ func (d *RPCSignerWalletImpl) BuildChainControl(
 	rpcKeyRing, err := rpcwallet.NewRPCKeyRing(
 		baseKeyRing, walletController,
 		d.DefaultWalletImpl.cfg.RemoteSigner, walletConfig.CoinType,
-		rpcwallet.DefaultRPCTimeout,
 	)
 	if err != nil {
 		err := fmt.Errorf("unable to create RPC remote signing wallet "+

lncfg/remotesigner.go

@@ -1,9 +1,36 @@
 package lncfg
 
+import (
+	"fmt"
+	"time"
+)
+
+const (
+	// DefaultRemoteSignerRPCTimeout is the default timeout that is used
+	// when forwarding a request to the remote signer through RPC.
+	DefaultRemoteSignerRPCTimeout = 5 * time.Second
+)
+
 // RemoteSigner holds the configuration options for a remote RPC signer.
 type RemoteSigner struct {
-	Enable       bool   `long:"enable" description:"Use a remote signer for signing any on-chain related transactions or messages. Only recommended if local wallet is initialized as watch-only. Remote signer must use the same seed/root key as the local watch-only wallet but must have private keys."`
+	Enable       bool          `long:"enable" description:"Use a remote signer for signing any on-chain related transactions or messages. Only recommended if local wallet is initialized as watch-only. Remote signer must use the same seed/root key as the local watch-only wallet but must have private keys."`
-	RPCHost      string `long:"rpchost" description:"The remote signer's RPC host:port"`
+	RPCHost      string        `long:"rpchost" description:"The remote signer's RPC host:port"`
-	MacaroonPath string `long:"macaroonpath" description:"The macaroon to use for authenticating with the remote signer"`
+	MacaroonPath string        `long:"macaroonpath" description:"The macaroon to use for authenticating with the remote signer"`
-	TLSCertPath  string `long:"tlscertpath" description:"The TLS certificate to use for establishing the remote signer's identity"`
+	TLSCertPath  string        `long:"tlscertpath" description:"The TLS certificate to use for establishing the remote signer's identity"`
+	Timeout      time.Duration `long:"timeout" description:"The timeout for connecting to and signing requests with the remote signer. Valid time units are {s, m, h}."`
+}
+
+// Validate checks the values configured for our remote RPC signer.
+func (r *RemoteSigner) Validate() error {
+	if !r.Enable {
+		return nil
+	}
+
+	if r.Timeout < time.Millisecond {
+		return fmt.Errorf("remote signer: timeout of %v is invalid, "+
+			"cannot be smaller than %v", r.Timeout,
+			time.Millisecond)
+	}
+
+	return nil
 }

lnwallet/rpcwallet/rpcwallet.go

@@ -31,12 +31,6 @@ import (
 	"gopkg.in/macaroon.v2"
 )
 
-const (
-	// DefaultRPCTimeout is the default timeout that is used when forwarding
-	// a request to the remote signer through RPC.
-	DefaultRPCTimeout = 5 * time.Second
-)
-
 var (
 	// ErrRemoteSigningPrivateKeyNotAvailable is the error that is returned
 	// if an operation is requested from the RPC wallet that is not
@@ -74,12 +68,11 @@ var _ lnwallet.WalletController = (*RPCKeyRing)(nil)
 // delegates any signing or ECDH operations to the remove signer through RPC.
 func NewRPCKeyRing(watchOnlyKeyRing keychain.SecretKeyRing,
 	watchOnlyWalletController lnwallet.WalletController,
-	remoteSigner *lncfg.RemoteSigner, coinType uint32,
+	remoteSigner *lncfg.RemoteSigner, coinType uint32) (*RPCKeyRing, error) {
-	rpcTimeout time.Duration) (*RPCKeyRing, error) {
 
 	rpcConn, err := connectRPC(
 		remoteSigner.RPCHost, remoteSigner.TLSCertPath,
-		remoteSigner.MacaroonPath,
+		remoteSigner.MacaroonPath, remoteSigner.Timeout,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("error connecting to the remote "+
@@ -90,7 +83,7 @@ func NewRPCKeyRing(watchOnlyKeyRing keychain.SecretKeyRing,
 		WalletController: watchOnlyWalletController,
 		watchOnlyKeyRing: watchOnlyKeyRing,
 		coinType:         coinType,
-		rpcTimeout:       rpcTimeout,
+		rpcTimeout:       remoteSigner.Timeout,
 		signerClient:     signrpc.NewSignerClient(rpcConn),
 		walletClient:     walletrpc.NewWalletKitClient(rpcConn),
 	}, nil
@@ -708,8 +701,8 @@ func (r *RPCKeyRing) remoteSign(tx *wire.MsgTx, signDesc *input.SignDescriptor,
 
 // connectRPC tries to establish an RPC connection to the given host:port with
 // the supplied certificate and macaroon.
-func connectRPC(hostPort, tlsCertPath, macaroonPath string) (*grpc.ClientConn,
+func connectRPC(hostPort, tlsCertPath, macaroonPath string,
-	error) {
+	timeout time.Duration) (*grpc.ClientConn, error) {
 
 	certBytes, err := ioutil.ReadFile(tlsCertPath)
 	if err != nil {
@@ -743,8 +736,11 @@ func connectRPC(hostPort, tlsCertPath, macaroonPath string) (*grpc.ClientConn,
 			cp, "",
 		)),
 		grpc.WithPerRPCCredentials(macCred),
+		grpc.WithBlock(),
 	}
-	conn, err := grpc.Dial(hostPort, opts...)
+	ctxt, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	conn, err := grpc.DialContext(ctxt, hostPort, opts...)
 	if err != nil {
 		return nil, fmt.Errorf("unable to connect to RPC server: %v",
 			err)

sample-lnd.conf

@@ -1253,6 +1253,9 @@ litecoin.node=ltcd
 ; The TLS certificate to use for establishing the remote signer's identity.
 ; remotesigner.tlscertpath=/path/to/remote/signer/tls.cert
 
+; The timeout for connecting to and signing requests with the remote signer.
+; Valid time units are {s, m, h}.
+; remotesigner.timeout=5s
 
 [gossip]