multi: support config bitcoind fee estimate mode

chainregistry.go

@@ -343,7 +343,8 @@ func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
 			HTTPPostMode:         true,
 		}
 		if cfg.Bitcoin.Active && !cfg.Bitcoin.RegTest {
-			ltndLog.Infof("Initializing bitcoind backed fee estimator")
+			ltndLog.Infof("Initializing bitcoind backed fee estimator in "+
+				"%s mode", bitcoindMode.EstimateMode)
 
 			// Finally, we'll re-initialize the fee estimator, as
 			// if we're using bitcoind as a backend, then we can
@@ -351,7 +352,8 @@ func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
 			// coded value.
 			fallBackFeeRate := chainfee.SatPerKVByte(25 * 1000)
 			cc.feeEstimator, err = chainfee.NewBitcoindEstimator(
-				*rpcConfig, fallBackFeeRate.FeePerKWeight(),
+				*rpcConfig, bitcoindMode.EstimateMode,
+				fallBackFeeRate.FeePerKWeight(),
 			)
 			if err != nil {
 				return nil, err
@@ -360,7 +362,8 @@ func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
 				return nil, err
 			}
 		} else if cfg.Litecoin.Active && !cfg.Litecoin.RegTest {
-			ltndLog.Infof("Initializing litecoind backed fee estimator")
+			ltndLog.Infof("Initializing litecoind backed fee estimator in "+
+				"%s mode", bitcoindMode.EstimateMode)
 
 			// Finally, we'll re-initialize the fee estimator, as
 			// if we're using litecoind as a backend, then we can
@@ -368,7 +371,8 @@ func newChainControlFromConfig(cfg *config, chanDB *channeldb.DB,
 			// coded value.
 			fallBackFeeRate := chainfee.SatPerKVByte(25 * 1000)
 			cc.feeEstimator, err = chainfee.NewBitcoindEstimator(
-				*rpcConfig, fallBackFeeRate.FeePerKWeight(),
+				*rpcConfig, bitcoindMode.EstimateMode,
+				fallBackFeeRate.FeePerKWeight(),
 			)
 			if err != nil {
 				return nil, err

config.go

@@ -152,6 +152,11 @@ var (
 	defaultTorSOCKS   = net.JoinHostPort("localhost", strconv.Itoa(defaultTorSOCKSPort))
 	defaultTorDNS     = net.JoinHostPort(defaultTorDNSHost, strconv.Itoa(defaultTorDNSPort))
 	defaultTorControl = net.JoinHostPort("localhost", strconv.Itoa(defaultTorControlPort))
+
+	// bitcoindEsimateModes defines all the legal values for bitcoind's
+	// estimatesmartfee RPC call.
+	defaultBitcoindEstimateMode = "CONSERVATIVE"
+	bitcoindEstimateModes       = [2]string{"ECONOMICAL", defaultBitcoindEstimateMode}
 )
 
 type chainConfig struct {
@@ -200,6 +205,7 @@ type bitcoindConfig struct {
 	RPCPass        string `long:"rpcpass" default-mask:"-" description:"Password for RPC connections"`
 	ZMQPubRawBlock string `long:"zmqpubrawblock" description:"The address listening for ZMQ connections to deliver raw block notifications"`
 	ZMQPubRawTx    string `long:"zmqpubrawtx" description:"The address listening for ZMQ connections to deliver raw transaction notifications"`
+	EstimateMode   string `long:"estimatemode" description:"The fee estimate mode. Must be either ECONOMICAL or CONSERVATIVE."`
 }
 
 type autoPilotConfig struct {
@@ -386,6 +392,7 @@ func loadConfig() (*config, error) {
 		BitcoindMode: &bitcoindConfig{
 			Dir:          defaultBitcoindDir,
 			RPCHost:      defaultRPCHost,
+			EstimateMode: defaultBitcoindEstimateMode,
 		},
 		Litecoin: &chainConfig{
 			MinHTLCIn:     defaultLitecoinMinHTLCInMSat,
@@ -403,6 +410,7 @@ func loadConfig() (*config, error) {
 		LitecoindMode: &bitcoindConfig{
 			Dir:          defaultLitecoindDir,
 			RPCHost:      defaultRPCHost,
+			EstimateMode: defaultBitcoindEstimateMode,
 		},
 		UnsafeDisconnect:   true,
 		MaxPendingChannels: DefaultMaxPendingChannels,
@@ -1211,6 +1219,15 @@ func parseRPCParams(cConfig *chainConfig, nodeConfig interface{}, net chainCode,
 			}
 		}
 
+		// Ensure that if the estimate mode is set, that it is a legal
+		// value.
+		if conf.EstimateMode != "" {
+			err := checkEstimateMode(conf.EstimateMode)
+			if err != nil {
+				return err
+			}
+		}
+
 		// If all of RPCUser, RPCPass, ZMQBlockHost, and ZMQTxHost are
 		// set, we assume those parameters are good to use.
 		if conf.RPCUser != "" && conf.RPCPass != "" &&
@@ -1448,6 +1465,18 @@ func checkZMQOptions(zmqBlockHost, zmqTxHost string) error {
 	return nil
 }
 
+// checkEstimateMode ensures that the provided estimate mode is legal.
+func checkEstimateMode(estimateMode string) error {
+	for _, mode := range bitcoindEstimateModes {
+		if estimateMode == mode {
+			return nil
+		}
+	}
+
+	return fmt.Errorf("estimatemode must be one of the following: %v",
+		bitcoindEstimateModes[:])
+}
+
 // normalizeNetwork returns the common name of a network type used to create
 // file paths. This allows differently versioned networks to use the same path.
 func normalizeNetwork(network string) string {

docs/INSTALL.md

@@ -208,6 +208,7 @@ bitcoind:
       --bitcoind.rpcpass=                                     Password for RPC connections
       --bitcoind.zmqpubrawblock=                              The address listening for ZMQ connections to deliver raw block notifications
       --bitcoind.zmqpubrawtx=                                 The address listening for ZMQ connections to deliver raw transaction notifications
+      --bitcoind.estimatemode=                                The fee estimate mode. Must be either "ECONOMICAL" or "CONSERVATIVE". (default: CONSERVATIVE)
 ```
 
 ## Using btcd
@@ -367,6 +368,9 @@ lnd --bitcoin.active --bitcoin.testnet --debuglevel=debug --bitcoin.node=bitcoin
   the default `bitcoind` settings, having more than one instance of `lnd`, or
   `lnd` plus any application that consumes the RPC could cause `lnd` to miss
   crucial updates from the backend.
+- The default fee estimate mode in `bitcoind` is CONSERVATIVE. You can set
+  `bitcoind.estimatemode=ECONOMICAL` to change it into ECONOMICAL. Futhermore,
+  if you start `bitcoind` in `regtest`, this configuration won't take any effect.
 
 
 # Creating a wallet

lnwallet/chainfee/estimator.go

@@ -286,6 +286,11 @@ type BitcoindEstimator struct {
 	// through the network.
 	minFeePerKW SatPerKWeight
 
+	// feeMode is the estimate_mode to use when calling "estimatesmartfee".
+	// It can be either "ECONOMICAL" or "CONSERVATIVE", and it's default
+	// to "CONSERVATIVE".
+	feeMode string
+
 	bitcoindConn *rpcclient.Client
 }
 
@@ -294,7 +299,7 @@ type BitcoindEstimator struct {
 // bitcoind node, and also a fall back fee rate. The fallback fee rate is used
 // in the occasion that the estimator has insufficient data, or returns zero
 // for a fee estimate.
-func NewBitcoindEstimator(rpcConfig rpcclient.ConnConfig,
+func NewBitcoindEstimator(rpcConfig rpcclient.ConnConfig, feeMode string,
 	fallBackFeeRate SatPerKWeight) (*BitcoindEstimator, error) {
 
 	rpcConfig.DisableConnectOnNew = true
@@ -309,6 +314,7 @@ func NewBitcoindEstimator(rpcConfig rpcclient.ConnConfig,
 	return &BitcoindEstimator{
 		fallbackFeePerKW: fallBackFeeRate,
 		bitcoindConn:     chainConn,
+		feeMode:          feeMode,
 	}, nil
 }
 
@@ -403,9 +409,15 @@ func (b *BitcoindEstimator) fetchEstimate(confTarget uint32) (SatPerKWeight, err
 	if err != nil {
 		return 0, err
 	}
-	// TODO: Allow selection of economical/conservative modifiers.
+
+	// The mode must be either ECONOMICAL or CONSERVATIVE.
+	mode, err := json.Marshal(b.feeMode)
+	if err != nil {
+		return 0, err
+	}
+
 	resp, err := b.bitcoindConn.RawRequest(
-		"estimatesmartfee", []json.RawMessage{target},
+		"estimatesmartfee", []json.RawMessage{target, mode},
 	)
 	if err != nil {
 		return 0, err

sample-lnd.conf

@@ -230,6 +230,9 @@ bitcoin.node=btcd
 ; bitcoind.zmqpubrawblock=tcp://127.0.0.1:28332
 ; bitcoind.zmqpubrawtx=tcp://127.0.0.1:28333
 
+; Fee estimate mode for bitcoind. It must be either "ECONOMICAL" or "CONSERVATIVE".
+; If unset, the default value is "CONSERVATIVE".
+; bitcoind.estimatemode=CONSERVATIVE
 
 [neutrino]
 
@@ -311,6 +314,9 @@ litecoin.node=ltcd
 ; litecoind.zmqpubrawblock=tcp://127.0.0.1:28332
 ; litecoind.zmqpubrawtx=tcp://127.0.0.1:28333
 
+; Fee estimate mode for litecoind. It must be either "ECONOMICAL" or "CONSERVATIVE".
+; If unset, the default value is "CONSERVATIVE".
+; litecoind.estimatemode=CONSERVATIVE
 
 [autopilot]