Merge pull request #881 from Roasbeef/autopilot-target-chan-size

funding+pilot: increase min channel size, allow specifying chan size range for autopilot

config.go

@@ -121,10 +121,11 @@ type bitcoindConfig struct {
 }
 
 type autoPilotConfig struct {
-	// TODO(roasbeef): add
-	Active      bool    `long:"active" description:"If the autopilot agent should be active or not."`
-	MaxChannels int     `long:"maxchannels" description:"The maximum number of channels that should be created"`
-	Allocation  float64 `long:"allocation" description:"The percentage of total funds that should be committed to automatic channel establishment"`
+	Active         bool    `long:"active" description:"If the autopilot agent should be active or not."`
+	MaxChannels    int     `long:"maxchannels" description:"The maximum number of channels that should be created"`
+	Allocation     float64 `long:"allocation" description:"The percentage of total funds that should be committed to automatic channel establishment"`
+	MinChannelSize int64   `long:"minchansize" description:"The smallest channel that the autopilot agent should create"`
+	MaxChannelSize int64   `long:"maxchansize" description:"The larget channel taht the autopilot agent should create"`
 }
 
 type torConfig struct {
@@ -249,8 +250,10 @@ func loadConfig() (*config, error) {
 		MaxPendingChannels: defaultMaxPendingChannels,
 		NoEncryptWallet:    defaultNoEncryptWallet,
 		Autopilot: &autoPilotConfig{
-			MaxChannels: 5,
-			Allocation:  0.6,
+			MaxChannels:    5,
+			Allocation:     0.6,
+			MinChannelSize: int64(minChanFundingSize),
+			MaxChannelSize: int64(maxFundingAmount),
 		},
 		TrickleDelay: defaultTrickleDelay,
 		Alias:        defaultAlias,
@@ -333,6 +336,42 @@ func loadConfig() (*config, error) {
 	cfg.BitcoindMode.Dir = cleanAndExpandPath(cfg.BitcoindMode.Dir)
 	cfg.LitecoindMode.Dir = cleanAndExpandPath(cfg.LitecoindMode.Dir)
 
+	// Ensure that the user didn't attempt to specify negative values for
+	// any of the autopilot params.
+	if cfg.Autopilot.MaxChannelSize < 0 {
+		str := "%s: autopilot.maxchansize must be greater than zero"
+		err := fmt.Errorf(str)
+		fmt.Fprintln(os.Stderr, err)
+		return nil, err
+	}
+	if cfg.Autopilot.Allocation < 0 {
+		str := "%s: autopilot.allocation must be greater than zero"
+		err := fmt.Errorf(str)
+		fmt.Fprintln(os.Stderr, err)
+		return nil, err
+	}
+	if cfg.Autopilot.MinChannelSize < 0 {
+		str := "%s: autopilot.minchansize must be greater than zero"
+		err := fmt.Errorf(str)
+		fmt.Fprintln(os.Stderr, err)
+		return nil, err
+	}
+	if cfg.Autopilot.MaxChannelSize < 0 {
+		str := "%s: autopilot.maxchansize must be greater than zero"
+		err := fmt.Errorf(str)
+		fmt.Fprintln(os.Stderr, err)
+		return nil, err
+	}
+
+	// Ensure that the specified values for the min and max channel size
+	// don't are within the bounds of the normal chan size constraints.
+	if cfg.Autopilot.MinChannelSize < int64(minChanFundingSize) {
+		cfg.Autopilot.MinChannelSize = int64(minChanFundingSize)
+	}
+	if cfg.Autopilot.MaxChannelSize > int64(maxFundingAmount) {
+		cfg.Autopilot.MaxChannelSize = int64(maxFundingAmount)
+	}
+
 	// Setup dial and DNS resolution functions depending on the specified
 	// options. The default is to use the standard golang "net" package
 	// functions. When Tor's proxy is specified, the dial function is set to

fundingmanager.go

@@ -60,6 +60,10 @@ const (
 	// for the funding transaction to be confirmed before forgetting about
 	// the channel. 288 blocks is ~48 hrs
 	maxWaitNumBlocksFundingConf = 288
+
+	// minChanFundingSize is the smallest channel that we'll allow to be
+	// created over the RPC interface.
+	minChanFundingSize = btcutil.Amount(20000)
 )
 
 // reservationWithCtx encapsulates a pending channel reservation. This wrapper

pilot.go

@@ -142,11 +142,9 @@ func initAutoPilot(svr *server, cfg *autoPilotConfig) (*autopilot.Agent, error)
 
 	// First, we'll create the preferential attachment heuristic,
 	// initialized with the passed auto pilot configuration parameters.
-	//
-	// TODO(roasbeef): switch here to dispatch specified heuristic
-	minChanSize := svr.cc.wallet.Cfg.DefaultConstraints.DustLimit * 5
 	prefAttachment := autopilot.NewConstrainedPrefAttachment(
-		minChanSize, maxFundingAmount,
+		btcutil.Amount(cfg.MinChannelSize),
+		btcutil.Amount(cfg.MaxChannelSize),
 		uint16(cfg.MaxChannels), cfg.Allocation,
 	)
 

rpcserver.go

@@ -701,17 +701,12 @@ func (r *rpcServer) OpenChannel(in *lnrpc.OpenChannelRequest,
 			"channel size is: %v", maxFundingAmount)
 	}
 
-	const minChannelSize = btcutil.Amount(6000)
-
-	// Restrict the size of the channel we'll actually open. Atm, we
-	// require the amount to be above 6k satoshis we currently hard-coded
-	// a 5k satoshi fee in several areas. As a result 6k sat is the min
-	// channel size that allows us to safely sit above the dust threshold
-	// after fees are applied
-	// TODO(roasbeef): remove after dynamic fees are in
-	if localFundingAmt < minChannelSize {
+	// Restrict the size of the channel we'll actually open. At a later
+	// level, we'll ensure that the output we create after accounting for
+	// fees that a dust output isn't created.
+	if localFundingAmt < minChanFundingSize {
 		return fmt.Errorf("channel is too small, the minimum channel "+
-			"size is: %v (6k sat)", minChannelSize)
+			"size is: %v SAT", int64(minChanFundingSize))
 	}
 
 	var (
@@ -864,6 +859,14 @@ func (r *rpcServer) OpenChannelSync(ctx context.Context,
 			"initial state must be below the local funding amount")
 	}
 
+	// Restrict the size of the channel we'll actually open. At a later
+	// level, we'll ensure that the output we create after accounting for
+	// fees that a dust output isn't created.
+	if localFundingAmt < minChanFundingSize {
+		return nil, fmt.Errorf("channel is too small, the minimum channel "+
+			"size is: %v SAT", int64(minChanFundingSize))
+	}
+
 	// Based on the passed fee related parameters, we'll determine an
 	// appropriate fee rate for the funding transaction.
 	feeRate, err := determineFeePerVSize(