lnd+routerrpc: configure server with new estimator

We add new lnd.conf configuration options for both probability
estimators. Note that this is a breaking change for the existing apriori
parameters.

lnrpc/routerrpc/config.go

@@ -42,14 +42,23 @@ type Config struct {
 // DefaultConfig defines the config defaults.
 func DefaultConfig() *Config {
 	defaultRoutingConfig := RoutingConfig{
-		AprioriHopProbability: routing.DefaultAprioriHopProbability,
-		AprioriWeight:         routing.DefaultAprioriWeight,
-		MinRouteProbability:   routing.DefaultMinRouteProbability,
-		PenaltyHalfLife:       routing.DefaultPenaltyHalfLife,
-		AttemptCost:           routing.DefaultAttemptCost.ToSatoshis(),
-		AttemptCostPPM:        routing.DefaultAttemptCostPPM,
-		MaxMcHistory:          routing.DefaultMaxMcHistory,
-		McFlushInterval:       routing.DefaultMcFlushInterval,
+		ProbabilityEstimatorType: routing.DefaultEstimator,
+		MinRouteProbability:      routing.DefaultMinRouteProbability,
+
+		AttemptCost:     routing.DefaultAttemptCost.ToSatoshis(),
+		AttemptCostPPM:  routing.DefaultAttemptCostPPM,
+		MaxMcHistory:    routing.DefaultMaxMcHistory,
+		McFlushInterval: routing.DefaultMcFlushInterval,
+		AprioriConfig: &AprioriConfig{
+			HopProbability:  routing.DefaultAprioriHopProbability,
+			Weight:          routing.DefaultAprioriWeight,
+			PenaltyHalfLife: routing.DefaultPenaltyHalfLife,
+		},
+		BimodalConfig: &BimodalConfig{
+			Scale:      int64(routing.DefaultBimodalScaleMsat),
+			NodeWeight: routing.DefaultBimodalNodeWeight,
+			DecayTime:  routing.DefaultBimodalDecayTime,
+		},
 	}
 
 	return &Config{
@@ -60,13 +69,21 @@ func DefaultConfig() *Config {
 // GetRoutingConfig returns the routing config based on this sub server config.
 func GetRoutingConfig(cfg *Config) *RoutingConfig {
 	return &RoutingConfig{
-		AprioriHopProbability: cfg.AprioriHopProbability,
-		AprioriWeight:         cfg.AprioriWeight,
-		MinRouteProbability:   cfg.MinRouteProbability,
-		AttemptCost:           cfg.AttemptCost,
-		AttemptCostPPM:        cfg.AttemptCostPPM,
-		PenaltyHalfLife:       cfg.PenaltyHalfLife,
-		MaxMcHistory:          cfg.MaxMcHistory,
-		McFlushInterval:       cfg.McFlushInterval,
+		ProbabilityEstimatorType: cfg.ProbabilityEstimatorType,
+		MinRouteProbability:      cfg.MinRouteProbability,
+		AttemptCost:              cfg.AttemptCost,
+		AttemptCostPPM:           cfg.AttemptCostPPM,
+		MaxMcHistory:             cfg.MaxMcHistory,
+		McFlushInterval:          cfg.McFlushInterval,
+		AprioriConfig: &AprioriConfig{
+			HopProbability:  cfg.AprioriConfig.HopProbability,
+			Weight:          cfg.AprioriConfig.Weight,
+			PenaltyHalfLife: cfg.AprioriConfig.PenaltyHalfLife,
+		},
+		BimodalConfig: &BimodalConfig{
+			Scale:      cfg.BimodalConfig.Scale,
+			NodeWeight: cfg.BimodalConfig.NodeWeight,
+			DecayTime:  cfg.BimodalConfig.DecayTime,
+		},
 	}
 }

lnrpc/routerrpc/routing_config.go

@@ -7,28 +7,16 @@ import (
 )
 
 // RoutingConfig contains the configurable parameters that control routing.
+//
+//nolint:lll
 type RoutingConfig struct {
+	// ProbabilityEstimatorType sets the estimator to use.
+	ProbabilityEstimatorType string `long:"estimator" choice:"apriori" choice:"bimodal" description:"Probability estimator used for pathfinding." `
+
 	// MinRouteProbability is the minimum required route success probability
 	// to attempt the payment.
 	MinRouteProbability float64 `long:"minrtprob" description:"Minimum required route success probability to attempt the payment"`
 
-	// AprioriHopProbability is the assumed success probability of a hop in
-	// a route when no other information is available.
-	AprioriHopProbability float64 `long:"apriorihopprob" description:"Assumed success probability of a hop in a route when no other information is available."`
-
-	// AprioriWeight is a value in the range [0, 1] that defines to what
-	// extent historical results should be extrapolated to untried
-	// connections. Setting it to one will completely ignore historical
-	// results and always assume the configured a priori probability for
-	// untried connections. A value of zero will ignore the a priori
-	// probability completely and only base the probability on historical
-	// results, unless there are none available.
-	AprioriWeight float64 `long:"aprioriweight" description:"Weight of the a priori probability in success probability estimation. Valid values are in [0, 1]."`
-
-	// PenaltyHalfLife defines after how much time a penalized node or
-	// channel is back at 50% probability.
-	PenaltyHalfLife time.Duration `long:"penaltyhalflife" description:"Defines the duration after which a penalized node or channel is back at 50% probability"`
-
 	// AttemptCost is the fixed virtual cost in path finding of a failed
 	// payment attempt. It is used to trade off potentially better routes
 	// against their probability of succeeding.
@@ -47,4 +35,51 @@ type RoutingConfig struct {
 	// McFlushInterval defines the timer interval to use to flush mission
 	// control state to the DB.
 	McFlushInterval time.Duration `long:"mcflushinterval" description:"the timer interval to use to flush mission control state to the DB"`
+
+	// AprioriConfig defines parameters for the apriori probability.
+	AprioriConfig *AprioriConfig `group:"apriori" namespace:"apriori" description:"configuration for the apriori pathfinding probability estimator"`
+
+	// BimodalConfig defines parameters for the bimodal probability.
+	BimodalConfig *BimodalConfig `group:"bimodal" namespace:"bimodal" description:"configuration for the bimodal pathfinding probability estimator"`
+}
+
+// AprioriConfig defines parameters for the apriori probability.
+//
+//nolint:lll
+type AprioriConfig struct {
+	// HopProbability is the assumed success probability of a hop in a route
+	// when no other information is available.
+	HopProbability float64 `long:"hopprob" description:"Assumed success probability of a hop in a route when no other information is available."`
+
+	// Weight is a value in the range [0, 1] that defines to what extent
+	// historical results should be extrapolated to untried connections.
+	// Setting it to one will completely ignore historical results and
+	// always assume the configured a priori probability for untried
+	// connections. A value of zero will ignore the a priori probability
+	// completely and only base the probability on historical results,
+	// unless there are none available.
+	Weight float64 `long:"weight" description:"Weight of the a priori probability in success probability estimation. Valid values are in [0, 1]."`
+
+	// PenaltyHalfLife defines after how much time a penalized node or
+	// channel is back at 50% probability.
+	PenaltyHalfLife time.Duration `long:"penaltyhalflife" description:"Defines the duration after which a penalized node or channel is back at 50% probability"`
+}
+
+// BimodalConfig defines parameters for the bimodal probability.
+//
+//nolint:lll
+type BimodalConfig struct {
+	// Scale describes the scale over which channels still have some
+	// liquidity left on both channel ends. A value of 0 means that we
+	// assume perfectly unbalanced channels, a very high value means
+	// randomly balanced channels.
+	Scale int64 `long:"scale" description:"Defines the unbalancedness assumed for the network, the amount defined in msat."`
+
+	// NodeWeight defines how strongly non-routed channels should be taken
+	// into account for probability estimation. Valid values are in [0,1].
+	NodeWeight float64 `long:"nodeweight" description:"Defines how strongly non-routed channels should be taken into account for probability estimation. Valid values are in [0, 1]."`
+
+	// DecayTime is the scale for the exponential information decay over
+	// time for previous successes or failures.
+	DecayTime time.Duration `long:"decaytime" description:"Describes the information decay of knowledge about previous successes and failures in channels."`
 }