lnd+routing+rpc: switch mc to (external) estimator

We use a more general `Estimator` interface for probability estimation
in missioncontrol.

The estimator is created outside of `NewMissionControl`, passed in as a
`MissionControlConfig` field, to facilitate usage of externally supplied
estimators.

routing/integrated_routing_context_test.go

@@ -11,6 +11,7 @@ import (
 	"github.com/lightningnetwork/lnd/lnwire"
 	"github.com/lightningnetwork/lnd/routing/route"
 	"github.com/lightningnetwork/lnd/zpay32"
+	"github.com/stretchr/testify/require"
 )
 
 const (
@@ -68,6 +69,14 @@ func newIntegratedRoutingContext(t *testing.T) *integratedRoutingContext {
 	// defaults would break the unit tests. The actual values picked aren't
 	// critical to excite certain behavior, but do need to be aligned with
 	// the test case assertions.
+	aCfg := AprioriConfig{
+		PenaltyHalfLife:       30 * time.Minute,
+		AprioriHopProbability: 0.6,
+		AprioriWeight:         0.5,
+	}
+	estimator, err := NewAprioriEstimator(aCfg)
+	require.NoError(t, err)
+
 	ctx := integratedRoutingContext{
 		t:           t,
 		graph:       graph,
@@ -75,11 +84,7 @@ func newIntegratedRoutingContext(t *testing.T) *integratedRoutingContext {
 		finalExpiry: 40,
 
 		mcCfg: MissionControlConfig{
-			AprioriConfig: AprioriConfig{
-				PenaltyHalfLife:       30 * time.Minute,
-				AprioriHopProbability: 0.6,
-				AprioriWeight:         0.5,
-			},
+			Estimator: estimator,
 		},
 
 		pathFindingCfg: PathFindingConfig{

routing/integrated_routing_test.go

@@ -67,7 +67,10 @@ func TestProbabilityExtrapolation(t *testing.T) {
 	// If we use a static value for the node probability (no extrapolation
 	// of data from other channels), all ten bad channels will be tried
 	// first before switching to the paid channel.
-	ctx.mcCfg.AprioriWeight = 1
+	estimator, ok := ctx.mcCfg.Estimator.(*AprioriEstimator)
+	if ok {
+		estimator.AprioriWeight = 1
+	}
 	attempts, err = ctx.testPayment(1)
 	require.NoError(t, err, "payment failed")
 	if len(attempts) != 11 {

routing/missioncontrol.go

@@ -103,7 +103,7 @@ type MissionControl struct {
 
 	// estimator is the probability estimator that is used with the payment
 	// results that mission control collects.
-	estimator *AprioriEstimator
+	estimator Estimator
 
 	sync.Mutex
 
@@ -116,8 +116,8 @@ type MissionControl struct {
 // MissionControlConfig defines parameters that control mission control
 // behaviour.
 type MissionControlConfig struct {
-	// AprioriConfig is the config we will use for probability calculations.
-	AprioriConfig
+	// Estimator gives probability estimates for node pairs.
+	Estimator Estimator
 
 	// MaxMcHistory defines the maximum number of payment results that are
 	// held on disk.
@@ -134,10 +134,6 @@ type MissionControlConfig struct {
 }
 
 func (c *MissionControlConfig) validate() error {
-	if err := c.AprioriConfig.validate(); err != nil {
-		return err
-	}
-
 	if c.MaxMcHistory < 0 {
 		return ErrInvalidMcHistory
 	}
@@ -151,11 +147,8 @@ func (c *MissionControlConfig) validate() error {
 
 // String returns a string representation of a mission control config.
 func (c *MissionControlConfig) String() string {
-	return fmt.Sprintf("Penalty Half Life: %v, Apriori Hop "+
-		"Probablity: %v, Maximum History: %v, Apriori Weight: %v, "+
-		"Minimum Failure Relax Interval: %v", c.PenaltyHalfLife,
-		c.AprioriHopProbability, c.MaxMcHistory, c.AprioriWeight,
-		c.MinFailureRelaxInterval)
+	return fmt.Sprintf("maximum history: %v, minimum failure relax "+
+		"interval: %v", c.MaxMcHistory, c.MinFailureRelaxInterval)
 }
 
 // TimedPairResult describes a timestamped pair result.
@@ -211,7 +204,8 @@ type paymentResult struct {
 func NewMissionControl(db kvdb.Backend, self route.Vertex,
 	cfg *MissionControlConfig) (*MissionControl, error) {
 
-	log.Debugf("Instantiating mission control with config: %v", cfg)
+	log.Debugf("Instantiating mission control with config: %v, %v", cfg,
+		cfg.Estimator)
 
 	if err := cfg.validate(); err != nil {
 		return nil, err
@@ -224,17 +218,12 @@ func NewMissionControl(db kvdb.Backend, self route.Vertex,
 		return nil, err
 	}
 
-	estimator := &AprioriEstimator{
-		AprioriConfig:          cfg.AprioriConfig,
-		prevSuccessProbability: prevSuccessProbability,
-	}
-
 	mc := &MissionControl{
 		state:     newMissionControlState(cfg.MinFailureRelaxInterval),
 		now:       time.Now,
 		selfNode:  self,
 		store:     store,
-		estimator: estimator,
+		estimator: cfg.Estimator,
 	}
 
 	if err := mc.init(); err != nil {
@@ -283,7 +272,7 @@ func (m *MissionControl) GetConfig() *MissionControlConfig {
 	defer m.Unlock()
 
 	return &MissionControlConfig{
-		AprioriConfig:           m.estimator.AprioriConfig,
+		Estimator:               m.estimator,
 		MaxMcHistory:            m.store.maxRecords,
 		McFlushInterval:         m.store.flushInterval,
 		MinFailureRelaxInterval: m.state.minFailureRelaxInterval,
@@ -304,11 +293,12 @@ func (m *MissionControl) SetConfig(cfg *MissionControlConfig) error {
 	m.Lock()
 	defer m.Unlock()
 
-	log.Infof("Updating mission control cfg: %v", cfg)
+	log.Infof("Active mission control cfg: %v, estimator: %v", cfg,
+		cfg.Estimator)
 
 	m.store.maxRecords = cfg.MaxMcHistory
 	m.state.minFailureRelaxInterval = cfg.MinFailureRelaxInterval
-	m.estimator.AprioriConfig = cfg.AprioriConfig
+	m.estimator = cfg.Estimator
 
 	return nil
 }

routing/missioncontrol_test.go

@@ -90,15 +90,17 @@ func (ctx *mcTestContext) restartMc() {
 		require.NoError(ctx.t, ctx.mc.store.storeResults())
 	}
 
+	aCfg := AprioriConfig{
+		PenaltyHalfLife:       testPenaltyHalfLife,
+		AprioriHopProbability: testAprioriHopProbability,
+		AprioriWeight:         testAprioriWeight,
+	}
+	estimator, err := NewAprioriEstimator(aCfg)
+	require.NoError(ctx.t, err)
+
 	mc, err := NewMissionControl(
 		ctx.db, mcTestSelf,
-		&MissionControlConfig{
-			AprioriConfig: AprioriConfig{
-				PenaltyHalfLife:       testPenaltyHalfLife,
-				AprioriHopProbability: testAprioriHopProbability,
-				AprioriWeight:         testAprioriWeight,
-			},
-		},
+		&MissionControlConfig{Estimator: estimator},
 	)
 	if err != nil {
 		ctx.t.Fatal(err)

routing/router_test.go

@@ -119,13 +119,15 @@ func createTestCtxFromGraphInstanceAssumeValid(t *testing.T,
 		AttemptCost:    100,
 	}
 
-	mcConfig := &MissionControlConfig{
-		AprioriConfig: AprioriConfig{
-			PenaltyHalfLife:       time.Hour,
-			AprioriHopProbability: 0.9,
-			AprioriWeight:         0.5,
-		},
+	aCfg := AprioriConfig{
+		PenaltyHalfLife:       time.Hour,
+		AprioriHopProbability: 0.9,
+		AprioriWeight:         0.5,
 	}
+	estimator, err := NewAprioriEstimator(aCfg)
+	require.NoError(t, err)
+
+	mcConfig := &MissionControlConfig{Estimator: estimator}
 
 	mc, err := NewMissionControl(
 		graphInstance.graphBackend, route.Vertex{}, mcConfig,