routing: separate MissionControl from MissionControlManager

This commit renames the previous MissionControl to MissionController and
the previous MissionController interface to MissionControlQuerier. This
is done because soon the (new) MissionController will back multiple
namespaced MissionControl instances.  For now, it just houses a single
MissionControl in the default namespace.

This commit also replaces the MissionControl's `now` function with a
`clock.Clock`.

routing/missioncontrol.go

@@ -9,6 +9,7 @@ import (
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcwallet/walletdb"
 	"github.com/lightningnetwork/lnd/channeldb"
+	"github.com/lightningnetwork/lnd/clock"
 	"github.com/lightningnetwork/lnd/fn"
 	"github.com/lightningnetwork/lnd/kvdb"
 	"github.com/lightningnetwork/lnd/lnwire"
@@ -90,6 +91,16 @@ var (
 // NodeResults contains previous results from a node to its peers.
 type NodeResults map[route.Vertex]TimedPairResult
 
+// mcConfig holds various config members that will be required by all
+// MissionControl instances and will be the same regardless of namespace.
+type mcConfig struct {
+	// clock is a time source used by mission control.
+	clock clock.Clock
+
+	// selfNode is our pubkey.
+	selfNode route.Vertex
+}
+
 // MissionControl contains state which summarizes the past attempts of HTLC
 // routing by external callers when sending payments throughout the network. It
 // acts as a shared memory during routing attempts with the goal to optimize the
@@ -100,17 +111,12 @@ type NodeResults map[route.Vertex]TimedPairResult
 // since the last failure is used to estimate a success probability that is fed
 // into the path finding process for subsequent payment attempts.
 type MissionControl struct {
+	cfg *mcConfig
+
 	// state is the internal mission control state that is input for
 	// probability estimation.
 	state *missionControlState
 
-	// now is expected to return the current time. It is supplied as an
-	// external function to enable deterministic unit tests.
-	now func() time.Time
-
-	// selfNode is our pubkey.
-	selfNode route.Vertex
-
 	store *missionControlStore
 
 	// estimator is the probability estimator that is used with the payment
@@ -122,6 +128,16 @@ type MissionControl struct {
 	onConfigUpdate fn.Option[func(cfg *MissionControlConfig)]
 
 	mu sync.Mutex
+}
+
+// MissionController manages MissionControl instances in various namespaces.
+//
+// NOTE: currently it only has a MissionControl in the default namespace.
+type MissionController struct {
+	cfg *mcConfig
+
+	mc *MissionControl
+	mu sync.Mutex
 
 	// TODO(roasbeef): further counters, if vertex continually unavailable,
 	// add to another generation
@@ -129,6 +145,14 @@ type MissionControl struct {
 	// TODO(roasbeef): also add favorable metrics for nodes
 }
 
+// GetDefaultStore returns the MissionControl in the default namespace.
+func (m *MissionController) GetDefaultStore() *MissionControl {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	return m.mc
+}
+
 // MissionControlConfig defines parameters that control mission control
 // behaviour.
 type MissionControlConfig struct {
@@ -220,9 +244,9 @@ type paymentResult struct {
 	failure            lnwire.FailureMessage
 }
 
-// NewMissionControl returns a new instance of missionControl.
-func NewMissionControl(db kvdb.Backend, self route.Vertex,
-	cfg *MissionControlConfig) (*MissionControl, error) {
+// NewMissionController returns a new instance of MissionController.
+func NewMissionController(db kvdb.Backend, self route.Vertex,
+	cfg *MissionControlConfig) (*MissionController, error) {
 
 	log.Debugf("Instantiating mission control with config: %v, %v", cfg,
 		cfg.Estimator)
@@ -239,18 +263,26 @@ func NewMissionControl(db kvdb.Backend, self route.Vertex,
 		return nil, err
 	}
 
-	mc := &MissionControl{
-		state: newMissionControlState(
-			cfg.MinFailureRelaxInterval,
-		),
-		now:            time.Now,
-		selfNode:       self,
+	mcCfg := &mcConfig{
+		clock:    clock.NewDefaultClock(),
+		selfNode: self,
+	}
+
+	// Create a mission control in the default namespace.
+	defaultMC := &MissionControl{
+		cfg:            mcCfg,
+		state:          newMissionControlState(cfg.MinFailureRelaxInterval),
 		store:          store,
 		estimator:      cfg.Estimator,
 		onConfigUpdate: cfg.OnConfigUpdate,
 	}
 
-	if err := mc.init(); err != nil {
+	mc := &MissionController{
+		cfg: mcCfg,
+		mc:  defaultMC,
+	}
+
+	if err := mc.mc.init(); err != nil {
 		return nil, err
 	}
 
@@ -258,22 +290,31 @@ func NewMissionControl(db kvdb.Backend, self route.Vertex,
 }
 
 // RunStoreTicker runs the mission control store's ticker.
-func (m *MissionControl) RunStoreTicker() {
-	m.store.run()
+func (m *MissionController) RunStoreTicker() {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.mc.store.run()
 }
 
 // StopStoreTicker stops the mission control store's ticker.
-func (m *MissionControl) StopStoreTicker() {
+func (m *MissionController) StopStoreTicker() {
 	log.Debug("Stopping mission control store ticker")
 	defer log.Debug("Mission control store ticker stopped")
 
-	m.store.stop()
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.mc.store.stop()
 }
 
 // init initializes mission control with historical data.
 func (m *MissionControl) init() error {
 	log.Debugf("Mission control state reconstruction started")
 
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
 	start := time.Now()
 
 	results, err := m.store.fetchAll()
@@ -282,7 +323,7 @@ func (m *MissionControl) init() error {
 	}
 
 	for _, result := range results {
-		m.applyPaymentResult(result)
+		_ = m.applyPaymentResult(result)
 	}
 
 	log.Debugf("Mission control state reconstruction finished: "+
@@ -360,11 +401,11 @@ func (m *MissionControl) GetProbability(fromNode, toNode route.Vertex,
 	m.mu.Lock()
 	defer m.mu.Unlock()
 
-	now := m.now()
+	now := m.cfg.clock.Now()
 	results, _ := m.state.getLastPairResult(fromNode)
 
 	// Use a distinct probability estimation function for local channels.
-	if fromNode == m.selfNode {
+	if fromNode == m.cfg.selfNode {
 		return m.estimator.LocalPairProbability(now, results, toNode)
 	}
 
@@ -436,7 +477,7 @@ func (m *MissionControl) ReportPaymentFail(paymentID uint64, rt *route.Route,
 	failureSourceIdx *int, failure lnwire.FailureMessage) (
 	*channeldb.FailureReason, error) {
 
-	timestamp := m.now()
+	timestamp := m.cfg.clock.Now()
 
 	result := &paymentResult{
 		success:          false,
@@ -456,7 +497,7 @@ func (m *MissionControl) ReportPaymentFail(paymentID uint64, rt *route.Route,
 func (m *MissionControl) ReportPaymentSuccess(paymentID uint64,
 	rt *route.Route) error {
 
-	timestamp := m.now()
+	timestamp := m.cfg.clock.Now()
 
 	result := &paymentResult{
 		timeFwd:   timestamp,