Strip down router code (#1627)

router/default.go

@@ -3,7 +3,6 @@ package router
 import (
 	"errors"
 	"fmt"
-	"math"
 	"sort"
 	"strings"
 	"sync"
@@ -19,18 +18,6 @@ var (
 	AdvertiseEventsTick = 10 * time.Second
 	// DefaultAdvertTTL is default advertisement TTL
 	DefaultAdvertTTL = 2 * time.Minute
-	// AdvertSuppress is advert suppression threshold
-	AdvertSuppress = 200.0
-	// AdvertRecover is advert recovery threshold
-	AdvertRecover = 20.0
-	// Penalty for routes processed multiple times
-	Penalty = 100.0
-	// PenaltyHalfLife is the time the advert penalty decays to half its value
-	PenaltyHalfLife = 30.0
-	// MaxSuppressTime defines time after which the suppressed advert is deleted
-	MaxSuppressTime = 90 * time.Second
-	// PenaltyDecay is a coefficient which controls the speed the advert penalty decays
-	PenaltyDecay = math.Log(2) / PenaltyHalfLife
 )
 
 // router implements default router
@@ -269,68 +256,8 @@ func (r *router) publishAdvert(advType AdvertType, events []*Event) {
 	r.sub.RUnlock()
 }
 
-// advert contains a route event to be advertised
-type advert struct {
-	// event received from routing table
-	event *Event
-	// lastSeen records the time of the last advert update
-	lastSeen time.Time
-	// penalty is current advert penalty
-	penalty float64
-	// isSuppressed flags the advert suppression
-	isSuppressed bool
-	// suppressTime records the time interval the advert has been suppressed for
-	suppressTime time.Time
-}
-
 // adverts maintains a map of router adverts
-type adverts map[uint64]*advert
-
-// process processes advert
-// It updates advert timestamp, increments its penalty and
-// marks upresses or recovers it if it reaches configured thresholds
-func (m adverts) process(a *advert) error {
-	// lookup advert in adverts
-	hash := a.event.Route.Hash()
-	a, ok := m[hash]
-	if !ok {
-		return fmt.Errorf("advert not found")
-	}
-
-	// decay the event penalty
-	delta := time.Since(a.lastSeen).Seconds()
-
-	// decay advert penalty
-	a.penalty = a.penalty * math.Exp(-delta*PenaltyDecay)
-	service := a.event.Route.Service
-	address := a.event.Route.Address
-
-	// suppress/recover the event based on its penalty level
-	switch {
-	case a.penalty > AdvertSuppress && !a.isSuppressed:
-		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-			logger.Debugf("Router suppressing advert %d %.2f for route %s %s", hash, a.penalty, service, address)
-		}
-		a.isSuppressed = true
-		a.suppressTime = time.Now()
-	case a.penalty < AdvertRecover && a.isSuppressed:
-		if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-			logger.Debugf("Router recovering advert %d %.2f for route %s %s", hash, a.penalty, service, address)
-		}
-		a.isSuppressed = false
-	}
-
-	// if suppressed, checked how long has it been suppressed for
-	if a.isSuppressed {
-		// max suppression time threshold has been reached, delete the advert
-		if time.Since(a.suppressTime) > MaxSuppressTime {
-			delete(m, hash)
-			return nil
-		}
-	}
-
-	return nil
-}
+type adverts map[uint64]*Event
 
 // advertiseEvents advertises routing table events
 // It suppresses unhealthy flapping events and advertises healthy events upstream.
@@ -396,21 +323,9 @@ func (r *router) advertiseEvents() error {
 			var events []*Event
 
 			// collect all events which are not flapping
-			for key, advert := range adverts {
-				// process the advert
-				if err := adverts.process(advert); err != nil {
-					if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-						logger.Debugf("Router failed processing advert %d: %v", key, err)
-					}
-					continue
-				}
-				// if suppressed go to the next advert
-				if advert.isSuppressed {
-					continue
-				}
-
+			for key, event := range adverts {
 				// if we only advertise local routes skip processing anything not link local
-				if r.options.Advertise == AdvertiseLocal && advert.event.Route.Link != "local" {
+				if r.options.Advertise == AdvertiseLocal && event.Route.Link != "local" {
 					continue
 				}
 
@@ -418,7 +333,7 @@ func (r *router) advertiseEvents() error {
 				e := new(Event)
 				// this is ok, because router.Event only contains builtin types
 				// and no references so this creates a deep copy of struct Event
-				*e = *(advert.event)
+				*e = *event
 				events = append(events, e)
 				// delete the advert from adverts
 				delete(adverts, key)
@@ -447,44 +362,22 @@ func (r *router) advertiseEvents() error {
 				continue
 			}
 
-			now := time.Now()
-
 			if logger.V(logger.DebugLevel, logger.DefaultLogger) {
 				logger.Debugf("Router processing table event %s for service %s %s", e.Type, e.Route.Service, e.Route.Address)
 			}
 
 			// check if we have already registered the route
 			hash := e.Route.Hash()
-			a, ok := adverts[hash]
+			ev, ok := adverts[hash]
 			if !ok {
-				a = &advert{
-					event:    e,
-					penalty:  Penalty,
-					lastSeen: now,
-				}
-				adverts[hash] = a
+				ev = e
+				adverts[hash] = e
 				continue
 			}
 
 			// override the route event only if the previous event was different
-			if a.event.Type != e.Type {
-				a.event = e
-			}
-
-			// process the advert
-			if err := adverts.process(a); err != nil {
-				if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-					logger.Debugf("Router error processing advert  %d: %v", hash, err)
-				}
-				continue
-			}
-
-			// update event penalty and timestamp
-			a.lastSeen = now
-			// increment the penalty
-			a.penalty += Penalty
-			if logger.V(logger.DebugLevel, logger.DefaultLogger) {
-				logger.Debugf("Router advert %d for route %s %s event penalty: %f", hash, a.event.Route.Service, a.event.Route.Address, a.penalty)
+			if ev.Type != e.Type {
+				ev = e
 			}
 		case <-r.exit:
 			if w != nil {