Simplified processEvents loop; Added router Announcement.

network/router/default.go

@@ -38,6 +38,7 @@ type router struct {
 	exit       chan struct{}
 	eventChan  chan *table.Event
 	advertChan chan *Advert
+	advertWg   *sync.WaitGroup
 	wg         *sync.WaitGroup
 	sync.RWMutex
 }
@@ -58,6 +59,7 @@ func newRouter(opts ...Option) Router {
 		exit:       make(chan struct{}),
 		eventChan:  make(chan *table.Event),
 		advertChan: make(chan *Advert),
+		advertWg:   &sync.WaitGroup{},
 		wg:         &sync.WaitGroup{},
 	}
 }
@@ -97,7 +99,7 @@ func (r *router) Network() string {
 
 // manageServiceRoutes manages routes for a given service.
 // It returns error of the routing table action fails.
-func (r *router) manageServiceRoutes(service *registry.Service, action string, metric int) error {
+func (r *router) manageServiceRoutes(service *registry.Service, action string) error {
 	// action is the routing table action
 	action = strings.ToLower(action)
 	// take route action on each service node
@@ -107,7 +109,7 @@ func (r *router) manageServiceRoutes(service *registry.Service, action string, m
 			Gateway:     node.Address,
 			Router:      r.opts.Address,
 			Network:     r.opts.Network,
-			Metric:      metric,
+			Metric:      table.DefaultLocalMetric,
 		}
 		switch action {
 		case "insert", "create":
@@ -127,7 +129,7 @@ func (r *router) manageServiceRoutes(service *registry.Service, action string, m
 
 // manageRegistryRoutes manages routes for each service found in the registry.
 // It returns error if either the services failed to be listed or the routing table action fails.
-func (r *router) manageRegistryRoutes(reg registry.Registry, action string, metric int) error {
+func (r *router) manageRegistryRoutes(reg registry.Registry, action string) error {
 	services, err := reg.ListServices()
 	if err != nil {
 		return fmt.Errorf("failed listing services: %v", err)
@@ -143,7 +145,7 @@ func (r *router) manageRegistryRoutes(reg registry.Registry, action string, metr
 		}
 		// manage the routes for all returned services
 		for _, s := range srvs {
-			if err := r.manageServiceRoutes(s, action, metric); err != nil {
+			if err := r.manageServiceRoutes(s, action); err != nil {
 				return err
 			}
 		}
@@ -177,7 +179,7 @@ func (r *router) watchServices(w registry.Watcher) error {
 
 		log.Logf("r.watchServices() new service event: Action: %s Service: %v", res.Action, res.Service)
 
-		if err := r.manageServiceRoutes(res.Service, res.Action, table.DefaultLocalMetric); err != nil {
+		if err := r.manageServiceRoutes(res.Service, res.Action); err != nil {
 			return err
 		}
 	}
@@ -224,6 +226,29 @@ func (r *router) watchTable(w table.Watcher) error {
 	return watchErr
 }
 
+func (r *router) advertEvents(advType AdvertType, events []*table.Event) {
+	defer r.advertWg.Done()
+
+	log.Logf("r.advertEvents(): start event: %s", advType)
+
+	a := &Advert{
+		ID:        r.ID(),
+		Type:      advType,
+		Timestamp: time.Now(),
+		Events:    events,
+	}
+
+	select {
+	case r.advertChan <- a:
+		log.Logf("r.advertEvents(): advertised event: %s", advType)
+	case <-r.exit:
+		log.Logf("r.advertEvents(): DONE exit")
+		return
+	}
+
+	log.Logf("r.advertEvents(): REGULAR exit")
+}
+
 // isFlapping detects if the event is flapping based on the current and previous event status.
 func isFlapping(curr, prev *table.Event) bool {
 	if curr.Type == table.Update && prev.Type == table.Update {
@@ -259,18 +284,12 @@ func (r *router) processEvents() error {
 	ticker := time.NewTicker(AdvertiseTick)
 	// eventMap is a map of advert events
 	eventMap := make(map[uint64]*updateEvent)
-	// lock to protect access to eventMap
-	mu := &sync.RWMutex{}
-	// waitgroup to manage advertisement goroutines
-	var wg sync.WaitGroup
 
-processLoop:
 	for {
 		select {
 		case <-ticker.C:
 			var events []*table.Event
 			// collect all events which are not flapping
-			mu.Lock()
 			for key, event := range eventMap {
 				if !event.isFlapping && !event.isSuppressed {
 					e := new(table.Event)
@@ -280,29 +299,10 @@ processLoop:
 					delete(eventMap, key)
 				}
 			}
-			mu.Unlock()
 
 			if len(events) > 0 {
-				wg.Add(1)
+				r.advertWg.Add(1)
-				go func(events []*table.Event) {
+				go r.advertEvents(Update, events)
-					defer wg.Done()
-
-					log.Logf("go advertise(): start")
-
-					a := &Advert{
-						ID:        r.ID(),
-						Timestamp: time.Now(),
-						Events:    events,
-					}
-
-					select {
-					case r.advertChan <- a:
-					case <-r.exit:
-						log.Logf("go advertise(): exit")
-						return
-					}
-					log.Logf("go advertise(): exit")
-				}(events)
 			}
 		case e := <-r.eventChan:
 			// event timestamp
@@ -348,15 +348,16 @@ processLoop:
 				event.isFlapping = isFlapping(e, event.Event)
 			}
 		case <-r.exit:
-			break processLoop
-		}
-	}
-
 			// first wait for the advertiser to finish
-	wg.Wait()
+			r.advertWg.Wait()
 			// close the advert channel
 			close(r.advertChan)
+			log.Logf("r.processEvents(): event processor stopped")
+			return nil
+		}
+	}
 
+	// we probably never reach this place
 	log.Logf("r.processEvents(): event processor stopped")
 
 	return nil
@@ -395,9 +396,11 @@ func (r *router) watchErrors(errChan <-chan error) {
 		// drain the advertise channel
 		for range r.advertChan {
 		}
+		log.Logf("r.watchErrors(): advert channel drained")
 		// drain the event channel
 		for range r.eventChan {
 		}
+		log.Logf("r.watchErrors(): event channel drained")
 	}
 
 	log.Logf("r.watchErrors(): watchErrors exit")
@@ -411,10 +414,15 @@ func (r *router) Advertise() (<-chan *Advert, error) {
 
 	if r.status.Code != Running {
 		// add all local service routes into the routing table
-		if err := r.manageRegistryRoutes(r.opts.Registry, "insert", table.DefaultLocalMetric); err != nil {
+		if err := r.manageRegistryRoutes(r.opts.Registry, "insert"); err != nil {
-			return nil, fmt.Errorf("failed adding routes: %v", err)
+			return nil, fmt.Errorf("failed adding routes: %s", err)
 		}
 		log.Logf("Routing table:\n%s", r.opts.Table)
+		// list routing table routes to announce
+		routes, err := r.opts.Table.List()
+		if err != nil {
+			return nil, fmt.Errorf("failed listing routes: %s", err)
+		}
 		// add default gateway into routing table
 		if r.opts.Gateway != "" {
 			// note, the only non-default value is the gateway
@@ -431,14 +439,15 @@ func (r *router) Advertise() (<-chan *Advert, error) {
 		}
 
 		// NOTE: we only need to recreate these if the router errored or was stopped
+		// TODO: These probably dont need to be struct members
 		if r.status.Code == Error || r.status.Code == Stopped {
 			r.exit = make(chan struct{})
 			r.eventChan = make(chan *table.Event)
 			r.advertChan = make(chan *Advert)
 		}
 
-		// routing table watcher which watches all routes i.e. to every destination
+		// routing table watcher
-		tableWatcher, err := r.opts.Table.Watch(table.WatchDestination("*"))
+		tableWatcher, err := r.opts.Table.Watch()
 		if err != nil {
 			return nil, fmt.Errorf("failed creating routing table watcher: %v", err)
 		}
@@ -478,11 +487,24 @@ func (r *router) Advertise() (<-chan *Advert, error) {
 			log.Logf("r.Advertise(): r.processEvents() exit")
 		}()
 
+		// watch for errors and cleanup
 		r.wg.Add(1)
 		go r.watchErrors(errChan)
 
-		// TODO: send router announcement update comes here
+		// announce yourself with all the existing routes
-		// the announcement update contains routes from routing table
+		events := make([]*table.Event, len(routes))
+		for i, route := range routes {
+			event := &table.Event{
+				Type:      table.Insert,
+				Timestamp: time.Now(),
+				Route:     route,
+			}
+			events[i] = event
+		}
+
+		// advertise your presence
+		r.advertWg.Add(1)
+		go r.advertEvents(Announce, events)
 
 		// mark router as running and set its Error to nil
 		status := Status{

network/router/router.go

@@ -41,19 +41,19 @@ type Router interface {
 // Option used by the router
 type Option func(*Options)
 
-// UpdateType is route advertisement update type
+// AdvertType is route advertisement type
-type UpdateType int
+type AdvertType int
 
 const (
 	// Announce is advertised when the router announces itself
-	Announce UpdateType = iota
+	Announce AdvertType = iota
 	// Update advertises route updates
 	Update
 )
 
 // String returns string representation of update event
-func (ut UpdateType) String() string {
+func (at AdvertType) String() string {
-	switch ut {
+	switch at {
 	case Announce:
 		return "ANNOUNCE"
 	case Update:
@@ -67,6 +67,8 @@ func (ut UpdateType) String() string {
 type Advert struct {
 	// ID is the router ID
 	ID string
+	// Type is type of advert
+	Type AdvertType
 	// Timestamp marks the time when the update is sent
 	Timestamp time.Time
 	// TTL is Advert TTL