Merge pull request #553 from milosgajdos83/router-network

Changed router interface. Added table watcher. Advertise routes

network/router/default_router.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/micro/go-micro/registry"
 	"github.com/olekukonko/tablewriter"
@@ -12,15 +13,15 @@ import (
 // router provides default router implementation
 type router struct {
 	opts       Options
+	status     Status
+	advertChan chan *Update
 	exit       chan struct{}
 	wg         *sync.WaitGroup
+	sync.RWMutex
 }
 
 // newRouter creates new router and returns it
 func newRouter(opts ...Option) Router {
-	// TODO: we need to add default GW entry here
-	// Should default GW be part of router options?
-
 	// get default options
 	options := DefaultOptions()
 
@@ -31,6 +32,8 @@ func newRouter(opts ...Option) Router {
 
 	return &router{
 		opts:       options,
+		status:     Status{Error: nil, Code: Init},
+		advertChan: make(chan *Update),
 		exit:       make(chan struct{}),
 		wg:         &sync.WaitGroup{},
 	}
@@ -69,43 +72,17 @@ func (r *router) Network() string {
 	return r.opts.Network
 }
 
-// Advertise advertises the routes to the network. It is a blocking function.
-// It returns error if any of the launched goroutines fail with error.
-func (r *router) Advertise() error {
-	// add local service routes into the routing table
-	if err := r.addServiceRoutes(r.opts.Registry, "local", DefaultLocalMetric); err != nil {
-		return fmt.Errorf("failed adding routes: %v", err)
-	}
-
-	localWatcher, err := r.opts.Registry.Watch()
-	if err != nil {
-		return fmt.Errorf("failed to create registry watcher: %v", err)
-	}
-
-	// error channel collecting goroutine errors
-	errChan := make(chan error, 1)
-
-	r.wg.Add(1)
-	go func() {
-		defer r.wg.Done()
-		// watch local registry and register routes in routine table
-		errChan <- r.manageServiceRoutes(localWatcher, DefaultLocalMetric)
-	}()
-
-	return <-errChan
-}
-
 // addServiceRoutes adds all services in given registry to the routing table.
 // NOTE: this is a one-off operation done when bootstrapping the routing table
 // It returns error if either the services failed to be listed or
-// if the routes could not be added to the routing table.
+// if any of the the routes could not be added to the routing table.
 func (r *router) addServiceRoutes(reg registry.Registry, network string, metric int) error {
 	services, err := reg.ListServices()
 	if err != nil {
 		return fmt.Errorf("failed to list services: %v", err)
 	}
 
-	// add each service node as a separate route;
+	// add each service node as a separate route
 	for _, service := range services {
 		// get the service to retrieve all its info
 		srvs, err := reg.GetService(service.Name)
@@ -121,13 +98,13 @@ func (r *router) addServiceRoutes(reg registry.Registry, network string, metric
 
 		// range over the flat slice of nodes
 		for _, node := range nodes {
-			gw := node.Address
+			gateway := node.Address
 			if node.Port > 0 {
-				gw = fmt.Sprintf("%s:%d", node.Address, node.Port)
+				gateway = fmt.Sprintf("%s:%d", node.Address, node.Port)
 			}
 			route := Route{
 				Destination: service.Name,
-				Gateway:     gw,
+				Gateway:     gateway,
 				Router:      r.opts.Address,
 				Network:     r.opts.Network,
 				Metric:      metric,
@@ -157,12 +134,10 @@ func (r *router) manageServiceRoutes(w registry.Watcher, metric int) error {
 
 	for {
 		res, err := w.Next()
-		if err == registry.ErrWatcherStopped {
-			break
-		}
-
 		if err != nil {
+			if err != registry.ErrWatcherStopped {
 				watchErr = err
+			}
 			break
 		}
 
@@ -190,10 +165,190 @@ func (r *router) manageServiceRoutes(w registry.Watcher, metric int) error {
 	return watchErr
 }
 
+// watchTable watches routing table entries and either adds or deletes locally registered service to/from network registry
+// It returns error if the locally registered services either fails to be added/deleted to/from network registry.
+func (r *router) watchTable(w Watcher) error {
+	// wait in the background for the router to stop
+	// when the router stops, stop the watcher and exit
+	r.wg.Add(1)
+	go func() {
+		defer r.wg.Done()
+		<-r.exit
+		w.Stop()
+	}()
+
+	var watchErr error
+
+exit:
+	for {
+		event, err := w.Next()
+		if err != nil {
+			if err != ErrWatcherStopped {
+				watchErr = err
+			}
+			break
+		}
+
+		u := &Update{
+			ID:        r.ID(),
+			Timestamp: time.Now(),
+			Event:     event,
+		}
+
+		select {
+		case <-r.exit:
+			break exit
+		case r.advertChan <- u:
+		}
+	}
+
+	// close the advertisement channel
+	close(r.advertChan)
+
+	return watchErr
+}
+
+// watchError watches router errors
+func (r *router) watchError(errChan <-chan error) {
+	defer r.wg.Done()
+
+	var code StatusCode
+	var err error
+
+	select {
+	case <-r.exit:
+		code = Stopped
+	case err = <-errChan:
+		code = Error
+	}
+
+	r.Lock()
+	defer r.Unlock()
+	status := Status{
+		Code:  code,
+		Error: err,
+	}
+	r.status = status
+
+	// stop the router if some error happened
+	if err != nil && code != Stopped {
+		close(r.exit)
+	}
+}
+
+// Advertise advertises the routes to the network.
+// It returns error if any of the launched goroutines fail with error.
+func (r *router) Advertise() (<-chan *Update, error) {
+	r.Lock()
+	defer r.Unlock()
+
+	if r.status.Code != Running {
+		// add local service routes into the routing table
+		if err := r.addServiceRoutes(r.opts.Registry, "local", DefaultLocalMetric); err != nil {
+			return nil, fmt.Errorf("failed adding routes: %v", err)
+		}
+		// add default gateway into routing table
+		if r.opts.Gateway != "" {
+			// note, the only non-default value is the gateway
+			route := Route{
+				Destination: "*",
+				Gateway:     r.opts.Gateway,
+				Router:      "*",
+				Network:     "*",
+				Metric:      DefaultLocalMetric,
+			}
+			if err := r.opts.Table.Add(route); err != nil {
+				return nil, fmt.Errorf("error to add default gateway route: %s", err)
+			}
+		}
+
+		// NOTE: we only need to recreate the exit/advertChan if the router errored or was stopped
+		if r.status.Code == Error || r.status.Code == Stopped {
+			r.exit = make(chan struct{})
+			r.advertChan = make(chan *Update)
+		}
+
+		// routing table watcher which watches all routes i.e. to every destination
+		tableWatcher, err := r.opts.Table.Watch(WatchDestination("*"))
+		if err != nil {
+			return nil, fmt.Errorf("failed to create routing table watcher: %v", err)
+		}
+		// registry watcher
+		regWatcher, err := r.opts.Registry.Watch()
+		if err != nil {
+			return nil, fmt.Errorf("failed to create registry watcher: %v", err)
+		}
+
+		// error channel collecting goroutine errors
+		errChan := make(chan error, 2)
+
+		r.wg.Add(1)
+		go func() {
+			defer r.wg.Done()
+			// watch local registry and register routes in routine table
+			errChan <- r.manageServiceRoutes(regWatcher, DefaultLocalMetric)
+		}()
+
+		r.wg.Add(1)
+		go func() {
+			defer r.wg.Done()
+			// watch local registry and register routes in routing table
+			errChan <- r.watchTable(tableWatcher)
+		}()
+
+		r.wg.Add(1)
+		go r.watchError(errChan)
+
+		// mark router as running and set its Error to nil
+		status := Status{
+			Code:  Running,
+			Error: nil,
+		}
+		r.status = status
+	}
+
+	return r.advertChan, nil
+}
+
+// Update updates the routing table using the advertised values
+func (r *router) Update(a *Update) error {
+	// we extract the route from advertisement and update the routing table
+	route := Route{
+		Destination: a.Event.Route.Destination,
+		Gateway:     a.Event.Route.Gateway,
+		Router:      a.Event.Route.Router,
+		Network:     a.Event.Route.Network,
+		Metric:      a.Event.Route.Metric,
+		Policy:      AddIfNotExists,
+	}
+
+	return r.opts.Table.Update(route)
+}
+
+// Status returns router status
+func (r *router) Status() Status {
+	r.RLock()
+	defer r.RUnlock()
+
+	// make a copy of the status
+	status := r.status
+
+	return status
+}
+
 // Stop stops the router
 func (r *router) Stop() error {
+	r.RLock()
+	// only close the channel if the router is running
+	if r.status.Code == Running {
 		// notify all goroutines to finish
 		close(r.exit)
+	}
+	r.RUnlock()
+
+	// drain the advertise channel
+	for range r.advertChan {
+	}
 
 	// wait for all goroutines to finish
 	r.wg.Wait()
@@ -206,13 +361,14 @@ func (r *router) String() string {
 	sb := &strings.Builder{}
 
 	table := tablewriter.NewWriter(sb)
-	table.SetHeader([]string{"ID", "Address", "Network", "Table"})
+	table.SetHeader([]string{"ID", "Address", "Network", "Table", "Status"})
 
 	data := []string{
 		r.opts.ID,
 		r.opts.Address,
 		r.opts.Network,
 		fmt.Sprintf("%d", r.opts.Table.Size()),
+		r.status.Code.String(),
 	}
 	table.Append(data)
 

network/router/default_table.go

@@ -129,6 +129,12 @@ func (t *table) Update(r Route) error {
 
 	// check if the destAddr has ANY routes in the table
 	if _, ok := t.m[destAddr]; !ok {
+		if r.Policy == AddIfNotExists {
+			t.m[destAddr] = make(map[uint64]Route)
+			t.m[destAddr][sum] = r
+			go t.sendEvent(&Event{Type: CreateEvent, Route: r})
+			return nil
+		}
 		return ErrRouteNotFound
 	}
 
@@ -279,7 +285,7 @@ func (t *table) String() string {
 // hash hashes the route using router gateway and network address
 func (t *table) hash(r Route) uint64 {
 	t.h.Reset()
-	t.h.Write([]byte(r.Destination + r.Gateway + r.Router + r.Network))
+	t.h.Write([]byte(r.Destination + r.Gateway + r.Network))
 
 	return t.h.Sum64()
 }

network/router/options.go

@@ -8,6 +8,8 @@ import (
 var (
 	// DefaultAddress is default router address
 	DefaultAddress = ":9093"
+	// DefaultNetwork is default micro network
+	DefaultNetwork = "local"
 )
 
 // Options are router options
@@ -18,6 +20,8 @@ type Options struct {
 	Address string
 	// Network is micro network
 	Network string
+	// Gateway is micro network gateway
+	Gateway string
 	// Registry is the local registry
 	Registry registry.Registry
 	// Table is routing table
@@ -45,6 +49,13 @@ func Network(n string) Option {
 	}
 }
 
+// Gateway sets network gateway
+func Gateway(g string) Option {
+	return func(o *Options) {
+		o.Gateway = g
+	}
+}
+
 // RoutingTable sets the routing table
 func RoutingTable(t Table) Option {
 	return func(o *Options) {
@@ -61,12 +72,11 @@ func Registry(r registry.Registry) Option {
 
 // DefaultOptions returns router default options
 func DefaultOptions() Options {
-	// NOTE: by default both local and network registies use default registry i.e. mdns
 	return Options{
 		ID:       uuid.New().String(),
 		Address:  DefaultAddress,
+		Network:  DefaultNetwork,
 		Registry: registry.DefaultRegistry,
 		Table:    NewTable(),
-		Network:  "local",
 	}
 }

network/router/route.go

@@ -20,6 +20,8 @@ type RoutePolicy int
 const (
 	// OverrideIfExists overrides route if it already exists
 	OverrideIfExists RoutePolicy = iota
+	// AddIfNotExist adds the route if it does not exist
+	AddIfNotExists
 	// IgnoreIfExists instructs to not modify existing route
 	IgnoreIfExists
 )
@@ -28,9 +30,11 @@ const (
 func (p RoutePolicy) String() string {
 	switch p {
 	case OverrideIfExists:
-		return "OVERRIDE"
+		return "OVERRIDE_IF_EXISTS"
+	case AddIfNotExists:
+		return "ADD_IF_NOT_EXISTS"
 	case IgnoreIfExists:
-		return "IGNORE"
+		return "IGNORE_IF_EXISTS"
 	default:
 		return "UNKNOWN"
 	}

network/router/router.go

@@ -1,6 +1,13 @@
 // Package router provides a network routing control plane
 package router
 
+import "time"
+
+var (
+	// DefaultRouter is default network router
+	DefaultRouter = NewRouter()
+)
+
 // Router is an interface for a routing control plane
 type Router interface {
 	// Init initializes the router with options
@@ -15,21 +22,69 @@ type Router interface {
 	Address() string
 	// Network returns the network address of the router
 	Network() string
-	// Advertise starts advertising the routes to the network
-	Advertise() error
+	// Advertise starts advertising routes to the network
+	Advertise() (<-chan *Update, error)
+	// Update updates the routing table
+	Update(*Update) error
+	// Status returns router status
+	Status() Status
 	// Stop stops the router
 	Stop() error
 	// String returns debug info
 	String() string
 }
 
+// Update is sent by the router to the network
+type Update struct {
+	// ID is the router ID
+	ID string
+	// Timestamp marks the time when update is sent
+	Timestamp time.Time
+	// Event defines advertisement even
+	Event *Event
+}
+
+// StatusCode defines router status
+type StatusCode int
+
+// Status is router status
+type Status struct {
+	// Error is router error
+	Error error
+	// Code defines router status
+	Code StatusCode
+}
+
+const (
+	// Init means the rotuer has just been initialized
+	Init StatusCode = iota
+	// Running means the router is running
+	Running
+	// Error means the router has crashed with error
+	Error
+	// Stopped means the router has stopped
+	Stopped
+)
+
+// String returns human readable status code
+func (sc StatusCode) String() string {
+	switch sc {
+	case Init:
+		return "INITIALIZED"
+	case Running:
+		return "RUNNING"
+	case Error:
+		return "ERROR"
+	case Stopped:
+		return "STOPPED"
+	default:
+		return "UNKNOWN"
+	}
+}
+
 // Option used by the router
 type Option func(*Options)
 
-var (
-	DefaultRouter = NewRouter()
-)
-
 // NewRouter creates new Router and returns it
 func NewRouter(opts ...Option) Router {
 	return newRouter(opts...)

network/router/table_watcher.go

@@ -9,7 +9,7 @@ import (
 
 var (
 	// ErrWatcherStopped is returned when routing table watcher has been stopped
-	ErrWatcherStopped = errors.New("routing table watcher stopped")
+	ErrWatcherStopped = errors.New("watcher stopped")
 )
 
 // EventType defines routing table event
@@ -81,7 +81,7 @@ type tableWatcher struct {
 }
 
 // Next returns the next noticed action taken on table
-// TODO: this needs to be thought through properly; we only allow watching particular route destination
+// TODO: this needs to be thought through properly; we only allow watching particular route destination for now
 func (w *tableWatcher) Next() (*Event, error) {
 	for {
 		select {
@@ -93,6 +93,7 @@ func (w *tableWatcher) Next() (*Event, error) {
 				if w.opts.Destination == res.Route.Destination {
 					return res, nil
 				}
+				continue
 			}
 		case <-w.done:
 			return nil, ErrWatcherStopped

registry/mdns_watcher.go

@@ -1,7 +1,6 @@
 package registry
 
 import (
-	"errors"
 	"strings"
 
 	"github.com/micro/mdns"
@@ -63,7 +62,7 @@ func (m *mdnsWatcher) Next() (*Result, error) {
 				Service: service,
 			}, nil
 		case <-m.exit:
-			return nil, errors.New("watcher stopped")
+			return nil, ErrWatcherStopped
 		}
 	}
 }