update the gossiper

registry/gossip/gossip.go

@@ -1,4 +1,4 @@
-// Package gossip provides a zero dependency registry using the gossip protocol SWIM
+// Package Gossip provides a gossip registry based on hashicorp/memberlist
 package gossip
 
 import (
@@ -15,22 +15,13 @@ import (
 	"github.com/micro/go-log"
 	"github.com/micro/go-micro/registry"
 	pb "github.com/micro/go-micro/registry/gossip/proto"
+	"github.com/mitchellh/hashstructure"
 )
 
-type gossipRegistry struct {
-	opts       registry.Options
-	queue      *memberlist.TransmitLimitedQueue
-	memberlist *memberlist.Memberlist
-	delegate   *delegate
-
-	sync.RWMutex
-	services map[string][]*registry.Service
-	watchers map[string]*watcher
-}
-
-var (
-	// defaults to random port
-	defaultPort = 0
+const (
+	addAction  = "update"
+	delAction  = "delete"
+	syncAction = "sync"
 )
 
 type broadcast struct {
@@ -39,8 +30,134 @@ type broadcast struct {
 }
 
 type delegate struct {
+	queue   *memberlist.TransmitLimitedQueue
+	updates chan *update
+}
+
+type gossipRegistry struct {
 	queue    *memberlist.TransmitLimitedQueue
-	registry *gossipRegistry
+	updates  chan *update
+	options  registry.Options
+	member   *memberlist.Memberlist
+	interval time.Duration
+
+	sync.RWMutex
+	services map[string][]*registry.Service
+
+	s        sync.RWMutex
+	watchers map[string]chan *registry.Result
+}
+
+type update struct {
+	Update  *pb.Update
+	Service *registry.Service
+	sync    chan *registry.Service
+}
+
+var (
+	// You should change this if using secure
+	DefaultSecret = []byte("gossip")
+	ExpiryTick    = time.Second * 5
+)
+
+func configure(g *gossipRegistry, opts ...registry.Option) error {
+	// loop through address list and get valid entries
+	addrs := func(curAddrs []string) []string {
+		var newAddrs []string
+		for _, addr := range curAddrs {
+			if trimAddr := strings.TrimSpace(addr); len(trimAddr) > 0 {
+				newAddrs = append(newAddrs, trimAddr)
+			}
+		}
+		return newAddrs
+	}
+
+	// current address list
+	curAddrs := addrs(g.options.Addrs)
+
+	// parse options
+	for _, o := range opts {
+		o(&g.options)
+	}
+
+	// new address list
+	newAddrs := addrs(g.options.Addrs)
+
+	// no new nodes and existing member. no configure
+	if (len(newAddrs) == len(curAddrs)) && g.member != nil {
+		return nil
+	}
+
+	// shutdown old member
+	if g.member != nil {
+		g.member.Shutdown()
+	}
+
+	// replace addresses
+	curAddrs = newAddrs
+
+	// create a queue
+	queue := &memberlist.TransmitLimitedQueue{
+		NumNodes: func() int {
+			return len(curAddrs)
+		},
+		RetransmitMult: 3,
+	}
+
+	// machine hostname
+	hostname, _ := os.Hostname()
+
+	// create a new default config
+	c := memberlist.DefaultLocalConfig()
+
+	// set bind to random port
+	c.BindPort = 0
+
+	// set the name
+	c.Name = strings.Join([]string{"micro", hostname, uuid.New().String()}, "-")
+
+	// set the delegate
+	c.Delegate = &delegate{
+		updates: g.updates,
+		queue:   queue,
+	}
+
+	// log to dev null
+	c.LogOutput = ioutil.Discard
+
+	// set a secret key if secure
+	if g.options.Secure {
+		k, ok := g.options.Context.Value(contextSecretKey{}).([]byte)
+		if !ok {
+			// use the default secret
+			k = DefaultSecret
+		}
+		c.SecretKey = k
+	}
+
+	// TODO: set advertise addr to advertise behind nat
+
+	// create the memberlist
+	m, err := memberlist.Create(c)
+	if err != nil {
+		return err
+	}
+
+	// join the memberlist
+	if len(curAddrs) > 0 {
+		_, err := m.Join(curAddrs)
+		if err != nil {
+			return err
+		}
+	}
+
+	// set internals
+	g.queue = queue
+	g.member = m
+	g.interval = c.GossipInterval
+
+	log.Logf("Registry Listening on %s", m.LocalNode().Address())
+	return nil
 }
 
 func (b *broadcast) Invalidates(other memberlist.Broadcast) bool {
@@ -91,56 +208,35 @@ func (d *delegate) NotifyMsg(b []byte) {
 		return
 	}
 
-	up := new(pb.Update)
-	if err := proto.Unmarshal(b, up); err != nil {
-		return
-	}
-
-	// only process service action
-	if up.Type != "service" {
-		return
-	}
-
-	var service *registry.Service
-
-	switch up.Metadata["Content-Type"] {
-	case "application/json":
-		if err := json.Unmarshal(up.Data, &service); err != nil {
+	go func() {
+		up := new(pb.Update)
+		if err := proto.Unmarshal(b, up); err != nil {
 			return
 		}
-	// no other content type
-	default:
-		return
-	}
 
-	d.registry.Lock()
-	defer d.registry.Unlock()
-
-	// get existing service
-	s := d.registry.services[service.Name]
-
-	// save update
-	switch up.Action {
-	case "update":
-		d.registry.services[service.Name] = addServices(s, []*registry.Service{service})
-	case "delete":
-		services := delServices(s, []*registry.Service{service})
-		if len(services) == 0 {
-			delete(d.registry.services, service.Name)
+		// only process service action
+		if up.Type != "service" {
 			return
 		}
-		d.registry.services[service.Name] = services
-	default:
-		return
-	}
 
-	// notify watchers
-	for _, w := range d.registry.watchers {
-		select {
-		case w.ch <- &registry.Result{Action: up.Action, Service: service}:
+		var service *registry.Service
+
+		switch up.Metadata["Content-Type"] {
+		case "application/json":
+			if err := json.Unmarshal(up.Data, &service); err != nil {
+				return
+			}
+		// no other content type
 		default:
+			return
 		}
-	}
+
+		// send update
+		d.updates <- &update{
+			Update:  up,
+			Service: service,
+		}
+	}()
 }
 
 func (d *delegate) GetBroadcasts(overhead, limit int) [][]byte {
@@ -148,9 +244,25 @@ func (d *delegate) GetBroadcasts(overhead, limit int) [][]byte {
 }
 
 func (d *delegate) LocalState(join bool) []byte {
-	d.registry.RLock()
-	b, _ := json.Marshal(d.registry.services)
-	d.registry.RUnlock()
+	if !join {
+		return []byte{}
+	}
+
+	syncCh := make(chan *registry.Service, 1)
+	services := map[string][]*registry.Service{}
+
+	d.updates <- &update{
+		Update: &pb.Update{
+			Action: syncAction,
+		},
+		sync: syncCh,
+	}
+
+	for srv := range syncCh {
+		services[srv.Name] = append(services[srv.Name], srv)
+	}
+
+	b, _ := json.Marshal(services)
 	return b
 }
 
@@ -161,37 +273,164 @@ func (d *delegate) MergeRemoteState(buf []byte, join bool) {
 	if !join {
 		return
 	}
+
 	var services map[string][]*registry.Service
 	if err := json.Unmarshal(buf, &services); err != nil {
 		return
 	}
 
-	d.registry.Lock()
-	for k, v := range services {
-		d.registry.services[k] = addServices(d.registry.services[k], v)
+	for _, service := range services {
+		for _, srv := range service {
+			d.updates <- &update{
+				Update:  &pb.Update{Action: addAction},
+				Service: srv,
+				sync:    nil,
+			}
+		}
+	}
+}
+
+func (g *gossipRegistry) publish(action string, services []*registry.Service) {
+	g.s.RLock()
+	for _, sub := range g.watchers {
+		go func(sub chan *registry.Result) {
+			for _, service := range services {
+				sub <- &registry.Result{Action: action, Service: service}
+			}
+		}(sub)
+	}
+	g.s.RUnlock()
+}
+
+func (g *gossipRegistry) subscribe() (chan *registry.Result, chan bool) {
+	next := make(chan *registry.Result, 10)
+	exit := make(chan bool)
+
+	id := uuid.New().String()
+
+	g.s.Lock()
+	g.watchers[id] = next
+	g.s.Unlock()
+
+	go func() {
+		<-exit
+		g.s.Lock()
+		delete(g.watchers, id)
+		close(next)
+		g.s.Unlock()
+	}()
+
+	return next, exit
+}
+
+func (g *gossipRegistry) run() {
+	var mtx sync.Mutex
+	updates := map[uint64]*update{}
+
+	// expiry loop
+	go func() {
+		t := time.NewTicker(ExpiryTick)
+		defer t.Stop()
+
+		for _ = range t.C {
+			now := uint64(time.Now().UnixNano())
+
+			mtx.Lock()
+
+			// process all the updates
+			for k, v := range updates {
+				// check if expiry time has passed
+				if d := (v.Update.Timestamp + v.Update.Expires); d < now {
+					// delete from records
+					delete(updates, k)
+					// set to delete
+					v.Update.Action = delAction
+					// fire a new update
+					g.updates <- v
+				}
+			}
+
+			mtx.Unlock()
+		}
+	}()
+
+	// process the updates
+	for u := range g.updates {
+		switch u.Update.Action {
+		case addAction:
+			g.Lock()
+			if service, ok := g.services[u.Service.Name]; !ok {
+				g.services[u.Service.Name] = []*registry.Service{u.Service}
+
+			} else {
+				g.services[u.Service.Name] = addServices(service, []*registry.Service{u.Service})
+			}
+			g.Unlock()
+
+			// publish update to watchers
+			go g.publish(addAction, []*registry.Service{u.Service})
+
+			// we need to expire the node at some point in the future
+			if u.Update.Expires > 0 {
+				// create a hash of this service
+				if hash, err := hashstructure.Hash(u.Service, nil); err == nil {
+					mtx.Lock()
+					updates[hash] = u
+					mtx.Unlock()
+				}
+			}
+		case delAction:
+			g.Lock()
+			if service, ok := g.services[u.Service.Name]; ok {
+				if services := delServices(service, []*registry.Service{u.Service}); len(services) == 0 {
+					delete(g.services, u.Service.Name)
+				} else {
+					g.services[u.Service.Name] = services
+				}
+			}
+			g.Unlock()
+
+			// publish update to watchers
+			go g.publish(delAction, []*registry.Service{u.Service})
+
+			// delete from expiry checks
+			if hash, err := hashstructure.Hash(u.Service, nil); err == nil {
+				mtx.Lock()
+				delete(updates, hash)
+				mtx.Unlock()
+			}
+		case syncAction:
+			// no sync channel provided
+			if u.sync == nil {
+				continue
+			}
+
+			g.RLock()
+
+			// push all services through the sync chan
+			for _, service := range g.services {
+				for _, srv := range service {
+					u.sync <- srv
+				}
+
+				// publish to watchers
+				go g.publish(addAction, service)
+			}
+
+			g.RUnlock()
+
+			// close the sync chan
+			close(u.sync)
+		}
 	}
-	d.registry.Unlock()
 }
 
 func (g *gossipRegistry) Init(opts ...registry.Option) error {
-	addrs := g.opts.Addrs
-	for _, o := range opts {
-		o(&g.opts)
-	}
-
-	// if we have memberlist join it
-	if len(addrs) != len(g.opts.Addrs) {
-		_, err := g.memberlist.Join(g.opts.Addrs)
-		if err != nil {
-			return err
-		}
-	}
-
-	return nil
+	return configure(g, opts...)
 }
 
 func (g *gossipRegistry) Options() registry.Options {
-	return g.opts
+	return g.options
 }
 
 func (g *gossipRegistry) Register(s *registry.Service, opts ...registry.RegisterOption) error {
@@ -201,12 +440,22 @@ func (g *gossipRegistry) Register(s *registry.Service, opts ...registry.Register
 	}
 
 	g.Lock()
-	g.services[s.Name] = addServices(g.services[s.Name], []*registry.Service{s})
+	if service, ok := g.services[s.Name]; !ok {
+		g.services[s.Name] = []*registry.Service{s}
+	} else {
+		g.services[s.Name] = addServices(service, []*registry.Service{s})
+	}
 	g.Unlock()
 
+	var options registry.RegisterOptions
+	for _, o := range opts {
+		o(&options)
+	}
+
 	up := &pb.Update{
 		Id:        uuid.New().String(),
 		Timestamp: uint64(time.Now().UnixNano()),
+		Expires:   uint64(options.TTL.Nanoseconds()),
 		Action:    "update",
 		Type:      "service",
 		Metadata: map[string]string{
@@ -220,6 +469,9 @@ func (g *gossipRegistry) Register(s *registry.Service, opts ...registry.Register
 		notify: nil,
 	})
 
+	// wait
+	<-time.After(g.interval * 2)
+
 	return nil
 }
 
@@ -230,7 +482,13 @@ func (g *gossipRegistry) Deregister(s *registry.Service) error {
 	}
 
 	g.Lock()
-	g.services[s.Name] = delServices(g.services[s.Name], []*registry.Service{s})
+	if service, ok := g.services[s.Name]; ok {
+		if services := delServices(service, []*registry.Service{s}); len(services) == 0 {
+			delete(g.services, s.Name)
+		} else {
+			g.services[s.Name] = services
+		}
+	}
 	g.Unlock()
 
 	up := &pb.Update{
@@ -249,135 +507,59 @@ func (g *gossipRegistry) Deregister(s *registry.Service) error {
 		notify: nil,
 	})
 
+	// wait
+	<-time.After(g.interval * 2)
+
 	return nil
 }
 
 func (g *gossipRegistry) GetService(name string) ([]*registry.Service, error) {
 	g.RLock()
-	if s, ok := g.services[name]; ok {
-		service := cp(s)
-		g.RUnlock()
-		return service, nil
-	}
+	service, ok := g.services[name]
 	g.RUnlock()
-	return nil, registry.ErrNotFound
+	if !ok {
+		return nil, registry.ErrNotFound
+	}
+	return service, nil
 }
 
 func (g *gossipRegistry) ListServices() ([]*registry.Service, error) {
 	var services []*registry.Service
 	g.RLock()
-	for name, _ := range g.services {
-		services = append(services, &registry.Service{Name: name})
+	for _, service := range g.services {
+		services = append(services, service...)
 	}
 	g.RUnlock()
 	return services, nil
 }
 
 func (g *gossipRegistry) Watch(opts ...registry.WatchOption) (registry.Watcher, error) {
-	var options registry.WatchOptions
-	for _, o := range opts {
-		o(&options)
-	}
-
-	// watcher id
-	id := uuid.New().String()
-
-	// create watcher
-	w := &watcher{
-		ch:   make(chan *registry.Result, 1),
-		exit: make(chan bool),
-		id:   id,
-		// filter service
-		srv: options.Service,
-		// delete self
-		fn: func() {
-			g.Lock()
-			delete(g.watchers, id)
-			g.Unlock()
-		},
-	}
-
-	// save watcher
-	g.Lock()
-	g.watchers[w.id] = w
-	g.Unlock()
-
-	return w, nil
+	n, e := g.subscribe()
+	return newGossipWatcher(n, e, opts...)
 }
 
 func (g *gossipRegistry) String() string {
 	return "gossip"
 }
 
-func (g *gossipRegistry) run() error {
-	hostname, _ := os.Hostname()
-
-	// delegates
-	d := new(delegate)
-
-	// create a new default config
-	c := memberlist.DefaultLocalConfig()
-
-	// assign the delegate
-	c.Delegate = d
-
-	// Set the bind port
-	c.BindPort = defaultPort
-
-	// set the name
-	c.Name = strings.Join([]string{"micro", hostname, uuid.New().String()}, "-")
-
-	// log to dev null
-	c.LogOutput = ioutil.Discard
-
-	// TODO: set advertise addr to advertise behind nat
-
-	// create the memberlist
-	m, err := memberlist.Create(c)
-	if err != nil {
-		return err
-	}
-
-	// if we have memberlist join it
-	if len(g.opts.Addrs) > 0 {
-		_, err := m.Join(g.opts.Addrs)
-		if err != nil {
-			return err
-		}
-	}
-
-	// Set the broadcast limit and number of nodes
-	d.queue = &memberlist.TransmitLimitedQueue{
-		NumNodes: func() int {
-			return m.NumMembers()
-		},
-		RetransmitMult: 3,
-	}
-
-	g.queue = d.queue
-	g.memberlist = m
-	g.delegate = d
-	d.registry = g
-
-	return nil
-}
-
-// NewRegistry returns a new gossip registry
 func NewRegistry(opts ...registry.Option) registry.Registry {
-	var options registry.Options
-	for _, o := range opts {
-		o(&options)
-	}
-
-	g := &gossipRegistry{
-		opts:     options,
+	gossip := &gossipRegistry{
+		options:  registry.Options{},
+		updates:  make(chan *update, 100),
 		services: make(map[string][]*registry.Service),
-	}
-	if err := g.run(); err != nil {
-		log.Fatal(err)
+		watchers: make(map[string]chan *registry.Result),
 	}
 
-	log.Logf("Registry Listening on %s", g.memberlist.LocalNode().Address())
-	// return gossip registry
-	return g
+	// configure the gossiper
+	if err := configure(gossip, opts...); err != nil {
+		log.Fatal("Error configuring registry: %v", err)
+	}
+
+	// run the updater
+	go gossip.run()
+
+	// wait for setup
+	<-time.After(gossip.interval * 2)
+
+	return gossip
 }