update the gossiper

cmd/cmd.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/micro/cli"
+	"github.com/micro/go-log"
 	"github.com/micro/go-micro/client"
 	"github.com/micro/go-micro/server"
 
@@ -301,10 +302,15 @@ func (c *cmd) Before(ctx *cli.Context) error {
 		serverOpts = append(serverOpts, server.Registry(*c.opts.Registry))
 		clientOpts = append(clientOpts, client.Registry(*c.opts.Registry))
 
-		(*c.opts.Selector).Init(selector.Registry(*c.opts.Registry))
+		if err := (*c.opts.Selector).Init(selector.Registry(*c.opts.Registry)); err != nil {
+			log.Fatalf("Error configuring registry: %v", err)
+		}
+
 		clientOpts = append(clientOpts, client.Selector(*c.opts.Selector))
 
-		(*c.opts.Broker).Init(broker.Registry(*c.opts.Registry))
+		if err := (*c.opts.Broker).Init(broker.Registry(*c.opts.Registry)); err != nil {
+			log.Fatalf("Error configuring broker: %v", err)
+		}
 	}
 
 	// Set the selector
@@ -349,15 +355,21 @@ func (c *cmd) Before(ctx *cli.Context) error {
 	}
 
 	if len(ctx.String("broker_address")) > 0 {
-		(*c.opts.Broker).Init(broker.Addrs(strings.Split(ctx.String("broker_address"), ",")...))
+		if err := (*c.opts.Broker).Init(broker.Addrs(strings.Split(ctx.String("broker_address"), ",")...)); err != nil {
+			log.Fatalf("Error configuring broker: %v", err)
+		}
 	}
 
 	if len(ctx.String("registry_address")) > 0 {
-		(*c.opts.Registry).Init(registry.Addrs(strings.Split(ctx.String("registry_address"), ",")...))
+		if err := (*c.opts.Registry).Init(registry.Addrs(strings.Split(ctx.String("registry_address"), ",")...)); err != nil {
+			log.Fatalf("Error configuring registry: %v", err)
+		}
 	}
 
 	if len(ctx.String("transport_address")) > 0 {
-		(*c.opts.Transport).Init(transport.Addrs(strings.Split(ctx.String("transport_address"), ",")...))
+		if err := (*c.opts.Transport).Init(transport.Addrs(strings.Split(ctx.String("transport_address"), ",")...)); err != nil {
+			log.Fatalf("Error configuring transport: %v", err)
+		}
 	}
 
 	if len(ctx.String("server_name")) > 0 {
@@ -412,12 +424,16 @@ func (c *cmd) Before(ctx *cli.Context) error {
 	// We have some command line opts for the server.
 	// Lets set it up
 	if len(serverOpts) > 0 {
-		(*c.opts.Server).Init(serverOpts...)
+		if err := (*c.opts.Server).Init(serverOpts...); err != nil {
+			log.Fatalf("Error configuring server: %v", err)
+		}
 	}
 
 	// Use an init option?
 	if len(clientOpts) > 0 {
-		(*c.opts.Client).Init(clientOpts...)
+		if err := (*c.opts.Client).Init(clientOpts...); err != nil {
+			log.Fatalf("Error configuring client: %v", err)
+		}
 	}
 
 	return nil

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 {
+const (
-	opts       registry.Options
+	addAction  = "update"
-	queue      *memberlist.TransmitLimitedQueue
+	delAction  = "delete"
-	memberlist *memberlist.Memberlist
+	syncAction = "sync"
-	delegate   *delegate
-
-	sync.RWMutex
-	services map[string][]*registry.Service
-	watchers map[string]*watcher
-}
-
-var (
-	// defaults to random port
-	defaultPort = 0
 )
 
 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)
+	go func() {
-	if err := proto.Unmarshal(b, up); err != nil {
+		up := new(pb.Update)
-		return
+		if err := proto.Unmarshal(b, up); err != nil {
-	}
-
-	// 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 {
 			return
 		}
-	// no other content type
-	default:
-		return
-	}
 
-	d.registry.Lock()
+		// only process service action
-	defer d.registry.Unlock()
+		if up.Type != "service" {
-
-	// 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)
 			return
 		}
-		d.registry.services[service.Name] = services
-	default:
-		return
-	}
 
-	// notify watchers
+		var service *registry.Service
-	for _, w := range d.registry.watchers {
+
-		select {
+		switch up.Metadata["Content-Type"] {
-		case w.ch <- &registry.Result{Action: up.Action, Service: service}:
+		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()
+	if !join {
-	b, _ := json.Marshal(d.registry.services)
+		return []byte{}
-	d.registry.RUnlock()
+	}
+
+	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 _, service := range services {
-	for k, v := range services {
+		for _, srv := range service {
-		d.registry.services[k] = addServices(d.registry.services[k], v)
+			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
+	return configure(g, opts...)
-	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
 }
 
 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, ok := g.services[name]
-		service := cp(s)
-		g.RUnlock()
-		return service, nil
-	}
 	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 {
+	for _, service := range g.services {
-		services = append(services, &registry.Service{Name: name})
+		services = append(services, service...)
 	}
 	g.RUnlock()
 	return services, nil
 }
 
 func (g *gossipRegistry) Watch(opts ...registry.WatchOption) (registry.Watcher, error) {
-	var options registry.WatchOptions
+	n, e := g.subscribe()
-	for _, o := range opts {
+	return newGossipWatcher(n, e, 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
 }
 
 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
+	gossip := &gossipRegistry{
-	for _, o := range opts {
+		options:  registry.Options{},
-		o(&options)
+		updates:  make(chan *update, 100),
-	}
-
-	g := &gossipRegistry{
-		opts:     options,
 		services: make(map[string][]*registry.Service),
-	}
+		watchers: make(map[string]chan *registry.Result),
-	if err := g.run(); err != nil {
-		log.Fatal(err)
 	}
 
-	log.Logf("Registry Listening on %s", g.memberlist.LocalNode().Address())
+	// configure the gossiper
-	// return gossip registry
+	if err := configure(gossip, opts...); err != nil {
-	return g
+		log.Fatal("Error configuring registry: %v", err)
+	}
+
+	// run the updater
+	go gossip.run()
+
+	// wait for setup
+	<-time.After(gossip.interval * 2)
+
+	return gossip
 }

registry/gossip/options.go

@@ -0,0 +1,17 @@
+package gossip
+
+import (
+	"context"
+
+	"github.com/micro/go-micro/registry"
+)
+
+type contextSecretKey struct{}
+
+// Secret specifies an encryption key. The value should be either
+// 16, 24, or 32 bytes to select AES-128, AES-192, or AES-256.
+func Secret(k []byte) registry.Option {
+	return func(o *registry.Options) {
+		o.Context = context.WithValue(o.Context, contextSecretKey{}, k)
+	}
+}

registry/gossip/proto/gossip.pb.go

@@ -1,20 +1,13 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // source: github.com/micro/go-micro/registry/gossip/proto/gossip.proto
 
-/*
-Package gossip is a generated protocol buffer package.
-
-It is generated from these files:
-	github.com/micro/go-micro/registry/gossip/proto/gossip.proto
-
-It has these top-level messages:
-	Update
-*/
 package gossip
 
-import proto "github.com/golang/protobuf/proto"
+import (
-import fmt "fmt"
+	fmt "fmt"
-import math "math"
+	proto "github.com/golang/protobuf/proto"
+	math "math"
+)
 
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
@@ -25,28 +18,53 @@ var _ = math.Inf
 // is compatible with the proto package it is being compiled against.
 // A compilation error at this line likely means your copy of the
 // proto package needs to be updated.
-const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
 
 // Update is the message broadcast
 type Update struct {
 	// unique id of update
-	Id string `protobuf:"bytes,1,opt,name=id" json:"id,omitempty"`
+	Id string `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
 	// unix nano timestamp of update
-	Timestamp uint64 `protobuf:"varint,2,opt,name=timestamp" json:"timestamp,omitempty"`
+	Timestamp uint64 `protobuf:"varint,2,opt,name=timestamp,proto3" json:"timestamp,omitempty"`
+	// time to live for entry
+	Expires uint64 `protobuf:"varint,3,opt,name=expires,proto3" json:"expires,omitempty"`
 	// type of update; service
-	Type string `protobuf:"bytes,3,opt,name=type" json:"type,omitempty"`
+	Type string `protobuf:"bytes,4,opt,name=type,proto3" json:"type,omitempty"`
 	// what action is taken; add, del, put
-	Action string `protobuf:"bytes,4,opt,name=action" json:"action,omitempty"`
+	Action string `protobuf:"bytes,5,opt,name=action,proto3" json:"action,omitempty"`
 	// any other associated metadata about the data
-	Metadata map[string]string `protobuf:"bytes,5,rep,name=metadata" json:"metadata,omitempty" protobuf_key:"bytes,1,opt,name=key" protobuf_val:"bytes,2,opt,name=value"`
+	Metadata map[string]string `protobuf:"bytes,6,rep,name=metadata,proto3" json:"metadata,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
 	// the payload data;
-	Data []byte `protobuf:"bytes,6,opt,name=data,proto3" json:"data,omitempty"`
+	Data                 []byte   `protobuf:"bytes,7,opt,name=data,proto3" json:"data,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
-func (m *Update) Reset()                    { *m = Update{} }
+func (m *Update) Reset()         { *m = Update{} }
-func (m *Update) String() string            { return proto.CompactTextString(m) }
+func (m *Update) String() string { return proto.CompactTextString(m) }
-func (*Update) ProtoMessage()               {}
+func (*Update) ProtoMessage()    {}
-func (*Update) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
+func (*Update) Descriptor() ([]byte, []int) {
+	return fileDescriptor_18cba623e76e57f3, []int{0}
+}
+
+func (m *Update) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Update.Unmarshal(m, b)
+}
+func (m *Update) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Update.Marshal(b, m, deterministic)
+}
+func (m *Update) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Update.Merge(m, src)
+}
+func (m *Update) XXX_Size() int {
+	return xxx_messageInfo_Update.Size(m)
+}
+func (m *Update) XXX_DiscardUnknown() {
+	xxx_messageInfo_Update.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Update proto.InternalMessageInfo
 
 func (m *Update) GetId() string {
 	if m != nil {
@@ -62,6 +80,13 @@ func (m *Update) GetTimestamp() uint64 {
 	return 0
 }
 
+func (m *Update) GetExpires() uint64 {
+	if m != nil {
+		return m.Expires
+	}
+	return 0
+}
+
 func (m *Update) GetType() string {
 	if m != nil {
 		return m.Type
@@ -92,27 +117,29 @@ func (m *Update) GetData() []byte {
 
 func init() {
 	proto.RegisterType((*Update)(nil), "gossip.Update")
+	proto.RegisterMapType((map[string]string)(nil), "gossip.Update.MetadataEntry")
 }
 
 func init() {
-	proto.RegisterFile("github.com/micro/go-micro/registry/gossip/proto/gossip.proto", fileDescriptor0)
+	proto.RegisterFile("github.com/micro/go-micro/registry/gossip/proto/gossip.proto", fileDescriptor_18cba623e76e57f3)
 }
 
-var fileDescriptor0 = []byte{
+var fileDescriptor_18cba623e76e57f3 = []byte{
-	// 237 bytes of a gzipped FileDescriptorProto
+	// 251 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x54, 0x8f, 0xcf, 0x4a, 0xc4, 0x30,
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x54, 0x90, 0xcf, 0x4a, 0xc4, 0x30,
-	0x10, 0xc6, 0x49, 0xdb, 0x0d, 0x76, 0xfc, 0x83, 0x0c, 0x22, 0x41, 0xf6, 0x50, 0x3c, 0xf5, 0x62,
+	0x10, 0x87, 0x69, 0xb6, 0x9b, 0xb5, 0xe3, 0x1f, 0x64, 0x10, 0x09, 0xb2, 0x87, 0xe2, 0xa9, 0x17,
-	0x0b, 0x7a, 0x59, 0xd4, 0xab, 0x47, 0x2f, 0x01, 0x1f, 0x20, 0xdb, 0x86, 0x1a, 0x34, 0x9b, 0x90,
+	0x5b, 0xd0, 0xcb, 0xa2, 0x5e, 0x3d, 0x7a, 0x09, 0xf8, 0x00, 0xd9, 0x36, 0xd4, 0xa0, 0xd9, 0x84,
-	0xce, 0x0a, 0x7d, 0x68, 0xdf, 0x41, 0x9a, 0x04, 0xc5, 0xdb, 0xef, 0x37, 0xf9, 0xc2, 0x7c, 0x03,
+	0x64, 0x56, 0xec, 0x13, 0xf8, 0xda, 0xb2, 0x69, 0x54, 0xbc, 0x7d, 0xdf, 0xcc, 0x24, 0x99, 0x5f,
-	0xcf, 0x93, 0xa1, 0xf7, 0xe3, 0xbe, 0x1b, 0x9c, 0xed, 0xad, 0x19, 0x82, 0xeb, 0x27, 0x77, 0x97,
+	0xe0, 0x71, 0x34, 0xf4, 0xba, 0xdf, 0xb6, 0xbd, 0xb3, 0x9d, 0x35, 0x7d, 0x70, 0xdd, 0xe8, 0x6e,
-	0x20, 0xe8, 0xc9, 0xcc, 0x14, 0x96, 0x7e, 0x72, 0xf3, 0x6c, 0x7c, 0xef, 0x83, 0x23, 0x97, 0xa5,
+	0x66, 0x08, 0x7a, 0x34, 0x91, 0xc2, 0xd4, 0x8d, 0x2e, 0x46, 0xe3, 0x3b, 0x1f, 0x1c, 0xb9, 0x2c,
-	0x8b, 0x82, 0x3c, 0xd9, 0xed, 0x37, 0x03, 0xfe, 0xe6, 0x47, 0x45, 0x1a, 0x2f, 0xa0, 0x30, 0xa3,
+	0x6d, 0x12, 0xe4, 0xb3, 0x5d, 0x7f, 0x31, 0xe0, 0x2f, 0x7e, 0x50, 0xa4, 0xf1, 0x0c, 0x98, 0x19,
-	0x60, 0x0d, 0x6b, 0x6b, 0x59, 0x98, 0x11, 0xb7, 0x50, 0x93, 0xb1, 0x7a, 0x26, 0x65, 0xbd, 0x28,
+	0x44, 0x51, 0x17, 0x4d, 0x25, 0x99, 0x19, 0x70, 0x0d, 0x15, 0x19, 0xab, 0x23, 0x29, 0xeb, 0x05,
-	0x1a, 0xd6, 0x56, 0xf2, 0x6f, 0x80, 0x08, 0x15, 0x2d, 0x5e, 0x8b, 0x32, 0xe6, 0x23, 0xe3, 0x35,
+	0xab, 0x8b, 0xa6, 0x94, 0x7f, 0x05, 0x14, 0xb0, 0xd2, 0x9f, 0xde, 0x04, 0x1d, 0xc5, 0x22, 0xf5,
-	0x70, 0x35, 0x90, 0x71, 0x07, 0x51, 0xc5, 0x69, 0x36, 0xdc, 0xc1, 0x89, 0xd5, 0xa4, 0x46, 0x45,
+	0x7e, 0x14, 0x11, 0x4a, 0x9a, 0xbc, 0x16, 0x65, 0xba, 0x29, 0x31, 0x5e, 0x02, 0x57, 0x3d, 0x19,
-	0x4a, 0x6c, 0x9a, 0xb2, 0x3d, 0xbd, 0xdf, 0x76, 0xb9, 0x4d, 0xda, 0xdd, 0xbd, 0xe6, 0xe7, 0x97,
+	0xb7, 0x13, 0xcb, 0x54, 0xcd, 0x86, 0x1b, 0x38, 0xb2, 0x9a, 0xd4, 0xa0, 0x48, 0x09, 0x5e, 0x2f,
-	0x03, 0x85, 0x45, 0xfe, 0xa6, 0xd7, 0x2d, 0xf1, 0x17, 0x6f, 0x58, 0x7b, 0x26, 0x23, 0xdf, 0x3c,
+	0x9a, 0xe3, 0xdb, 0x75, 0x9b, 0xf7, 0x9c, 0xb7, 0x6a, 0x9f, 0x73, 0xfb, 0x69, 0x47, 0x61, 0x92,
-	0xc1, 0xf9, 0xbf, 0x38, 0x5e, 0x42, 0xf9, 0xa1, 0x97, 0xdc, 0x7c, 0x45, 0xbc, 0x82, 0xcd, 0x97,
+	0xbf, 0xd3, 0x87, 0x57, 0xd2, 0xa9, 0x55, 0x5d, 0x34, 0x27, 0x32, 0xf1, 0xd5, 0x03, 0x9c, 0xfe,
-	0xfa, 0x3c, 0xea, 0x58, 0xbb, 0x96, 0x49, 0x1e, 0x8b, 0x1d, 0xdb, 0xf3, 0x78, 0xfe, 0xc3, 0x4f,
+	0x1b, 0xc7, 0x73, 0x58, 0xbc, 0xe9, 0x29, 0x67, 0x3a, 0x20, 0x5e, 0xc0, 0xf2, 0x43, 0xbd, 0xef,
-	0x00, 0x00, 0x00, 0xff, 0xff, 0xf0, 0x49, 0xa9, 0xd7, 0x3e, 0x01, 0x00, 0x00,
+	0x75, 0x0a, 0x54, 0xc9, 0x59, 0xee, 0xd9, 0xa6, 0xd8, 0xf2, 0xf4, 0x31, 0x77, 0xdf, 0x01, 0x00,
+	0x00, 0xff, 0xff, 0x06, 0x6e, 0x00, 0x3c, 0x58, 0x01, 0x00, 0x00,
 }

registry/gossip/proto/gossip.proto

@@ -8,12 +8,14 @@ message Update {
 	string id = 1;
 	// unix nano timestamp of update
 	uint64 timestamp = 2;
+	// time to live for entry
+	uint64 expires = 3;
 	// type of update; service
-	string type = 3;
+	string type = 4;
 	// what action is taken; add, del, put
-	string action = 4;
+	string action = 5;
 	// any other associated metadata about the data
-	map<string, string> metadata = 5;
+	map<string, string> metadata = 6;
 	// the payload data;
-	bytes data = 6;
+	bytes data = 7;
 }

registry/gossip/watcher.go

@@ -4,37 +4,48 @@ import (
 	"github.com/micro/go-micro/registry"
 )
 
-type watcher struct {
+type gossipWatcher struct {
-	id   string
+	wo   registry.WatchOptions
-	srv  string
+	next chan *registry.Result
-	ch   chan *registry.Result
+	stop chan bool
-	exit chan bool
-	fn   func()
 }
 
-func (w *watcher) Next() (*registry.Result, error) {
+func newGossipWatcher(ch chan *registry.Result, stop chan bool, opts ...registry.WatchOption) (registry.Watcher, error) {
+	var wo registry.WatchOptions
+	for _, o := range opts {
+		o(&wo)
+	}
+
+	return &gossipWatcher{
+		wo:   wo,
+		next: ch,
+		stop: stop,
+	}, nil
+}
+
+func (m *gossipWatcher) Next() (*registry.Result, error) {
 	for {
 		select {
-		case r := <-w.ch:
+		case r, ok := <-m.next:
-			if r.Service == nil {
+			if !ok {
-				continue
+				return nil, registry.ErrWatcherStopped
 			}
-			if len(w.srv) > 0 && (r.Service.Name != w.srv) {
+			// check watch options
+			if len(m.wo.Service) > 0 && r.Service.Name != m.wo.Service {
 				continue
 			}
 			return r, nil
-		case <-w.exit:
+		case <-m.stop:
 			return nil, registry.ErrWatcherStopped
 		}
 	}
 }
 
-func (w *watcher) Stop() {
+func (m *gossipWatcher) Stop() {
 	select {
-	case <-w.exit:
+	case <-m.stop:
 		return
 	default:
-		close(w.exit)
+		close(m.stop)
-		w.fn()
 	}
 }