gossip registry
This commit is contained in:
Asim Aslam
375
registry/gossip/gossip.go
Normal file
375
registry/gossip/gossip.go
Normal file
@@ -0,0 +1,375 @@
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// Package gossip provides a zero dependency registry using the gossip protocol SWIM
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package gossip
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import (
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"encoding/json"
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"os"
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"strings"
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"sync"
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"time"
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"github.com/golang/protobuf/proto"
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"github.com/google/uuid"
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"github.com/hashicorp/memberlist"
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"github.com/micro/go-log"
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"github.com/micro/go-micro/registry"
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pb "github.com/micro/go-micro/registry/gossip/proto"
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)
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type gossipRegistry struct {
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opts registry.Options
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queue *memberlist.TransmitLimitedQueue
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memberlist *memberlist.Memberlist
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delegate *delegate
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sync.RWMutex
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services map[string][]*registry.Service
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watchers map[string]*watcher
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}
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var (
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defaultPort = 8118
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)
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type broadcast struct {
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update *pb.Update
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notify chan<- struct{}
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}
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type delegate struct {
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queue *memberlist.TransmitLimitedQueue
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registry *gossipRegistry
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}
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func (b *broadcast) Invalidates(other memberlist.Broadcast) bool {
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up := new(pb.Update)
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if err := proto.Unmarshal(other.Message(), up); err != nil {
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return false
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}
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// ids do not match
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if b.update.Id == up.Id {
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return false
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}
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// timestamps do not match
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if b.update.Timestamp != up.Timestamp {
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return false
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}
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// type does not match
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if b.update.Type != up.Type {
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return false
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}
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// invalidates
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return true
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}
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func (b *broadcast) Message() []byte {
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up, err := proto.Marshal(b.update)
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if err != nil {
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return nil
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}
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return up
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}
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func (b *broadcast) Finished() {
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if b.notify != nil {
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close(b.notify)
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}
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}
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func (d *delegate) NodeMeta(limit int) []byte {
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return []byte{}
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}
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func (d *delegate) NotifyMsg(b []byte) {
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if len(b) == 0 {
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return
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}
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up := new(pb.Update)
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if err := proto.Unmarshal(b, up); err != nil {
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return
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}
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// only process service action
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if up.Type != "service" {
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return
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}
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var service *registry.Service
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switch up.Metadata["Content-Type"] {
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case "application/json":
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if err := json.Unmarshal(up.Data, &service); err != nil {
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return
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}
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// no other content type
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default:
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return
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}
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d.registry.Lock()
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defer d.registry.Unlock()
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// get existing service
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s := d.registry.services[service.Name]
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// save update
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switch up.Action {
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case "update":
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d.registry.services[service.Name] = addServices(s, []*registry.Service{service})
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case "delete":
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services := delServices(s, []*registry.Service{service})
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if len(services) == 0 {
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delete(d.registry.services, service.Name)
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return
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}
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d.registry.services[service.Name] = services
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default:
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return
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}
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// notify watchers
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for _, w := range d.registry.watchers {
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select {
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case w.ch <- ®istry.Result{Action: up.Action, Service: service}:
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default:
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}
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}
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}
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func (d *delegate) GetBroadcasts(overhead, limit int) [][]byte {
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return d.queue.GetBroadcasts(overhead, limit)
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}
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func (d *delegate) LocalState(join bool) []byte {
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d.registry.RLock()
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b, _ := json.Marshal(d.registry.services)
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d.registry.RUnlock()
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return b
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}
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func (d *delegate) MergeRemoteState(buf []byte, join bool) {
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if len(buf) == 0 {
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return
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}
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if !join {
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return
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}
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var services map[string][]*registry.Service
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if err := json.Unmarshal(buf, &services); err != nil {
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return
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}
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d.registry.Lock()
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for k, v := range services {
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d.registry.services[k] = addServices(d.registry.services[k], v)
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}
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d.registry.Unlock()
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}
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func (g *gossipRegistry) Init(opts ...registry.Option) error {
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addrs := g.opts.Addrs
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for _, o := range opts {
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o(&g.opts)
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}
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// if we have memberlist join it
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if len(addrs) != len(g.opts.Addrs) {
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_, err := g.memberlist.Join(g.opts.Addrs)
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if err != nil {
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return err
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}
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}
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return nil
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}
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func (g *gossipRegistry) Options() registry.Options {
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return g.opts
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}
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func (g *gossipRegistry) Register(s *registry.Service, opts ...registry.RegisterOption) error {
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b, err := json.Marshal(s)
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if err != nil {
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return err
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}
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g.Lock()
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g.services[s.Name] = addServices(g.services[s.Name], []*registry.Service{s})
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g.Unlock()
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up := &pb.Update{
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Id: uuid.New().String(),
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Timestamp: uint64(time.Now().UnixNano()),
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Action: "update",
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Type: "service",
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Metadata: map[string]string{
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"Content-Type": "application/json",
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},
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Data: b,
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}
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g.queue.QueueBroadcast(&broadcast{
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update: up,
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notify: nil,
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})
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return nil
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}
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func (g *gossipRegistry) Deregister(s *registry.Service) error {
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b, err := json.Marshal(s)
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if err != nil {
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return err
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}
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g.Lock()
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g.services[s.Name] = delServices(g.services[s.Name], []*registry.Service{s})
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g.Unlock()
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up := &pb.Update{
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Id: uuid.New().String(),
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Timestamp: uint64(time.Now().UnixNano()),
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Action: "delete",
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Type: "service",
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Metadata: map[string]string{
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"Content-Type": "application/json",
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},
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Data: b,
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}
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g.queue.QueueBroadcast(&broadcast{
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update: up,
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notify: nil,
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})
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return nil
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}
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func (g *gossipRegistry) GetService(name string) ([]*registry.Service, error) {
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g.RLock()
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if s, ok := g.services[name]; ok {
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service := cp(s)
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g.RUnlock()
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return service, nil
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}
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g.RUnlock()
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return nil, registry.ErrNotFound
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}
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func (g *gossipRegistry) ListServices() ([]*registry.Service, error) {
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var services []*registry.Service
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g.RLock()
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for name, _ := range g.services {
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services = append(services, ®istry.Service{Name: name})
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}
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g.RUnlock()
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return services, nil
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}
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func (g *gossipRegistry) Watch(opts ...registry.WatchOption) (registry.Watcher, error) {
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var options registry.WatchOptions
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for _, o := range opts {
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o(&options)
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}
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// watcher id
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id := uuid.New().String()
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// create watcher
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w := &watcher{
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ch: make(chan *registry.Result, 1),
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exit: make(chan bool),
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id: id,
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// filter service
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srv: options.Service,
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// delete self
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fn: func() {
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g.Lock()
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delete(g.watchers, id)
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g.Unlock()
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},
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}
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// save watcher
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g.Lock()
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g.watchers[w.id] = w
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g.Unlock()
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return w, nil
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}
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func (g *gossipRegistry) String() string {
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return "gossip"
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}
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func (g *gossipRegistry) run() error {
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hostname, _ := os.Hostname()
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// delegates
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d := new(delegate)
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// create a new default config
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c := memberlist.DefaultLocalConfig()
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// assign the delegate
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c.Delegate = d
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// Set the bind port
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c.BindPort = defaultPort
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// set the name
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c.Name = strings.Join([]string{"micro", hostname, uuid.New().String()}, "-")
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// TODO: set advertise addr to advertise behind nat
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// create the memberlist
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m, err := memberlist.Create(c)
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if err != nil {
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return err
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}
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// if we have memberlist join it
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if len(g.opts.Addrs) > 0 {
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_, err := m.Join(g.opts.Addrs)
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if err != nil {
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return err
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}
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}
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// Set the broadcast limit and number of nodes
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d.queue = &memberlist.TransmitLimitedQueue{
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NumNodes: func() int {
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return m.NumMembers()
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},
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RetransmitMult: 3,
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}
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g.memberlist = m
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g.delegate = d
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d.registry = g
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return nil
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}
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// NewRegistry returns a new gossip registry
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func NewRegistry(opts ...registry.Option) registry.Registry {
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var options registry.Options
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for _, o := range opts {
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o(&options)
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}
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g := &gossipRegistry{
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opts: options,
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}
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if err := g.run(); err != nil {
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log.Fatal(err)
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}
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// return gossip registry
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return g
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}
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