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Set MDNS as default registry

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This commit is contained in:
Asim Aslam 2019-01-15 16:50:37 +00:00 committed by Vasiliy Tolstov
parent 3f821c9940
commit d1d6608f90
6 changed files with 3 additions and 828 deletions
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73
encoding.go
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@ -1,73 +0,0 @@
package mdns
import (
"bytes"
"compress/zlib"
"encoding/hex"
"encoding/json"
"io/ioutil"
"strings"
)
func encode(txt *mdnsTxt) ([]string, error) {
b, err := json.Marshal(txt)
if err != nil {
return nil, err
}
var buf bytes.Buffer
defer buf.Reset()
w := zlib.NewWriter(&buf)
if _, err := w.Write(b); err != nil {
return nil, err
}
w.Close()
encoded := hex.EncodeToString(buf.Bytes())
// individual txt limit
if len(encoded) <= 255 {
return []string{encoded}, nil
}
// split encoded string
var record []string
for len(encoded) > 255 {
record = append(record, encoded[:255])
encoded = encoded[255:]
}
record = append(record, encoded)
return record, nil
}
func decode(record []string) (*mdnsTxt, error) {
encoded := strings.Join(record, "")
hr, err := hex.DecodeString(encoded)
if err != nil {
return nil, err
}
br := bytes.NewReader(hr)
zr, err := zlib.NewReader(br)
if err != nil {
return nil, err
}
rbuf, err := ioutil.ReadAll(zr)
if err != nil {
return nil, err
}
var txt *mdnsTxt
if err := json.Unmarshal(rbuf, &txt); err != nil {
return nil, err
}
return txt, nil
}

67
encoding_test.go
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@ -1,67 +0,0 @@
package mdns
import (
"testing"
"github.com/micro/go-micro/registry"
)
func TestEncoding(t *testing.T) {
testData := []*mdnsTxt{
&mdnsTxt{
Version: "1.0.0",
Metadata: map[string]string{
"foo": "bar",
},
Endpoints: []*registry.Endpoint{
&registry.Endpoint{
Name: "endpoint1",
Request: &registry.Value{
Name: "request",
Type: "request",
},
Response: &registry.Value{
Name: "response",
Type: "response",
},
Metadata: map[string]string{
"foo1": "bar1",
},
},
},
},
}
for _, d := range testData {
encoded, err := encode(d)
if err != nil {
t.Fatal(err)
}
for _, txt := range encoded {
if len(txt) > 255 {
t.Fatalf("One of parts for txt is %d characters", len(txt))
}
}
decoded, err := decode(encoded)
if err != nil {
t.Fatal(err)
}
if decoded.Version != d.Version {
t.Fatalf("Expected version %s got %s", d.Version, decoded.Version)
}
if len(decoded.Endpoints) != len(d.Endpoints) {
t.Fatalf("Expected %d endpoints, got %d", len(d.Endpoints), len(decoded.Endpoints))
}
for k, v := range d.Metadata {
if val := decoded.Metadata[k]; val != v {
t.Fatalf("Expected %s=%s got %s=%s", k, v, k, val)
}
}
}
}

334
mdns.go
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@ -1,339 +1,11 @@
// Package mdns is a multicast dns registry // Package mdns provides a multicast dns registry
package mdns package mdns
/*
MDNS is a multicast dns registry for service discovery
This creates a zero dependency system which is great
where multicast dns is available. This usually depends
on the ability to leverage udp and multicast/broadcast.
*/
import ( import (
"net"
"strings"
"sync"
"time"
"github.com/micro/go-micro/registry" "github.com/micro/go-micro/registry"
"github.com/micro/mdns"
hash "github.com/mitchellh/hashstructure"
) )
type mdnsTxt struct { // NewRegistry returns a new mdns registry
Service string
Version string
Endpoints []*registry.Endpoint
Metadata map[string]string
}
type mdnsEntry struct {
hash uint64
id string
node *mdns.Server
}
type mdnsRegistry struct {
opts registry.Options
sync.Mutex
services map[string][]*mdnsEntry
}
func newRegistry(opts ...registry.Option) registry.Registry {
options := registry.Options{
Timeout: time.Millisecond * 100,
}
return &mdnsRegistry{
opts: options,
services: make(map[string][]*mdnsEntry),
}
}
func (m *mdnsRegistry) Init(opts ...registry.Option) error {
for _, o := range opts {
o(&m.opts)
}
return nil
}
func (m *mdnsRegistry) Options() registry.Options {
return m.opts
}
func (m *mdnsRegistry) Register(service *registry.Service, opts ...registry.RegisterOption) error {
m.Lock()
defer m.Unlock()
entries, ok := m.services[service.Name]
// first entry, create wildcard used for list queries
if !ok {
s, err := mdns.NewMDNSService(
service.Name,
"_services",
"",
"",
9999,
[]net.IP{net.ParseIP("0.0.0.0")},
nil,
)
if err != nil {
return err
}
srv, err := mdns.NewServer(&mdns.Config{Zone: &mdns.DNSSDService{s}})
if err != nil {
return err
}
// append the wildcard entry
entries = append(entries, &mdnsEntry{id: "*", node: srv})
}
var gerr error
for _, node := range service.Nodes {
// create hash of service; uint64
h, err := hash.Hash(node, nil)
if err != nil {
gerr = err
continue
}
var seen bool
var e *mdnsEntry
for _, entry := range entries {
if node.Id == entry.id {
seen = true
e = entry
break
}
}
// already registered, continue
if seen && e.hash == h {
continue
// hash doesn't match, shutdown
} else if seen {
e.node.Shutdown()
// doesn't exist
} else {
e = &mdnsEntry{hash: h}
}
txt, err := encode(&mdnsTxt{
Service: service.Name,
Version: service.Version,
Endpoints: service.Endpoints,
Metadata: node.Metadata,
})
if err != nil {
gerr = err
continue
}
// we got here, new node
s, err := mdns.NewMDNSService(
node.Id,
service.Name,
"",
"",
node.Port,
[]net.IP{net.ParseIP(node.Address)},
txt,
)
if err != nil {
gerr = err
continue
}
srv, err := mdns.NewServer(&mdns.Config{Zone: s})
if err != nil {
gerr = err
continue
}
e.id = node.Id
e.node = srv
entries = append(entries, e)
}
// save
m.services[service.Name] = entries
return gerr
}
func (m *mdnsRegistry) Deregister(service *registry.Service) error {
m.Lock()
defer m.Unlock()
var newEntries []*mdnsEntry
// loop existing entries, check if any match, shutdown those that do
for _, entry := range m.services[service.Name] {
var remove bool
for _, node := range service.Nodes {
if node.Id == entry.id {
entry.node.Shutdown()
remove = true
break
}
}
// keep it?
if !remove {
newEntries = append(newEntries, entry)
}
}
// last entry is the wildcard for list queries. Remove it.
if len(newEntries) == 1 && newEntries[0].id == "*" {
newEntries[0].node.Shutdown()
delete(m.services, service.Name)
} else {
m.services[service.Name] = newEntries
}
return nil
}
func (m *mdnsRegistry) GetService(service string) ([]*registry.Service, error) {
p := mdns.DefaultParams(service)
p.Timeout = m.opts.Timeout
entryCh := make(chan *mdns.ServiceEntry, 10)
p.Entries = entryCh
exit := make(chan bool)
defer close(exit)
serviceMap := make(map[string]*registry.Service)
go func() {
for {
select {
case e := <-entryCh:
// list record so skip
if p.Service == "_services" {
continue
}
if e.TTL == 0 {
continue
}
txt, err := decode(e.InfoFields)
if err != nil {
continue
}
if txt.Service != service {
continue
}
s, ok := serviceMap[txt.Version]
if !ok {
s = &registry.Service{
Name: txt.Service,
Version: txt.Version,
Endpoints: txt.Endpoints,
}
}
s.Nodes = append(s.Nodes, &registry.Node{
Id: strings.TrimSuffix(e.Name, "."+p.Service+"."+p.Domain+"."),
Address: e.AddrV4.String(),
Port: e.Port,
Metadata: txt.Metadata,
})
serviceMap[txt.Version] = s
case <-exit:
return
}
}
}()
if err := mdns.Query(p); err != nil {
return nil, err
}
// create list and return
var services []*registry.Service
for _, service := range serviceMap {
services = append(services, service)
}
return services, nil
}
func (m *mdnsRegistry) ListServices() ([]*registry.Service, error) {
p := mdns.DefaultParams("_services")
p.Timeout = m.opts.Timeout
entryCh := make(chan *mdns.ServiceEntry, 10)
p.Entries = entryCh
exit := make(chan bool)
defer close(exit)
serviceMap := make(map[string]bool)
var services []*registry.Service
go func() {
for {
select {
case e := <-entryCh:
if e.TTL == 0 {
continue
}
name := strings.TrimSuffix(e.Name, "."+p.Service+"."+p.Domain+".")
if !serviceMap[name] {
serviceMap[name] = true
services = append(services, &registry.Service{Name: name})
}
case <-exit:
return
}
}
}()
if err := mdns.Query(p); err != nil {
return nil, err
}
return services, nil
}
func (m *mdnsRegistry) Watch(opts ...registry.WatchOption) (registry.Watcher, error) {
var wo registry.WatchOptions
for _, o := range opts {
o(&wo)
}
md := &mdnsWatcher{
wo: wo,
ch: make(chan *mdns.ServiceEntry, 32),
exit: make(chan struct{}),
}
go func() {
if err := mdns.Listen(md.ch, md.exit); err != nil {
md.Stop()
}
}()
return md, nil
}
func (m *mdnsRegistry) String() string {
return "mdns"
}
func NewRegistry(opts ...registry.Option) registry.Registry { func NewRegistry(opts ...registry.Option) registry.Registry {
return newRegistry(opts...) return registry.NewRegistry(opts...)
} }

134
mdns_test.go
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@ -1,134 +0,0 @@
package mdns
import (
"testing"
"time"
"github.com/micro/go-micro/registry"
)
func TestMDNS(t *testing.T) {
testData := []*registry.Service{
&registry.Service{
Name: "test1",
Version: "1.0.1",
Nodes: []*registry.Node{
&registry.Node{
Id: "test1-1",
Address: "10.0.0.1",
Port: 10001,
Metadata: map[string]string{
"foo": "bar",
},
},
},
},
&registry.Service{
Name: "test2",
Version: "1.0.2",
Nodes: []*registry.Node{
&registry.Node{
Id: "test2-1",
Address: "10.0.0.2",
Port: 10002,
Metadata: map[string]string{
"foo2": "bar2",
},
},
},
},
&registry.Service{
Name: "test3",
Version: "1.0.3",
Nodes: []*registry.Node{
&registry.Node{
Id: "test3-1",
Address: "10.0.0.3",
Port: 10003,
Metadata: map[string]string{
"foo3": "bar3",
},
},
},
},
}
// new registry
r := NewRegistry()
for _, service := range testData {
// register service
if err := r.Register(service); err != nil {
t.Fatal(err)
}
// get registered service
s, err := r.GetService(service.Name)
if err != nil {
t.Fatal(err)
}
if len(s) != 1 {
t.Fatalf("Expected one result for %s got %d", service.Name, len(s))
}
if s[0].Name != service.Name {
t.Fatalf("Expected name %s got %s", service.Name, s[0].Name)
}
if s[0].Version != service.Version {
t.Fatalf("Expected version %s got %s", service.Version, s[0].Version)
}
if len(s[0].Nodes) != 1 {
t.Fatalf("Expected 1 node, got %d", len(s[0].Nodes))
}
node := s[0].Nodes[0]
if node.Id != service.Nodes[0].Id {
t.Fatalf("Expected node id %s got %s", service.Nodes[0].Id, node.Id)
}
if node.Address != service.Nodes[0].Address {
t.Fatalf("Expected node address %s got %s", service.Nodes[0].Address, node.Address)
}
if node.Port != service.Nodes[0].Port {
t.Fatalf("Expected node port %d got %d", service.Nodes[0].Port, node.Port)
}
}
services, err := r.ListServices()
if err != nil {
t.Fatal(err)
}
for _, service := range testData {
var seen bool
for _, s := range services {
if s.Name == service.Name {
seen = true
break
}
}
if !seen {
t.Fatalf("Expected service %s got nothing", service.Name)
}
// deregister
if err := r.Deregister(service); err != nil {
t.Fatal(err)
}
time.Sleep(time.Millisecond * 5)
// check its gone
s, _ := r.GetService(service.Name)
if len(s) > 0 {
t.Fatalf("Expected nothing got %+v", s[0])
}
}
}

79
watcher.go
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@ -1,79 +0,0 @@
package mdns
import (
"errors"
"strings"
"github.com/micro/go-micro/registry"
"github.com/micro/mdns"
)
type mdnsWatcher struct {
wo registry.WatchOptions
ch chan *mdns.ServiceEntry
exit chan struct{}
}
func (m *mdnsWatcher) Next() (*registry.Result, error) {
for {
select {
case e := <-m.ch:
txt, err := decode(e.InfoFields)
if err != nil {
continue
}
if len(txt.Service) == 0 || len(txt.Version) == 0 {
continue
}
// Filter watch options
// wo.Service: Only keep services we care about
if len(m.wo.Service) > 0 && txt.Service != m.wo.Service {
continue
}
var action string
if e.TTL == 0 {
action = "delete"
} else {
action = "create"
}
service := &registry.Service{
Name: txt.Service,
Version: txt.Version,
Endpoints: txt.Endpoints,
}
// TODO: don't hardcode .local.
if !strings.HasSuffix(e.Name, "."+service.Name+".local.") {
continue
}
service.Nodes = append(service.Nodes, &registry.Node{
Id: strings.TrimSuffix(e.Name, "."+service.Name+".local."),
Address: e.AddrV4.String(),
Port: e.Port,
Metadata: txt.Metadata,
})
return &registry.Result{
Action: action,
Service: service,
}, nil
case <-m.exit:
return nil, errors.New("watcher stopped")
}
}
}
func (m *mdnsWatcher) Stop() {
select {
case <-m.exit:
return
default:
close(m.exit)
}
}

144
watcher_test.go
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@ -1,144 +0,0 @@
package mdns
import (
"testing"
"github.com/micro/go-micro/registry"
)
func TestWatcher(t *testing.T) {
testData := []*registry.Service{
&registry.Service{
Name: "test1",
Version: "1.0.1",
Nodes: []*registry.Node{
&registry.Node{
Id: "test1-1",
Address: "10.0.0.1",
Port: 10001,
Metadata: map[string]string{
"foo": "bar",
},
},
},
},
&registry.Service{
Name: "test2",
Version: "1.0.2",
Nodes: []*registry.Node{
&registry.Node{
Id: "test2-1",
Address: "10.0.0.2",
Port: 10002,
Metadata: map[string]string{
"foo2": "bar2",
},
},
},
},
&registry.Service{
Name: "test3",
Version: "1.0.3",
Nodes: []*registry.Node{
&registry.Node{
Id: "test3-1",
Address: "10.0.0.3",
Port: 10003,
Metadata: map[string]string{
"foo3": "bar3",
},
},
},
},
}
testFn := func(service, s *registry.Service) {
if s == nil {
t.Fatalf("Expected one result for %s got nil", service.Name)
}
if s.Name != service.Name {
t.Fatalf("Expected name %s got %s", service.Name, s.Name)
}
if s.Version != service.Version {
t.Fatalf("Expected version %s got %s", service.Version, s.Version)
}
if len(s.Nodes) != 1 {
t.Fatalf("Expected 1 node, got %d", len(s.Nodes))
}
node := s.Nodes[0]
if node.Id != service.Nodes[0].Id {
t.Fatalf("Expected node id %s got %s", service.Nodes[0].Id, node.Id)
}
if node.Address != service.Nodes[0].Address {
t.Fatalf("Expected node address %s got %s", service.Nodes[0].Address, node.Address)
}
if node.Port != service.Nodes[0].Port {
t.Fatalf("Expected node port %d got %d", service.Nodes[0].Port, node.Port)
}
}
// new registry
r := NewRegistry()
w, err := r.Watch()
if err != nil {
t.Fatal(err)
}
defer w.Stop()
for _, service := range testData {
// register service
if err := r.Register(service); err != nil {
t.Fatal(err)
}
for {
res, err := w.Next()
if err != nil {
t.Fatal(err)
}
if res.Service.Name != service.Name {
continue
}
if res.Action != "create" {
t.Fatalf("Expected create event got %s for %s", res.Action, res.Service.Name)
}
testFn(service, res.Service)
break
}
// deregister
if err := r.Deregister(service); err != nil {
t.Fatal(err)
}
for {
res, err := w.Next()
if err != nil {
t.Fatal(err)
}
if res.Service.Name != service.Name {
continue
}
if res.Action != "delete" {
continue
}
testFn(service, res.Service)
break
}
}
}