First attempt at mdns
This commit is contained in:
parent
65a880fadd
commit
6c108d95b2
@ -20,6 +20,7 @@ import (
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// registries
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"github.com/micro/go-micro/registry"
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"github.com/micro/go-micro/registry/consul"
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"github.com/micro/go-micro/registry/mdns"
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// selectors
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"github.com/micro/go-micro/selector"
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@ -139,6 +140,7 @@ var (
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DefaultRegistries = map[string]func(...registry.Option) registry.Registry{
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"consul": consul.NewRegistry,
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"mdns": mdns.NewRegistry,
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}
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DefaultSelectors = map[string]func(...selector.Option) selector.Selector{
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124
registry/mdns/encoding.go
Normal file
124
registry/mdns/encoding.go
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@ -0,0 +1,124 @@
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package mdns
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import (
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"bytes"
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"compress/zlib"
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"encoding/hex"
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"encoding/json"
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"io/ioutil"
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"github.com/micro/go-micro/registry"
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)
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func encode(buf []byte) string {
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var b bytes.Buffer
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defer b.Reset()
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w := zlib.NewWriter(&b)
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if _, err := w.Write(buf); err != nil {
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return ""
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}
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w.Close()
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return hex.EncodeToString(b.Bytes())
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}
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func decode(d string) []byte {
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hr, err := hex.DecodeString(d)
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if err != nil {
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return nil
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}
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br := bytes.NewReader(hr)
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zr, err := zlib.NewReader(br)
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if err != nil {
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return nil
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}
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rbuf, err := ioutil.ReadAll(zr)
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if err != nil {
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return nil
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}
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return rbuf
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}
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func encodeEndpoints(en []*registry.Endpoint) []string {
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var tags []string
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for _, e := range en {
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if b, err := json.Marshal(e); err == nil {
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tags = append(tags, "e-"+encode(b))
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}
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}
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return tags
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}
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func decodeEndpoints(tags []string) []*registry.Endpoint {
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var en []*registry.Endpoint
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for _, tag := range tags {
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if len(tag) == 0 || tag[0] != 'e' || tag[1] != '-' {
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continue
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}
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buf := decode(tag[2:])
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var e *registry.Endpoint
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if err := json.Unmarshal(buf, &e); err == nil {
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en = append(en, e)
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}
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}
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return en
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}
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func encodeMetadata(md map[string]string) []string {
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var tags []string
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for k, v := range md {
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if b, err := json.Marshal(map[string]string{
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k: v,
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}); err == nil {
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// new encoding
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tags = append(tags, "t-"+encode(b))
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}
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}
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return tags
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}
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func decodeMetadata(tags []string) map[string]string {
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md := make(map[string]string)
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for _, tag := range tags {
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if len(tag) == 0 || tag[0] != 't' || tag[1] != '-' {
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continue
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}
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buf := decode(tag[2:])
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var kv map[string]string
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// Now unmarshal
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if err := json.Unmarshal(buf, &kv); err == nil {
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for k, v := range kv {
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md[k] = v
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}
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}
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}
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return md
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}
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func encodeVersion(v string) []string {
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return []string{
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// new encoding,
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"v-" + encode([]byte(v)),
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}
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}
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func decodeVersion(tags []string) (string, bool) {
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for _, tag := range tags {
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if len(tag) < 2 || tag[0] != 'v' || tag[1] != '-' {
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continue
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}
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return string(decode(tag[2:])), true
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}
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return "", false
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}
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147
registry/mdns/encoding_test.go
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147
registry/mdns/encoding_test.go
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@ -0,0 +1,147 @@
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package mdns
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import (
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"encoding/json"
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"testing"
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"github.com/micro/go-micro/registry"
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)
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func TestEncodingEndpoints(t *testing.T) {
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eps := []*registry.Endpoint{
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®istry.Endpoint{
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Name: "endpoint1",
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Request: ®istry.Value{
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Name: "request",
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Type: "request",
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},
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Response: ®istry.Value{
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Name: "response",
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Type: "response",
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},
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Metadata: map[string]string{
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"foo1": "bar1",
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},
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},
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®istry.Endpoint{
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Name: "endpoint2",
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Request: ®istry.Value{
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Name: "request",
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Type: "request",
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},
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Response: ®istry.Value{
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Name: "response",
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Type: "response",
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},
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Metadata: map[string]string{
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"foo2": "bar2",
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},
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},
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®istry.Endpoint{
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Name: "endpoint3",
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Request: ®istry.Value{
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Name: "request",
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Type: "request",
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},
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Response: ®istry.Value{
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Name: "response",
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Type: "response",
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},
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Metadata: map[string]string{
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"foo3": "bar3",
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},
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},
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}
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testEp := func(ep *registry.Endpoint, enc string) {
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// encode endpoint
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e := encodeEndpoints([]*registry.Endpoint{ep})
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// check there are two tags; old and new
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if len(e) != 1 {
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t.Fatalf("Expected 1 encoded tag, got %v", e)
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}
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// check old encoding
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var seen bool
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for _, en := range e {
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if en == enc {
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seen = true
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break
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}
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}
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if !seen {
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t.Fatalf("Expected %s but not found", enc)
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}
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// decode
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d := decodeEndpoints([]string{enc})
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if len(d) == 0 {
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t.Fatalf("Expected %v got %v", ep, d)
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}
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// check name
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if d[0].Name != ep.Name {
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t.Fatalf("Expected ep %s got %s", ep.Name, d[0].Name)
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}
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// check all the metadata exists
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for k, v := range ep.Metadata {
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if gv := d[0].Metadata[k]; gv != v {
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t.Fatalf("Expected key %s val %s got val %s", k, v, gv)
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}
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}
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}
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for _, ep := range eps {
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// JSON encoded
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jencoded, err := json.Marshal(ep)
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if err != nil {
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t.Fatal(err)
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}
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// HEX encoded
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hencoded := encode(jencoded)
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// endpoint tag
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hepTag := "e-" + hencoded
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testEp(ep, hepTag)
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}
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}
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func TestEncodingVersion(t *testing.T) {
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testData := []struct {
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decoded string
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encoded string
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}{
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{"1.0.0", "v-789c32d433d03300040000ffff02ce00ee"},
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{"latest", "v-789cca492c492d2e01040000ffff08cc028e"},
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}
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for _, data := range testData {
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e := encodeVersion(data.decoded)
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if e[0] != data.encoded {
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t.Fatalf("Expected %s got %s", data.encoded, e)
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}
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d, ok := decodeVersion(e)
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if !ok {
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t.Fatalf("Unexpected %t for %s", ok, data.encoded)
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}
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if d != data.decoded {
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t.Fatalf("Expected %s got %s", data.decoded, d)
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}
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d, ok = decodeVersion([]string{data.encoded})
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if !ok {
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t.Fatalf("Unexpected %t for %s", ok, data.encoded)
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}
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if d != data.decoded {
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t.Fatalf("Expected %s got %s", data.decoded, d)
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}
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}
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}
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284
registry/mdns/mdns.go
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284
registry/mdns/mdns.go
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@ -0,0 +1,284 @@
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package mdns
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/*
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MDNS is a multicast dns registry for service discovery
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This creates a zero dependency system which is great
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where multicast dns is available. This usually depends
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on the ability to leverage udp and multicast/broadcast.
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*/
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import (
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"net"
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"strings"
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"sync"
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"time"
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"github.com/hashicorp/mdns"
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"github.com/micro/go-micro/registry"
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hash "github.com/mitchellh/hashstructure"
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)
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type mdnsEntry struct {
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hash uint64
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id string
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node *mdns.Server
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}
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type mdnsRegistry struct {
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opts registry.Options
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sync.Mutex
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services map[string][]*mdnsEntry
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}
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func newRegistry(opts ...registry.Option) registry.Registry {
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options := registry.Options{
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Timeout: time.Millisecond * 100,
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}
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return &mdnsRegistry{
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opts: options,
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services: make(map[string][]*mdnsEntry),
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}
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}
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func (m *mdnsRegistry) Register(service *registry.Service, opts ...registry.RegisterOption) error {
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m.Lock()
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defer m.Unlock()
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entries, ok := m.services[service.Name]
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// first entry, create wildcard used for list queries
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if !ok {
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s, err := mdns.NewMDNSService(
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service.Name,
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"_services",
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"",
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"",
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9999,
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[]net.IP{net.ParseIP("0.0.0.0")},
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nil,
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)
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if err != nil {
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return err
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}
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srv, err := mdns.NewServer(&mdns.Config{Zone: s})
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if err != nil {
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return err
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}
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// append the wildcard entry
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entries = append(entries, &mdnsEntry{id: "*", node: srv})
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}
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var gerr error
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for _, node := range service.Nodes {
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// create hash of service; uint64
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h, err := hash.Hash(node, nil)
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if err != nil {
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gerr = err
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continue
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}
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var seen bool
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var e *mdnsEntry
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for _, entry := range entries {
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if node.Id == entry.id {
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seen = true
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e = entry
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break
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}
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}
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// already registered, continue
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if seen && e.hash == h {
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continue
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// hash doesn't match, shutdown
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} else if seen {
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e.node.Shutdown()
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// doesn't exist
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} else {
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e = &mdnsEntry{hash: h}
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}
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var txt []string
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txt = append(txt, encodeVersion(service.Version)...)
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txt = append(txt, encodeMetadata(node.Metadata)...)
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// txt = append(txt, encodeEndpoints(service.Endpoints)...)
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// we got here, new node
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s, err := mdns.NewMDNSService(
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node.Id,
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service.Name,
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"",
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"",
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node.Port,
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[]net.IP{net.ParseIP(node.Address)},
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txt,
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)
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if err != nil {
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gerr = err
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continue
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}
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srv, err := mdns.NewServer(&mdns.Config{Zone: s})
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if err != nil {
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gerr = err
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continue
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}
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e.id = node.Id
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e.node = srv
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entries = append(entries, e)
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}
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// save
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m.services[service.Name] = entries
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return gerr
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}
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func (m *mdnsRegistry) Deregister(service *registry.Service) error {
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m.Lock()
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defer m.Unlock()
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var newEntries []*mdnsEntry
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// loop existing entries, check if any match, shutdown those that do
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for _, entry := range m.services[service.Name] {
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var remove bool
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for _, node := range service.Nodes {
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if node.Id == entry.id {
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entry.node.Shutdown()
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remove = true
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break
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}
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}
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// keep it?
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if !remove {
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newEntries = append(newEntries, entry)
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}
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}
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// last entry is the wildcard for list queries. Remove it.
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if len(newEntries) == 1 && newEntries[0].id == "*" {
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newEntries[0].node.Shutdown()
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delete(m.services, service.Name)
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} else {
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m.services[service.Name] = newEntries
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}
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return nil
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}
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func (m *mdnsRegistry) GetService(service string) ([]*registry.Service, error) {
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p := mdns.DefaultParams(service)
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p.Timeout = m.opts.Timeout
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entryCh := make(chan *mdns.ServiceEntry, 10)
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p.Entries = entryCh
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exit := make(chan bool)
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defer close(exit)
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serviceMap := make(map[string]*registry.Service)
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go func() {
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for {
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select {
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case e := <-entryCh:
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// list record so skip
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if p.Service == "_services" {
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continue
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}
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version, exists := decodeVersion(e.InfoFields)
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if !exists {
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continue
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}
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s, ok := serviceMap[version]
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if !ok {
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s = ®istry.Service{
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Name: service,
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Version: version,
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// Endpoints: decodeEndpoints(e.InfoFields),
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}
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}
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s.Nodes = append(s.Nodes, ®istry.Node{
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Id: strings.TrimSuffix(e.Name, "."+p.Service+"."+p.Domain+"."),
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Address: e.AddrV4.String(),
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Port: e.Port,
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Metadata: decodeMetadata(e.InfoFields),
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})
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serviceMap[version] = s
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case <-exit:
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return
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}
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}
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}()
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if err := mdns.Query(p); err != nil {
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return nil, err
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}
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// create list and return
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var services []*registry.Service
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for _, service := range serviceMap {
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services = append(services, service)
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}
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return services, nil
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}
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func (m *mdnsRegistry) ListServices() ([]*registry.Service, error) {
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p := mdns.DefaultParams("_services")
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p.Timeout = m.opts.Timeout
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entryCh := make(chan *mdns.ServiceEntry, 10)
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p.Entries = entryCh
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exit := make(chan bool)
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defer close(exit)
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serviceMap := make(map[string]bool)
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var services []*registry.Service
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go func() {
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for {
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select {
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case e := <-entryCh:
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name := strings.TrimSuffix(e.Name, "."+p.Service+"."+p.Domain+".")
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if !serviceMap[name] {
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serviceMap[name] = true
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services = append(services, ®istry.Service{Name: name})
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}
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case <-exit:
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return
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}
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}
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}()
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if err := mdns.Query(p); err != nil {
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return nil, err
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}
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return services, nil
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}
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func (m *mdnsRegistry) Watch() (registry.Watcher, error) {
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return nil, nil
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}
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func (m *mdnsRegistry) String() string {
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return "mdns"
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}
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func NewRegistry(opts ...registry.Option) registry.Registry {
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return newRegistry(opts...)
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}
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