add mdns prototype

serverplugin/mdns.go

@@ -0,0 +1,118 @@
+package serverplugin
+
+import (
+	"encoding/json"
+	"errors"
+	"net"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/grandcat/zeroconf"
+	metrics "github.com/rcrowley/go-metrics"
+)
+
+type serviceMeta struct {
+	Service        string
+	Meta           string
+	ServiceAddress string
+}
+
+// MDNSRegisterPlugin implements mdns/dns-sd registry.
+type MDNSRegisterPlugin struct {
+	// service address, for example, tcp@127.0.0.1:8972, quic@127.0.0.1:1234
+	ServiceAddress string
+	port           int
+	Metrics        metrics.Registry
+	// Registered services
+	Services       []*serviceMeta
+	UpdateInterval time.Duration
+
+	server *zeroconf.Server
+}
+
+// Start starts to connect etcd cluster
+func (p *MDNSRegisterPlugin) Start() error {
+	data, _ := json.Marshal(p.Services)
+	s := url.QueryEscape(string(data))
+	host, _ := os.Hostname()
+
+	addr := p.ServiceAddress
+	i := strings.Index(addr, "@")
+	if i > 0 {
+		addr = addr[i+1:]
+	}
+	_, portStr, err := net.SplitHostPort(addr)
+	if err != nil {
+		panic(err)
+	}
+	p.port, err = strconv.Atoi(portStr)
+	if err != nil {
+		panic(err)
+	}
+
+	server, err := zeroconf.Register(host, "_rpcxservices", "local.", p.port, []string{s}, nil)
+	if err != nil {
+		panic(err)
+	}
+	p.server = server
+
+	if p.UpdateInterval > 0 {
+		ticker := time.NewTicker(p.UpdateInterval)
+		go func() {
+			p.server.Shutdown()
+
+			// refresh service TTL
+			for range ticker.C {
+				clientMeter := metrics.GetOrRegisterMeter("clientMeter", p.Metrics)
+				data := []byte(strconv.FormatInt(clientMeter.Count()/60, 10))
+				//set this same metrics for all services at this server
+				for _, sm := range p.Services {
+					v, _ := url.ParseQuery(string(sm.Meta))
+					v.Set("tps", string(data))
+					sm.Meta = v.Encode()
+				}
+				ss, _ := json.Marshal(p.Services)
+				s := url.QueryEscape(string(ss))
+				p.server.SetText([]string{s})
+			}
+		}()
+	}
+
+	return nil
+}
+
+// HandleConnAccept handles connections from clients
+func (p *MDNSRegisterPlugin) HandleConnAccept(conn net.Conn) (net.Conn, bool) {
+	if p.Metrics != nil {
+		clientMeter := metrics.GetOrRegisterMeter("clientMeter", p.Metrics)
+		clientMeter.Mark(1)
+	}
+	return conn, true
+}
+
+// Register handles registering event.
+// this service is registered at BASE/serviceName/thisIpAddress node
+func (p *MDNSRegisterPlugin) Register(name string, rcvr interface{}, metadata string) (err error) {
+	if "" == strings.TrimSpace(name) {
+		err = errors.New("Register service `name` can't be empty")
+		return
+	}
+	if p.server == nil {
+		return errors.New("MDNSRegisterPlugin has not started")
+	}
+
+	sm := &serviceMeta{
+		Service:        name,
+		Meta:           metadata,
+		ServiceAddress: p.ServiceAddress,
+	}
+
+	p.Services = append(p.Services, sm)
+	ss, _ := json.Marshal(p.Services)
+	s := url.QueryEscape(string(ss))
+	p.server.SetText([]string{s})
+	return
+}