nats migration

2021-11-11 11:07:20 -03:00
parent 5b590ab31b
commit 581b4def8a
7 changed files with 295 additions and 52 deletions
@@ -0,0 +1,154 @@
+package svc
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"github.com/nats-io/nats.go"
+	"log"
+	"os"
+	"reflect"
+	"strings"
+	"time"
+	"unicode"
+)
+
+var nc *nats.Conn
+
+var compname string
+
+func Init(s string) error {
+	var err error
+	compname = s
+	var apikey string
+	if nc == nil {
+		apikey = os.Getenv("REPLAY_APIKEY")
+		if apikey == "" {
+			log.Printf("Connecting to NATS Server w/o TK.")
+			nc, err = nats.Connect(nats.DefaultURL, nats.Name(compname))
+		} else {
+			log.Printf("Connecting to NATS Server w TK: " + apikey)
+			nc, err = nats.Connect(nats.DefaultURL, nats.Name(compname), nats.Token(apikey))
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return err
+}
+
+func Close() error {
+	err := nc.Drain()
+	chEnd <- struct{}{}
+	return err
+}
+
+var chEnd chan struct{}
+
+func Serve() {
+	chEnd = make(chan struct{})
+	<-chEnd
+}
+
+func NormalizeName(s string) string {
+	sb := strings.Builder{}
+	for i, v := range s {
+		if unicode.IsUpper(v) && i != 0 {
+			sb.WriteString(".")
+		}
+		sb.WriteRune(unicode.ToLower(v))
+
+	}
+	return sb.String()
+}
+
+func Register(h interface{}) {
+	var err error
+	tp := reflect.TypeOf(h)
+	for i := 0; i < tp.NumMethod(); i++ {
+		mtd := tp.Method(i)
+		mtdt := mtd.Type
+		intp := mtdt.In(1)
+		isPtr := false
+		if intp.Kind() == reflect.Ptr {
+			isPtr = true
+			intp = intp.Elem()
+		}
+		mn := NormalizeName(compname) + "." + NormalizeName(mtd.Name)
+		err = nc.Publish("sub", []byte(mn))
+		if err != nil {
+			log.Printf(err.Error())
+		}
+		_, err = nc.Subscribe(mn, func(msg *nats.Msg) {
+			ni := reflect.New(intp).Interface()
+			var err error
+			if intp.Kind() == reflect.Ptr {
+				err = json.Unmarshal(msg.Data, ni)
+			} else {
+				err = json.Unmarshal(msg.Data, &ni)
+			}
+
+			if err != nil {
+				log.Printf(err.Error())
+			}
+			var rawret []reflect.Value
+			if isPtr {
+				rawret = mtd.Func.Call([]reflect.Value{reflect.ValueOf(h), reflect.ValueOf(ni)})
+			} else {
+				rawret = mtd.Func.Call([]reflect.Value{reflect.ValueOf(h), reflect.ValueOf(ni).Elem()})
+			}
+			ret := rawret[0].Interface()
+			err1 := rawret[1].Interface()
+			//if err1 != nil {
+			//    log.Printf(err1.(error).Error())
+			//}
+			var bs []byte
+			rmsg := &nats.Msg{}
+			rmsg.Data = bs
+			bs, err = json.Marshal(ret)
+			if err1 != nil {
+				rmsg.Header = nats.Header{}
+				rmsg.Header.Set("ERR", fmt.Sprintf("%#v", err1))
+			}
+			if err != nil {
+				log.Printf(err.Error())
+			}
+			rmsg.Data = bs
+			err = msg.RespondMsg(rmsg)
+			if err != nil {
+				log.Printf(err.Error())
+			}
+		})
+		if err != nil {
+			log.Printf(err.Error())
+		}
+		if err != nil {
+			nc.Publish("err", []byte(err.Error()))
+		}
+	}
+}
+
+func Nc() *nats.Conn {
+	return nc
+}
+
+func Call(s string, in interface{}, out interface{}) error {
+	bs, err := json.Marshal(in)
+	if err != nil {
+		return err
+	}
+	msg, err := nc.Request(s, bs, time.Minute)
+	if err != nil {
+		return err
+	}
+
+	err = json.Unmarshal(msg.Data, out)
+	if err != nil {
+		return err
+	}
+	errstr := msg.Header.Get("ERR")
+	if errstr != "" {
+		return errors.New(errstr)
+	}
+	return nil
+}