nats discovery

tools/nats_caller.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 
 	"cloud.o-forge.io/core/oc-lib/config"
+	"cloud.o-forge.io/core/oc-lib/logs"
 	"github.com/nats-io/nats.go"
 )
 
@@ -14,6 +15,7 @@ type NATSMethod int
 const (
 	REMOVE NATSMethod = iota
 	CREATE
+	DISCOVERY
 )
 
 // NameToMethod returns the NATSMethod enum value from a string
@@ -43,6 +45,33 @@ func NewNATSCaller() *natsCaller {
 	return &natsCaller{}
 }
 
+// on workflows' scheduling. Messages must contain
+// workflow execution ID, to allow retrieval of execution infos
+func (s *natsCaller) ListenNats(chanName string, exec func(msg map[string]interface{})) {
+	log := logs.GetLogger()
+	if config.GetConfig().NATSUrl == "" {
+		log.Error().Msg(" -> NATS_SERVER is not set")
+		return
+	}
+	nc, err := nats.Connect(config.GetConfig().NATSUrl)
+	if err != nil {
+		log.Error().Msg(" -> Could not reach NATS server : " + err.Error())
+		return
+	}
+	ch := make(chan *nats.Msg, 64)
+	subs, err := nc.ChanSubscribe(chanName, ch)
+	if err != nil {
+		log.Error().Msg("Error listening to NATS : " + err.Error())
+	}
+	defer subs.Unsubscribe()
+
+	for msg := range ch {
+		map_mess := map[string]interface{}{}
+		json.Unmarshal(msg.Data, &map_mess)
+		exec(map_mess)
+	}
+}
+
 // SetNATSPub sets a message to the NATS server
 func (o *natsCaller) SetNATSPub(dataName string, method NATSMethod, data interface{}) string {
 	if config.GetConfig().NATSUrl == "" {