From dbcd9cf004b68d7018d1984909a526e5417f938e Mon Sep 17 00:00:00 2001
From: mr <mr>
Date: Thu, 17 Oct 2024 13:53:57 +0200
Subject: [PATCH] nats discovery

---
 tools/api.go         | 19 +++++++++++++++++++
 tools/nats_caller.go | 29 +++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/tools/api.go b/tools/api.go
index a8408ee..f54fa61 100644
--- a/tools/api.go
+++ b/tools/api.go
@@ -6,6 +6,7 @@ import (
 
 	"cloud.o-forge.io/core/oc-lib/config"
 	"cloud.o-forge.io/core/oc-lib/dbs/mongo"
+	beego "github.com/beego/beego/v2/server/web"
 )
 
 /*
@@ -70,6 +71,24 @@ func (a *API) GetState() (State, int, error) {
 	return ALIVE, 200, nil // If everything is up, return alive
 }
 
+func (a *API) ListenRouter(exec func(msg map[string]interface{})) {
+	nats := NewNATSCaller()
+	go nats.ListenNats(DISCOVERY.GenerateKey("api"), exec)
+}
+
+func (a *API) SubscribeRouter() {
+	nats := NewNATSCaller()
+	discovery := map[string]interface{}{}
+	for _, info := range beego.BeeApp.Handlers.GetAllControllerInfo() {
+		methods := []string{}
+		for k := range info.GetMethod() {
+			methods = append(methods, k)
+		}
+		discovery[info.GetPattern()] = methods
+	}
+	nats.SetNATSPub("api", DISCOVERY, discovery)
+}
+
 // CheckRemotePeer checks the state of a remote peer
 func (a *API) CheckRemotePeer(url string) (State, map[string]int) {
 	// Check if the database is up
diff --git a/tools/nats_caller.go b/tools/nats_caller.go
index d4aa7fc..7ef63e2 100644
--- a/tools/nats_caller.go
+++ b/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 == "" {