Fix monitored connections before request (#608)

Signed-off-by: Artem Glazychev <artem.glazychev@xored.com>

main.go

@@ -31,6 +31,8 @@ import (
 	"os/signal"
 	"syscall"
 
+	"github.com/pkg/errors"
+
 	nested "github.com/antonfisher/nested-logrus-formatter"
 	"github.com/edwarnicke/genericsync"
 	"github.com/edwarnicke/grpcfd"
@@ -242,43 +244,15 @@ func main() {
 		// Update network services configs
 		id := fmt.Sprintf("%s-%d", c.Name, i)
 
-		var monitoredConnections genericsync.Map[string, *networkservice.Connection]
 		monitorCtx, cancelMonitor := context.WithTimeout(signalCtx, c.RequestTimeout)
-		stream, err := monitorClient.MonitorConnections(monitorCtx, &networkservice.MonitorScopeSelector{
-			PathSegments: []*networkservice.PathSegment{
-				{
-					Id: id,
-				},
-			},
-		})
-		if err != nil {
-			logger.Fatalf("error from monitorConnectionClient: %v", err.Error())
-		}
-
-		// Recv initial event
-		event, err := stream.Recv()
+		monitoredConnections, err := startMonitoring(monitorCtx, monitorClient, id)
 		if err != nil {
-			logger.Errorf("error from monitorConnection stream: %v ", err.Error())
-		}
-		for k, conn := range event.Connections {
-			monitoredConnections.Store(k, conn)
+			logger.Errorf("failed connect to monitor connections: %v", err.Error())
 		}
 
-		go func() {
-			for {
-				event, err := stream.Recv()
-				if err != nil {
-					break
-				}
-				for k, conn := range event.Connections {
-					monitoredConnections.Store(k, conn)
-				}
-			}
-		}()
-
 		for {
 			// Construct a request
-			request := constructRequest(ctx, c, id, &c.NetworkServices[i], &monitoredConnections)
+			request := constructRequest(ctx, c, id, &c.NetworkServices[i], monitoredConnections)
 
 			resp, err := nsmClient.Request(ctx, request)
 			if err != nil {
@@ -302,6 +276,47 @@ func main() {
 	<-signalCtx.Done()
 }
 
+func startMonitoring(ctx context.Context, monitorClient networkservice.MonitorConnectionClient, id string) (*genericsync.Map[string, *networkservice.Connection], error) {
+	var monitoredConnections genericsync.Map[string, *networkservice.Connection]
+	stream, err := monitorClient.MonitorConnections(ctx, &networkservice.MonitorScopeSelector{
+		PathSegments: []*networkservice.PathSegment{
+			{
+				Id: id,
+			},
+		},
+	})
+	if err != nil {
+		return &monitoredConnections, errors.Wrap(err, "error from monitorConnectionClient")
+	}
+
+	// Recv initial event
+	event, err := stream.Recv()
+	if err != nil {
+		return &monitoredConnections, errors.Wrap(err, "error from monitorConnection stream")
+	}
+	for k, conn := range event.Connections {
+		monitoredConnections.Store(k, conn)
+	}
+
+	// Start monitoring in the background
+	go func() {
+		for {
+			event, err := stream.Recv()
+			if err != nil {
+				break
+			}
+			for k, conn := range event.Connections {
+				if event.GetType() == networkservice.ConnectionEventType_DELETE {
+					conn.State = networkservice.State_DOWN
+				}
+				monitoredConnections.Store(k, conn)
+			}
+		}
+	}()
+
+	return &monitoredConnections, nil
+}
+
 func constructRequest(ctx context.Context, c *config.Config, connectionID string, networkService *url.URL, monitoredConnections *genericsync.Map[string, *networkservice.Connection]) *networkservice.NetworkServiceRequest {
 	u := (*nsurl.NSURL)(networkService)
 
@@ -320,7 +335,7 @@ func constructRequest(ctx context.Context, c *config.Config, connectionID string
 	monitoredConnections.Range(func(key string, conn *networkservice.Connection) bool {
 		path := conn.GetPath()
 		if path.Index == 1 && path.PathSegments[0].Id == connectionID && conn.Mechanism.Type == u.Mechanism().Type {
-			request.Connection = conn
+			request.Connection = conn.Clone()
 			request.Connection.Path.Index = 0
 			request.Connection.Id = connectionID
 			return false
@@ -337,7 +352,6 @@ func constructRequest(ctx context.Context, c *config.Config, connectionID string
 		log.FromContext(ctx).Infof("NetworkServiceEndpoint %v is unavailable. Reconnection...", request.GetConnection().NetworkServiceEndpointName)
 		request.GetConnection().Mechanism = nil
 		request.GetConnection().NetworkServiceEndpointName = ""
-		request.GetConnection().Context = nil
 		request.GetConnection().State = networkservice.State_RESELECT_REQUESTED
 	}
 	return request