cleanup after fetch

service/subscription.go

@@ -6,6 +6,7 @@ import (
 	"net"
 	"net/http"
 	"regexp"
+	"strings"
 	"time"
 
 	"github.com/sagernet/sing-box/adapter"
@@ -47,6 +48,10 @@ type subscriptionProvider struct {
 
 // NewSubscription creates a new subscription service.
 func NewSubscription(ctx context.Context, router adapter.Router, logger log.ContextLogger, logFactory log.Factory, options option.Service) (*Subscription, error) {
+	if options.Tag == "" {
+		// required for outbounds clean up
+		return nil, E.New("subscription tag is required")
+	}
 	nproviders := len(options.SubscriptionOptions.Providers)
 	if nproviders == 0 {
 		return nil, E.New("missing subscription providers")
@@ -128,27 +133,64 @@ func (s *Subscription) fetchLoop() {
 	ticker := time.NewTicker(s.interval)
 	defer ticker.Stop()
 
-	if err := s.fetch(); err != nil {
-		s.logger.Error("fetch subscription: ", err)
-	}
+	s.refresh()
 L:
 	for {
 		select {
 		case <-s.ctx.Done():
 			break L
 		case <-ticker.C:
-			if err := s.fetch(); err != nil {
-				s.logger.Error("fetch subscription: ", err)
-			}
+			s.refresh()
 		}
 	}
 }
 
-func (s *Subscription) fetch() error {
+func (s *Subscription) refresh() {
+	opts, err := s.fetch()
+	if err != nil {
+		s.logger.Error("fetch subscription: ", err)
+	}
+	s.updateOutbounds(opts)
+}
+
+func (s *Subscription) updateOutbounds(opts []*option.Outbound) {
+	outbounds := s.router.Outbounds()
+	knownOutbounds := make(map[string]struct{})
+	for _, opt := range opts {
+		tag := opt.Tag
+		knownOutbounds[tag] = struct{}{}
+		outbound, err := outbound.New(
+			s.parentCtx,
+			s.router,
+			s.logFactory.NewLogger(F.ToString("outbound/", opt.Type, "[", tag, "]")),
+			*opt,
+		)
+		if err != nil {
+			s.logger.Warn("create outbound [", tag, "]: ", err)
+		}
+		s.router.AddOutbound(outbound)
+		s.logger.Info("created outbound [", tag, "]")
+	}
+	// remove outbounds that are not in the latest list
+	tagPrefix := s.tag + "."
+	for _, outbound := range outbounds {
+		tag := outbound.Tag()
+		if !strings.HasPrefix(tag, tagPrefix) {
+			continue
+		}
+		if _, ok := knownOutbounds[tag]; ok {
+			continue
+		}
+		s.router.RemoveOutbound(tag)
+	}
+}
+
+func (s *Subscription) fetch() ([]*option.Outbound, error) {
 	client, err := s.client()
 	if err != nil {
-		return err
+		return nil, err
 	}
+	opts := make([]*option.Outbound, 0)
 	for i, provider := range s.providers {
 		var tag string
 		if provider.tag != "" {
@@ -168,20 +210,10 @@ func (s *Subscription) fetch() error {
 				continue
 			}
 			s.applyOptions(opt, provider)
-			outbound, err := outbound.New(
-				s.parentCtx,
-				s.router,
-				s.logFactory.NewLogger(F.ToString("outbound/", opt.Type, "[", opt.Tag, "]")),
-				*opt,
-			)
-			if err != nil {
-				s.logger.Warn("create outbound [", opt.Tag, "]: ", err)
-			}
-			s.router.AddOutbound(outbound)
-			s.logger.Info("created outbound [", opt.Tag, "]")
+			opts = append(opts, opt)
 		}
 	}
-	return nil
+	return opts, nil
 }
 
 func selectedByTag(tag string, provider *subscriptionProvider) bool {