Invalidate remote rule-set cache when URL changes

adapter/experimental.go

@@ -61,11 +61,12 @@ type SavedBinary struct {
 	Content     []byte
 	LastUpdated time.Time
 	LastEtag    string
+	URLHash     []byte
 }
 
 func (s *SavedBinary) MarshalBinary() ([]byte, error) {
 	var buffer bytes.Buffer
-	err := binary.Write(&buffer, binary.BigEndian, uint8(1))
+	err := binary.Write(&buffer, binary.BigEndian, uint8(2))
 	if err != nil {
 		return nil, err
 	}
@@ -89,6 +90,14 @@ func (s *SavedBinary) MarshalBinary() ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
+	_, err = varbin.WriteUvarint(&buffer, uint64(len(s.URLHash)))
+	if err != nil {
+		return nil, err
+	}
+	_, err = buffer.Write(s.URLHash)
+	if err != nil {
+		return nil, err
+	}
 	return buffer.Bytes(), nil
 }
 
@@ -130,6 +139,21 @@ func (s *SavedBinary) UnmarshalBinary(data []byte) error {
 		return err
 	}
 	s.LastEtag = string(etagBytes)
+	if version < 2 {
+		return nil
+	}
+	urlHashLength, err := binary.ReadUvarint(reader)
+	if err != nil {
+		return err
+	}
+	if urlHashLength > uint64(reader.Len()) {
+		return E.New("invalid url hash length: ", urlHashLength)
+	}
+	s.URLHash = make([]byte, urlHashLength)
+	_, err = io.ReadFull(reader, s.URLHash)
+	if err != nil {
+		return err
+	}
 	return nil
 }
 

route/rule/rule_set_remote.go

@@ -3,6 +3,7 @@ package rule
 import (
 	"bytes"
 	"context"
+	"crypto/sha256"
 	"io"
 	"net/http"
 	"path/filepath"
@@ -38,6 +39,7 @@ type RemoteRuleSet struct {
 	outbound       adapter.OutboundManager
 	tag            string
 	url            string
+	urlHash        [32]byte
 	initialPath    string
 	options        option.RuleSet
 	updateInterval time.Duration
@@ -66,13 +68,15 @@ func NewRemoteRuleSet(ctx context.Context, logger logger.ContextLogger, tag stri
 		initialPath = filemanager.BasePath(ctx, strings.ReplaceAll(options.RemoteOptions.InitialPath, C.RuleSetTagPlaceholder, tag))
 		initialPath, _ = filepath.Abs(initialPath)
 	}
+	url := strings.ReplaceAll(options.RemoteOptions.URL, C.RuleSetTagPlaceholder, tag)
 	return &RemoteRuleSet{
 		ctx:            ctx,
 		cancel:         cancel,
 		outbound:       service.FromContext[adapter.OutboundManager](ctx),
 		logger:         logger,
 		tag:            tag,
-		url:            strings.ReplaceAll(options.RemoteOptions.URL, C.RuleSetTagPlaceholder, tag),
+		url:            url,
+		urlHash:        sha256.Sum256([]byte(url)),
 		initialPath:    initialPath,
 		options:        options,
 		updateInterval: updateInterval,
@@ -97,13 +101,18 @@ func (s *RemoteRuleSet) StartContext(ctx context.Context, startContext *adapter.
 	startContext.Register(transport)
 	s.httpClient = &http.Client{Transport: transport}
 	if s.cacheFile != nil {
-		if savedSet := s.cacheFile.LoadRuleSet(s.tag); savedSet != nil {
-			err = s.loadBytes(savedSet.Content)
-			if err != nil {
-				s.logger.Warn(E.Cause(err, "restore cached rule-set, will refetch"))
+		savedSet := s.cacheFile.LoadRuleSet(s.tag)
+		if savedSet != nil {
+			if len(savedSet.URLHash) > 0 && !bytes.Equal(savedSet.URLHash, s.urlHash[:]) {
+				s.logger.Info("cached rule-set was downloaded from another URL, will refetch")
 			} else {
-				s.lastUpdated = savedSet.LastUpdated
-				s.lastEtag = savedSet.LastEtag
+				err = s.loadBytes(savedSet.Content)
+				if err != nil {
+					s.logger.Warn(E.Cause(err, "restore cached rule-set, will refetch"))
+				} else {
+					s.lastUpdated = savedSet.LastUpdated
+					s.lastEtag = savedSet.LastEtag
+				}
 			}
 		}
 	}
@@ -249,6 +258,7 @@ func (s *RemoteRuleSet) fetch(ctx context.Context, isStart bool) error {
 			savedRuleSet := s.cacheFile.LoadRuleSet(s.tag)
 			if savedRuleSet != nil {
 				savedRuleSet.LastUpdated = s.lastUpdated
+				savedRuleSet.URLHash = s.urlHash[:]
 				err = s.cacheFile.SaveRuleSet(s.tag, savedRuleSet)
 				if err != nil {
 					s.logger.Error("save rule-set updated time: ", err)
@@ -279,6 +289,7 @@ func (s *RemoteRuleSet) fetch(ctx context.Context, isStart bool) error {
 			LastUpdated: s.lastUpdated,
 			Content:     content,
 			LastEtag:    s.lastEtag,
+			URLHash:     s.urlHash[:],
 		})
 		if err != nil {
 			s.logger.Error("save rule-set cache: ", err)