Fix Fortinet SSO again

experimental/cachefile/cache.go

@@ -45,6 +45,7 @@ type CacheFile struct {
 	logger             logger.Logger
 	path               string
 	cacheID            []byte
+	cacheIDText        string
 	storeFakeIP        bool
 	storeRDRC          bool
 	storeDNS           bool
@@ -104,6 +105,7 @@ func New(ctx context.Context, logger logger.Logger, options option.CacheFileOpti
 		logger:       logger,
 		path:         filemanager.BasePath(ctx, path),
 		cacheID:      cacheIDBytes,
+		cacheIDText:  options.CacheID,
 		storeFakeIP:  options.StoreFakeIP,
 		storeRDRC:    options.StoreRDRC,
 		storeDNS:     options.StoreDNS,
@@ -124,6 +126,10 @@ func (c *CacheFile) Dependencies() []string {
 	return nil
 }
 
+func (c *CacheFile) CacheID() string {
+	return c.cacheIDText
+}
+
 func (c *CacheFile) SetOptimisticTimeout(timeout time.Duration) {
 	c.optimisticTimeout = timeout
 }