inspect symlinks to auto-reload k8s secrets

internal/watch/file_watcher.go

@@ -18,7 +18,9 @@ package watch
 
 import (
 	"log"
+	"os"
 	"path"
+	"path/filepath"
 	"strings"
 
 	"github.com/fsnotify/fsnotify"
@@ -60,15 +62,31 @@ func (f *OSFileWatcher) watch() error {
 	}
 	f.watcher = watcher
 
+	realFile, err := filepath.EvalSymlinks(f.file)
+	if err != nil {
+		return err
+	}
+
 	dir, file := path.Split(f.file)
 	go func(file string) {
 		for {
 			select {
 			case event := <-watcher.Events:
-				if (event.Op&fsnotify.Write == fsnotify.Write ||
-					event.Op&fsnotify.Create == fsnotify.Create) &&
-					strings.HasSuffix(event.Name, file) {
-					f.onEvent()
+				if event.Op&fsnotify.Create == fsnotify.Create ||
+					event.Op&fsnotify.Write == fsnotify.Write {
+					if finfo, err := os.Lstat(event.Name); err != nil {
+						log.Printf("can not lstat file: %v\n", err)
+					} else if finfo.Mode()&os.ModeSymlink != 0 {
+						if currentRealFile, err := filepath.EvalSymlinks(f.file); err == nil &&
+							currentRealFile != realFile {
+							f.onEvent()
+							realFile = currentRealFile
+						}
+						continue
+					}
+					if strings.HasSuffix(event.Name, file) {
+						f.onEvent()
+					}
 				}
 			case err := <-watcher.Errors:
 				if err != nil {