fix issue #27137: kubelet detects pod manifest files in the directory using inotify

pkg/kubelet/config/file_linux.go

@@ -0,0 +1,124 @@
+// +build linux
+
+/*
+Copyright 2016 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Reads the pod configuration from file or a directory of files.
+package config
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/golang/glog"
+	"golang.org/x/exp/inotify"
+
+	"k8s.io/kubernetes/pkg/api"
+	kubetypes "k8s.io/kubernetes/pkg/kubelet/types"
+)
+
+type podEventType int
+
+const (
+	podAdd podEventType = iota
+	podModify
+	podDelete
+)
+
+func (s *sourceFile) watch() error {
+	_, err := os.Stat(s.path)
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return err
+		}
+		// Emit an update with an empty PodList to allow FileSource to be marked as seen
+		s.updates <- kubetypes.PodUpdate{Pods: []*api.Pod{}, Op: kubetypes.SET, Source: kubetypes.FileSource}
+		return fmt.Errorf("path does not exist, ignoring")
+	}
+
+	w, err := inotify.NewWatcher()
+	if err != nil {
+		return fmt.Errorf("unable to create inotify: %v", err)
+	}
+	defer w.Close()
+
+	err = w.AddWatch(s.path, inotify.IN_DELETE_SELF|inotify.IN_CREATE|inotify.IN_MOVED_TO|inotify.IN_MODIFY|inotify.IN_MOVED_FROM|inotify.IN_DELETE)
+	if err != nil {
+		return fmt.Errorf("unable to create inotify for path %q: %v", s.path, err)
+	}
+
+	// Reset store with config files already existing when starting
+	if err := s.resetStoreFromPath(); err != nil {
+		return fmt.Errorf("unable to read config path %q: %v", s.path, err)
+	}
+
+	for {
+		select {
+		case event := <-w.Event:
+			err = s.processEvent(event)
+			if err != nil {
+				return fmt.Errorf("error while processing event (%+v): %v", event, err)
+			}
+		case err = <-w.Error:
+			return fmt.Errorf("error while watching %q: %v", s.path, err)
+		}
+	}
+}
+
+func (s *sourceFile) processEvent(e *inotify.Event) error {
+	var eventType podEventType
+	switch {
+	case (e.Mask & inotify.IN_ISDIR) > 0:
+		glog.V(1).Infof("Not recursing into config path %q", s.path)
+		return nil
+	case (e.Mask & inotify.IN_CREATE) > 0:
+		eventType = podAdd
+	case (e.Mask & inotify.IN_MOVED_TO) > 0:
+		eventType = podAdd
+	case (e.Mask & inotify.IN_MODIFY) > 0:
+		eventType = podModify
+	case (e.Mask & inotify.IN_DELETE) > 0:
+		eventType = podDelete
+	case (e.Mask & inotify.IN_MOVED_FROM) > 0:
+		eventType = podDelete
+	case (e.Mask & inotify.IN_DELETE_SELF) > 0:
+		return fmt.Errorf("the watched path is deleted")
+	default:
+		// Ignore rest events
+		return nil
+	}
+
+	switch eventType {
+	case podAdd, podModify:
+		if pod, err := s.extractFromFile(e.Name); err != nil {
+			glog.Errorf("can't process config file %q: %v", e.Name, err)
+		} else {
+			return s.store.Add(pod)
+		}
+	case podDelete:
+		if objKey, keyExist := s.fileKeyMapping[e.Name]; keyExist {
+			pod, podExist, err := s.store.GetByKey(objKey)
+			if err != nil {
+				return err
+			} else if !podExist {
+				return fmt.Errorf("the pod with key %s doesn't exist in cache", objKey)
+			} else {
+				return s.store.Delete(pod)
+			}
+		}
+	}
+	return nil
+}