vendor files

vendor/k8s.io/kubernetes/pkg/kubelet/reason_cache.go

@@ -0,0 +1,105 @@
+/*
+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.
+*/
+
+package kubelet
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/golang/groupcache/lru"
+	"k8s.io/apimachinery/pkg/types"
+	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
+)
+
+// ReasonCache stores the failure reason of the latest container start
+// in a string, keyed by <pod_UID>_<container_name>. The goal is to
+// propagate this reason to the container status. This endeavor is
+// "best-effort" for two reasons:
+//   1. The cache is not persisted.
+//   2. We use an LRU cache to avoid extra garbage collection work. This
+//      means that some entries may be recycled before a pod has been
+//      deleted.
+// TODO(random-liu): Use more reliable cache which could collect garbage of failed pod.
+// TODO(random-liu): Move reason cache to somewhere better.
+type ReasonCache struct {
+	lock  sync.Mutex
+	cache *lru.Cache
+}
+
+// Reason is the cached item in ReasonCache
+type reasonItem struct {
+	Err     error
+	Message string
+}
+
+// maxReasonCacheEntries is the cache entry number in lru cache. 1000 is a proper number
+// for our 100 pods per node target. If we support more pods per node in the future, we
+// may want to increase the number.
+const maxReasonCacheEntries = 1000
+
+// NewReasonCache creates an instance of 'ReasonCache'.
+func NewReasonCache() *ReasonCache {
+	return &ReasonCache{cache: lru.New(maxReasonCacheEntries)}
+}
+
+func (c *ReasonCache) composeKey(uid types.UID, name string) string {
+	return fmt.Sprintf("%s_%s", uid, name)
+}
+
+// add adds error reason into the cache
+func (c *ReasonCache) add(uid types.UID, name string, reason error, message string) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Add(c.composeKey(uid, name), reasonItem{reason, message})
+}
+
+// Update updates the reason cache with the SyncPodResult. Only SyncResult with
+// StartContainer action will change the cache.
+func (c *ReasonCache) Update(uid types.UID, result kubecontainer.PodSyncResult) {
+	for _, r := range result.SyncResults {
+		if r.Action != kubecontainer.StartContainer {
+			continue
+		}
+		name := r.Target.(string)
+		if r.Error != nil {
+			c.add(uid, name, r.Error, r.Message)
+		} else {
+			c.Remove(uid, name)
+		}
+	}
+}
+
+// Remove removes error reason from the cache
+func (c *ReasonCache) Remove(uid types.UID, name string) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Remove(c.composeKey(uid, name))
+}
+
+// Get gets error reason from the cache. The return values are error reason, error message and
+// whether an error reason is found in the cache. If no error reason is found, empty string will
+// be returned for error reason and error message.
+func (c *ReasonCache) Get(uid types.UID, name string) (*reasonItem, bool) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	value, ok := c.cache.Get(c.composeKey(uid, name))
+	if !ok {
+		return nil, false
+	}
+	info := value.(reasonItem)
+	return &info, true
+}