Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

1 files changed, 199 insertions, 0 deletions

diff --git a/vendor/k8s.io/kubernetes/pkg/kubelet/container/cache.go b/vendor/k8s.io/kubernetes/pkg/kubelet/container/cache.go
new file mode 100644
index 000000000..82852a9d9
--- /dev/null
+++ b/vendor/k8s.io/kubernetes/pkg/kubelet/container/cache.go
@@ -0,0 +1,199 @@
+/*
+Copyright 2015 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 container
+
+import (
+	"sync"
+	"time"
+
+	"k8s.io/apimachinery/pkg/types"
+)
+
+// Cache stores the PodStatus for the pods. It represents *all* the visible
+// pods/containers in the container runtime. All cache entries are at least as
+// new or newer than the global timestamp (set by UpdateTime()), while
+// individual entries may be slightly newer than the global timestamp. If a pod
+// has no states known by the runtime, Cache returns an empty PodStatus object
+// with ID populated.
+//
+// Cache provides two methods to retrive the PodStatus: the non-blocking Get()
+// and the blocking GetNewerThan() method. The component responsible for
+// populating the cache is expected to call Delete() to explicitly free the
+// cache entries.
+type Cache interface {
+	Get(types.UID) (*PodStatus, error)
+	Set(types.UID, *PodStatus, error, time.Time)
+	// GetNewerThan is a blocking call that only returns the status
+	// when it is newer than the given time.
+	GetNewerThan(types.UID, time.Time) (*PodStatus, error)
+	Delete(types.UID)
+	UpdateTime(time.Time)
+}
+
+type data struct {
+	// Status of the pod.
+	status *PodStatus
+	// Error got when trying to inspect the pod.
+	err error
+	// Time when the data was last modified.
+	modified time.Time
+}
+
+type subRecord struct {
+	time time.Time
+	ch   chan *data
+}
+
+// cache implements Cache.
+type cache struct {
+	// Lock which guards all internal data structures.
+	lock sync.RWMutex
+	// Map that stores the pod statuses.
+	pods map[types.UID]*data
+	// A global timestamp represents how fresh the cached data is. All
+	// cache content is at the least newer than this timestamp. Note that the
+	// timestamp is nil after initialization, and will only become non-nil when
+	// it is ready to serve the cached statuses.
+	timestamp *time.Time
+	// Map that stores the subscriber records.
+	subscribers map[types.UID][]*subRecord
+}
+
+// NewCache creates a pod cache.
+func NewCache() Cache {
+	return &cache{pods: map[types.UID]*data{}, subscribers: map[types.UID][]*subRecord{}}
+}
+
+// Get returns the PodStatus for the pod; callers are expected not to
+// modify the objects returned.
+func (c *cache) Get(id types.UID) (*PodStatus, error) {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	d := c.get(id)
+	return d.status, d.err
+}
+
+func (c *cache) GetNewerThan(id types.UID, minTime time.Time) (*PodStatus, error) {
+	ch := c.subscribe(id, minTime)
+	d := <-ch
+	return d.status, d.err
+}
+
+// Set sets the PodStatus for the pod.
+func (c *cache) Set(id types.UID, status *PodStatus, err error, timestamp time.Time) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	defer c.notify(id, timestamp)
+	c.pods[id] = &data{status: status, err: err, modified: timestamp}
+}
+
+// Delete removes the entry of the pod.
+func (c *cache) Delete(id types.UID) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	delete(c.pods, id)
+}
+
+//  UpdateTime modifies the global timestamp of the cache and notify
+//  subscribers if needed.
+func (c *cache) UpdateTime(timestamp time.Time) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.timestamp = &timestamp
+	// Notify all the subscribers if the condition is met.
+	for id := range c.subscribers {
+		c.notify(id, *c.timestamp)
+	}
+}
+
+func makeDefaultData(id types.UID) *data {
+	return &data{status: &PodStatus{ID: id}, err: nil}
+}
+
+func (c *cache) get(id types.UID) *data {
+	d, ok := c.pods[id]
+	if !ok {
+		// Cache should store *all* pod/container information known by the
+		// container runtime. A cache miss indicates that there are no states
+		// regarding the pod last time we queried the container runtime.
+		// What this *really* means is that there are no visible pod/containers
+		// associated with this pod. Simply return an default (mostly empty)
+		// PodStatus to reflect this.
+		return makeDefaultData(id)
+	}
+	return d
+}
+
+// getIfNewerThan returns the data it is newer than the given time.
+// Otherwise, it returns nil. The caller should acquire the lock.
+func (c *cache) getIfNewerThan(id types.UID, minTime time.Time) *data {
+	d, ok := c.pods[id]
+	globalTimestampIsNewer := (c.timestamp != nil && c.timestamp.After(minTime))
+	if !ok && globalTimestampIsNewer {
+		// Status is not cached, but the global timestamp is newer than
+		// minTime, return the default status.
+		return makeDefaultData(id)
+	}
+	if ok && (d.modified.After(minTime) || globalTimestampIsNewer) {
+		// Status is cached, return status if either of the following is true.
+		//   * status was modified after minTime
+		//   * the global timestamp of the cache is newer than minTime.
+		return d
+	}
+	// The pod status is not ready.
+	return nil
+}
+
+// notify sends notifications for pod with the given id, if the requirements
+// are met. Note that the caller should acquire the lock.
+func (c *cache) notify(id types.UID, timestamp time.Time) {
+	list, ok := c.subscribers[id]
+	if !ok {
+		// No one to notify.
+		return
+	}
+	newList := []*subRecord{}
+	for i, r := range list {
+		if timestamp.Before(r.time) {
+			// Doesn't meet the time requirement; keep the record.
+			newList = append(newList, list[i])
+			continue
+		}
+		r.ch <- c.get(id)
+		close(r.ch)
+	}
+	if len(newList) == 0 {
+		delete(c.subscribers, id)
+	} else {
+		c.subscribers[id] = newList
+	}
+}
+
+func (c *cache) subscribe(id types.UID, timestamp time.Time) chan *data {
+	ch := make(chan *data, 1)
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	d := c.getIfNewerThan(id, timestamp)
+	if d != nil {
+		// If the cache entry is ready, send the data and return immediately.
+		ch <- d
+		return ch
+	}
+	// Add the subscription record.
+	c.subscribers[id] = append(c.subscribers[id], &subRecord{time: timestamp, ch: ch})
+	return ch
+}