Fix update container resources

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/store/container/client.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2017 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"
+
+	"github.com/containerd/containerd"
+)
+
+// Client holds the containerd container client.
+// containerd.Container is a pointer underlying. New assignment won't affect
+// the previous pointer, so simply lock around is enough.
+type Client struct {
+	lock      sync.RWMutex
+	container containerd.Container
+}
+
+// Get containerd container client.
+func (c *Client) Get() containerd.Container {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	return c.container
+}
+
+// Set containerd container client.
+func (c *Client) Set(container containerd.Container) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.container = container
+}

pkg/store/container/container.go

@@ -32,8 +32,8 @@ type Container struct {
 	Metadata
 	// Status stores the status of the container.
 	Status StatusStorage
-	// Containerd container
-	Container containerd.Container
+	// Container is the containerd container client.
+	Container *Client
 	// Container IO
 	IO *cio.ContainerIO
 	// TODO(random-liu): Add stop channel to get rid of stop poll waiting.
@@ -45,7 +45,7 @@ type Opts func(*Container) error
 // WithContainer adds the containerd Container to the internal data store.
 func WithContainer(cntr containerd.Container) Opts {
 	return func(c *Container) error {
-		c.Container = cntr
+		c.Container = &Client{container: cntr}
 		return nil
 	}
 }

pkg/store/container/metadata.go

@@ -51,6 +51,8 @@ type Metadata struct {
 	// SandboxID is the sandbox id the container belongs to.
 	SandboxID string
 	// Config is the CRI container config.
+	// NOTE(random-liu): Resource limits are updatable, the source
+	// of truth for resource limits are in containerd.
 	Config *runtime.ContainerConfig
 	// ImageRef is the reference of image used by the container.
 	ImageRef string

pkg/store/sandbox/sandbox.go

@@ -29,7 +29,7 @@ import (
 type Sandbox struct {
 	// Metadata is the metadata of the sandbox, it is immutable after created.
 	Metadata
-	// Containerd sandbox container
+	// Container is the containerd sandbox container client
 	Container containerd.Container
 	// CNI network namespace client
 	NetNS *NetNS