Implement CRI container and pods stats

See https://kep.k8s.io/2371

* Implement new CRI RPCs - `ListPodSandboxStats` and `PodSandboxStats`
  * `ListPodSandboxStats` and `PodSandboxStats` which return stats about
    pod sandbox. To obtain pod sandbox stats, underlying metrics are
    read from the pod sandbox cgroup parent.
  * Process info is obtained by calling into the underlying task
  * Network stats are taken by looking up network metrics based on the
    pod sandbox network namespace path
* Return more detailed stats for cpu and memory for existing container
  stats. These metrics use the underlying task's metrics to obtain
  stats.

Signed-off-by: David Porter <porterdavid@google.com>

pkg/cri/store/container/container.go

@@ -24,6 +24,7 @@ import (
 	cio "github.com/containerd/containerd/pkg/cri/io"
 	"github.com/containerd/containerd/pkg/cri/store"
 	"github.com/containerd/containerd/pkg/cri/store/label"
+	"github.com/containerd/containerd/pkg/cri/store/stats"
 	"github.com/containerd/containerd/pkg/cri/store/truncindex"
 
 	runtime "k8s.io/cri-api/pkg/apis/runtime/v1"
@@ -46,6 +47,8 @@ type Container struct {
 	// IsStopSignaledWithTimeout the default is 0, and it is set to 1 after sending
 	// the signal once to avoid repeated sending of the signal.
 	IsStopSignaledWithTimeout *uint32
+	// Stats contains (mutable) stats for the container
+	Stats *stats.ContainerStats
 }
 
 // Opts sets specific information to newly created Container.
@@ -166,6 +169,27 @@ func (s *Store) List() []Container {
 	return containers
 }
 
+func (s *Store) UpdateContainerStats(id string, newContainerStats *stats.ContainerStats) error {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+	id, err := s.idIndex.Get(id)
+	if err != nil {
+		if err == truncindex.ErrNotExist {
+			err = errdefs.ErrNotFound
+		}
+		return err
+	}
+
+	if _, ok := s.containers[id]; !ok {
+		return errdefs.ErrNotFound
+	}
+
+	c := s.containers[id]
+	c.Stats = newContainerStats
+	s.containers[id] = c
+	return nil
+}
+
 // Delete deletes the container from store with specified id.
 func (s *Store) Delete(id string) {
 	s.lock.Lock()

pkg/cri/store/container/container_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containerd/containerd/errdefs"
 	cio "github.com/containerd/containerd/pkg/cri/io"
 	"github.com/containerd/containerd/pkg/cri/store/label"
+	"github.com/containerd/containerd/pkg/cri/store/stats"
 
 	"github.com/opencontainers/selinux/go-selinux"
 	assertlib "github.com/stretchr/testify/assert"
@@ -132,6 +133,25 @@ func TestContainerStore(t *testing.T) {
 			Removing:   true,
 		},
 	}
+
+	stats := map[string]*stats.ContainerStats{
+		"1": {
+			Timestamp:            time.Now(),
+			UsageCoreNanoSeconds: 1,
+		},
+		"2abcd": {
+			Timestamp:            time.Now(),
+			UsageCoreNanoSeconds: 2,
+		},
+		"4a333": {
+			Timestamp:            time.Now(),
+			UsageCoreNanoSeconds: 3,
+		},
+		"4abcd": {
+			Timestamp:            time.Now(),
+			UsageCoreNanoSeconds: 4,
+		},
+	}
 	assert := assertlib.New(t)
 	containers := map[string]Container{}
 	for id := range metadatas {
@@ -163,12 +183,26 @@ func TestContainerStore(t *testing.T) {
 		got, err := s.Get(genTruncIndex(id))
 		assert.NoError(err)
 		assert.Equal(c, got)
+		assert.Nil(c.Stats)
 	}
 
 	t.Logf("should be able to list containers")
 	cs := s.List()
 	assert.Len(cs, len(containers))
 
+	t.Logf("should be able to update stats on container")
+	for id := range containers {
+		err := s.UpdateContainerStats(id, stats[id])
+		assert.NoError(err)
+	}
+
+	// Validate stats were updated
+	cs = s.List()
+	assert.Len(cs, len(containers))
+	for _, c := range cs {
+		assert.Equal(stats[c.ID], c.Stats)
+	}
+
 	if selinux.GetEnabled() {
 		t.Logf("should have reserved labels (requires -tag selinux)")
 		assert.Equal(map[string]bool{