Add methods for listing and fetching container stats

This uses the previously unusued lib/stats.go code to return data
about container stats to the CRI API. Helpers have been built around
filtering based on the OCI API, and CPU stat reporting has been fixed.

No data on filesystem layer usage is returned at this time.

Fixes one-half of #1248

Signed-off-by: Yann Ramin <atrus@stackworks.net>

lib/stats.go

@@ -15,8 +15,8 @@ import (
 type ContainerStats struct {
 	Container   string
 	CPU         float64
-	cpuNano     uint64
-	systemNano  uint64
+	CPUNano     uint64
+	SystemNano  int64
 	MemUsage    uint64
 	MemLimit    uint64
 	MemPerc     float64
@@ -29,8 +29,8 @@ type ContainerStats struct {
 
 // GetContainerStats gets the running stats for a given container
 func (c *ContainerServer) GetContainerStats(ctr *oci.Container, previousStats *ContainerStats) (*ContainerStats, error) {
-	previousCPU := previousStats.cpuNano
-	previousSystem := previousStats.systemNano
+	previousCPU := previousStats.CPUNano
+	previousSystem := previousStats.SystemNano
 	libcontainerStats, err := c.LibcontainerStats(ctr)
 	if err != nil {
 		return nil, err
@@ -38,6 +38,8 @@ func (c *ContainerServer) GetContainerStats(ctr *oci.Container, previousStats *C
 	cgroupStats := libcontainerStats.CgroupStats
 	stats := new(ContainerStats)
 	stats.Container = ctr.ID()
+	stats.CPUNano = cgroupStats.CpuStats.CpuUsage.TotalUsage
+	stats.SystemNano = time.Now().UnixNano()
 	stats.CPU = calculateCPUPercent(libcontainerStats, previousCPU, previousSystem)
 	stats.MemUsage = cgroupStats.MemoryStats.Usage.Usage
 	stats.MemLimit = getMemLimit(cgroupStats.MemoryStats.Usage.Limit)
@@ -84,11 +86,11 @@ func getContainerNetIO(stats *libcontainer.Stats) (received uint64, transmitted
 	return
 }
 
-func calculateCPUPercent(stats *libcontainer.Stats, previousCPU, previousSystem uint64) float64 {
+func calculateCPUPercent(stats *libcontainer.Stats, previousCPU uint64, previousSystem int64) float64 {
 	var (
 		cpuPercent  = 0.0
 		cpuDelta    = float64(stats.CgroupStats.CpuStats.CpuUsage.TotalUsage - previousCPU)
-		systemDelta = float64(uint64(time.Now().UnixNano()) - previousSystem)
+		systemDelta = float64(uint64(time.Now().UnixNano()) - uint64(previousSystem))
 	)
 	if systemDelta > 0.0 && cpuDelta > 0.0 {
 		// gets a ratio of container cpu usage total, multiplies it by the number of cores (4 cores running

server/container_list.go

@@ -28,24 +28,9 @@ func filterContainer(c *pb.Container, filter *pb.ContainerFilter) bool {
 	return true
 }
 
-// ListContainers lists all containers by filters.
-func (s *Server) ListContainers(ctx context.Context, req *pb.ListContainersRequest) (resp *pb.ListContainersResponse, err error) {
-	const operation = "list_containers"
-	defer func() {
-		recordOperation(operation, time.Now())
-		recordError(operation, err)
-	}()
-	logrus.Debugf("ListContainersRequest %+v", req)
-
-	var ctrs []*pb.Container
-	filter := req.GetFilter()
-	ctrList, err := s.ContainerServer.ListContainers()
-	if err != nil {
-		return nil, err
-	}
-
-	if filter != nil {
-
+// filterContainerList applies a protobuf-defined filter to retrieve only intended containers. Not matching
+// the filter is not considered an error but will return an empty response.
+func (s *Server) filterContainerList(filter *pb.ContainerFilter) (ctrList []*oci.Container, err error) {
 	// Filter using container id and pod id first.
 	if filter.Id != "" {
 		id, err := s.CtrIDIndex().Get(filter.Id)
@@ -53,7 +38,7 @@ func (s *Server) ListContainers(ctx context.Context, req *pb.ListContainersReque
 			// If we don't find a container ID with a filter, it should not
 			// be considered an error.  Log a warning and return an empty struct
 			logrus.Warn("unable to find container ID %s", filter.Id)
-				return &pb.ListContainersResponse{}, nil
+			return []*oci.Container{}, nil
 		}
 		c := s.ContainerServer.GetContainer(id)
 		if c != nil {
@@ -78,6 +63,30 @@ func (s *Server) ListContainers(ctx context.Context, req *pb.ListContainersReque
 			}
 		}
 	}
+	return
+}
+
+// ListContainers lists all containers by filters.
+func (s *Server) ListContainers(ctx context.Context, req *pb.ListContainersRequest) (resp *pb.ListContainersResponse, err error) {
+	const operation = "list_containers"
+	defer func() {
+		recordOperation(operation, time.Now())
+		recordError(operation, err)
+	}()
+	logrus.Debugf("ListContainersRequest %+v", req)
+
+	var ctrs []*pb.Container
+	filter := req.GetFilter()
+	ctrList, err := s.ContainerServer.ListContainers()
+	if err != nil {
+		return nil, err
+	}
+
+	if filter != nil {
+		ctrList, err = s.filterContainerList(filter)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	for _, ctr := range ctrList {

server/container_stats.go

@@ -4,10 +4,32 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/kubernetes-incubator/cri-o/lib"
+	"github.com/kubernetes-incubator/cri-o/oci"
 	"golang.org/x/net/context"
 	pb "k8s.io/kubernetes/pkg/kubelet/apis/cri/v1alpha1/runtime"
 )
 
+func buildContainerStats(stats *lib.ContainerStats, container *oci.Container) *pb.ContainerStats {
+	return &pb.ContainerStats{
+		Attributes: &pb.ContainerAttributes{
+			Id:          container.ID(),
+			Metadata:    container.Metadata(),
+			Labels:      container.Labels(),
+			Annotations: container.Annotations(),
+		},
+		Cpu: &pb.CpuUsage{
+			Timestamp:            stats.SystemNano,
+			UsageCoreNanoSeconds: &pb.UInt64Value{Value: stats.CPUNano},
+		},
+		Memory: &pb.MemoryUsage{
+			Timestamp:       stats.SystemNano,
+			WorkingSetBytes: &pb.UInt64Value{Value: stats.MemUsage},
+		},
+		WritableLayer: nil,
+	}
+}
+
 // ContainerStats returns stats of the container. If the container does not
 // exist, the call returns an error.
 func (s *Server) ContainerStats(ctx context.Context, req *pb.ContainerStatsRequest) (resp *pb.ContainerStatsResponse, err error) {
@@ -16,5 +38,16 @@ func (s *Server) ContainerStats(ctx context.Context, req *pb.ContainerStatsReque
 		recordOperation(operation, time.Now())
 		recordError(operation, err)
 	}()
-	return nil, fmt.Errorf("not implemented")
+
+	container := s.GetContainer(req.ContainerId)
+	if container == nil {
+		return nil, fmt.Errorf("invalid container")
+	}
+
+	stats, err := s.GetContainerStats(container, &lib.ContainerStats{})
+	if err != nil {
+		return nil, err
+	}
+
+	return &pb.ContainerStatsResponse{Stats: buildContainerStats(stats, container)}, nil
 }

server/container_stats_list.go

@@ -1,9 +1,10 @@
 package server
 
 import (
-	"fmt"
 	"time"
 
+	"github.com/kubernetes-incubator/cri-o/lib"
+	"github.com/sirupsen/logrus"
 	"golang.org/x/net/context"
 	pb "k8s.io/kubernetes/pkg/kubelet/apis/cri/v1alpha1/runtime"
 )
@@ -15,5 +16,37 @@ func (s *Server) ListContainerStats(ctx context.Context, req *pb.ListContainerSt
 		recordOperation(operation, time.Now())
 		recordError(operation, err)
 	}()
-	return nil, fmt.Errorf("not implemented")
+
+	ctrList, err := s.ContainerServer.ListContainers()
+	if err != nil {
+		return nil, err
+	}
+	filter := req.GetFilter()
+	if filter != nil {
+		cFilter := &pb.ContainerFilter{
+			Id:            req.Filter.Id,
+			PodSandboxId:  req.Filter.PodSandboxId,
+			LabelSelector: req.Filter.LabelSelector,
+		}
+		ctrList, err = s.filterContainerList(cFilter)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	var allStats []*pb.ContainerStats
+
+	for _, container := range ctrList {
+		stats, err := s.GetContainerStats(container, &lib.ContainerStats{})
+		if err != nil {
+			logrus.Warn("unable to get stats for container %s", container.ID())
+			continue
+		}
+		response := buildContainerStats(stats, container)
+		allStats = append(allStats, response)
+	}
+
+	return &pb.ListContainerStatsResponse{
+		Stats: allStats,
+	}, nil
 }