Use runc events --stats for collecting stats

runc `events --stats` now has stable output so we don't need to bind to
libcontainer directly to get stats output for the containers.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

runtime/container.go

@@ -523,7 +523,7 @@ func hostIDFromMap(id uint32, mp []ocs.IDMapping) int {
 func (c *container) Pids() ([]int, error) {
 	out, err := exec.Command(c.runtime, "ps", "--format=json", c.id).CombinedOutput()
 	if err != nil {
-		return nil, fmt.Errorf(string(out))
+		return nil, fmt.Errorf("%s", out)
 	}
 	var pids []int
 	if err := json.Unmarshal(out, &pids); err != nil {
@@ -533,19 +533,19 @@ func (c *container) Pids() ([]int, error) {
 }
 
 func (c *container) Stats() (*Stat, error) {
-	container, err := c.getLibctContainer()
-	if err != nil {
-		return nil, err
-	}
 	now := time.Now()
-	stats, err := container.Stats()
+	out, err := exec.Command(c.runtime, "events", "--stats", c.id).CombinedOutput()
 	if err != nil {
+		return nil, fmt.Errorf("%s", out)
+	}
+	s := struct {
+		Data *Stat `json:"data"`
+	}{}
+	if err := json.Unmarshal(out, &s); err != nil {
 		return nil, err
 	}
-	return &Stat{
-		Timestamp: now,
-		Data:      stats,
-	}, nil
+	s.Data.Timestamp = now
+	return s.Data, nil
 }
 
 func (c *container) OOM() (OOM, error) {
@@ -575,7 +575,7 @@ func (c *container) Status() (State, error) {
 
 	out, err := exec.Command(c.runtime, args...).CombinedOutput()
 	if err != nil {
-		return "", fmt.Errorf(string(out))
+		return "", fmt.Errorf("%s", out)
 	}
 
 	// We only require the runtime json output to have a top level Status field.

runtime/runtime.go

@@ -97,13 +97,3 @@ type ProcessState struct {
 
 	PlatformProcessState
 }
-
-type Stat struct {
-	// Timestamp is the time that the statistics where collected
-	Timestamp time.Time
-	// Data is the raw stats
-	// TODO: it is currently an interface because we don't know what type of exec drivers
-	// we will have or what the structure should look like at the moment os the containers
-	// can return what they want and we could marshal to json or whatever.
-	Data interface{}
-}

runtime/stats.go

@@ -0,0 +1,77 @@
+package runtime
+
+import "time"
+
+type Stat struct {
+	// Timestamp is the time that the statistics where collected
+	Timestamp time.Time
+	Cpu       Cpu                `json:"cpu"`
+	Memory    Memory             `json:"memory"`
+	Pids      Pids               `json:"pids"`
+	Blkio     Blkio              `json:"blkio"`
+	Hugetlb   map[string]Hugetlb `json:"hugetlb"`
+}
+
+type Hugetlb struct {
+	Usage   uint64 `json:"usage,omitempty"`
+	Max     uint64 `json:"max,omitempty"`
+	Failcnt uint64 `json:"failcnt"`
+}
+
+type BlkioEntry struct {
+	Major uint64 `json:"major,omitempty"`
+	Minor uint64 `json:"minor,omitempty"`
+	Op    string `json:"op,omitempty"`
+	Value uint64 `json:"value,omitempty"`
+}
+
+type Blkio struct {
+	IoServiceBytesRecursive []BlkioEntry `json:"ioServiceBytesRecursive,omitempty"`
+	IoServicedRecursive     []BlkioEntry `json:"ioServicedRecursive,omitempty"`
+	IoQueuedRecursive       []BlkioEntry `json:"ioQueueRecursive,omitempty"`
+	IoServiceTimeRecursive  []BlkioEntry `json:"ioServiceTimeRecursive,omitempty"`
+	IoWaitTimeRecursive     []BlkioEntry `json:"ioWaitTimeRecursive,omitempty"`
+	IoMergedRecursive       []BlkioEntry `json:"ioMergedRecursive,omitempty"`
+	IoTimeRecursive         []BlkioEntry `json:"ioTimeRecursive,omitempty"`
+	SectorsRecursive        []BlkioEntry `json:"sectorsRecursive,omitempty"`
+}
+
+type Pids struct {
+	Current uint64 `json:"current,omitempty"`
+	Limit   uint64 `json:"limit,omitempty"`
+}
+
+type Throttling struct {
+	Periods          uint64 `json:"periods,omitempty"`
+	ThrottledPeriods uint64 `json:"throttledPeriods,omitempty"`
+	ThrottledTime    uint64 `json:"throttledTime,omitempty"`
+}
+
+type CpuUsage struct {
+	// Units: nanoseconds.
+	Total  uint64   `json:"total,omitempty"`
+	Percpu []uint64 `json:"percpu,omitempty"`
+	Kernel uint64   `json:"kernel"`
+	User   uint64   `json:"user"`
+}
+
+type Cpu struct {
+	Usage      CpuUsage   `json:"usage,omitempty"`
+	Throttling Throttling `json:"throttling,omitempty"`
+}
+
+type MemoryEntry struct {
+	Limit   uint64 `json:"limit"`
+	Usage   uint64 `json:"usage,omitempty"`
+	Max     uint64 `json:"max,omitempty"`
+	Failcnt uint64 `json:"failcnt"`
+}
+
+type Memory struct {
+	Cache     uint64            `json:"cache,omitempty"`
+	Usage     MemoryEntry       `json:"usage,omitempty"`
+	Swap      MemoryEntry       `json:"swap,omitempty"`
+	Kernel    MemoryEntry       `json:"kernel,omitempty"`
+	KernelTCP MemoryEntry       `json:"kernelTCP,omitempty"`
+	Raw       map[string]uint64 `json:"raw,omitempty"`
+}