Added stats.go which provides strong types for all stats that will be exported by libcontainer. This commit only introduces the strong type.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)

libcontainer/cgroups/stats.go

@@ -0,0 +1,59 @@
+package cgroups
+
+type ThrottlingData struct {
+	// Number of periods with throttling active
+	Periods int64 `json:"periods,omitempty"`
+	// Number of periods when the container hit its throttling limit.
+	ThrottledPeriods int64 `json:"throttled_periods,omitempty"`
+	// Aggregate time the container was throttled for in nanoseconds.
+	ThrottledTime int64 `json:"throttled_time,omitempty"`
+}
+
+type CpuUsage struct {
+	// percentage of available CPUs currently being used.
+	PercentUsage int64 `json:"percent_usage,omitempty"`
+	// nanoseconds of cpu time consumed over the last 100 ms.
+	CurrentUsage int64 `json:"current_usage,omitempty"`
+}
+
+type CpuStats struct {
+	CpuUsage       CpuUsage       `json:"cpu_usage,omitempty"`
+	ThrottlingData ThrottlingData `json:"throlling_data,omitempty"`
+}
+
+type MemoryStats struct {
+	// current res_counter usage for memory
+	Usage int64 `json:"usage,omitempty"`
+	// maximum usage ever recorded.
+	MaxUsage int64 `json:"max_usage,omitempty"`
+	// TODO(vishh): Export these as stronger types.
+	// all the stats exported via memory.stat.
+	Stats map[string]int64 `json:"stats,omitempty"`
+}
+
+type BlkioStatEntry struct {
+	Major int64  `json:"major,omitempty"`
+	Minor int64  `json:"minor,omitempty"`
+	Op    string `json:"op,omitempty"`
+	Value int64  `json:"value,omitempty"`
+}
+
+type BlockioStats struct {
+	// number of bytes tranferred to and from the block device
+	IoServiceBytesRecursive []BlkioStatEntry `json:"io_service_bytes_recursive,omitempty"`
+	IoServicedRecursive     []BlkioStatEntry `json:"io_serviced_recusrive,omitempty"`
+	IoQueuedRecursive       []BlkioStatEntry `json:"io_queue_recursive,omitempty"`
+}
+
+// TODO(Vishh): Remove freezer from stats since it does not logically belong in stats.
+type FreezerStats struct {
+	ParentState string `json:"parent_state,omitempty"`
+	SelfState   string `json:"self_state,omitempty"`
+}
+
+type Stats struct {
+	CpuStats     CpuStats     `json:"cpu_stats,omitempty"`
+	MemoryStats  MemoryStats  `json:"memory_stats,omitempty"`
+	BlockioStats BlockioStats `json:"blockio_stats,omitempty"`
+	FreezerStats FreezerStats `json:"freezer_stats,omitempty"`
+}