kpod stats

Move kpod stats to the libpod backend.

Signed-off-by: baude <bbaude@redhat.com>

Closes: #113
Approved by: baude

1 files changed, 120 insertions, 0 deletions

diff --git a/libpod/stats.go b/libpod/stats.go
new file mode 100644
index 000000000..86da0679e
--- /dev/null
+++ b/libpod/stats.go
@@ -0,0 +1,120 @@
+package libpod
+
+import (
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/containerd/cgroups"
+	"github.com/opencontainers/runc/libcontainer"
+	"github.com/pkg/errors"
+)
+
+// ContainerStats contains the statistics information for a running container
+type ContainerStats struct {
+	ContainerID string
+	CPU         float64
+	CPUNano     uint64
+	SystemNano  uint64
+	MemUsage    uint64
+	MemLimit    uint64
+	MemPerc     float64
+	NetInput    uint64
+	NetOutput   uint64
+	BlockInput  uint64
+	BlockOutput uint64
+	PIDs        uint64
+}
+
+// GetContainerStats gets the running stats for a given container
+func (c *Container) GetContainerStats(previousStats *ContainerStats) (*ContainerStats, error) {
+	stats := new(ContainerStats)
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	if err := c.syncContainer(); err != nil {
+		return stats, errors.Wrapf(err, "error updating container %s state", c.ID())
+	}
+	cgroup, err := cgroups.Load(cgroups.V1, c.CGroupPath())
+	if err != nil {
+		return stats, errors.Wrapf(err, "unable to load cgroup at %+v", c.CGroupPath())
+	}
+
+	cgroupStats, err := cgroup.Stat()
+	if err != nil {
+		return stats, errors.Wrapf(err, "unable to obtain cgroup stats")
+	}
+	conState := c.state.State
+	if err != nil {
+		return stats, errors.Wrapf(err, "unable to determine container state")
+	}
+
+	previousCPU := previousStats.CPUNano
+	previousSystem := previousStats.SystemNano
+	stats.ContainerID = c.ID()
+	stats.CPU = calculateCPUPercent(cgroupStats, previousCPU, previousSystem)
+	stats.MemUsage = cgroupStats.Memory.Usage.Usage
+	stats.MemLimit = getMemLimit(cgroupStats.Memory.Usage.Limit)
+	stats.MemPerc = (float64(stats.MemUsage) / float64(stats.MemLimit)) * 100
+	stats.PIDs = 0
+	if conState == ContainerStateRunning {
+		stats.PIDs = cgroupStats.Pids.Current - 1
+	}
+	stats.BlockInput, stats.BlockOutput = calculateBlockIO(cgroupStats)
+	stats.CPUNano = cgroupStats.Cpu.Usage.Total
+	stats.SystemNano = cgroupStats.Cpu.Usage.Kernel
+	// TODO Figure out where to get the Netout stuff.
+	//stats.NetInput, stats.NetOutput = getContainerNetIO(cgroupStats)
+	return stats, nil
+}
+
+// getMemory limit returns the memory limit for a given cgroup
+// If the configured memory limit is larger than the total memory on the sys, the
+// physical system memory size is returned
+func getMemLimit(cgroupLimit uint64) uint64 {
+	si := &syscall.Sysinfo_t{}
+	err := syscall.Sysinfo(si)
+	if err != nil {
+		return cgroupLimit
+	}
+
+	physicalLimit := uint64(si.Totalram)
+	if cgroupLimit > physicalLimit {
+		return physicalLimit
+	}
+	return cgroupLimit
+}
+
+// Returns the total number of bytes transmitted and received for the given container stats
+func getContainerNetIO(stats *libcontainer.Stats) (received uint64, transmitted uint64) { //nolint
+	for _, iface := range stats.Interfaces {
+		received += iface.RxBytes
+		transmitted += iface.TxBytes
+	}
+	return
+}
+
+func calculateCPUPercent(stats *cgroups.Stats, previousCPU, previousSystem uint64) float64 {
+	var (
+		cpuPercent  = 0.0
+		cpuDelta    = float64(stats.Cpu.Usage.Total - previousCPU)
+		systemDelta = float64(uint64(time.Now().UnixNano()) - 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
+		// at 100% utilization should be 400% utilization), and multiplies that by 100 to get a percentage
+		cpuPercent = (cpuDelta / systemDelta) * float64(len(stats.Cpu.Usage.PerCpu)) * 100
+	}
+	return cpuPercent
+}
+
+func calculateBlockIO(stats *cgroups.Stats) (read uint64, write uint64) {
+	for _, blkIOEntry := range stats.Blkio.IoServiceBytesRecursive {
+		switch strings.ToLower(blkIOEntry.Op) {
+		case "read":
+			read += blkIOEntry.Value
+		case "write":
+			write += blkIOEntry.Value
+		}
+	}
+	return
+}