telegraf/plugins/inputs/docker/stats_helpers.go

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// Helper functions copied from
// https://github.com/docker/cli/blob/master/cli/command/container/stats_helpers.go
package docker
import "github.com/docker/docker/api/types"
func calculateCPUPercentUnix(previousCPU, previousSystem uint64, v *types.StatsJSON) float64 {
var (
cpuPercent = 0.0
// calculate the change for the cpu usage of the container in between readings
cpuDelta = float64(v.CPUStats.CPUUsage.TotalUsage) - float64(previousCPU)
// calculate the change for the entire system between readings
systemDelta = float64(v.CPUStats.SystemUsage) - float64(previousSystem)
onlineCPUs = float64(v.CPUStats.OnlineCPUs)
)
if onlineCPUs == 0.0 {
onlineCPUs = float64(len(v.CPUStats.CPUUsage.PercpuUsage))
}
if systemDelta > 0.0 && cpuDelta > 0.0 {
cpuPercent = (cpuDelta / systemDelta) * onlineCPUs * 100.0
}
return cpuPercent
}
func calculateCPUPercentWindows(v *types.StatsJSON) float64 {
// Max number of 100ns intervals between the previous time read and now
possIntervals := uint64(v.Read.Sub(v.PreRead).Nanoseconds()) // Start with number of ns intervals
possIntervals /= 100 // Convert to number of 100ns intervals
possIntervals *= uint64(v.NumProcs) // Multiple by the number of processors
// Intervals used
intervalsUsed := v.CPUStats.CPUUsage.TotalUsage - v.PreCPUStats.CPUUsage.TotalUsage
// Percentage avoiding divide-by-zero
if possIntervals > 0 {
return float64(intervalsUsed) / float64(possIntervals) * 100.0
}
return 0.00
}
// calculateMemUsageUnixNoCache calculate memory usage of the container.
// Page cache is intentionally excluded to avoid misinterpretation of the output.
func calculateMemUsageUnixNoCache(mem types.MemoryStats) float64 {
return float64(mem.Usage - mem.Stats["cache"])
}
func calculateMemPercentUnixNoCache(limit float64, usedNoCache float64) float64 {
// MemoryStats.Limit will never be 0 unless the container is not running and we haven't
// got any data from cgroup
if limit != 0 {
return usedNoCache / limit * 100.0
}
return 0
}