wings/environment/docker/stats.go

132 lines
4.0 KiB
Go

package docker
import (
"context"
"encoding/json"
"github.com/apex/log"
"github.com/docker/docker/api/types"
"github.com/pkg/errors"
"github.com/pterodactyl/wings/environment"
"io"
"math"
"sync/atomic"
)
// Attach to the instance and then automatically emit an event whenever the resource usage for the
// server process changes.
func (e *Environment) pollResources(ctx context.Context) error {
l := log.WithField("container_id", e.Id)
l.Debug("starting resource polling for container")
defer l.Debug("stopped resource polling for container")
if e.st.Load() == environment.ProcessOfflineState {
return errors.New("cannot enable resource polling on a stopped server")
}
stats, err := e.client.ContainerStats(context.Background(), e.Id, true)
if err != nil {
return errors.WithStack(err)
}
defer stats.Body.Close()
dec := json.NewDecoder(stats.Body)
for {
select {
case <-ctx.Done():
return ctx.Err()
default:
var v *types.StatsJSON
if err := dec.Decode(&v); err != nil {
if err != io.EOF {
l.WithField("error", errors.WithStack(err)).Warn("error while processing Docker stats output for container")
} else {
l.Debug("io.EOF encountered during stats decode, stopping polling...")
}
return nil
}
// Disable collection if the server is in an offline state and this process is still running.
if e.st.Load() == environment.ProcessOfflineState {
l.Debug("process in offline state while resource polling is still active; stopping poll")
return nil
}
var rx uint64
var tx uint64
for _, nw := range v.Networks {
atomic.AddUint64(&rx, nw.RxBytes)
atomic.AddUint64(&tx, nw.RxBytes)
}
st := &environment.Stats{
Memory: calculateDockerMemory(v.MemoryStats),
MemoryLimit: v.MemoryStats.Limit,
CpuAbsolute: calculateDockerAbsoluteCpu(&v.PreCPUStats, &v.CPUStats),
Network: struct {
RxBytes uint64 `json:"rx_bytes"`
TxBytes uint64 `json:"tx_bytes"`
}{
RxBytes: rx,
TxBytes: tx,
},
}
if b, err := json.Marshal(st); err != nil {
l.WithField("error", errors.WithStack(err)).Warn("error while marshaling stats object for environment")
} else {
e.Events().Publish(environment.ResourceEvent, string(b))
}
}
}
}
// The "docker stats" CLI call does not return the same value as the types.MemoryStats.Usage
// value which can be rather confusing to people trying to compare panel usage to
// their stats output.
//
// This math is straight up lifted from their CLI repository in order to show the same
// values to avoid people bothering me about it. It should also reflect a slightly more
// correct memory value anyways.
//
// @see https://github.com/docker/cli/blob/96e1d1d6/cli/command/container/stats_helpers.go#L227-L249
func calculateDockerMemory(stats types.MemoryStats) uint64 {
if v, ok := stats.Stats["total_inactive_file"]; ok && v < stats.Usage {
return stats.Usage - v
}
if v := stats.Stats["inactive_file"]; v < stats.Usage {
return stats.Usage - v
}
return stats.Usage
}
// Calculates the absolute CPU usage used by the server process on the system, not constrained
// by the defined CPU limits on the container.
//
// @see https://github.com/docker/cli/blob/aa097cf1aa19099da70930460250797c8920b709/cli/command/container/stats_helpers.go#L166
func calculateDockerAbsoluteCpu(pStats *types.CPUStats, stats *types.CPUStats) float64 {
// Calculate the change in CPU usage between the current and previous reading.
cpuDelta := float64(stats.CPUUsage.TotalUsage) - float64(pStats.CPUUsage.TotalUsage)
// Calculate the change for the entire system's CPU usage between current and previous reading.
systemDelta := float64(stats.SystemUsage) - float64(pStats.SystemUsage)
// Calculate the total number of CPU cores being used.
cpus := float64(stats.OnlineCPUs)
if cpus == 0.0 {
cpus = float64(len(stats.CPUUsage.PercpuUsage))
}
percent := 0.0
if systemDelta > 0.0 && cpuDelta > 0.0 {
percent = (cpuDelta / systemDelta) * cpus * 100.0
}
return math.Round(percent*1000) / 1000
}