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 }