125 lines
3.3 KiB
Go
125 lines
3.3 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
|
|
// SPDX-License-Identifier: BSD-3-Clause
|
|
|
|
// Package sockstatlog provides a logger for capturing and storing network socket stats.
|
|
package sockstatlog
|
|
|
|
import (
|
|
"encoding/json"
|
|
"os"
|
|
"path/filepath"
|
|
"time"
|
|
|
|
"tailscale.com/logtail/filch"
|
|
"tailscale.com/net/sockstats"
|
|
"tailscale.com/util/mak"
|
|
)
|
|
|
|
// pollPeriod specifies how often to poll for socket stats.
|
|
const pollPeriod = time.Second / 10
|
|
|
|
// Logger logs statistics about network sockets.
|
|
type Logger struct {
|
|
ticker time.Ticker
|
|
logbuffer *filch.Filch
|
|
}
|
|
|
|
// deltaStat represents the bytes transferred during a time period.
|
|
// The first element is transmitted bytes, the second element is received bytes.
|
|
type deltaStat [2]uint64
|
|
|
|
// event represents the socket stats on a specific interface during a time period.
|
|
type event struct {
|
|
// Time is when the event started as a Unix timestamp in milliseconds.
|
|
Time int64 `json:"t"`
|
|
|
|
// Duration is the duration of this event in milliseconds.
|
|
Duration int64 `json:"d"`
|
|
|
|
// IsCellularInterface is set to 1 if the traffic was sent over a cellular interface.
|
|
IsCellularInterface int `json:"c,omitempty"`
|
|
|
|
// Stats records the stats for each Label during the time period.
|
|
Stats map[sockstats.Label]deltaStat `json:"s"`
|
|
}
|
|
|
|
// NewLogger returns a new Logger that will store stats in logdir.
|
|
// On platforms that do not support sockstat logging, a nil Logger will be returned.
|
|
// The returned Logger is not yet running.
|
|
func NewLogger(logdir string) (*Logger, error) {
|
|
if !sockstats.IsAvailable {
|
|
return nil, nil
|
|
}
|
|
|
|
if err := os.MkdirAll(logdir, 0755); err != nil && !os.IsExist(err) {
|
|
return nil, err
|
|
}
|
|
filchPrefix := filepath.Join(logdir, "sockstats")
|
|
filch, err := filch.New(filchPrefix, filch.Options{ReplaceStderr: false})
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return &Logger{
|
|
ticker: *time.NewTicker(pollPeriod),
|
|
logbuffer: filch,
|
|
}, nil
|
|
}
|
|
|
|
func (l *Logger) Start() {
|
|
go l.poll()
|
|
}
|
|
|
|
// poll fetches the current socket stats at the configured time interval,
|
|
// calculates the delta since the last poll, and logs any non-zero values.
|
|
// This method does not return.
|
|
func (l *Logger) poll() {
|
|
// last is the last set of socket stats we saw.
|
|
var lastStats *sockstats.SockStats
|
|
var lastTime time.Time
|
|
|
|
enc := json.NewEncoder(l.logbuffer)
|
|
for t := range l.ticker.C {
|
|
stats := sockstats.Get()
|
|
if lastStats != nil {
|
|
diffstats := delta(lastStats, stats)
|
|
if len(diffstats) > 0 {
|
|
e := event{
|
|
Time: lastTime.UnixMilli(),
|
|
Duration: t.Sub(lastTime).Milliseconds(),
|
|
Stats: diffstats,
|
|
}
|
|
if stats.CurrentInterfaceCellular {
|
|
e.IsCellularInterface = 1
|
|
}
|
|
enc.Encode(e)
|
|
}
|
|
}
|
|
lastTime = t
|
|
lastStats = stats
|
|
}
|
|
}
|
|
|
|
func (l *Logger) Shutdown() {
|
|
l.ticker.Stop()
|
|
l.logbuffer.Close()
|
|
}
|
|
|
|
// delta calculates the delta stats between two SockStats snapshots.
|
|
// b is assumed to have occurred after a.
|
|
// Zero values are omitted from the returned map, and an empty map is returned if no bytes were transferred.
|
|
func delta(a, b *sockstats.SockStats) (stats map[sockstats.Label]deltaStat) {
|
|
if a == nil || b == nil {
|
|
return nil
|
|
}
|
|
for label, bs := range b.Stats {
|
|
as := a.Stats[label]
|
|
if as.TxBytes == bs.TxBytes && as.RxBytes == bs.RxBytes {
|
|
// fast path for unchanged stats
|
|
continue
|
|
}
|
|
mak.Set(&stats, label, deltaStat{bs.TxBytes - as.TxBytes, bs.RxBytes - as.RxBytes})
|
|
}
|
|
return stats
|
|
}
|