mirror of https://github.com/tailscale/tailscale/
ipn,log: add logger for sockstat deltas
Signed-off-by: Will Norris <will@tailscale.com> Co-authored-by: Melanie Warrick <warrick@tailscale.com>pull/7526/head
Will Norris
2 years ago
committed by
Will Norris
parent
5e8a80b845
commit
a1d9f65354
@ -0,0 +1,124 @@
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// Package sockstatlog provides a logger for capturing and storing network socket stats.
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package sockstatlog
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import (
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"encoding/json"
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"os"
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"path/filepath"
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"time"
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"tailscale.com/logtail/filch"
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"tailscale.com/net/sockstats"
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"tailscale.com/util/mak"
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)
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// pollPeriod specifies how often to poll for socket stats.
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const pollPeriod = time.Second / 10
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// Logger logs statistics about network sockets.
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type Logger struct {
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ticker time.Ticker
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logbuffer *filch.Filch
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}
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// deltaStat represents the bytes transferred during a time period.
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// The first element is transmitted bytes, the second element is received bytes.
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type deltaStat [2]uint64
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// event represents the socket stats on a specific interface during a time period.
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type event struct {
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// Time is when the event started as a Unix timestamp in milliseconds.
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Time int64 `json:"t"`
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// Duration is the duration of this event in milliseconds.
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Duration int64 `json:"d"`
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// IsCellularInterface is set to 1 if the traffic was sent over a cellular interface.
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IsCellularInterface int `json:"c,omitempty"`
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// Stats records the stats for each Label during the time period.
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Stats map[sockstats.Label]deltaStat `json:"s"`
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}
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// NewLogger returns a new Logger that will store stats in logdir.
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// On platforms that do not support sockstat logging, a nil Logger will be returned.
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// The returned Logger is not yet running.
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func NewLogger(logdir string) (*Logger, error) {
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if !sockstats.IsAvailable {
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return nil, nil
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}
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if err := os.MkdirAll(logdir, 0755); err != nil && !os.IsExist(err) {
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return nil, err
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}
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filchPrefix := filepath.Join(logdir, "sockstats")
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filch, err := filch.New(filchPrefix, filch.Options{ReplaceStderr: false})
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if err != nil {
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return nil, err
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}
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return &Logger{
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ticker: *time.NewTicker(pollPeriod),
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logbuffer: filch,
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}, nil
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}
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func (l *Logger) Start() {
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go l.poll()
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}
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// poll fetches the current socket stats at the configured time interval,
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// calculates the delta since the last poll, and logs any non-zero values.
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// This method does not return.
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func (l *Logger) poll() {
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// last is the last set of socket stats we saw.
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var lastStats *sockstats.SockStats
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var lastTime time.Time
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enc := json.NewEncoder(l.logbuffer)
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for t := range l.ticker.C {
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stats := sockstats.Get()
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if lastStats != nil {
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diffstats := delta(lastStats, stats)
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if len(diffstats) > 0 {
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e := event{
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Time: lastTime.UnixMilli(),
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Duration: t.Sub(lastTime).Milliseconds(),
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Stats: diffstats,
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}
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if stats.CurrentInterfaceCellular {
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e.IsCellularInterface = 1
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}
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enc.Encode(e)
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}
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}
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lastTime = t
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lastStats = stats
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}
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}
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func (l *Logger) Shutdown() {
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l.ticker.Stop()
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l.logbuffer.Close()
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}
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// delta calculates the delta stats between two SockStats snapshots.
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// b is assumed to have occurred after a.
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// Zero values are omitted from the returned map, and an empty map is returned if no bytes were transferred.
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func delta(a, b *sockstats.SockStats) (stats map[sockstats.Label]deltaStat) {
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if a == nil || b == nil {
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return nil
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}
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for label, bs := range b.Stats {
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as := a.Stats[label]
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if as.TxBytes == bs.TxBytes && as.RxBytes == bs.RxBytes {
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// fast path for unchanged stats
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continue
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}
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mak.Set(&stats, label, deltaStat{bs.TxBytes - as.TxBytes, bs.RxBytes - as.RxBytes})
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}
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return stats
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}
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@ -0,0 +1,119 @@
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package sockstatlog
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import (
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"testing"
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"github.com/google/go-cmp/cmp"
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"tailscale.com/net/sockstats"
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)
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func TestDelta(t *testing.T) {
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tests := []struct {
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name string
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a, b *sockstats.SockStats
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wantStats map[sockstats.Label]deltaStat
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}{
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{
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name: "nil a stat",
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a: nil,
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b: &sockstats.SockStats{},
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wantStats: nil,
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},
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{
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name: "nil b stat",
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a: &sockstats.SockStats{},
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b: nil,
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wantStats: nil,
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},
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{
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name: "no change",
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a: &sockstats.SockStats{
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Stats: map[sockstats.Label]sockstats.SockStat{
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sockstats.LabelDERPHTTPClient: {
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TxBytes: 10,
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TxBytesByInterface: map[string]uint64{
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"en0": 10,
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},
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},
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},
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},
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b: &sockstats.SockStats{
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Stats: map[sockstats.Label]sockstats.SockStat{
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sockstats.LabelDERPHTTPClient: {
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TxBytes: 10,
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TxBytesByInterface: map[string]uint64{
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"en0": 10,
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},
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},
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},
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},
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wantStats: nil,
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},
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{
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name: "tx after empty stat",
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a: &sockstats.SockStats{},
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b: &sockstats.SockStats{
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Stats: map[sockstats.Label]sockstats.SockStat{
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sockstats.LabelDERPHTTPClient: {
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TxBytes: 10,
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TxBytesByInterface: map[string]uint64{
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"en0": 10,
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},
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},
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},
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Interfaces: []string{"en0"},
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},
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wantStats: map[sockstats.Label]deltaStat{
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sockstats.LabelDERPHTTPClient: {10, 0},
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},
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},
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{
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name: "rx after non-empty stat",
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a: &sockstats.SockStats{
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Stats: map[sockstats.Label]sockstats.SockStat{
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sockstats.LabelDERPHTTPClient: {
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TxBytes: 10,
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RxBytes: 10,
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TxBytesByInterface: map[string]uint64{
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"en0": 10,
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},
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RxBytesByInterface: map[string]uint64{
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"en0": 10,
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},
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},
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},
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Interfaces: []string{"en0"},
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},
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b: &sockstats.SockStats{
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Stats: map[sockstats.Label]sockstats.SockStat{
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sockstats.LabelDERPHTTPClient: {
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TxBytes: 10,
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RxBytes: 30,
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TxBytesByInterface: map[string]uint64{
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"en0": 10,
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},
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RxBytesByInterface: map[string]uint64{
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"en0": 30,
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},
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},
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},
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Interfaces: []string{"en0"},
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},
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wantStats: map[sockstats.Label]deltaStat{
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sockstats.LabelDERPHTTPClient: {0, 20},
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},
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},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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gotStats := delta(tt.a, tt.b)
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if !cmp.Equal(gotStats, tt.wantStats) {
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t.Errorf("gotStats = %v, want %v", gotStats, tt.wantStats)
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}
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})
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}
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}
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