mirror of https://github.com/tailscale/tailscale/
sockstats: instrument networking code paths
Uses the hooks added by tailscale/go#45 to instrument the reads and writes on the major code paths that do network I/O in the client. The convention is to use "<package>.<type>:<label>" as the annotation for the responsible code path. Enabled on iOS, macOS and Android only, since mobile platforms are the ones we're most interested in, and we are less sensitive to any throughput degradation due to the per-I/O callback overhead (macOS is also enabled for ease of testing during development). For now just exposed as counters on a /v0/sockstats PeerAPI endpoint. We also keep track of the current interface so that we can break out the stats by interface. Updates tailscale/corp#9230 Updates #3363 Signed-off-by: Mihai Parparita <mihai@tailscale.com>pull/7415/head
Mihai Parparita
1 year ago
committed by
Mihai Parparita
parent
0c1510739c
commit
9cb332f0e2
@ -1 +1 @@
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ec180cbca39fcb5dc420399b37583e53fcf382c9
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fb11c0df588717a3ee13b09dacae1e7093279d67
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// Package sockstats collects statistics about network sockets used by
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// the Tailscale client. The context where sockets are used must be
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// instrumented with the WithSockStats() function.
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//
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// Only available on POSIX platforms when built with Tailscale's fork of Go.
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package sockstats
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import (
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"context"
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"tailscale.com/wgengine/monitor"
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)
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type SockStats struct {
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Stats map[string]SockStat
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Interfaces []string
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}
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type SockStat struct {
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TxBytes int64
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RxBytes int64
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TxBytesByInterface map[string]int64
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RxBytesByInterface map[string]int64
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}
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func WithSockStats(ctx context.Context, label string) context.Context {
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return withSockStats(ctx, label)
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}
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func Get() *SockStats {
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return get()
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}
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func SetLinkMonitor(lm *monitor.Mon) {
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setLinkMonitor(lm)
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}
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build !tailscale_go || !(darwin || ios || android)
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package sockstats
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import (
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"context"
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"tailscale.com/wgengine/monitor"
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)
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func withSockStats(ctx context.Context, label string) context.Context {
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return ctx
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}
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func get() *SockStats {
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return nil
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}
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func setLinkMonitor(lm *monitor.Mon) {
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}
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@ -0,0 +1,151 @@
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// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build tailscale_go && (darwin || ios || android)
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package sockstats
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import (
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"context"
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"log"
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"net"
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"sync"
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"sync/atomic"
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"tailscale.com/net/interfaces"
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"tailscale.com/wgengine/monitor"
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)
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type sockStatCounters struct {
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txBytes, rxBytes atomic.Uint64
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rxBytesByInterface, txBytesByInterface map[int]*atomic.Uint64
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}
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var sockStats = struct {
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// mu protects fields in this group. It should not be held in the per-read/
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// write callbacks.
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mu sync.Mutex
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countersByLabel map[string]*sockStatCounters
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knownInterfaces map[int]string // interface index -> name
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usedInterfaces map[int]int // set of interface indexes
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// Separate atomic since the current interface is accessed in the per-read/
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// write callbacks.
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currentInterface atomic.Uint32
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}{
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countersByLabel: make(map[string]*sockStatCounters),
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knownInterfaces: make(map[int]string),
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usedInterfaces: make(map[int]int),
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}
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func withSockStats(ctx context.Context, label string) context.Context {
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sockStats.mu.Lock()
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defer sockStats.mu.Unlock()
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counters, ok := sockStats.countersByLabel[label]
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if !ok {
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counters = &sockStatCounters{
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rxBytesByInterface: make(map[int]*atomic.Uint64),
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txBytesByInterface: make(map[int]*atomic.Uint64),
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}
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for iface := range sockStats.knownInterfaces {
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counters.rxBytesByInterface[iface] = &atomic.Uint64{}
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counters.txBytesByInterface[iface] = &atomic.Uint64{}
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}
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sockStats.countersByLabel[label] = counters
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}
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didRead := func(n int) {
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counters.rxBytes.Add(uint64(n))
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if currentInterface := int(sockStats.currentInterface.Load()); currentInterface != 0 {
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if a := counters.rxBytesByInterface[currentInterface]; a != nil {
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a.Add(uint64(n))
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}
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}
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}
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didWrite := func(n int) {
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counters.txBytes.Add(uint64(n))
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if currentInterface := int(sockStats.currentInterface.Load()); currentInterface != 0 {
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if a := counters.txBytesByInterface[currentInterface]; a != nil {
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a.Add(uint64(n))
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}
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}
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}
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willOverwrite := func(trace *net.SockTrace) {
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log.Printf("sockstats: trace %q was overwritten by another", label)
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}
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return net.WithSockTrace(ctx, &net.SockTrace{
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DidRead: didRead,
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DidWrite: didWrite,
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WillOverwrite: willOverwrite,
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})
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}
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func get() *SockStats {
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sockStats.mu.Lock()
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defer sockStats.mu.Unlock()
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r := &SockStats{
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Stats: make(map[string]SockStat),
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Interfaces: make([]string, 0, len(sockStats.usedInterfaces)),
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}
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for iface := range sockStats.usedInterfaces {
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r.Interfaces = append(r.Interfaces, sockStats.knownInterfaces[iface])
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}
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for label, counters := range sockStats.countersByLabel {
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r.Stats[label] = SockStat{
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TxBytes: int64(counters.txBytes.Load()),
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RxBytes: int64(counters.rxBytes.Load()),
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TxBytesByInterface: make(map[string]int64),
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RxBytesByInterface: make(map[string]int64),
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}
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for iface, a := range counters.rxBytesByInterface {
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ifName := sockStats.knownInterfaces[iface]
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r.Stats[label].RxBytesByInterface[ifName] = int64(a.Load())
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}
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for iface, a := range counters.txBytesByInterface {
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ifName := sockStats.knownInterfaces[iface]
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r.Stats[label].TxBytesByInterface[ifName] = int64(a.Load())
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}
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}
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return r
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}
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func setLinkMonitor(lm *monitor.Mon) {
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sockStats.mu.Lock()
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defer sockStats.mu.Unlock()
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// We intentionally populate all known interfaces now, so that we can
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// increment stats for them without holding mu.
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state := lm.InterfaceState()
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for ifName, iface := range state.Interface {
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sockStats.knownInterfaces[iface.Index] = ifName
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}
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if ifName := state.DefaultRouteInterface; ifName != "" {
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ifIndex := state.Interface[ifName].Index
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sockStats.currentInterface.Store(uint32(ifIndex))
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sockStats.usedInterfaces[ifIndex] = 1
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}
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lm.RegisterChangeCallback(func(changed bool, state *interfaces.State) {
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if changed {
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if ifName := state.DefaultRouteInterface; ifName != "" {
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ifIndex := state.Interface[ifName].Index
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sockStats.mu.Lock()
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defer sockStats.mu.Unlock()
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// Ignore changes to unknown interfaces -- it would require
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// updating the tx/rxBytesByInterface maps and thus
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// additional locking for every read/write. Most of the time
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// the set of interfaces is static.
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if _, ok := sockStats.knownInterfaces[ifIndex]; ok {
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sockStats.currentInterface.Store(uint32(ifIndex))
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sockStats.usedInterfaces[ifIndex] = 1
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} else {
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sockStats.currentInterface.Store(0)
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}
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}
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}
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})
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}
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