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fix: Improve agent connection tracking when agent is closed #5253

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Merged
merged 5 commits into from
Dec 2, 2022
Merged

fix: Improve agent connection tracking when agent is closed #5253

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874eff6
fix: Improve agent connection tracking when agent is closed
mafredri Dec 2, 2022
3b0fe00
Merge branch 'main' into mafredri/fix-agent-connection-tracking
mafredri Dec 2, 2022
71071d5
Also close tailnet if there was an error
mafredri Dec 2, 2022
6f9b319
Avoid double assign of `a.network`
mafredri Dec 2, 2022
a0de5a0
Revert "Avoid double assign of `a.network`"
mafredri Dec 2, 2022
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110 changes: 77 additions & 33 deletions agent/agent.go
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Original file line number Diff line number Diff line change
Expand Up @@ -231,13 +231,27 @@ func (a *agent) run(ctx context.Context) error {
return nil
}

func (a *agent) createTailnet(ctx context.Context, derpMap *tailcfg.DERPMap) (*tailnet.Conn, error) {
func (a *agent) trackConnGoroutine(fn func()) error {
a.closeMutex.Lock()
defer a.closeMutex.Unlock()
if a.isClosed() {
return xerrors.New("track conn goroutine: agent is closed")
}
a.connCloseWait.Add(1)
go func() {
defer a.connCloseWait.Done()
fn()
}()
return nil
}

func (a *agent) createTailnet(ctx context.Context, derpMap *tailcfg.DERPMap) (network *tailnet.Conn, err error) {
a.closeMutex.Lock()
if a.isClosed() {
a.closeMutex.Unlock()
return nil, xerrors.New("closed")
}
network, err := tailnet.NewConn(&tailnet.Options{
network, err = tailnet.NewConn(&tailnet.Options{
Addresses: []netip.Prefix{netip.PrefixFrom(codersdk.TailnetIP, 128)},
DERPMap: derpMap,
Logger: a.logger.Named("tailnet"),
Expand All @@ -247,31 +261,45 @@ func (a *agent) createTailnet(ctx context.Context, derpMap *tailcfg.DERPMap) (*t
a.closeMutex.Unlock()
return nil, xerrors.Errorf("create tailnet: %w", err)
}
defer func() {
if err != nil {
network.Close()
}
}()
a.network = network
a.connCloseWait.Add(4)
a.closeMutex.Unlock()

sshListener, err := network.Listen("tcp", ":"+strconv.Itoa(codersdk.TailnetSSHPort))
if err != nil {
return nil, xerrors.Errorf("listen on the ssh port: %w", err)
}
go func() {
defer a.connCloseWait.Done()
defer func() {
if err != nil {
_ = sshListener.Close()
}
}()
if err = a.trackConnGoroutine(func() {
for {
conn, err := sshListener.Accept()
if err != nil {
return
}
go a.sshServer.HandleConn(conn)
}
}()
}); err != nil {
return nil, err
}

reconnectingPTYListener, err := network.Listen("tcp", ":"+strconv.Itoa(codersdk.TailnetReconnectingPTYPort))
if err != nil {
return nil, xerrors.Errorf("listen for reconnecting pty: %w", err)
}
go func() {
defer a.connCloseWait.Done()
defer func() {
if err != nil {
_ = reconnectingPTYListener.Close()
}
}()
if err = a.trackConnGoroutine(func() {
for {
conn, err := reconnectingPTYListener.Accept()
if err != nil {
Expand All @@ -298,36 +326,48 @@ func (a *agent) createTailnet(ctx context.Context, derpMap *tailcfg.DERPMap) (*t
}
go a.handleReconnectingPTY(ctx, msg, conn)
}
}()
}); err != nil {
return nil, err
}

speedtestListener, err := network.Listen("tcp", ":"+strconv.Itoa(codersdk.TailnetSpeedtestPort))
if err != nil {
return nil, xerrors.Errorf("listen for speedtest: %w", err)
}
go func() {
defer a.connCloseWait.Done()
defer func() {
if err != nil {
_ = speedtestListener.Close()
}
}()
if err = a.trackConnGoroutine(func() {
for {
conn, err := speedtestListener.Accept()
if err != nil {
a.logger.Debug(ctx, "speedtest listener failed", slog.Error(err))
return
}
a.closeMutex.Lock()
a.connCloseWait.Add(1)
a.closeMutex.Unlock()
go func() {
defer a.connCloseWait.Done()
if err = a.trackConnGoroutine(func() {
_ = speedtest.ServeConn(conn)
}()
}); err != nil {
a.logger.Debug(ctx, "speedtest listener failed", slog.Error(err))
_ = conn.Close()
return
}
}
}()
}); err != nil {
return nil, err
}

statisticsListener, err := network.Listen("tcp", ":"+strconv.Itoa(codersdk.TailnetStatisticsPort))
if err != nil {
return nil, xerrors.Errorf("listen for statistics: %w", err)
}
go func() {
defer a.connCloseWait.Done()
defer func() {
if err != nil {
_ = statisticsListener.Close()
}
}()
if err = a.trackConnGoroutine(func() {
defer statisticsListener.Close()
server := &http.Server{
Handler: a.statisticsHandler(),
Expand All @@ -341,11 +381,13 @@ func (a *agent) createTailnet(ctx context.Context, derpMap *tailcfg.DERPMap) (*t
_ = server.Close()
}()

err = server.Serve(statisticsListener)
err := server.Serve(statisticsListener)
if err != nil && !xerrors.Is(err, http.ErrServerClosed) && !strings.Contains(err.Error(), "use of closed network connection") {
a.logger.Critical(ctx, "serve statistics HTTP server", slog.Error(err))
}
}()
}); err != nil {
return nil, err
}

return network, nil
}
Expand Down Expand Up @@ -527,12 +569,15 @@ func (a *agent) init(ctx context.Context) {
a.logger.Error(ctx, "report stats", slog.Error(err))
return
}
a.connCloseWait.Add(1)
go func() {
defer a.connCloseWait.Done()

if err = a.trackConnGoroutine(func() {
<-a.closed
cl.Close()
}()
_ = cl.Close()
}); err != nil {
a.logger.Error(ctx, "report stats goroutine", slog.Error(err))
_ = cl.Close()
return
}
}

func convertAgentStats(counts map[netlogtype.Connection]netlogtype.Counts) *codersdk.AgentStats {
Expand Down Expand Up @@ -787,9 +832,6 @@ func (a *agent) handleReconnectingPTY(ctx context.Context, msg codersdk.Reconnec
return
}

a.closeMutex.Lock()
a.connCloseWait.Add(1)
a.closeMutex.Unlock()
ctx, cancelFunc := context.WithCancel(ctx)
rpty = &reconnectingPTY{
activeConns: map[string]net.Conn{
Expand Down Expand Up @@ -818,7 +860,7 @@ func (a *agent) handleReconnectingPTY(ctx context.Context, msg codersdk.Reconnec
_ = process.Wait()
rpty.Close()
}()
go func() {
if err = a.trackConnGoroutine(func() {
buffer := make([]byte, 1024)
for {
read, err := rpty.ptty.Output().Read(buffer)
Expand Down Expand Up @@ -846,8 +888,10 @@ func (a *agent) handleReconnectingPTY(ctx context.Context, msg codersdk.Reconnec
_ = process.Kill()
rpty.Close()
a.reconnectingPTYs.Delete(msg.ID)
a.connCloseWait.Done()
}()
}); err != nil {
a.logger.Error(ctx, "start reconnecting pty routine", slog.F("id", msg.ID), slog.Error(err))
return
}
}
// Resize the PTY to initial height + width.
err := rpty.ptty.Resize(msg.Height, msg.Width)
Expand Down