swarm: fix uptime gauge update goroutine leak by introducing cleanup …

…functions (ethereum#19040)

swarm/swarm.go

@@ -79,7 +79,7 @@ type Swarm struct {
  swap *swap.Swap
  stateStore *state.DBStore
  accountingMetrics *protocols.AccountingMetrics
- startTime  time.Time
+ cleanupFuncs []func() error
 
  tracerClose io.Closer
 }
@@ -106,9 +106,10 @@ func NewSwarm(config *api.Config, mockStore *mock.NodeStore) (self *Swarm, err e
  }
 
  self = &Swarm{
- config: config,
- backend: backend,
- privateKey: config.ShiftPrivateKey(),
+ config: config,
+ backend: backend,
+ privateKey: config.ShiftPrivateKey(),
+ cleanupFuncs: []func() error{},
  }
  log.Debug("Setting up Swarm service components")
 
@@ -344,7 +345,7 @@ Start is called when the stack is started
 */
 // implements the node.Service interface
 func (self *Swarm) Start(srv *p2p.Server) error {
- self.startTime = time.Now()
+ startTime := time.Now()
 
  self.tracerClose = tracing.Closer
 
@@ -396,26 +397,28 @@ func (self *Swarm) Start(srv *p2p.Server) error {
  }()
  }
 
- self.periodicallyUpdateGauges()
+ doneC := make(chan struct{})
 
- startCounter.Inc(1)
- self.streamer.Start(srv)
- return nil
-}
+ self.cleanupFuncs = append(self.cleanupFuncs, func() error {
+  close(doneC)
+  return nil
+ })
 
-func (self *Swarm) periodicallyUpdateGauges() {
- ticker := time.NewTicker(updateGaugesPeriod)
-
- go func() {
- for range ticker.C {
- self.updateGauges()
+ go func(time.Time) {
+ for {
+ select {
+ case <-time.After(updateGaugesPeriod):
+ uptimeGauge.Update(time.Since(startTime).Nanoseconds())
+ requestsCacheGauge.Update(int64(self.netStore.RequestsCacheLen()))
+ case <-doneC:
+ return
+ }
  }
- }()
-}
+ }(startTime)
 
-func (self *Swarm) updateGauges() {
- uptimeGauge.Update(time.Since(self.startTime).Nanoseconds())
- requestsCacheGauge.Update(int64(self.netStore.RequestsCacheLen()))
+ startCounter.Inc(1)
+ self.streamer.Start(srv)
+ return nil
 }
 
 // implements the node.Service interface
@@ -452,6 +455,14 @@ func (self *Swarm) Stop() error {
  if self.stateStore != nil {
  self.stateStore.Close()
  }
+
+ for _, cleanF := range self.cleanupFuncs {
+ err = cleanF()
+ if err != nil {
+ log.Error("encountered an error while running cleanup function", "err", err)
+ break
+ }
+ }
  return err
 }