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Fixes memory leak when blocking on /event/list (#4482)
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banks authored Aug 2, 2018
1 parent ec755b4 commit 71dd3b4
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Showing 3 changed files with 14 additions and 11 deletions.
1 change: 1 addition & 0 deletions agent/event_endpoint.go
Original file line number Diff line number Diff line change
Expand Up @@ -125,6 +125,7 @@ SETUP_NOTIFY:
if b.MinQueryIndex > 0 {
notifyCh = make(chan struct{}, 1)
s.agent.eventNotify.Wait(notifyCh)
defer s.agent.eventNotify.Clear(notifyCh)
}

RUN_QUERY:
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7 changes: 0 additions & 7 deletions agent/notify.go
Original file line number Diff line number Diff line change
Expand Up @@ -46,10 +46,3 @@ func (n *NotifyGroup) Clear(ch chan struct{}) {
}
delete(n.notify, ch)
}

// WaitCh allocates a channel that is subscribed to notifications
func (n *NotifyGroup) WaitCh() chan struct{} {
ch := make(chan struct{}, 1)
n.Wait(ch)
return ch
}
17 changes: 13 additions & 4 deletions agent/notify_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -4,11 +4,20 @@ import (
"testing"
)

// Used to be defined in NotifyGroup.WaitCh but was only used in tests and prone
// to leaking memory if anything real did use it because there is no way to
// clear the chan later.
func testWaitCh(t *testing.T, grp *NotifyGroup) chan struct{} {
ch := make(chan struct{}, 1)
grp.Wait(ch)
return ch
}

func TestNotifyGroup(t *testing.T) {
grp := &NotifyGroup{}

ch1 := grp.WaitCh()
ch2 := grp.WaitCh()
ch1 := testWaitCh(t, grp)
ch2 := testWaitCh(t, grp)

select {
case <-ch1:
Expand All @@ -35,7 +44,7 @@ func TestNotifyGroup(t *testing.T) {
}

// Should be unregistered
ch3 := grp.WaitCh()
ch3 := testWaitCh(t, grp)
grp.Notify()

select {
Expand All @@ -58,7 +67,7 @@ func TestNotifyGroup(t *testing.T) {
func TestNotifyGroup_Clear(t *testing.T) {
grp := &NotifyGroup{}

ch1 := grp.WaitCh()
ch1 := testWaitCh(t, grp)
grp.Clear(ch1)

grp.Notify()
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