func (s *PresenceSuite) TestExpiry(c *gc.C) {
w := presence.NewWatcher(s.presence)
p := presence.NewPinger(s.presence, "a")
defer w.Stop()
defer p.Stop()
ch := make(chan presence.Change)
w.Watch("a", ch)
assertChange(c, ch, presence.Change{"a", false})
c.Assert(p.Start(), gc.IsNil)
w.StartSync()
assertChange(c, ch, presence.Change{"a", true})
// Still alive in previous slot.
presence.FakeTimeSlot(1)
w.StartSync()
assertNoChange(c, ch)
// Two last slots are empty.
presence.FakeTimeSlot(2)
w.StartSync()
assertChange(c, ch, presence.Change{"a", false})
// Already dead so killing isn't noticed.
p.Kill()
w.StartSync()
assertNoChange(c, ch)
}
func (s *PresenceSuite) TestFindAllBeings(c *gc.C) {
w := presence.NewWatcher(s.presence)
p := presence.NewPinger(s.presence, "a")
defer w.Stop()
defer p.Stop()
ch := make(chan presence.Change)
w.Watch("a", ch)
assertChange(c, ch, presence.Change{"a", false})
c.Assert(p.Start(), gc.IsNil)
done := make(chan bool)
go func() {
w.Sync()
done <- true
}()
assertChange(c, ch, presence.Change{"a", true})
results, err := presence.FindAllBeings(w)
c.Assert(err, gc.IsNil)
c.Assert(results, gc.HasLen, 1)
select {
case <-done:
case <-time.After(testing.LongWait):
c.Fatalf("Sync failed to returned")
}
}
func (s *PresenceSuite) TestStartSync(c *gc.C) {
w := presence.NewWatcher(s.presence)
p := presence.NewPinger(s.presence, "a")
defer w.Stop()
defer p.Stop()
ch := make(chan presence.Change)
w.Watch("a", ch)
assertChange(c, ch, presence.Change{"a", false})
c.Assert(p.Start(), gc.IsNil)
done := make(chan bool)
go func() {
w.StartSync()
w.StartSync()
w.StartSync()
done <- true
}()
select {
case <-done:
case <-time.After(testing.LongWait):
c.Fatalf("StartSync failed to return")
}
assertChange(c, ch, presence.Change{"a", true})
}
// SetAgentAlive signals that the agent for machine m is alive.
// It returns the started pinger.
func (m *Machine) SetAgentAlive() (*presence.Pinger, error) {
p := presence.NewPinger(m.st.presence, m.globalKey())
err := p.Start()
if err != nil {
return nil, err
}
return p, nil
}
// SetAgentAlive signals that the agent for unit u is alive.
// It returns the started pinger.
func (u *Unit) SetAgentAlive() (*presence.Pinger, error) {
p := presence.NewPinger(u.st.presence, u.globalKey())
err := p.Start()
if err != nil {
return nil, err
}
return p, nil
}
func (s *PresenceSuite) TestPingerPeriodAndResilience(c *gc.C) {
// This test verifies both the periodic pinging,
// and also a great property of the design: deaths
// also expire, which means erroneous scenarios are
// automatically recovered from.
const period = 1
presence.FakePeriod(period)
presence.RealTimeSlot()
w := presence.NewWatcher(s.presence)
p1 := presence.NewPinger(s.presence, "a")
p2 := presence.NewPinger(s.presence, "a")
defer w.Stop()
defer p1.Stop()
defer p2.Stop()
// Start p1 and let it go on.
c.Assert(p1.Start(), gc.IsNil)
w.Sync()
assertAlive(c, w, "a", true)
// Start and kill p2, which will temporarily
// invalidate p1 and set the key as dead.
c.Assert(p2.Start(), gc.IsNil)
c.Assert(p2.Kill(), gc.IsNil)
w.Sync()
assertAlive(c, w, "a", false)
// Wait for two periods, and check again. Since
// p1 is still alive, p2's death will expire and
// the key will come back.
time.Sleep(period * 2 * time.Second)
w.Sync()
assertAlive(c, w, "a", true)
}
func (s *PresenceSuite) TestRestartWithoutGaps(c *gc.C) {
p := presence.NewPinger(s.presence, "a")
c.Assert(p.Start(), gc.IsNil)
defer p.Stop()
done := make(chan bool)
go func() {
stop := false
for !stop {
if !c.Check(p.Stop(), gc.IsNil) {
break
}
if !c.Check(p.Start(), gc.IsNil) {
break
}
select {
case stop = <-done:
default:
}
}
}()
go func() {
stop := false
for !stop {
w := presence.NewWatcher(s.presence)
w.Sync()
alive, err := w.Alive("a")
c.Check(w.Stop(), gc.IsNil)
if !c.Check(err, gc.IsNil) || !c.Check(alive, gc.Equals, true) {
break
}
select {
case stop = <-done:
default:
}
}
}()
// TODO(jam): This forceful delay of 500ms sounds like a bad test,
// since we always sleep for the full timeout
time.Sleep(500 * time.Millisecond)
done <- true
done <- true
}
func (s *PresenceSuite) TestWatchPeriod(c *gc.C) {
presence.FakePeriod(1)
presence.RealTimeSlot()
w := presence.NewWatcher(s.presence)
p := presence.NewPinger(s.presence, "a")
defer w.Stop()
defer p.Stop()
ch := make(chan presence.Change)
w.Watch("a", ch)
assertChange(c, ch, presence.Change{"a", false})
// A single ping.
c.Assert(p.Start(), gc.IsNil)
c.Assert(p.Stop(), gc.IsNil)
// Wait for next periodic refresh.
time.Sleep(1 * time.Second)
assertChange(c, ch, presence.Change{"a", true})
}
func (s *PresenceSuite) TestSync(c *gc.C) {
w := presence.NewWatcher(s.presence)
p := presence.NewPinger(s.presence, "a")
defer w.Stop()
defer p.Stop()
ch := make(chan presence.Change)
w.Watch("a", ch)
assertChange(c, ch, presence.Change{"a", false})
// Nothing to do here.
w.Sync()
c.Assert(p.Start(), gc.IsNil)
done := make(chan bool)
go func() {
w.Sync()
done <- true
}()
select {
case <-done:
c.Fatalf("Sync returned too early")
// Note(jam): This used to wait 200ms to ensure that
// Sync was actually blocked waiting for a presence
// change. Is ShortWait long enough for this assurance?
case <-time.After(testing.ShortWait):
}
assertChange(c, ch, presence.Change{"a", true})
select {
case <-done:
case <-time.After(testing.LongWait):
c.Fatalf("Sync failed to returned")
}
}
func (s *PresenceSuite) TestScale(c *gc.C) {
const N = 1000
var ps []*presence.Pinger
defer func() {
for _, p := range ps {
p.Stop()
}
}()
c.Logf("Starting %d pingers...", N)
for i := 0; i < N; i++ {
p := presence.NewPinger(s.presence, strconv.Itoa(i))
c.Assert(p.Start(), gc.IsNil)
ps = append(ps, p)
}
c.Logf("Killing odd ones...")
for i := 1; i < N; i += 2 {
c.Assert(ps[i].Kill(), gc.IsNil)
}
c.Logf("Checking who's still alive...")
w := presence.NewWatcher(s.presence)
defer w.Stop()
w.Sync()
ch := make(chan presence.Change)
for i := 0; i < N; i++ {
k := strconv.Itoa(i)
w.Watch(k, ch)
if i%2 == 0 {
assertChange(c, ch, presence.Change{k, true})
} else {
assertChange(c, ch, presence.Change{k, false})
}
}
}
func (s *PresenceSuite) TestWorkflow(c *gc.C) {
w := presence.NewWatcher(s.presence)
pa := presence.NewPinger(s.presence, "a")
pb := presence.NewPinger(s.presence, "b")
defer w.Stop()
defer pa.Stop()
defer pb.Stop()
assertAlive(c, w, "a", false)
assertAlive(c, w, "b", false)
// Buffer one entry to avoid blocking the watcher here.
cha := make(chan presence.Change, 1)
chb := make(chan presence.Change, 1)
w.Watch("a", cha)
w.Watch("b", chb)
// Initial events with current status.
assertChange(c, cha, presence.Change{"a", false})
assertChange(c, chb, presence.Change{"b", false})
w.StartSync()
assertNoChange(c, cha)
assertNoChange(c, chb)
c.Assert(pa.Start(), gc.IsNil)
w.StartSync()
assertChange(c, cha, presence.Change{"a", true})
assertNoChange(c, cha)
assertNoChange(c, chb)
assertAlive(c, w, "a", true)
assertAlive(c, w, "b", false)
// Changes while the channel is out are not observed.
w.Unwatch("a", cha)
assertNoChange(c, cha)
pa.Kill()
w.Sync()
pa = presence.NewPinger(s.presence, "a")
pa.Start()
w.StartSync()
assertNoChange(c, cha)
// We can still query it manually, though.
assertAlive(c, w, "a", true)
assertAlive(c, w, "b", false)
// Initial positive event. No refresh needed.
w.Watch("a", cha)
assertChange(c, cha, presence.Change{"a", true})
c.Assert(pb.Start(), gc.IsNil)
w.StartSync()
assertChange(c, chb, presence.Change{"b", true})
assertNoChange(c, cha)
assertNoChange(c, chb)
c.Assert(pa.Stop(), gc.IsNil)
w.StartSync()
assertNoChange(c, cha)
assertNoChange(c, chb)
// pb is running, pa isn't.
c.Assert(pa.Kill(), gc.IsNil)
c.Assert(pb.Kill(), gc.IsNil)
w.StartSync()
assertChange(c, cha, presence.Change{"a", false})
assertChange(c, chb, presence.Change{"b", false})
c.Assert(w.Stop(), gc.IsNil)
}