// WatchValue returns a NotifyWatcher that triggers
// when the given value changes. Its Wait and Err methods
// never return a non-nil error.
func WatchValue(val *voyeur.Value) state.NotifyWatcher {
n := ¬ifier{
w: val.Watch(),
changes: make(chan struct{}),
}
go n.loop()
return n
}
func (s *workerSuite) TestSetMembersErrorIsNotFatal(c *gc.C) {
st := newFakeState()
initState(c, st, 3)
st.session.setStatus(mkStatuses("0p 1s 2s"))
var isSet voyeur.Value
count := 0
setErrorFuncFor("Session.Set", func() error {
isSet.Set(count)
count++
return errors.New("sample")
})
s.PatchValue(&initialRetryInterval, 10*time.Microsecond)
s.PatchValue(&maxRetryInterval, coretesting.ShortWait/4)
expectedIterations := 0
for d := initialRetryInterval; d < maxRetryInterval*2; d *= 2 {
expectedIterations++
}
w := newWorker(st, noPublisher{})
defer func() {
c.Check(worker.Stop(w), gc.IsNil)
}()
isSetWatcher := isSet.Watch()
n0 := mustNext(c, isSetWatcher).(int)
time.Sleep(maxRetryInterval * 2)
n1 := mustNext(c, isSetWatcher).(int)
// The worker should have backed off exponentially...
c.Assert(n1-n0, jc.LessThan, expectedIterations+1)
c.Logf("actual iterations %d; expected iterations %d", n1-n0, expectedIterations)
// ... but only up to the maximum retry interval
n0 = mustNext(c, isSetWatcher).(int)
time.Sleep(maxRetryInterval * 2)
n1 = mustNext(c, isSetWatcher).(int)
c.Assert(n1-n0, jc.LessThan, 3)
}