func manipulateCapacity(res doorman.Resource, current float64, id string) {
clientRequested := new(expvar.Float)
for range time.Tick(*interval) {
r := rand.Float64()
log.V(2).Infof("r=%v decreaseChance=%v increaseChance=%v", r, *decreaseChance, *increaseChance)
switch {
case r < *decreaseChance:
current -= *step
log.Infof("client %v will request less: %v.", id, current)
case r < *decreaseChance+*increaseChance:
log.Infof("client %v will request more: %v.", id, current)
current += *step
default:
log.V(2).Infof("client %v not changing requested capacity", id)
continue
}
if current > *maxCapacity {
current = *maxCapacity
}
if current < *minCapacity {
current = *minCapacity
}
log.Infof("client %v will request %v", id, current)
if err := res.Ask(current); err != nil {
log.Errorf("res.Ask(%v): %v", current, err)
askErrors.Add(1)
continue
}
clientRequested.Set(current)
requested.Set(id, clientRequested)
}
}
func determineProperties(sizes []int) *expvar.Map {
var sum int
props := new(expvar.Map).Init()
for _, n := range sizes {
sum += n
}
// Determine properties
sort.Ints(sizes)
if len(sizes) > 0 {
summary := map[string]int{
"min": sizes[0],
"max": sizes[len(sizes)-1],
"length": len(sizes),
"sum": sum,
"95e": sizes[int(float64(len(sizes))*0.95)],
}
mean := float64(sum) / float64(summary["length"])
// Pack them into an expvar Map
for k, v := range summary {
n := new(expvar.Int)
n.Set(int64(v))
props.Set(k, n)
}
avge := new(expvar.Float)
avge.Set(mean)
props.Set("avg", avge)
}
return props
}
// TrackMetrics decorates a MessageHandler to collect metrics about successes, failures and runtime reports in ms*10.
func TrackMetrics(successes, failures *expvar.Int, timing *expvar.Float) MessageHandlerDecorator {
ema := movingaverage.New(5 * time.Second)
return func(fn sqsconsumer.MessageHandlerFunc) sqsconsumer.MessageHandlerFunc {
return func(ctx context.Context, msg string) error {
start := time.Now()
defer func() {
v := ema.Update(time.Since(start).Seconds() * 1000)
timing.Set(v)
}()
err := fn(ctx, msg)
if err != nil {
failures.Add(1)
} else {
successes.Add(1)
}
return err
}
}
}