Created
April 18, 2018 23:31
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package main | |
import ( | |
"fmt" | |
"sort" | |
"sync" | |
"time" | |
"github.com/nats-io/go-nats" | |
) | |
const ( | |
NatsServer = "nats://127.0.0.1:4222" | |
//NatsServer = "nats://demo.nats.io:4222" | |
MeasureTimes = 10000 | |
TargetPubRate = 1000 // pubs per second, -1 == none | |
) | |
func main() { | |
c1, err1 := nats.Connect(NatsServer) | |
c2, err2 := nats.Connect(NatsServer) | |
if err1 != nil || err2 != nil { | |
panic("uh oh") | |
} | |
// Duration tracking | |
durations := make([]time.Duration, 0, MeasureTimes) | |
// Wait for all messages to be received. | |
var wg sync.WaitGroup | |
wg.Add(1) | |
received := 0 | |
// Async Subscriber (Runs in own Go routine) | |
c1.Subscribe("foo", func(msg *nats.Msg) { | |
var t time.Time | |
t.UnmarshalBinary(msg.Data) | |
durations = append(durations, time.Since(t)) | |
received++ | |
if received >= MeasureTimes { | |
wg.Done() | |
} | |
}) | |
// Make sure interest is set for subscribe before publish since a different connection. | |
c1.Flush() | |
// For publish throttle | |
delay := time.Second / TargetPubRate | |
if delay < time.Microsecond { | |
delay = 0 | |
} | |
start := time.Now() | |
// Now publish | |
for i := 0; i < MeasureTimes; i++ { | |
now := time.Now() | |
msg, _ := now.MarshalBinary() | |
c2.Publish("foo", msg) | |
// Throttle logic, crude I know. | |
if delay > 0 { | |
r := rps(i+1, time.Since(start)) | |
adj := delay / 20 // 5% | |
if r < TargetPubRate { | |
delay -= adj | |
} else if r > TargetPubRate { | |
delay += adj | |
} | |
time.Sleep(delay) | |
} | |
} | |
pubDur := time.Since(start) | |
wg.Wait() | |
// Print results | |
fmt.Printf("Total time: %v\n", time.Since(start)) | |
fmt.Printf("Time to publish: %v\n", pubDur) | |
fmt.Printf("Publish rate (desired vs actual): %d, %d\n", TargetPubRate, rps(MeasureTimes, pubDur)) | |
sort.Slice(durations, func(i, j int) bool { return durations[i] < durations[j] }) | |
fmt.Printf("Receive Latency (min, median, max): %v, %v, %v\n", | |
time.Duration(durations[0]), | |
time.Duration(durations[len(durations)/2]), | |
time.Duration(durations[len(durations)-1])) | |
} | |
const fsecs = float64(time.Second) | |
func rps(count int, elapsed time.Duration) int { | |
return int(float64(count) / (float64(elapsed) / fsecs)) | |
} |
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