improve upsert perfomance

cmd/simulator/main.go

@@ -2,9 +2,11 @@ package main
 
 import (
 	"context"
+	"errors"
 	"log"
 	"os"
 	"os/signal"
+	"runtime"
 	"strconv"
 	"sync/atomic"
 	"time"
@@ -38,18 +40,26 @@ func main() {
 	deviceCountStr := os.Getenv("DEVSIM_DEVICE_COUNT")
 	delayStr := os.Getenv("DEVSIM_REQUEST_DELAY")
 
-	deviceCount, err := strconv.Atoi(deviceCountStr)
-	if err != nil {
-		log.Fatalf("parsing device count: %v", err)
+	deviceCount := runtime.GOMAXPROCS(0)
+	if deviceCountStr != "" {
+		var err error
+		deviceCount, err = strconv.Atoi(deviceCountStr)
+		if err != nil {
+			log.Fatalf("parsing device count: %v", err)
+		}
 	}
 
 	if dstAddr == "" {
 		log.Fatal("no destination address provided")
 	}
 
-	delay, err := time.ParseDuration(delayStr)
-	if err != nil {
-		log.Fatalf("parsing delay duration: %v", err)
+	delay := time.Millisecond * 20
+	if delayStr != "" {
+		var err error
+		delay, err = time.ParseDuration(delayStr)
+		if err != nil {
+			log.Fatalf("parsing delay duration: %v", err)
+		}
 	}
 
 	log.Printf("running application with settings: destination=%s device_count=%d delay=%s", dstAddr, deviceCount, delay)
@@ -113,6 +123,10 @@ func (h *deviceHandler) loop(ctx context.Context) {
 
 		err := h.client.Upsert(ctx, h.stats)
 		if err != nil {
+			if errors.Is(err, context.Canceled) {
+				return
+			}
+
 			log.Printf("%q: unable to upsert metrics: %v", h.stats.ID, err)
 			failedCount++
 			if failedCount > 10 {