Write spamming time inforation to disk

packages/spammer/spammer.go

@@ -3,6 +3,7 @@ package spammer
 import (
 	"math/rand"
 	"os"
+	"strconv"
 	"sync/atomic"
 	"time"
 
@@ -52,9 +53,17 @@ func (spammer *Spammer) run(rate int, timeUnit time.Duration, processID int64) {
 		log.Fatal(err)
 	}
 
-	start := time.Now()
+	_, err = fileIntervals.WriteString(
+			"startTimestamp," +
+			"payloadTime," +
+			"endTimestamp," +
+			"remainingTime," +
+			"msgInterval\n")
 
 	for {
+		start := time.Now()
+		startNano := time.Now().UnixNano()
+
 		if atomic.LoadInt64(&spammer.processID) != processID {
 			return
 		}
@@ -65,19 +74,29 @@ func (spammer *Spammer) run(rate int, timeUnit time.Duration, processID int64) {
 			// can't issue msg because node not in sync
 			return
 		}
+		end := time.Now().UnixNano()
 
 		currentInterval := time.Since(start)
+		remainingTime := time.Duration(0)
 
 		// emit messages by intervals whose random duration is exponentially distributed
 		msgInterval := time.Duration(float64(timeUnit.Nanoseconds()) * rand.ExpFloat64() / float64(rate))
 		if currentInterval < msgInterval {
+			remainingTime = msgInterval - currentInterval
 			//there is still time, sleep until msgInterval
 			time.Sleep(msgInterval - currentInterval)
-			fileIntervals.WriteString((msgInterval - currentInterval).String() + "\n")
-		} else {
-			fileIntervals.WriteString("0\n")
 		}
 		// when currentInterval > msgInterval, the node can't issue msgs as fast as requested, will do as fast as it can
-		start = time.Now()
+
+		_, err = fileIntervals.WriteString(
+			strconv.FormatInt(startNano, 10) + "," +	// start timestamp
+			currentInterval.String() + "," +	// time needed to send the payload
+			strconv.FormatInt(end, 10) + "," +	// time after sending the payload
+			remainingTime.String() + "," +	// remaining time 
+			msgInterval.String() + "\n")		// interval between two spam messages
+
+		if err != nil {
+			log.Fatalf("Error while writing to a file. Err: %s", err.Error())
+		}
 	}
 }