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@jasonsalas
Last active July 5, 2020 07:07
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Using worker pools & buffered channels in Go
/* using worker pools & buffered channels in Go */
// h/t: Naveen Ramanathan @ golangbot.com
// https://golangbot.com/buffered-channels-worker-pools/
package main
import (
"fmt"
"math/rand"
"sync"
"time"
)
type Job struct {
id int
randomno int
}
type Result struct {
job Job
sumofdigits int
}
var jobs = make(chan Job, 10)
var results = make(chan Result, 10)
func digits(number int) int {
sum := 0
no := number
for no != 0 {
digit := no % 10
sum += digit
no /= 10
}
time.Sleep(time.Second * 2)
return sum
}
func worker(wg *sync.WaitGroup) {
for job := range jobs {
output := Result{job, digits(job.randomno)}
results <- output
}
wg.Done()
}
func createWorkerPool(noOfWorkers int) {
var wg sync.WaitGroup
for i := 0; i < noOfWorkers; i++ {
wg.Add(1)
go worker(&wg)
}
wg.Wait()
close(results)
}
func allocate(noOfJobs int) {
for i := 0; i < noOfJobs; i++ {
randomno := rand.Intn(999)
job := Job{i, randomno}
jobs <- job
}
close(jobs)
}
func result(done chan bool) {
for result := range results {
fmt.Printf("Job id: %d | input random number: %d | sum of digits: %d\n",
result.job.id, result.job.randomno, result.sumofdigits)
}
done <- true
}
func main() {
startTime := time.Now()
noOfJobs := 100
go allocate(noOfJobs)
done := make(chan bool)
go result(done)
noOfWorkers := 10
createWorkerPool(noOfWorkers)
<-done
endTime := time.Now()
diff := endTime.Sub(startTime)
fmt.Println("total time taken: ", diff.Seconds(), "seconds")
}
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