Goroutine-2of3-time_sleep.go

package main

import (
  "fmt"
  "math/rand"
  "time"
)

var program_start_time time.Time
var program_end_time time.Time
var total_completed_jobs = 0
var total_worker_busyness = 0

func init() {
  rand.Seed(time.Now().UnixNano())
}

func main() {
  program_start_time = time.Now()
  fmt.Println("----------------------------------------------------")
  go do_some_work("A")
  go do_some_work("B")
  go do_some_work("C")
  go do_some_work("D")
  time.Sleep(1 * time.Second)
  fmt.Println("----------------------------------------------------")
  program_end_time = time.Now()
  produce_final_report()
}

func do_some_work(work_id string) {
  const NUM_OF_JOBS = 5
  for job_id := 1; job_id <= NUM_OF_JOBS; job_id++ {
    wait_ms := random_wait()
    fmt.Printf("job%d of work%s took:     %d ms\n", job_id, work_id, wait_ms)
    total_completed_jobs++
    total_worker_busyness += wait_ms
  }
}

func random_wait() int {
  const MIN_WAIT_MS = 50
  const MAX_WAIT_MS = 350
  wait_milliseconds := MIN_WAIT_MS + rand.Intn(MAX_WAIT_MS-MIN_WAIT_MS)
  time.Sleep(time.Duration(wait_milliseconds) * time.Millisecond)
  return wait_milliseconds
}

func produce_final_report() {
  fmt.Println("         Program time: ", program_end_time.Sub(program_start_time))
  fmt.Println(" Total completed jobs: ", total_completed_jobs)
  fmt.Println("Total worker busyness: ", total_worker_busyness, "ms")
}

output_1

----------------------------------------------------
job1 of workB took:     84 ms
job1 of workA took:     126 ms
job1 of workC took:     140 ms
job2 of workA took:     107 ms
job1 of workD took:     255 ms
job2 of workD took:     66 ms
job2 of workB took:     277 ms
job3 of workA took:     206 ms
job3 of workD took:     128 ms
job2 of workC took:     335 ms
job3 of workB took:     118 ms
job3 of workC took:     149 ms
job4 of workD took:     234 ms
job4 of workA took:     294 ms
job4 of workC took:     150 ms
job4 of workB took:     299 ms
job5 of workA took:     55 ms
job5 of workD took:     103 ms
job5 of workC took:     98 ms
job5 of workB took:     169 ms
----------------------------------------------------
         Program time:  1.001243381s
 Total completed jobs:  20
Total worker busyness:  3393 ms

output_2

----------------------------------------------------
job1 of workD took:     143 ms
job1 of workB took:     149 ms
job1 of workA took:     250 ms
job1 of workC took:     344 ms
job2 of workD took:     249 ms
job2 of workB took:     254 ms
job2 of workC took:     196 ms
job2 of workA took:     303 ms
job3 of workD took:     237 ms
job3 of workB took:     283 ms
job3 of workA took:     157 ms
job3 of workC took:     180 ms
job4 of workA took:     60 ms
job4 of workC took:     119 ms
job4 of workB took:     175 ms
job4 of workD took:     304 ms
job5 of workC took:     135 ms
----------------------------------------------------
         Program time:  1.000816761s
 Total completed jobs:  17
Total worker busyness:  3538 ms