go study(implementing apache benchmark)

goab.go

package main

import (
	"fmt"
	"flag"
	"time"
)

type result struct {
	seq int
	start int64
	end int64
}

func main() {
	c := flag.Int("c", 3, "concurrency")
	n := flag.Int("n", 10, "number of requests")

	fmt.Printf("concurrency:%d\n", *c)
	fmt.Printf("number of requests:%d\n", *n)

	seqCh := sequence(*n)
	resultCh := make(chan *result, *c)

	totalStart := time.Now().UnixNano()

	for i := 0; i < *c; i++ {
		go test(resultCh, seqCh)
	}

	numDone := 0
	for result := range(resultCh) {
		if result == nil {
			numDone++
			if numDone >= *c {
				break
			}
			continue
		}
		fmt.Printf("result(%d)\n", result.seq)
	}

	totalEnd := time.Now().UnixNano()

	fmt.Printf("start=%d, end=%d\n", totalStart, totalEnd)
	fmt.Printf("total(ms)=%d\n", (totalEnd - totalStart) / 1000000)
}

func test(resultCh chan *result, seqCh chan int) {
	for {
		seq, ok := <-seqCh
		if !ok {
			resultCh<-nil
			return
		}
		start := time.Now().UnixNano()
		<-time.After(time.Second * 1)
		end := time.Now().UnixNano()
		resultCh<-&result{seq, start, end}
	}
}

func sequence(max int) chan int {
	ch := make(chan int)
	go func() {
		for i := 1; i <= max; i++ {
			ch<-i
		}
		close(ch)
	}()
	return ch
}

つくりかけ