Gorutine Training

gorutine_training.go

package main

import "fmt"
import "time"
import "os"
import "flag"

func main() {
	buffer_size := func() int {
		b := 0
		flag.IntVar(&b, "buffer_size", 0, "buffer_size")
		flag.Parse()
		return b
	}()

	doit("html", "urlstring", buffer_size)
}

func doit(format string, url string, buffer_size int) {
	fmt.Println("start of doit")

	source := make(chan string, buffer_size)
	post_done := make(chan int)

	source_count := prepair_source(source, url)
	go post(post_done, source)

	exit_if(func() bool {
		fmt.Println("  #start of exit_if block")
		posted_count := 0
		for {
			posted_count = posted_count + <-post_done
			if source_count <= posted_count {
				break
			}
		}
		fmt.Println("  #end of set exit_if block")
		return true
	})

	fmt.Println("end of doit")
}

func post(post_done chan int, source chan string) {
	fmt.Println("  !start of post")
	for {
		time.Sleep(time.Second + time.Second)

		fmt.Println("    !start of for")
		fmt.Println("      !post! " + <-source)
		fmt.Println("    !end of for")
		post_done <- 1
	}
	fmt.Println("  !end of post")
}

func prepair_source(source chan string, url string) int {
	fmt.Println("  @start of prepair_source")
	go func() {
		fmt.Println("    @start of gorutine in prepair_source")
		fmt.Println("      @set url1")
		source <- url + "1"

		time.Sleep(time.Second)

		fmt.Println("      @set url2")
		source <- url + "2"

		time.Sleep(time.Second)

		fmt.Println("      @set url3")
		source <- url + "3"
		fmt.Println("    @end of gorutine in prepair_source")
	}()
	fmt.Println("  @end of set prepair_source")
	return 3
}

func exit_if(condition func() bool) {
	if condition() {
		fmt.Println("EXIT!!!!!!!!!!")
		os.Exit(0)
	}
}

result

## チャネルのバッファが3＝読み込み全部バッファに入る数

````sh
go run gorutine_training.go -buffer_size 3
````

````
start of doit
  @start of prepair_source
  @end of set prepair_source
    @start of gorutine in prepair_source
  #start of exit_if block
      @set url1
  !start of post
      @set url2
    !start of for
      !post! urlstring1
    !end of for
      @set url3
    @end of gorutine in prepair_source
    !start of for
      !post! urlstring2
    !end of for
    !start of for
      !post! urlstring3
    !end of for
  #end of set exit_if block
EXIT!!!!!!!!!!
````

## チャネルのバッファがゼロ＝実質シーケンシャルな動き

````sh
go run gorutine_training.go -buffer_size 0
````

````
start of doit
  @start of prepair_source
  @end of set prepair_source
    @start of gorutine in prepair_source
  #start of exit_if block
      @set url1
  !start of post
    !start of for
      !post! urlstring1
    !end of for
      @set url2
    !start of for
      !post! urlstring2
    !end of for
      @set url3
    !start of for
      !post! urlstring3
    @end of gorutine in prepair_source
    !end of for
  #end of set exit_if block
EXIT!!!!!!!!!!
````