go_search_file

go_search_file.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"strings"
	"sync"
	"time"
)

var sem = make(chan bool, 700) //control the goroutine avoid open too many files
var wg sync.WaitGroup

func main() {
	fmt.Println("start searching...")
	start := time.Now()
	dirname := "/home/test/txt/"
	files, err := ioutil.ReadDir(dirname)
	if err != nil {
		log.Fatal(err)
	}
	wg.Add(len(files))
	fmt.Println(len(files))

	for _, f := range files {
		sem <- true
		go searchFile(dirname + f.Name())
	}
	wg.Wait()
	close(sem)
	took := time.Since(start)
	log.Printf("took %s", took)
}

func searchFile(path string) {
	defer func() { <-sem }()
	rw, _ := os.Open(path)
	rb := bufio.NewReader(rw)
	for {
		line, _, err := rb.ReadLine()
		if err == io.EOF {
			break
		}
		var s = string(line)
		if strings.Contains(s, "hello") {
			fmt.Println(s)
		}
	}
	wg.Done()
}