How to run filepath.Walkfunc as a goroutine - performance

Question

I'm trying to parse a large image dataset. I'm using filepath.Walk ]and processing each file I find there. I'd like the filepath.
package main
import (
"fmt"
"image/color"
"image/png"
"math/rand"
"os"
)
var (
Black = color.Gray{0}
)
func getRandFloatNumber(min, max float32) float32 {
return (rand.Float32()*2 - min) * max
}
func openImage(path string, info os.FileInfo, err error) error {
infile, _ := os.Open(path)
defer infile.Close()
img, err := png.Decode(infile)
if err != nil {
return nil
}
array := make([]float32, 128*128)
for y := 0; y < 128; y++ {
for x := 0; x < 128; x++ {
c := color.GrayModel.Convert(img.At(x, y)).(color.Gray)
if c == Black {
array[x*y] = getRandFloatNumber(0.7, 0.95)
} else {
array[x*y] = getRandFloatNumber(0.1, 0.25)
}
}
}
fmt.Println(info.Name())
return nil
}
How to run openImage as a gorutine?
Or how to optimize this code?

Answer 1

You can't get filepath.Walk to call your function in a goroutine, but you can simply start a goroutine in your WalkFunc.
package main
import (
"os"
"path/filepath"
)
func main() {
filepath.Walk("/my/dir", func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() {
return nil
}
// Check more criteria if necessary. Also consider limiting the number
// of concurrent goroutines.
go openImage(path, info)
return nil
})
}
func openImage(path string, info os.FileInfo) {
}