Sample golang code that pipes the dynamic .dot file data to external graphviz process to write the .png file

golang-pipe-to-graphviz.go

// -- IMPORTSS NOT SHOWN
  path, _ := exec.LookPath("dot")
	cmd := exec.Command(path, fmt.Sprintf("-T%s", "png"))
	stdin, err := cmd.StdinPipe()
	if err != nil {
		log.Fatal(err)
	}
	go func() {
		defer stdin.Close()
    // Writes the data to stdin.
		Render(data, stdin)
	}()
	writeCmd, err := cmd.Output()
	if err != nil {
		log.Fatal(err)
	}
	mode := int(0644)
	ioutil.WriteFile("out.png", writeCmd, os.FileMode(mode))
}