Print All Processes with A Tree format

print_processes.go

package main

import (
	"bytes"
	"fmt"
	"github.com/mitchellh/go-ps"
	"io"
	"os"
)

func main() {
	printProcessTree()
}

func printProcessTree() {
	var w bytes.Buffer
	entry := []int{1}
	printLayer(New(), entry, &w, 0)
	w.WriteTo(os.Stdout)
}

type Processes struct {
	descents   map[int][]int  // ppid -> []pid
	executable map[int]string // pid -> executable string
}

func New() *Processes {
	pros, _ := ps.Processes()
	m := make(map[int][]int)         // ppid -> []pid
	processM := make(map[int]string) // pid -> string

	for _, p := range pros {
		processM[p.Pid()] = p.Executable()

		v, ok := m[p.PPid()]
		if !ok {
			m[p.PPid()] = []int{p.Pid()}
			continue
		}
		m[p.PPid()] = append(v, p.Pid())
	}
	return &Processes{
		descents:   m,
		executable: processM,
	}
}

func printLayer(p *Processes, entry []int, w io.Writer, ident int) {
	for _, e := range entry {
		strLine := fmt.Sprintf("%s%d: %s\n", printIndent(ident), e, p.executable[e])
		w.Write([]byte(strLine))
		list, ok := p.descents[e]
		if !ok {
			continue
		}
		printLayer(p, list, w, ident+1)
	}
}

func printIndent(number int) string {
	var idents string
	for i := 0; i < number-1; i++ {
		idents += "\t"
	}
	idents += "|_______"
	return idents
}

The output is: