Get goroutine id for debugging

get_go_routine_id.go

package main

// 80195: doc/faq: explain why goroutines are anonymous | https://go-review.googlesource.com/c/go/+/80195
// faq: document why there is no way to get a goroutine ID | https://github.com/golang/go/issues/22770

import (
	"fmt"
	"runtime"
	"strconv"
	"strings"
	"sync"
)

func goid() int {
	var buf [64]byte
	n := runtime.Stack(buf[:], false)
	idField := strings.Fields(strings.TrimPrefix(string(buf[:n]), "goroutine "))[0]
	id, err := strconv.Atoi(idField)
	if err != nil {
		panic(fmt.Sprintf("cannot get goroutine id: %v", err))
	}
	return id
}

func main() {
	fmt.Println("main", goid())
	var wg sync.WaitGroup
	for i := 0; i < 10; i++ {
		i := i
		wg.Add(1)
		go func() {
			defer wg.Done()
			fmt.Println(i, goid())
		}()
	}
	wg.Wait()
}