How to convert uint64 to string

if you want to convert int64 to string, you can use :

strconv.FormatInt(time.Now().Unix(), 10)

or

strconv.FormatUint

strconv.Itoa() expects a value of type int, so you have to give it that:

log.Println("The amount is: " + strconv.Itoa(int(charge.Amount)))

But know that this may lose precision if int is 32-bit (while uint64 is 64), also sign-ness is different. strconv.FormatUint() would be better as that expects a value of type uint64:

log.Println("The amount is: " + strconv.FormatUint(charge.Amount, 10))

For more options, see this answer: Golang: format a string without printing?

If your purpose is to just print the value, you don't need to convert it, neither to int nor to string, use one of these:

log.Println("The amount is:", charge.Amount)
log.Printf("The amount is: %d\n", charge.Amount)