Zap logger values

Question

Hello I want to use zap global logger

right now I am using like this

        zap.L().Error("error receive",
            zap.Error(err),
            zap.String("uuid", msg.Id)
            zap.String("msg_f", msg_f),
        )

but the only problem is I am getting errors because of types of uuid and msg

type Message struct {
    Id   uuid.UUID
}

and msg_f type is []byte my question how can I print them but I don't what should I use

Answer 1

The definition of zap.String is:

func String(key string, val string) Field

So the second argument is a string; a UUID/[]byte is not a string so cannot be used as-is. This leaves you with two options:

• Pass a string to zap.String (converting what you have into a string) or;
• Use a function that accepts the type you want to log.

zap provides a number of functions that return a Field some of which accept []byte (e.g. Binary and ByteString. zap also provides Stringer which you can use with any type that implements the fmt.Stringer interface (which UUID does).

The below (playground) demonstrates:

zap.L().Error("error receive",
        zap.Error(err),
        zap.String("uuid", msg.Id.String()),
        zap.Stringer("uuid2", msg.Id),
        zap.ByteString("msg_f", msg_f),
        zap.Binary("msg_f2", msg_f),
        zap.String("msg_f3", string(msg_f)),
    )