Feature: customizd interface marshaler

[povsister]

Currently, when using logger.Debug().Interface("request_body", reqBody).Msg("request sent") to log the request detail with customized types, zerolog first assert if the "reqBody" is a LogObjectMarshaler or not, if not, it tries the std json marshaler to serialize the request body.

As you can see in the code snippet. It's hard coded to json.Marshal.

zerolog/internal/json/types.go

Lines 363 to 371 in 3c3b4a3

	// AppendInterface marshals the input interface to a string and
	// appends the encoded string to the input byte slice.
	func (e Encoder) AppendInterface(dst []byte, i interface{}) []byte {
	marshaled, err := json.Marshal(i)
	if err != nil {
	return e.AppendString(dst, fmt.Sprintf("marshaling error: %v", err))
	}
	return append(dst, marshaled...)
	}

However, for performance and convenient, mostly we do not use the standard json package for json encode/decode now.
I hope zerolog could have a package level InterfaceMarshaler variable, and use it to marshal object when needed.
It has the same signature with json.Marshal, so everyone can replace the internal reflection based marshaler at runtime without forking zerolog.

type InterfaceMarshaler func(obj interface{}) (data []byte, err error)

PS: I am using jsoniter and have registered many customized encoders/decoders for customized types. That's why I hope zerolog can benefit from jsoniter without additional works.

[rs]

Can you please send a PR?

[povsister]

Can you please send a PR?

Sure. Please take a look. #318