Third Attempt: Length-prefix Construction

main.go

const (
	payloadLen = 1
	sizeLen    = 4
	headerLen  = payloadLen + sizeLen
)

func msgHeader(data []byte) (hdr []byte, payload []byte) {
	hdr = make([]byte, headerLen)
	hdr[0] = byte(uint8(0))

	// Write length of payload into buf
	binary.BigEndian.PutUint32(hdr[payloadLen:], uint32(len(data)))
	return hdr, data
}

func handler(request events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
	message := &api.AliveResponse{Message: "Hello, world."}

	b, err := proto.Marshal(message)
	if err != nil {
		return events.APIGatewayProxyResponse{
			StatusCode: 500,
		}, err
	}

	hdr, data := msgHeader(b)

	hdr = append(hdr, data...)

	return events.APIGatewayProxyResponse{
		Body: base64.StdEncoding.EncodeToString(hdr),
		Headers: map[string]string{
			"Content-Type": "application/grpc+proto",
			"grpc-status":  "0",
		},
		IsBase64Encoded: true,
		StatusCode:      200,
	}, nil
}

Hey, Could you please share a boilerplate code for grpc based serverless applications