func BuildMessage()

in lib/ec2macossystemmonitor/relayd.go [24:77]

• 45 lines of code
• 7 McCabe index (conditional complexity)

func BuildMessage(tag string, data string, compress bool) ([]byte, error) {
	var payload SerialPayload
	// This determines if the data will be passed in as provided or zlib compressed and then base64 encoded
	// Some payload will exceed the limit of what can be sent on the serial device, so compression allows more data
	// to be sent. base64 encoding allows safe characters only to be passed on the device
	if compress {
		var b bytes.Buffer
		w, err := zlib.NewWriterLevel(&b, 9)
		if err != nil {
			return []byte{}, fmt.Errorf("ec2macossystemmonitor: couldn't get compression writer: %s", err)
		}
		_, err = w.Write([]byte(data))
		if err != nil {
			return []byte{}, fmt.Errorf("ec2macossystemmonitor: couldn't copy compressed data: %s", err)
		}
		err = w.Close()
		if err != nil {
			return []byte{}, fmt.Errorf("ec2macossystemmonitor: couldn't close compressor: %s", err)
		}

		encodedData := base64.StdEncoding.EncodeToString(b.Bytes())
		payload = SerialPayload{
			Tag:      tag,
			Compress: compress,
			Data:     encodedData,
		}
	} else {
		// No compression needed, simply create the SerialPayload
		payload = SerialPayload{
			Tag:      tag,
			Compress: compress,
			Data:     data,
		}
	}
	// Once the payload is created, it's converted to json
	payloadBytes, err := json.Marshal(payload)
	if err != nil {
		return []byte{}, fmt.Errorf("ec2macossystemmonitor: couldn't get %s into json", err)
	}
	// A checksum is computed on the json payload for the serial message
	checkSum := adler32.Checksum(payloadBytes)
	message := SerialMessage{
		Csum:    checkSum,
		Payload: string(payloadBytes),
	}
	// Once the message is created, it's converted to json
	messageBytes, err := json.Marshal(message)
	if err != nil {
		return []byte{}, fmt.Errorf("ec2macossystemmonitor: couldn't convert %s into json", err)
	}
	messageBytes = append(messageBytes, "\n"...)

	return messageBytes, nil
}