1  # SPDX-FileCopyrightText: 2018 Dave Astels for Adafruit Industries
 2  #
 3  # SPDX-License-Identifier: MIT
 4  
 5  """
 6  UART based message handler for CircuitPython logging.
 7  
 8  Adafruit invests time and resources providing this open source code.
 9  Please support Adafruit and open source hardware by purchasing
10  products from Adafruit!
11  
12  Written by Dave Astels for Adafruit Industries
13  Copyright (c) 2018 Adafruit Industries
14  Licensed under the MIT license.
15  
16  All text above must be included in any redistribution.
17  """
18  
19  
20  # Example:
21  #
22  # import board
23  # import busio
24  # from uart_handler import UartHandler
25  # import adafruit_logging as logging
26  #
27  # uart = busio.UART(board.TX, board.RX, baudrate=115200)
28  # logger = logging.getLogger('uart')
29  # logger.addHandler(UartHandler(uart))
30  # logger.level = logging.INFO
31  # logger.info('testing')
32  
33  from adafruit_logging import Handler
34  
35  class UartHandler(Handler):
36      """Send logging output to a serial port."""
37  
38      def __init__(self, uart):
39          """Create an instance.
40  
41          :param uart: the busio.UART instance to which to write messages
42          """
43          self._uart = uart
44  
45      def format(self, record):
46          """Generate a string to log.
47  
48          :param record: The record (message object) to be logged
49          """
50          return super().format(record) + '\r\n'
51  
52      def emit(self, record):
53          """Generate the message and write it to the UART.
54  
55          :param record: The record (message object) to be logged
56          """
57          self._uart.write(bytes(self.format(record), 'utf-8'))