log_sd.py

import os
import io

MP_EWOULDBLOCK = const(11)

class LoggingStream(io.IOBase):
    def __init__(self, path):
        self._f = open(path, "a")

    def read(self, sz=None):
        return None

    def readinto(self, buf):
        return -MP_EWOULDBLOCK

    def ioctl(self, op, arg):
        return 0

    def write(self, buf):
        self._f.write(buf)
        # optionally add:
        # self._f.flush()
        # if you don't expect to be able to call disable_logging
        # but this will slow down your program considerably

    def close(self):
        self._f.close()


stream = None

def enable_logging(path):
    global stream
    stream = LoggingStream(path)
    os.dupterm(stream)

def disable_logging():
    os.dupterm(None)
    stream.close()