How can INFO and DEBUG logging message be sent to stdout and higher level message to stderr

Question

Is there an easy way with python\'s logging module to send messages with a DEBUG or INFO level and the one with a higher level to different streams?

Is it a good ide

Answer 1

I had the same problem and wrote a custom logging handler called SplitStreamHandler:

import sys
import logging

class SplitStreamHandler(logging.Handler):
    def __init__(self):
        logging.Handler.__init__(self)

    def emit(self, record):
        # mostly copy-paste from logging.StreamHandler
        try:
            msg = self.format(record)
            if record.levelno < logging.WARNING:
                stream = sys.stdout
            else:
                stream = sys.stderr
            fs = "%s\n"

            try:
                if (isinstance(msg, unicode) and
                    getattr(stream, 'encoding', None)):
                    ufs = fs.decode(stream.encoding)
                    try:
                        stream.write(ufs % msg)
                    except UnicodeEncodeError:
                        stream.write((ufs % msg).encode(stream.encoding))
                else:
                    stream.write(fs % msg)
            except UnicodeError:
                stream.write(fs % msg.encode("UTF-8"))

            stream.flush()
        except (KeyboardInterrupt, SystemExit):
            raise
        except:
            self.handleError(record)