mitogen/ansible_mitogen/logging.py

# Copyright 2017, David Wilson
#
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# modification, are permitted provided that the following conditions are met:
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# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
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from __future__ import absolute_import
import logging
import os
import sys

import mitogen.core
import mitogen.utils


class Handler(logging.Handler):
    """
    Use Mitogen's log format, but send the result to a Display method.
    """
    def __init__(self, display, normal_method):
        logging.Handler.__init__(self)
        self.formatter = mitogen.utils.log_get_formatter()
        self.display = display
        self.normal_method = normal_method

    #: Set of target loggers that produce warnings and errors that spam the
    #: console needlessly. Their log level is forced to INFO. A better strategy
    #: may simply be to bury all target logs in DEBUG output, but not by
    #: overriding their log level as done here.
    NOISY_LOGGERS = frozenset([
        'dnf',  # issue #272; warns when a package is already installed.
    ])

    def emit(self, record):
        mitogen_name = getattr(record, 'mitogen_name', '')
        if mitogen_name == 'stderr':
            record.levelno = logging.ERROR
        if mitogen_name in self.NOISY_LOGGERS and record.levelno >= logging.WARNING:
            record.levelno = logging.DEBUG

        s = '[pid %d] %s' % (os.getpid(), self.format(record))
        if record.levelno >= logging.ERROR:
            self.display.error(s, wrap_text=False)
        elif record.levelno >= logging.WARNING:
            self.display.warning(s, formatted=True)
        else:
            self.normal_method(s)


def find_display():
    """
    Find the CLI tool's display variable somewhere up the stack. Why god why,
    right? Because it's the the simplest way to get access to the verbosity
    configured on the command line.
    """
    f = sys._getframe()
    while f:
        if 'display' in f.f_locals:
            return f.f_locals['display']
        f = f.f_back


def setup():
    """
    Install a handler for Mitogen's logger to redirect it into the Ansible
    display framework, and prevent propagation to the root logger.
    """
    display = find_display()

    logging.getLogger('ansible_mitogen').handlers = [Handler(display, display.vvv)]
    mitogen.core.LOG.handlers = [Handler(display, display.vvv)]
    mitogen.core.IOLOG.handlers = [Handler(display, display.vvvv)]
    mitogen.core.IOLOG.propagate = False

    if display.verbosity > 2:
        logging.getLogger('ansible_mitogen').setLevel(logging.DEBUG)
        mitogen.core.LOG.setLevel(logging.DEBUG)

    if display.verbosity > 3:
        mitogen.core.IOLOG.setLevel(logging.DEBUG)