blob: 66310a79a997be2f4e859218ce4d4f70e212ac9f [file] [log] [blame]
"""Nicer log formatting with colours.
Code copied from Tornado, Apache licensed.
"""
# Copyright 2012 Facebook
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import logging
import sys
try:
import curses
except ImportError:
curses = None
def _stderr_supports_color():
color = False
if curses and hasattr(sys.stderr, 'isatty') and sys.stderr.isatty():
try:
curses.setupterm()
if curses.tigetnum("colors") > 0:
color = True
except Exception:
pass
return color
class LogFormatter(logging.Formatter):
"""Log formatter with colour support
"""
DEFAULT_COLORS = {
logging.INFO: 2, # Green
logging.WARNING: 3, # Yellow
logging.ERROR: 1, # Red
logging.CRITICAL: 1,
}
def __init__(self, color=True, datefmt=None):
r"""
:arg bool color: Enables color support.
:arg string fmt: Log message format.
It will be applied to the attributes dict of log records. The
text between ``%(color)s`` and ``%(end_color)s`` will be colored
depending on the level if color support is on.
:arg dict colors: color mappings from logging level to terminal color
code
:arg string datefmt: Datetime format.
Used for formatting ``(asctime)`` placeholder in ``prefix_fmt``.
.. versionchanged:: 3.2
Added ``fmt`` and ``datefmt`` arguments.
"""
logging.Formatter.__init__(self, datefmt=datefmt)
self._colors = {}
if color and _stderr_supports_color():
# The curses module has some str/bytes confusion in
# python3. Until version 3.2.3, most methods return
# bytes, but only accept strings. In addition, we want to
# output these strings with the logging module, which
# works with unicode strings. The explicit calls to
# unicode() below are harmless in python2 but will do the
# right conversion in python 3.
fg_color = (curses.tigetstr("setaf") or
curses.tigetstr("setf") or "")
for levelno, code in self.DEFAULT_COLORS.items():
self._colors[levelno] = str(
curses.tparm(fg_color, code), "ascii")
self._normal = str(curses.tigetstr("sgr0"), "ascii")
scr = curses.initscr()
self.termwidth = scr.getmaxyx()[1]
curses.endwin()
else:
self._normal = ''
# Default width is usually 80, but too wide is
# worse than too narrow
self.termwidth = 70
def formatMessage(self, record):
mlen = len(record.message)
right_text = '{initial}-{name}'.format(initial=record.levelname[0],
name=record.name)
if mlen + len(right_text) < self.termwidth:
space = ' ' * (self.termwidth - (mlen + len(right_text)))
else:
space = ' '
if record.levelno in self._colors:
start_color = self._colors[record.levelno]
end_color = self._normal
else:
start_color = end_color = ''
return record.message + space + start_color + right_text + end_color
def enable_colourful_output(level=logging.INFO):
handler = logging.StreamHandler()
handler.setFormatter(LogFormatter())
logging.root.addHandler(handler)
logging.root.setLevel(level)