Python logging: use milliseconds in time format

Question

By default logging.Formatter(\'%(asctime)s\') prints with the following format:

2011-06-09 10:54:40,638

where 638 is the milli

Answer 1

tl;dr for folks looking here for an ISO formatted date:

instead of using something like '%Y-%m-%d %H:%M:%S.%03d%z', create your own class as @unutbu indicated. Here's one for iso date format:

import logging
from time import gmtime, strftime

class ISOFormatter(logging.Formatter):
    def formatTime(self, record, datefmt=None):
        t = strftime("%Y-%m-%dT%H:%M:%S", gmtime(record.created))
        z = strftime("%z",gmtime(record.created))
        s = "%s.%03d%s" % (t, record.msecs,z)        
        return s

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)

console = logging.StreamHandler()
logger.addHandler(console)

formatter = ISOFormatter(fmt='%(asctime)s - %(module)s - %(levelname)s - %(message)s')
console.setFormatter(formatter)

logger.debug('Jackdaws love my big sphinx of quartz.')
#2020-10-23T17:25:48.310-0800 - <stdin> - DEBUG - Jackdaws love my big sphinx of quartz.

Answer 2

Adding msecs was the better option, Thanks. Here is my amendment using this with Python 3.5.3 in Blender

import logging
logging.basicConfig(level=logging.DEBUG, format='%(asctime)s.%(msecs)03d %(levelname)s:\t%(message)s', datefmt='%Y-%m-%d %H:%M:%S')
log = logging.getLogger(__name__)
log.info("Logging Info")
log.debug("Logging Debug")

Answer 3

The simplest way I found was to override default_msec_format:

formatter = logging.Formatter('%(asctime)s')
formatter.default_msec_format = '%s.%03d'

Answer 4

If you are using arrow or if you don't mind using arrow. You can substitute python's time formatting for arrow's one.

import logging

from arrow.arrow import Arrow


class ArrowTimeFormatter(logging.Formatter):

    def formatTime(self, record, datefmt=None):
        arrow_time = Arrow.fromtimestamp(record.created)

        if datefmt:
            arrow_time = arrow_time.format(datefmt)

        return str(arrow_time)


logger = logging.getLogger(__name__)

default_handler = logging.StreamHandler()
default_handler.setFormatter(ArrowTimeFormatter(
    fmt='%(asctime)s',
    datefmt='YYYY-MM-DD HH:mm:ss.SSS'
))

logger.setLevel(logging.DEBUG)
logger.addHandler(default_handler)

Now you can use all of arrow's time formatting in datefmt attribute.