Question :
By default logging.Formatter('%(asctime)s')
prints with the following format:
2011-06-09 10:54:40,638
where 638 is the millisecond. I need to change the comma to a dot:
2011-06-09 10:54:40.638
To format the time I can use:
logging.Formatter(fmt='%(asctime)s',datestr=date_format_str)
however the documentation doesn’t specify how to format milliseconds. I’ve found this SO question which talks about microseconds, but a) I would prefer milliseconds and b) the following doesn’t work on Python 2.6 (which I’m working on) due to the %f
:
logging.Formatter(fmt='%(asctime)s',datefmt='%Y-%m-%d,%H:%M:%S.%f')
Answer #1:
Please note Craig McDaniel’s solution is clearly better.
logging.Formatter’s formatTime
method looks like this:
def formatTime(self, record, datefmt=None):
ct = self.converter(record.created)
if datefmt:
s = time.strftime(datefmt, ct)
else:
t = time.strftime("%Y-%m-%d %H:%M:%S", ct)
s = "%s,%03d" % (t, record.msecs)
return s
Notice the comma in "%s,%03d"
. This can not be fixed by specifying a datefmt
because ct
is a time.struct_time
and these objects do not record milliseconds.
If we change the definition of ct
to make it a datetime
object instead of a struct_time
, then (at least with modern versions of Python) we can call ct.strftime
and then we can use %f
to format microseconds:
import logging
import datetime as dt
class MyFormatter(logging.Formatter):
converter=dt.datetime.fromtimestamp
def formatTime(self, record, datefmt=None):
ct = self.converter(record.created)
if datefmt:
s = ct.strftime(datefmt)
else:
t = ct.strftime("%Y-%m-%d %H:%M:%S")
s = "%s,%03d" % (t, record.msecs)
return s
logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)
console = logging.StreamHandler()
logger.addHandler(console)
formatter = MyFormatter(fmt='%(asctime)s %(message)s',datefmt='%Y-%m-%d,%H:%M:%S.%f')
console.setFormatter(formatter)
logger.debug('Jackdaws love my big sphinx of quartz.')
# 2011-06-09,07:12:36.553554 Jackdaws love my big sphinx of quartz.
Or, to get milliseconds, change the comma to a decimal point, and omit the datefmt
argument:
class MyFormatter(logging.Formatter):
converter=dt.datetime.fromtimestamp
def formatTime(self, record, datefmt=None):
ct = self.converter(record.created)
if datefmt:
s = ct.strftime(datefmt)
else:
t = ct.strftime("%Y-%m-%d %H:%M:%S")
s = "%s.%03d" % (t, record.msecs)
return s
...
formatter = MyFormatter(fmt='%(asctime)s %(message)s')
...
logger.debug('Jackdaws love my big sphinx of quartz.')
# 2011-06-09 08:14:38.343 Jackdaws love my big sphinx of quartz.
Answer #2:
This should work too:
logging.Formatter(fmt='%(asctime)s.%(msecs)03d',datefmt='%Y-%m-%d,%H:%M:%S')
Answer #3:
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 #4:
The simplest way I found was to override default_msec_format:
formatter = logging.Formatter('%(asctime)s')
formatter.default_msec_format = '%s.%03d'
Answer #5:
After instantiating a Formatter
I usually set formatter.converter = gmtime
. So in order for @unutbu’s answer to work in this case you’ll need:
class MyFormatter(logging.Formatter):
def formatTime(self, record, datefmt=None):
ct = self.converter(record.created)
if datefmt:
s = time.strftime(datefmt, ct)
else:
t = time.strftime("%Y-%m-%d %H:%M:%S", ct)
s = "%s.%03d" % (t, record.msecs)
return s
Answer #6:
A simple expansion that doesn’t require the datetime
module and isn’t handicapped like some other solutions is to use simple string replacement like so:
import logging
import time
class MyFormatter(logging.Formatter):
def formatTime(self, record, datefmt=None):
ct = self.converter(record.created)
if datefmt:
if "%F" in datefmt:
msec = "%03d" % record.msecs
datefmt = datefmt.replace("%F", msec)
s = time.strftime(datefmt, ct)
else:
t = time.strftime("%Y-%m-%d %H:%M:%S", ct)
s = "%s,%03d" % (t, record.msecs)
return s
This way a date format can be written however you want, even allowing for region differences, by using %F
for milliseconds. For example:
log = logging.getLogger(__name__)
log.setLevel(logging.INFO)
sh = logging.StreamHandler()
log.addHandler(sh)
fm = MyFormatter(fmt='%(asctime)s-%(levelname)s-%(message)s',datefmt='%H:%M:%S.%F')
sh.setFormatter(fm)
log.info("Foo, Bar, Baz")
# 03:26:33.757-INFO-Foo, Bar, Baz
Answer #7:
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.
Answer #8:
If you prefer to use style='{'
, fmt="{asctime}.{msecs:0<3.0f}"
will 0-pad your microseconds to three places for consistency.