How to Change the time zone in Python logging? - python-2.7

Question

I would like to change the timestamp in the log file so that it reflects my current time zone so that i can debug errors at a faster rate,
is it possible that i can change the time zone in the log file ?
currently my config is:
logging.basicConfig(filename='audit.log',
filemode='w',
level=logging.INFO,
format='%(asctime)s %(message)s',
datefmt='%m/%d/%Y %I:%M:%S %p')

Answer 1

How to log the timezone
%Z from strftime format
Windows
>>> import logging
>>> logging.basicConfig(format="%(asctime)s %(message)s", datefmt="%m/%d/%Y %I:%M:%S %p %Z")
>>> logging.error('test')
11/03/2017 02:29:54 PM Mountain Daylight Time test
Linux
>>> import logging
>>> logging.basicConfig(format="%(asctime)s %(message)s", datefmt="%m/%d/%Y %I:%M:%S %p %Z")
>>> logging.error('test')
11/03/2017 02:30:50 PM MDT test
If the question is
How do I log in a different timezone than the local time on the server?
part of the answer is logging.Formatter.converter, however, you have to understand naive and aware datetime objects. Unless you want to write your own timezone module, I highly suggest the pytz library (pip install pytz). Python 3 includes a UTC and UTC offset timezone, but there's rules you'll have to implement for daylight saving or other offsets, so I would suggest the pytz library, even for python 3.
For example,
>>> import datetime
>>> utc_now = datetime.datetime.utcnow()
>>> utc_now.isoformat()
'2019-05-21T02:30:09.422638'
>>> utc_now.tzinfo
(None)
If I apply a timezone to this datetime object, the time won't change (or will issue a ValueError for < python 3.7ish).
>>> mst_now = utc_now.astimezone(pytz.timezone('America/Denver'))
>>> mst_now.isoformat()
'2019-05-21T02:30:09.422638-06:00'
>>> utc_now.isoformat()
'2019-05-21T02:30:09.422638'
However, if instead, I do
>>> import pytz
>>> utc_now = datetime.datetime.now(tz=pytz.timezone('UTC'))
>>> utc_now.tzinfo
<UTC>
now we can create a properly translated datetime object in whatever timezone we wish
>>> mst_now = utc_now.astimezone(pytz.timezone('America/Denver'))
>>> mst_now.isoformat()
'2019-05-20T20:31:44.913939-06:00'
Aha! Now to apply this to the logging module.
Epoch timestamp to string representation with timezone
The LogRecord.created attribute is set to the time when the LogRecord was created (as returned by time.time()), from the time module. This returns a timestamp (seconds since the epoch). You can do your own translation to a given timezone, but again, I suggest pytz, by overriding the converter.
import datetime
import logging
import pytz
class Formatter(logging.Formatter):
"""override logging.Formatter to use an aware datetime object"""
def converter(self, timestamp):
dt = datetime.datetime.fromtimestamp(timestamp)
tzinfo = pytz.timezone('America/Denver')
return tzinfo.localize(dt)
def formatTime(self, record, datefmt=None):
dt = self.converter(record.created)
if datefmt:
s = dt.strftime(datefmt)
else:
try:
s = dt.isoformat(timespec='milliseconds')
except TypeError:
s = dt.isoformat()
return s
Python 3.5, 2.7
>>> logger = logging.root
>>> handler = logging.StreamHandler()
>>> handler.setFormatter(Formatter("%(asctime)s %(message)s"))
>>> logger.addHandler(handler)
>>> logger.setLevel(logging.DEBUG)
>>> logger.debug('test')
2019-05-20T22:25:10.758782-06:00 test
Python 3.7
>>> logger = logging.root
>>> handler = logging.StreamHandler()
>>> handler.setFormatter(Formatter("%(asctime)s %(message)s"))
>>> logger.addHandler(handler)
>>> logger.setLevel(logging.DEBUG)
>>> logger.debug('test')
2019-05-20T22:29:21.678-06:00 test
Substitute America/Denver with America/Anchorage for the posix timezone as defined by pytz
>>> next(_ for _ in pytz.common_timezones if 'Alaska' in _)
'US/Alaska'
US/Alaska is deprecated
>>> [_ for _ in pytz.all_timezones if 'Anchorage' in _]
['America/Anchorage']
Local
If you got to this question and answers looking for how to log the local timezone, then instead of hardcoding the timezone, get tzlocal (pip install tzlocal) and replace
tzinfo = pytz.timezone('America/Denver')
with
tzinfo = tzlocal.get_localzone()
Now it will work on whatever server runs the script, with the timezone on the server.
Caveat when not logging UTC
I should add, depending on the application, logging in local time zones can create ambiguity or at least confusion twice a year, where 2 AM is skipped or 1 AM repeats, and possibly others.

Answer 2

#!/usr/bin/python
from datetime import datetime
from pytz import timezone
import logging
def timetz(*args):
return datetime.now(tz).timetuple()
tz = timezone('Asia/Shanghai') # UTC, Asia/Shanghai, Europe/Berlin
logging.Formatter.converter = timetz
logging.basicConfig(
format="%(asctime)s %(levelname)s: %(message)s",
level=logging.INFO,
datefmt="%Y-%m-%d %H:%M:%S",
)
logging.info('Timezone: ' + str(tz))
Using pytz to define a timezone relative to UTC.
Based on the example by: secsilm

Answer 3

#!/usr/bin/env python
from datetime import datetime
import logging
import time
from pytz import timezone, utc
def main():
logging.basicConfig(format="%(asctime)s %(message)s",
datefmt="%Y-%m-%d %H:%M:%S")
logger = logging.getLogger(__name__)
logger.error("default")
logging.Formatter.converter = time.localtime
logger.error("localtime")
logging.Formatter.converter = time.gmtime
logger.error("gmtime")
def customTime(*args):
utc_dt = utc.localize(datetime.utcnow())
my_tz = timezone("US/Eastern")
converted = utc_dt.astimezone(my_tz)
return converted.timetuple()
logging.Formatter.converter = customTime
logger.error("customTime")
# to find the string code for your desired tz...
# print(pytz.all_timezones)
# print(pytz.common_timezones)
if __name__ == "__main__":
main()
Ostensibly the pytz package is the blessed way of converting time zones in Python. So we start with datetime, convert, then get the (immutable) time_tuple to match return type of the time methods
Setting the logging.Formatter.converter function is recommended by this answer: (Python logging: How to set time to GMT).
Find your favorite TZ code by uncommenting the end lines

Answer 4

just add this pythonic line to your code (using pytz and datetime):
from pytz import timezone
from datetime import datetime
import logging
logging.Formatter.converter = lambda *args: datetime.now(tz=timezone('tz string name')).timetuple()
# quoting Ryan J McCall: to find the string name for your desired timezone...
# print(pytz.all_timezones)
# or print(pytz.common_timezones)

Answer 5

An alternative solution if you want to use logging configuration function:
import pytz
import logging
import logging.config
from datetime import datetime
tz = pytz.timezone('Asia/Tokyo')
class TokyoFormatter(logging.Formatter):
converter = lambda *args: datetime.now(tz).timetuple()
LOGGING = {
'version': 1,
'disable_existing_loggers': False,
'formatters': {
'Tokyo': {
'()': TokyoFormatter,
'format': '%(asctime)s %(levelname)s: %(message)s',
'datefmt': '%Y-%m-%d %H:%M:%S'
},
},
'handlers': {
'console': {
'class': 'logging.StreamHandler',
'formatter': 'Tokyo'
},
},
'loggers': {
'foo': {
'handlers': ['console'],
'level': 'INFO'
},
}
}
logging.config.dictConfig(LOGGING)
logger = logging.getLogger('foo')
logger.info('Just a test.')
Define the logging formatter, e.g., "TokyoFormatter". It has an attibute "converter", finishing the job of converting the time zone.
For more details, please refer to Customizing handlers with dictConfig().

Answer 6

import logging, time
from datetime import datetime, timedelta
logger = logging.getLogger(__name__)
converter = lambda x, y: (datetime.utcnow() - timedelta(
hours=7 if time.localtime().tm_isdst else 6)
).timetuple()
logging.Formatter.converter = converter
Edited as Elias points out the original answer didn't check for DST.

Answer 7

If you know your utc offset, you can define a function to correct the time and then pass it to logging.Formatter.converter.
For example, you want to convert the time to UTC+8 timezone, then:
import logging
import datetime
def beijing(sec, what):
'''sec and what is unused.'''
beijing_time = datetime.datetime.now() + datetime.timedelta(hours=8)
return beijing_time.timetuple()
logging.Formatter.converter = beijing
logging.basicConfig(
format="%(asctime)s %(levelname)s: %(message)s",
level=logging.INFO,
datefmt="%Y-%m-%d %H:%M:%S",
)
Just change the hours in datetime.timedelta(hours=8) depending on your situation.
Reference: https://alanlee.fun/2019/01/06/how-to-change-logging-date-timezone/