How to Customize the time format for Python logging?

From the official documentation regarding the Formatter class:

The constructor takes two optional arguments: a message format string and a date format string.

So change

# create formatterformatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s")

to

# create formatterformatter = logging.Formatter("%(asctime)s;%(levelname)s;%(message)s",                              "%Y-%m-%d %H:%M:%S")

Using logging.basicConfig, the following example works for me:

logging.basicConfig(    filename='HISTORYlistener.log',    level=logging.DEBUG,    format='%(asctime)s.%(msecs)03d %(levelname)s %(module)s - %(funcName)s: %(message)s',    datefmt='%Y-%m-%d %H:%M:%S',)

This allows you to format & config all in one line. A resulting log record looks as follows:

2014-05-26 12:22:52.376 CRITICAL historylistener - main: History log failed to start

To add to the other answers, here are the variable list from Python Documentation.

Directive   Meaning Notes%a  Locale’s abbreviated weekday name.   %A  Locale’s full weekday name.  %b  Locale’s abbreviated month name.     %B  Locale’s full month name.    %c  Locale’s appropriate date and time representation.   %d  Day of the month as a decimal number [01,31].    %H  Hour (24-hour clock) as a decimal number [00,23].    %I  Hour (12-hour clock) as a decimal number [01,12].    %j  Day of the year as a decimal number [001,366].   %m  Month as a decimal number [01,12].   %M  Minute as a decimal number [00,59].  %p  Locale’s equivalent of either AM or PM. (1)%S  Second as a decimal number [00,61]. (2)%U  Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0.    (3)%w  Weekday as a decimal number [0(Sunday),6].   %W  Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0.    (3)%x  Locale’s appropriate date representation.    %X  Locale’s appropriate time representation.    %y  Year without century as a decimal number [00,99].    %Y  Year with century as a decimal number.   %z  Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59].  %Z  Time zone name (no characters if no time zone exists).   %%  A literal '%' character.