Formatters have the following attributes and methods. They are
responsible for converting a LogRecord to (usually) a string
which can be interpreted by either a human or an external system. The
base
Formatter allows a formatting string to be specified. If none is
supplied, the default value of '%(message)s' is used.
A Formatter can be initialized with a format string which makes use of
knowledge of the LogRecord attributes - such as the default value
mentioned above making use of the fact that the user's message and
arguments are pre-formatted into a LogRecord's message
attribute. This format string contains standard python %-style
mapping keys. See section 2.3.6, ``String Formatting
Operations,'' for more information on string formatting.
Currently, the useful mapping keys in a LogRecord are:
Format
Description
%(name)s
Name of the logger (logging channel).
%(levelno)s
Numeric logging level for the message
(DEBUG, INFO,
WARNING, ERROR,
CRITICAL).
%(levelname)s
Text logging level for the message
('DEBUG', 'INFO',
'WARNING', 'ERROR',
'CRITICAL').
%(pathname)s
Full pathname of the source file where the logging
call was issued (if available).
%(filename)s
Filename portion of pathname.
%(module)s
Module (name portion of filename).
%(lineno)d
Source line number where the logging call was issued
(if available).
%(created)f
Time when the LogRecord was created (as
returned by time.time()).
%(asctime)s
Human-readable time when the LogRecord was created.
By default this is of the form
``2003-07-08 16:49:45,896'' (the numbers after the
comma are millisecond portion of the time).
%(msecs)d
Millisecond portion of the time when the
LogRecord was created.
%(thread)d
Thread ID (if available).
%(process)d
Process ID (if available).
%(message)s
The logged message, computed as msg % args.
classFormatter(
[fmt[, datefmt]])
Returns a new instance of the Formatter class. The
instance is initialized with a format string for the message as a whole,
as well as a format string for the date/time portion of a message. If
no fmt is specified, '%(message)s' is used. If no datefmt
is specified, the ISO8601 date format is used.
format(
record)
The record's attribute dictionary is used as the operand to a
string formatting operation. Returns the resulting string.
Before formatting the dictionary, a couple of preparatory steps
are carried out. The message attribute of the record is computed
using msg % args. If the formatting string contains
'(asctime)', formatTime() is called to format the
event time. If there is exception information, it is formatted using
formatException() and appended to the message.
formatTime(
record[, datefmt])
This method should be called from format() by a formatter which
wants to make use of a formatted time. This method can be overridden
in formatters to provide for any specific requirement, but the
basic behavior is as follows: if datefmt (a string) is specified,
it is used with time.strftime() to format the creation time of the
record. Otherwise, the ISO8601 format is used. The resulting
string is returned.
formatException(
exc_info)
Formats the specified exception information (a standard exception tuple
as returned by sys.exc_info()) as a string. This default
implementation just uses traceback.print_exception().
The resulting string is returned.
