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Package logging ::
Class Formatter
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Class Formatter
- Known Subclasses:
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HtmlFormatter
Formatter instances are used to convert a LogRecord to text.
Formatters need to know how a LogRecord is constructed. 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 "%s(message)\n" is used.
The Formatter can be initialized with a format string which makes use of
knowledge of the LogRecord attributes - e.g. the default value mentioned
above makes use of the fact that the user's message and arguments are pre-
formatted into a LogRecord's message attribute. Currently, the useful
attributes in a LogRecord are described by:
%(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 (time.time()
return value)
%(asctime)s Textual time when the LogRecord was created
%(msecs)d Millisecond portion of the creation time
%(relativeCreated)d Time in milliseconds when the LogRecord was created,
relative to the time the logging module was loaded
(typically at application startup time)
%(thread)d Thread ID (if available)
%(threadName)s Thread name (if available)
%(process)d Process ID (if available)
%(message)s The result of record.getMessage(), computed just as
the record is emitted
| Method Summary |
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__init__(self,
fmt,
datefmt)
Initialize the formatter with specified format strings. |
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format(self,
record)
Format the specified record as text. |
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formatException(self,
ei)
Format and return the specified exception information as a string. |
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formatTime(self,
record,
datefmt)
Return the creation time of the specified LogRecord as formatted
text. |
__init__(self,
fmt=None,
datefmt=None)
(Constructor)
Initialize the formatter with specified format strings.
Initialize the formatter either with the specified format string, or
a default as described above. Allow for specialized date formatting
with the optional datefmt argument (if omitted, you get the ISO8601
format).
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format(self,
record)
Format the specified record as text.
The record's attribute dictionary is used as the operand to a string
formatting operation which yields the returned string. Before
formatting the dictionary, a couple of preparatory steps are carried
out. The message attribute of the record is computed using
LogRecord.getMessage(). 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.
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formatException(self,
ei)
Format and return the specified exception information as a
string.
This default implementation just uses
traceback.print_exception()
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formatTime(self,
record,
datefmt=None)
Return the creation time of the specified LogRecord as formatted
text.
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
behaviour 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. This function uses a user-configurable function to convert
the creation time to a tuple. By default, time.localtime() is used; to
change this for a particular formatter instance, set the 'converter'
attribute to a function with the same signature as time.localtime() or
time.gmtime(). To change it for all formatters, for example if you want
all logging times to be shown in GMT, set the 'converter' attribute in
the Formatter class.
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