Class Formatter

Lib/logging/__init__.py:551–729

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

}

class Formatter(object):
    """
    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
    style-dependent default value, "%(message)s", "{message}", or
    "${message}", 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)
    %(funcName)s        Function name
    %(created)f         Time when the LogRecord was created (time.time_ns() / 1e9
                        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)
    %(taskName)s        Task name (if available)
    %(process)d         Process ID (if available)
    %(processName)s     Process name (if available)
    %(message)s         The result of record.getMessage(), computed just as
                        the record is emitted
    """

    converter = time.localtime

    def __init__(self, fmt=None, datefmt=None, style='%', validate=True, *,
                 defaults=None):
        """
        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 datefmt is omitted, you get an
        ISO8601-like (or RFC 3339-like) format.

        Use a style parameter of '%', '{' or '$' to specify that you want to