 |
 |
 |
Python Library Reference |  |
 |
 |
Loggers have the following attributes and methods. Note that Loggers are never instantiated directly, but always through the module-level function logging.getLogger(name).
| lvl) |
The term "delegation to the parent" means that if a logger has a level of NOTSET, its chain of ancestor loggers is traversed until either an ancestor with a level other than NOTSET is found, or the root is reached.
If an ancestor is found with a level other than NOTSET, then that ancestor's level is treated as the effective level of the logger where the ancestor search began, and is used to determine how a logging event is handled.
If the root is reached, and it has a level of NOTSET, then all messages will be processed. Otherwise, the root's level will be used as the effective level.
| lvl) |
| ) |
| msg[, *args[, **kwargs]]) |
There are two keyword arguments in kwargs which are inspected: exc_info which, if it does not evaluate as false, causes exception information to be added to the logging message. If an exception tuple (in the format returned by sys.exc_info()) is provided, it is used; otherwise, sys.exc_info() is called to get the exception information.
The other optional keyword argument is extra which can be used to pass a dictionary which is used to populate the __dict__ of the LogRecord created for the logging event with user-defined attributes. These custom attributes can then be used as you like. For example, they could be incorporated into logged messages. For example:
FORMAT = "%(asctime)-15s %(clientip)s %(user)-8s %(message)s"
logging.basicConfig(format=FORMAT)
dict = { 'clientip' : '192.168.0.1', 'user' : 'fbloggs' }
logger = logging.getLogger("tcpserver")
logger.warning("Protocol problem: %s", "connection reset", extra=d)
would print something like
2006-02-08 22:20:02,165 192.168.0.1 fbloggs Protocol problem: connection reset
The keys in the dictionary passed in extra should not clash with the keys used by the logging system. (See the Formatter documentation for more information on which keys are used by the logging system.)
If you choose to use these attributes in logged messages, you need to exercise some care. In the above example, for instance, the Formatter has been set up with a format string which expects 'clientip' and 'user' in the attribute dictionary of the LogRecord. If these are missing, the message will not be logged because a string formatting exception will occur. So in this case, you always need to pass the extra dictionary with these keys.
While this might be annoying, this feature is intended for use in specialized circumstances, such as multi-threaded servers where the same code executes in many contexts, and interesting conditions which arise are dependent on this context (such as remote client IP address and authenticated user name, in the above example). In such circumstances, it is likely that specialized Formatters would be used with particular Handlers.
Changed in version 2.5: extra was added.
| msg[, *args[, **kwargs]]) |
| msg[, *args[, **kwargs]]) |
| msg[, *args[, **kwargs]]) |
| msg[, *args[, **kwargs]]) |
| lvl, msg[, *args[, **kwargs]]) |
| msg[, *args]) |
| filt) |
| filt) |
| record) |
| hdlr) |
| hdlr) |
| ) |
| record) |
| name, lvl, fn, lno, msg, args, exc_info, func, extra) |
|
|
|
Python Library Reference | |
|
|