so I can add additional fields to my log message like so
logging.info("My log Message", extra={"someContext":1, "someOtherContext":2})
which is nice
but unclear how to extract all the extra fields in my log formatter
def format(self, record):
record_dict = record.__dict__.copy()
print(record_dict)
in the above i can see all my extra fields in the output dict but they are flattened in to a dict with load of other junk i dont want
{'name': 'root', 'msg': 'My log Message', 'args': (), 'levelname': 'INFO', 'levelno': 20, 'pathname': '.\\handler.py', 'filename': 'handler.py', 'module': 'handler', 'exc_info': None, 'exc_text': None, 'stack_info': None, 'lineno': 27, 'funcName': 'getPlan', 'created': 1575461352.0664868, 'msecs': 66.48683547973633, 'relativeCreated': 1253.0038356781006, 'thread': 15096, 'threadName': 'MainThread', 'processName': 'MainProcess', 'process': 23740, 'someContext': 1, 'someOtherContext':2}
is there any way of getting all my extra keys without having to know them all upfront,
i am writing a json formatter and want to create a dict a la
justMyExtra = ?????
to_log = {
"message" record_dict["message"],
**justMyExtra
}
If you read the source code of the logging.Logger.makeRecord method, which returns a LogRecord object with the given logging information, you'll find that it merges the extra dict with the __dict__ attribute of the returing LogRecord object, so you cannot retrieve the original extra dict afterwards in the formatter.
Instead, you can patch the logging.Logger.makeRecord method with a wrapper function that stores the given extra dict as the _extra attribute of the returning LogRecord object:
def make_record_with_extra(self, name, level, fn, lno, msg, args, exc_info, func=None, extra=None, sinfo=None):
record = original_makeRecord(self, name, level, fn, lno, msg, args, exc_info, func, extra, sinfo)
record._extra = extra
return record
original_makeRecord = logging.Logger.makeRecord
logging.Logger.makeRecord = make_record_with_extra
so that:
class myFormatter(logging.Formatter):
def format(self, record):
print('Got extra:', record._extra) # or do whatever you want with _extra
return super().format(record)
logger = logging.getLogger(__name__)
handler = logging.StreamHandler()
handler.setFormatter(myFormatter('%(name)s - %(levelname)s - %(message)s - %(foo)s'))
logger.addHandler(handler)
logger.warning('test', extra={'foo': 'bar'})
outputs:
Got extra: {'foo': 'bar'}
__main__ - WARNING - test - bar