logging.StreamHandler should call super().__init__()
logging.StreamHandler inherits from logging.Handler but does not call super().init()
so it misses to initialize level and formatter instance variables
by the way, logging.Handler should initialize formatter to a working formatter, not None.
e.g. if you create and add a new StreamHandler, it has no formatter set by default and any logging will generate an exception.
shutdown function of logging module does not empty _loggers
if I want to reuse logger after call shutdown(), I can recreate log_a , add file_handler , but it will failure on log.xxx
<pre>
Traceback (most recent call last):
...
File "logging.py", line 141, in info
File "logging.py", line 135, in log
File "logging.py", line 71, in emit
ValueError:
</pre>
the root cause is, after execute logging.shutdown() , all logger remain in _loggers variables, so all handlers remain in logger.handlers, but the old file_handlers was closed, so emit method failure.
we can run follow code to verify it.
<pre>
import logging
log_a = logging.getLogger('a')
log_a.setLevel(logging.DEBUG)
file_handler = logging.FileHandler('log.txt')
file_handler.setLevel(logging.DEBUG)
formatter = logging.Formatter("%(name)s - %(levelname)s - %(message)s")
file_handler.setFormatter(formatter)
log_a.addHandler(file_handler)
log_a.debug('write to file')
print(logging._loggers)
print(log_a.handlers)
logging.shutdown()
log_a = logging.getLogger('a')
log_a.setLevel(logging.DEBUG)
file_handler = logging.FileHandler('log.txt')
file_handler.setLevel(logging.DEBUG)
formatter = logging.Formatter("%(name)s - %(levelname)s - %(message)s")
file_handler.setFormatter(formatter)
log_a.addHandler(file_handler)
log_a.debug('write to file')
print(logging._loggers)
print(log_a.handlers)
</pre>
to fixed it, pass name to pop method in line 213
logging._loggers.pop(logger.name, None)
I also encountered this issue, and have added a PR to fix in #710.