fileConfig() disables any previously-used "named" loggers, even when getLogger() is called again.

[BobIgo]

BPO	17521
Nosy	@vsajip

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2013-03-23.11:23:27.512>
created_at = <Date 2013-03-22.16:45:50.539>
labels = ['type-bug', 'library']
title = 'fileConfig() disables any previously-used "named" loggers, even when getLogger() is called again.'
updated_at = <Date 2013-03-23.11:23:27.509>
user = 'https://bugs.python.org/BobIgo'

bugs.python.org fields:

activity = <Date 2013-03-23.11:23:27.509>
actor = 'python-dev'
assignee = 'none'
closed = True
closed_date = <Date 2013-03-23.11:23:27.512>
closer = 'python-dev'
components = ['Library (Lib)']
creation = <Date 2013-03-22.16:45:50.539>
creator = 'Bob.Igo'
dependencies = []
files = []
hgrepos = []
issue_num = 17521
keywords = []
message_count = 4.0
messages = ['184982', '185011', '185019', '185038']
nosy_count = 3.0
nosy_names = ['vinay.sajip', 'python-dev', 'Bob.Igo']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue17521'
versions = ['Python 2.7']

[BobIgo]

I am aware of the described behavior of fileConfig() when disable_existing_loggers is True, but what I am seeing happens whether disable_existing_loggers is True or False, and it also affects loggers obtained via future, fresh calls to getLogger(name).

Here's an example where disable_existing_loggers is True, but as I said, the same happens when it's False:

>>> import logging.config
>>> logging.config.fileConfig('unit_test_logging.conf')
>>> logger = logging.getLogger("foo")
>>> logger.critical("test")
2013-03-21 23:33:04,621    foo    CRITICAL    test
>>> logging.config.fileConfig('unit_test_logging.conf')
>>> logger = logging.getLogger("foo")
>>> logger.critical("test")
>>>

Note that the final logging attempt silently fails. The thing that appears to break logging for ever is the second fileConfig() call, and not the following getLogger() call.

I can get a fresh logger with a different name and use it. (Continued from the above session):

>>> logger = logging.getLogger("bar")
>>> logger.critical("test")
2013-03-21 23:38:35,613    bar    CRITICAL    test

This issue does not affect the root logger, when no name is given to getLogger():

>>> import logging.config
>>> logging.config.fileConfig('unit_test_logging.conf')
>>> logger = logging.getLogger()
>>> logger.critical("test")
2013-03-22 11:49:29,957    root    CRITICAL    test
>>> logging.config.fileConfig('unit_test_logging.conf')
>>> logger = logging.getLogger()
>>> logger.critical("test")
2013-03-22 11:49:44,966    root    CRITICAL    test

However, it _does_ affect the root logger when "root" is given as the name to getLogger():

>>> import logging.config
>>> logging.config.fileConfig('unit_test_logging.conf')
>>> logger = logging.getLogger("root")
>>> logger.critical("test")
2013-03-22 12:42:49,742	root	CRITICAL	test
>>> logging.config.fileConfig('unit_test_logging.conf')
>>> logger = logging.getLogger("root")
>>> logger.critical("test")
>>> 

I can attach the logging config file if desired, but it looks like the issue is unrelated. I will say that I'm relying on the root logger for all my logging, but that I use a different name to differentiate how the log is written.

[vsajip]

The logger obtained by logging.getLogger('root') is not the root logger, but a child of the root logger.

Please post your configuration, ideally the smallest version which allows you to reproduce the failure.

[BobIgo]

Any configuration I tried still generates the bug, but here's a pared-down config file:

[loggers]
keys=root

[handlers]
keys=screen

[formatters]
keys=

[logger_root]
level=DEBUG
handlers=screen

[handler_screen]
level=DEBUG
class=StreamHandler
args=(sys.stdout,)
formatter=

[python-dev]

New changeset 533b4a1d2b23 by Vinay Sajip in branch '2.7':
Issue bpo-17521: Corrected non-enabling of logger following two calls to fileConfig().
http://hg.python.org/cpython/rev/533b4a1d2b23

New changeset 49d54e4d95df by Vinay Sajip in branch '3.2':
Issue bpo-17521: Corrected non-enabling of logger following two calls to fileConfig().
http://hg.python.org/cpython/rev/49d54e4d95df

New changeset 1f6cda549b85 by Vinay Sajip in branch '3.3':
Issue bpo-17521: Merged fix from 3.2.
http://hg.python.org/cpython/rev/1f6cda549b85

New changeset aa01eb949636 by Vinay Sajip in branch 'default':
Closes bpo-17521: Merged fix from 3.3.
http://hg.python.org/cpython/rev/aa01eb949636