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#
SOME DESCRIPTIVE TITLE.
#
Copyright (C) 2001 Python Software Foundation
#
This file is distributed under the same license as the Python package.
#
FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
#,
fuzzy
msgid ""
msgstr ""
"
Project-Id-Version
:
Python 3.14\n
"
"
Report-Msgid-Bugs-To
:
\n
"
"
POT-Creation-Date
:
2026-09-15 09:12+0000\n
"
"
PO-Revision-Date
:
2025-09-16 00:00+0000\n
"
"
Language-Team
:
German (https://app.transifex.com/python-doc/teams/5390/de/)\n
"
"
Language
:
de\n
"
"
MIME-Version
:
1.0\n
"
"
Content-Type
:
text/plain; charset=UTF-8\n
"
"
Content-Transfer-Encoding
:
8bit\n
"
"
Plural-Forms
:
nplurals=2; plural=(n != 1);\n
"
#:
../../howto/logging-cookbook.rst:5
msgid
"Logging Cookbook"
msgstr
""
#:
../../howto/logging-cookbook.rst:0
msgid
"Author"
msgstr
""
#:
../../howto/logging-cookbook.rst:7
msgid
"Vinay Sajip <vinay_sajip at red-dove dot com>"
msgstr
""
#:
../../howto/logging-cookbook.rst:9
msgid
""
"This page contains a number of recipes related to logging, which have been "
"found useful in the past. For links to tutorial and reference information, "
"please see :ref:`cookbook-ref-links`."
msgstr
""
#:
../../howto/logging-cookbook.rst:16
msgid
"Using logging in multiple modules"
msgstr
""
#:
../../howto/logging-cookbook.rst:18
msgid
""
"Multiple calls to ``logging.getLogger('someLogger')`` return a reference to "
"the same logger object. This is true not only within the same module, but "
"also across modules as long as it is in the same Python interpreter "
"process. It is true for references to the same object; additionally, "
"application code can define and configure a parent logger in one module and "
"create (but not configure) a child logger in a separate module, and all "
"logger calls to the child will pass up to the parent. Here is a main "
"module::"
msgstr
""
#:
../../howto/logging-cookbook.rst:26
msgid
""
"import logging\n"
"import auxiliary_module\n"
"\n"
"# create logger with 'spam_application'\n"
"logger = logging.getLogger('spam_application')\n"
"logger.setLevel(logging.DEBUG)\n"
"# create file handler which logs even debug messages\n"
"fh = logging.FileHandler('spam.log')\n"
"fh.setLevel(logging.DEBUG)\n"
"# create console handler with a higher log level\n"
"ch = logging.StreamHandler()\n"
"ch.setLevel(logging.ERROR)\n"
"# create formatter and add it to the handlers\n"
"formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - "
"%(message)s')\n"
"fh.setFormatter(formatter)\n"
"ch.setFormatter(formatter)\n"
"# add the handlers to the logger\n"
"logger.addHandler(fh)\n"
"logger.addHandler(ch)\n"
"\n"
"logger.info('creating an instance of auxiliary_module.Auxiliary')\n"
"a = auxiliary_module.Auxiliary()\n"
"logger.info('created an instance of auxiliary_module.Auxiliary')\n"
"logger.info('calling auxiliary_module.Auxiliary.do_something')\n"
"a.do_something()\n"
"logger.info('finished auxiliary_module.Auxiliary.do_something')\n"
"logger.info('calling auxiliary_module.some_function()')\n"
"auxiliary_module.some_function()\n"
"logger.info('done with auxiliary_module.some_function()')"
msgstr
""
#:
../../howto/logging-cookbook.rst:56
msgid
"Here is the auxiliary module::"
msgstr
""
#:
../../howto/logging-cookbook.rst:58
msgid
""
"import logging\n"
"\n"
"# create logger\n"
"module_logger = logging.getLogger('spam_application.auxiliary')\n"
"\n"
"class Auxiliary:\n"
" def __init__(self):\n"
" self.logger = logging.getLogger('spam_application.auxiliary."
"Auxiliary')\n"
" self.logger.info('creating an instance of Auxiliary')\n"
"\n"
" def do_something(self):\n"
" self.logger.info('doing something')\n"
" a = 1 + 1\n"
" self.logger.info('done doing something')\n"
"\n"
"def some_function():\n"
" module_logger.info('received a call to
\"
some_function
\"
')"
msgstr
""
#:
../../howto/logging-cookbook.rst:76
msgid
"The output looks like this:"
msgstr
""
#:
../../howto/logging-cookbook.rst:78
msgid
""
"2005-03-23 23:47:11,663 - spam_application - INFO -\n"
" creating an instance of auxiliary_module.Auxiliary\n"
"2005-03-23 23:47:11,665 - spam_application.auxiliary.Auxiliary - INFO -\n"
" creating an instance of Auxiliary\n"
"2005-03-23 23:47:11,665 - spam_application - INFO -\n"
" created an instance of auxiliary_module.Auxiliary\n"
"2005-03-23 23:47:11,668 - spam_application - INFO -\n"
" calling auxiliary_module.Auxiliary.do_something\n"
"2005-03-23 23:47:11,668 - spam_application.auxiliary.Auxiliary - INFO -\n"
" doing something\n"
"2005-03-23 23:47:11,669 - spam_application.auxiliary.Auxiliary - INFO -\n"
" done doing something\n"
"2005-03-23 23:47:11,670 - spam_application - INFO -\n"
" finished auxiliary_module.Auxiliary.do_something\n"
"2005-03-23 23:47:11,671 - spam_application - INFO -\n"
" calling auxiliary_module.some_function()\n"
"2005-03-23 23:47:11,672 - spam_application.auxiliary - INFO -\n"
" received a call to 'some_function'\n"
"2005-03-23 23:47:11,673 - spam_application - INFO -\n"
" done with auxiliary_module.some_function()"
msgstr
""
#:
../../howto/logging-cookbook.rst:102
msgid
"Logging from multiple threads"
msgstr
""
#:
../../howto/logging-cookbook.rst:104
msgid
""
"Logging from multiple threads requires no special effort. The following "
"example shows logging from the main (initial) thread and another thread::"
msgstr
""
#:
../../howto/logging-cookbook.rst:107
msgid
""
"import logging\n"
"import threading\n"
"import time\n"
"\n"
"def worker(arg):\n"
" while not arg['stop']:\n"
" logging.debug('Hi from myfunc')\n"
" time.sleep(0.5)\n"
"\n"
"def main():\n"
" logging.basicConfig(level=logging.DEBUG, format='%(relativeCreated)6d "
"%(threadName)s %(message)s')\n"
" info = {'stop': False}\n"
" thread = threading.Thread(target=worker, args=(info,))\n"
" thread.start()\n"
" while True:\n"
" try:\n"
" logging.debug('Hello from main')\n"
" time.sleep(0.75)\n"
" except KeyboardInterrupt:\n"
" info['stop'] = True\n"
" break\n"
" thread.join()\n"
"\n"
"if __name__ == '__main__':\n"
" main()"
msgstr
""
#:
../../howto/logging-cookbook.rst:133
msgid
"When run, the script should print something like the following:"
msgstr
""
#:
../../howto/logging-cookbook.rst:135
msgid
""
" 0 Thread-1 Hi from myfunc\n"
" 3 MainThread Hello from main\n"
" 505 Thread-1 Hi from myfunc\n"
" 755 MainThread Hello from main\n"
"1007 Thread-1 Hi from myfunc\n"
"1507 MainThread Hello from main\n"
"1508 Thread-1 Hi from myfunc\n"
"2010 Thread-1 Hi from myfunc\n"
"2258 MainThread Hello from main\n"
"2512 Thread-1 Hi from myfunc\n"
"3009 MainThread Hello from main\n"
"3013 Thread-1 Hi from myfunc\n"
"3515 Thread-1 Hi from myfunc\n"
"3761 MainThread Hello from main\n"
"4017 Thread-1 Hi from myfunc\n"
"4513 MainThread Hello from main\n"
"4518 Thread-1 Hi from myfunc"
msgstr
""
#:
../../howto/logging-cookbook.rst:155
msgid
""
"This shows the logging output interspersed as one might expect. This "
"approach works for more threads than shown here, of course."
msgstr
""
#:
../../howto/logging-cookbook.rst:159
msgid
"Multiple handlers and formatters"
msgstr
""
#:
../../howto/logging-cookbook.rst:161
msgid
""
"Loggers are plain Python objects. The :meth:`~Logger.addHandler` method has "
"no minimum or maximum quota for the number of handlers you may add. "
"Sometimes it will be beneficial for an application to log all messages of "
"all severities to a text file while simultaneously logging errors or above "
"to the console. To set this up, simply configure the appropriate handlers. "
"The logging calls in the application code will remain unchanged. Here is a "
"slight modification to the previous simple module-based configuration "
"example::"
msgstr
""
#:
../../howto/logging-cookbook.rst:169
msgid
""
"import logging\n"
"\n"
"logger = logging.getLogger('simple_example')\n"
"logger.setLevel(logging.DEBUG)\n"
"# create file handler which logs even debug messages\n"
"fh = logging.FileHandler('spam.log')\n"
"fh.setLevel(logging.DEBUG)\n"
"# create console handler with a higher log level\n"
"ch = logging.StreamHandler()\n"
"ch.setLevel(logging.ERROR)\n"
"# create formatter and add it to the handlers\n"
"formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - "
"%(message)s')\n"
"ch.setFormatter(formatter)\n"
"fh.setFormatter(formatter)\n"
"# add the handlers to logger\n"
"logger.addHandler(ch)\n"
"logger.addHandler(fh)\n"
"\n"
"# 'application' code\n"
"logger.debug('debug message')\n"
"logger.info('info message')\n"
"logger.warning('warn message')\n"
"logger.error('error message')\n"
"logger.critical('critical message')"
msgstr
""
#:
../../howto/logging-cookbook.rst:194
msgid
""
"Notice that the 'application' code does not care about multiple handlers. "
"All that changed was the addition and configuration of a new handler named "
"*fh*."
msgstr
""
#:
../../howto/logging-cookbook.rst:197
msgid
""
"The ability to create new handlers with higher- or lower-severity filters "
"can be very helpful when writing and testing an application. Instead of "
"using many ``print`` statements for debugging, use ``logger.debug``: Unlike "
"the print statements, which you will have to delete or comment out later, "
"the logger.debug statements can remain intact in the source code and remain "
"dormant until you need them again. At that time, the only change that needs "
"to happen is to modify the severity level of the logger and/or handler to "
"debug."
msgstr
""
#:
../../howto/logging-cookbook.rst:208
msgid
"Logging to multiple destinations"
msgstr
""
#:
../../howto/logging-cookbook.rst:210
msgid
""
"Let's say you want to log to console and file with different message formats "
"and in differing circumstances. Say you want to log messages with levels of "
"DEBUG and higher to file, and those messages at level INFO and higher to the "
"console. Let's also assume that the file should contain timestamps, but the "
"console messages should not. Here's how you can achieve this::"
msgstr
""
#:
../../howto/logging-cookbook.rst:216
msgid
""
"import logging\n"
"\n"
"# set up logging to file - see previous section for more details\n"
"logging.basicConfig(level=logging.DEBUG,\n"
" format='%(asctime)s %(name)-12s %(levelname)-8s "
"%(message)s',\n"
" datefmt='%m-%d %H:%M',\n"
" filename='/tmp/myapp.log',\n"
" filemode='w')\n"
"# define a Handler which writes INFO messages or higher to the sys.stderr\n"
"console = logging.StreamHandler()\n"
"console.setLevel(logging.INFO)\n"
"# set a format which is simpler for console use\n"
"formatter = logging.Formatter('%(name)-12s: %(levelname)-8s %(message)s')\n"
"# tell the handler to use this format\n"
"console.setFormatter(formatter)\n"
"# add the handler to the root logger\n"
"logging.getLogger().addHandler(console)\n"
"\n"
"# Now, we can log to the root logger, or any other logger. First the "
"root...\n"
"logging.info('Jackdaws love my big sphinx of quartz.')\n"
"\n"
"# Now, define a couple of other loggers which might represent areas in your\n"
"# application:\n"
"\n"
"logger1 = logging.getLogger('myapp.area1')\n"
"logger2 = logging.getLogger('myapp.area2')\n"
"\n"
"logger1.debug('Quick zephyrs blow, vexing daft Jim.')\n"
"logger1.info('How quickly daft jumping zebras vex.')\n"
"logger2.warning('Jail zesty vixen who grabbed pay from quack.')\n"
"logger2.error('The five boxing wizards jump quickly.')"
msgstr
""
#:
../../howto/logging-cookbook.rst:248
msgid
"When you run this, on the console you will see"
msgstr
""
#:
../../howto/logging-cookbook.rst:250
msgid
""
"root : INFO Jackdaws love my big sphinx of quartz.\n"
"myapp.area1 : INFO How quickly daft jumping zebras vex.\n"
"myapp.area2 : WARNING Jail zesty vixen who grabbed pay from quack.\n"
"myapp.area2 : ERROR The five boxing wizards jump quickly."
msgstr
""
#:
../../howto/logging-cookbook.rst:257
msgid
"and in the file you will see something like"
msgstr
""
#:
../../howto/logging-cookbook.rst:259
msgid
""
"10-22 22:19 root INFO Jackdaws love my big sphinx of quartz.\n"
"10-22 22:19 myapp.area1 DEBUG Quick zephyrs blow, vexing daft Jim.\n"
"10-22 22:19 myapp.area1 INFO How quickly daft jumping zebras vex.\n"
"10-22 22:19 myapp.area2 WARNING Jail zesty vixen who grabbed pay from "
"quack.\n"
"10-22 22:19 myapp.area2 ERROR The five boxing wizards jump quickly."
msgstr
""
#:
../../howto/logging-cookbook.rst:267
msgid
""
"As you can see, the DEBUG message only shows up in the file. The other "
"messages are sent to both destinations."
msgstr
""
#:
../../howto/logging-cookbook.rst:270
msgid
""
"This example uses console and file handlers, but you can use any number and "
"combination of handlers you choose."
msgstr
""
#:
../../howto/logging-cookbook.rst:273
msgid
""
"Note that the above choice of log filename ``/tmp/myapp.log`` implies use of "
"a standard location for temporary files on POSIX systems. On Windows, you "
"may need to choose a different directory name for the log - just ensure that "
"the directory exists and that you have the permissions to create and update "
"files in it."
msgstr
""
#:
../../howto/logging-cookbook.rst:282
msgid
"Custom handling of levels"
msgstr
""
#:
../../howto/logging-cookbook.rst:284
msgid
""
"Sometimes, you might want to do something slightly different from the "
"standard handling of levels in handlers, where all levels above a threshold "
"get processed by a handler. To do this, you need to use filters. Let's look "
"at a scenario where you want to arrange things as follows:"
msgstr
""
#:
../../howto/logging-cookbook.rst:289
msgid
"Send messages of severity ``INFO`` and ``WARNING`` to ``sys.stdout``"
msgstr
""
#:
../../howto/logging-cookbook.rst:290
msgid
"Send messages of severity ``ERROR`` and above to ``sys.stderr``"
msgstr
""
#:
../../howto/logging-cookbook.rst:291
msgid
"Send messages of severity ``DEBUG`` and above to file ``app.log``"
msgstr
""
#:
../../howto/logging-cookbook.rst:293
msgid
"Suppose you configure logging with the following JSON:"
msgstr
""
#:
../../howto/logging-cookbook.rst:295
msgid
""
"{\n"
"
\"
version
\"
: 1,\n"
"
\"
disable_existing_loggers
\"
: false,\n"
"
\"
formatters
\"
: {\n"
"
\"
simple
\"
: {\n"
"
\"
format
\"
:
\"
%(levelname)-8s - %(message)s
\"
\n"
" }\n"
" },\n"
"
\"
handlers
\"
: {\n"
"
\"
stdout
\"
: {\n"
"
\"
class
\"
:
\"
logging.StreamHandler
\"
,\n"
"
\"
level
\"
:
\"
INFO
\"
,\n"
"
\"
formatter
\"
:
\"
simple
\"
,\n"
"
\"
stream
\"
:
\"
ext://sys.stdout
\"
\n"
" },\n"
"
\"
stderr
\"
: {\n"
"
\"
class
\"
:
\"
logging.StreamHandler
\"
,\n"
"
\"
level
\"
:
\"
ERROR
\"
,\n"
"
\"
formatter
\"
:
\"
simple
\"
,\n"
"
\"
stream
\"
:
\"
ext://sys.stderr
\"
\n"
" },\n"
"
\"
file
\"
: {\n"
"
\"
class
\"
:
\"
logging.FileHandler
\"
,\n"
"
\"
formatter
\"
:
\"
simple
\"
,\n"
"
\"
filename
\"
:
\"
app.log
\"
,\n"
"
\"
mode
\"
:
\"
w
\"
\n"
" }\n"
" },\n"
"
\"
root
\"
: {\n"
"
\"
level
\"
:
\"
DEBUG
\"
,\n"
"
\"
handlers
\"
: [\n"
"
\"
stderr
\"
,\n"
"
\"
stdout
\"
,\n"
"
\"
file
\"
\n"
" ]\n"
" }\n"
"}"
msgstr
""
#:
../../howto/logging-cookbook.rst:335
msgid
""
"This configuration does *almost* what we want, except that ``sys.stdout`` "
"would show messages of severity ``ERROR`` and only events of this severity "
"and higher will be tracked as well as ``INFO`` and ``WARNING`` messages. To "
"prevent this, we can set up a filter which excludes those messages and add "
"it to the relevant handler. This can be configured by adding a ``filters`` "
"section parallel to ``formatters`` and ``handlers``:"
msgstr
""
#:
../../howto/logging-cookbook.rst:341
msgid
""
"{\n"
"
\"
filters
\"
: {\n"
"
\"
warnings_and_below
\"
: {\n"
"
\"
()
\"
:
\"
__main__.filter_maker
\"
,\n"
"
\"
level
\"
:
\"
WARNING
\"
\n"
" }\n"
" }\n"
"}"
msgstr
""
#:
../../howto/logging-cookbook.rst:352
msgid
"and changing the section on the ``stdout`` handler to add it:"
msgstr
""
#:
../../howto/logging-cookbook.rst:354
msgid
""
"{\n"
"
\"
stdout
\"
: {\n"
"
\"
class
\"
:
\"
logging.StreamHandler
\"
,\n"
"
\"
level
\"
:
\"
INFO
\"
,\n"
"
\"
formatter
\"
:
\"
simple
\"
,\n"
"
\"
stream
\"
:
\"
ext://sys.stdout
\"
,\n"
"
\"
filters
\"
: [
\"
warnings_and_below
\"
]\n"
" }\n"
"}"
msgstr
""
#:
../../howto/logging-cookbook.rst:366
msgid
""
"A filter is just a function, so we can define the ``filter_maker`` (a "
"factory function) as follows:"
msgstr
""
#:
../../howto/logging-cookbook.rst:369
msgid
""
"def filter_maker(level):\n"
" level = getattr(logging, level)\n"
"\n"
" def filter(record):\n"
" return record.levelno <= level\n"
"\n"
" return filter"
msgstr
""
#:
../../howto/logging-cookbook.rst:379
msgid
""
"This converts the string argument passed in to a numeric level, and returns "
"a function which only returns ``True`` if the level of the passed in record "
"is at or below the specified level. Note that in this example I have defined "
"the ``filter_maker`` in a test script ``main.py`` that I run from the "
"command line, so its module will be ``__main__`` - hence the ``__main__."
"filter_maker`` in the filter configuration. You will need to change that if "
"you define it in a different module."
msgstr
""
#:
../../howto/logging-cookbook.rst:387
msgid
"With the filter added, we can run ``main.py``, which in full is:"
msgstr
""
#:
../../howto/logging-cookbook.rst:389
msgid
""
"import json\n"
"import logging\n"
"import logging.config\n"
"\n"
"CONFIG = '''\n"
"{\n"
"
\"
version
\"
: 1,\n"
"
\"
disable_existing_loggers
\"
: false,\n"
"
\"
formatters
\"
: {\n"
"
\"
simple
\"
: {\n"
"
\"
format
\"
:
\"
%(levelname)-8s - %(message)s
\"
\n"
" }\n"
" },\n"
"
\"
filters
\"
: {\n"
"
\"
warnings_and_below
\"
: {\n"
"
\"
()
\"
:
\"
__main__.filter_maker
\"
,\n"
"
\"
level
\"
:
\"
WARNING
\"
\n"
" }\n"
" },\n"
"
\"
handlers
\"
: {\n"
"
\"
stdout
\"
: {\n"
"
\"
class
\"
:
\"
logging.StreamHandler
\"
,\n"
"
\"
level
\"
:
\"
INFO
\"
,\n"
"
\"
formatter
\"
:
\"
simple
\"
,\n"
"
\"
stream
\"
:
\"
ext://sys.stdout
\"
,\n"
"
\"
filters
\"
: [
\"
warnings_and_below
\"
]\n"
" },\n"
"
\"
stderr
\"
: {\n"
"
\"
class
\"
:
\"
logging.StreamHandler
\"
,\n"
"
\"
level
\"
:
\"
ERROR
\"
,\n"
"
\"
formatter
\"
:
\"
simple
\"
,\n"
"
\"
stream
\"
:
\"
ext://sys.stderr
\"
\n"
" },\n"
"
\"
file
\"
: {\n"
"
\"
class
\"
:
\"
logging.FileHandler
\"
,\n"
"
\"
formatter
\"
:
\"
simple
\"
,\n"
"
\"
filename
\"
:
\"
app.log
\"
,\n"
"
\"
mode
\"
:
\"
w
\"
\n"
" }\n"
" },\n"
"
\"
root
\"
: {\n"
"
\"
level
\"
:
\"
DEBUG
\"
,\n"
"
\"
handlers
\"
: [\n"
"
\"
stderr
\"
,\n"
"
\"
stdout
\"
,\n"
"
\"
file
\"
\n"
" ]\n"
" }\n"
"}\n"
"'''\n"
"\n"
"def filter_maker(level):\n"
" level = getattr(logging, level)\n"
"\n"
" def filter(record):\n"
" return record.levelno <= level\n"
"\n"
" return filter\n"
"\n"
"logging.config.dictConfig(json.loads(CONFIG))\n"
"logging.debug('A DEBUG message')\n"
"logging.info('An INFO message')\n"
"logging.warning('A WARNING message')\n"
"logging.error('An ERROR message')\n"
"logging.critical('A CRITICAL message')"
msgstr
""
#:
../../howto/logging-cookbook.rst:457
msgid
"And after running it like this:"
msgstr
""
#:
../../howto/logging-cookbook.rst:459
msgid
"python main.py 2>stderr.log >stdout.log"
msgstr
""
#:
../../howto/logging-cookbook.rst:463
msgid
"We can see the results are as expected:"
msgstr
""
#:
../../howto/logging-cookbook.rst:465
msgid
""
"$ more *.log\n"
"::::::::::::::\n"
"app.log\n"
"::::::::::::::\n"
"DEBUG - A DEBUG message\n"
"INFO - An INFO message\n"
"WARNING - A WARNING message\n"
"ERROR - An ERROR message\n"
"CRITICAL - A CRITICAL message\n"
"::::::::::::::\n"
"stderr.log\n"
"::::::::::::::\n"
"ERROR - An ERROR message\n"
"CRITICAL - A CRITICAL message\n"
"::::::::::::::\n"
"stdout.log\n"
"::::::::::::::\n"
"INFO - An INFO message\n"
"WARNING - A WARNING message"
msgstr
""
#:
../../howto/logging-cookbook.rst:489
msgid
"Configuration server example"
msgstr
""
#:
../../howto/logging-cookbook.rst:491
msgid
"Here is an example of a module using the logging configuration server::"
msgstr
""
#:
../../howto/logging-cookbook.rst:493
msgid
""
"import logging\n"
"import logging.config\n"
"import time\n"
"import os\n"
"\n"
"# read initial config file\n"
"logging.config.fileConfig('logging.conf')\n"
"\n"
"# create and start listener on port 9999\n"
"t = logging.config.listen(9999)\n"
"t.start()\n"
"\n"
"logger = logging.getLogger('simpleExample')\n"
"\n"
"try:\n"
" # loop through logging calls to see the difference\n"
" # new configurations make, until Ctrl+C is pressed\n"
" while True:\n"
" logger.debug('debug message')\n"
" logger.info('info message')\n"
" logger.warning('warn message')\n"
" logger.error('error message')\n"
" logger.critical('critical message')\n"
" time.sleep(5)\n"
"except KeyboardInterrupt:\n"
" # cleanup\n"
" logging.config.stopListening()\n"
" t.join()"
msgstr
""
#:
../../howto/logging-cookbook.rst:522
msgid
""
"And here is a script that takes a filename and sends that file to the "
"server, properly preceded with the binary-encoded length, as the new logging "
"configuration::"
msgstr
""
#:
../../howto/logging-cookbook.rst:526
msgid
""
"#!/usr/bin/env python\n"
"import socket, sys, struct\n"
"\n"
"with open(sys.argv[1], 'rb') as f:\n"
" data_to_send = f.read()\n"
"\n"
"HOST = 'localhost'\n"
"PORT = 9999\n"
"s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)\n"
"print('connecting...')\n"
"s.connect((HOST, PORT))\n"
"print('sending config...')\n"
"s.send(struct.pack('>L', len(data_to_send)))\n"
"s.send(data_to_send)\n"
"s.close()\n"
"print('complete')"
msgstr
""
#:
../../howto/logging-cookbook.rst:547
msgid
"Dealing with handlers that block"
msgstr
""
#:
../../howto/logging-cookbook.rst:551
msgid
""
"Sometimes you have to get your logging handlers to do their work without "
"blocking the thread you're logging from. This is common in web applications, "
"though of course it also occurs in other scenarios."
msgstr
""
#:
../../howto/logging-cookbook.rst:555
msgid
""
"A common culprit which demonstrates sluggish behaviour is the :class:"
"`SMTPHandler`: sending emails can take a long time, for a number of reasons "
"outside the developer's control (for example, a poorly performing mail or "
"network infrastructure). But almost any network-based handler can block: "
"Even a :class:`SocketHandler` operation may do a DNS query under the hood "
"which is too slow (and this query can be deep in the socket library code, "
"below the Python layer, and outside your control)."
msgstr
""
#:
../../howto/logging-cookbook.rst:563
msgid
""
"One solution is to use a two-part approach. For the first part, attach only "
"a :class:`QueueHandler` to those loggers which are accessed from performance-"
"critical threads. They simply write to their queue, which can be sized to a "
"large enough capacity or initialized with no upper bound to their size. The "
"write to the queue will typically be accepted quickly, though you will "
"probably need to catch the :exc:`queue.Full` exception as a precaution in "
"your code. If you are a library developer who has performance-critical "
"threads in their code, be sure to document this (together with a suggestion "
"to attach only ``QueueHandlers`` to your loggers) for the benefit of other "
"developers who will use your code."
msgstr
""
#:
../../howto/logging-cookbook.rst:574
msgid
""
"The second part of the solution is :class:`QueueListener`, which has been "
"designed as the counterpart to :class:`QueueHandler`. A :class:"
"`QueueListener` is very simple: it's passed a queue and some handlers, and "
"it fires up an internal thread which listens to its queue for LogRecords "
"sent from ``QueueHandlers`` (or any other source of ``LogRecords``, for that "
"matter). The ``LogRecords`` are removed from the queue and passed to the "
"handlers for processing."
msgstr
""
#:
../../howto/logging-cookbook.rst:582
msgid
""
"The advantage of having a separate :class:`QueueListener` class is that you "
"can use the same instance to service multiple ``QueueHandlers``. This is "
"more resource-friendly than, say, having threaded versions of the existing "
"handler classes, which would eat up one thread per handler for no particular "
"benefit."
msgstr
""
#:
../../howto/logging-cookbook.rst:587
msgid
"An example of using these two classes follows (imports omitted)::"
msgstr
""
#:
../../howto/logging-cookbook.rst:589
msgid
""
"que = queue.Queue(-1) # no limit on size\n"
"queue_handler = QueueHandler(que)\n"
"handler = logging.StreamHandler()\n"
"listener = QueueListener(que, handler)\n"
"root = logging.getLogger()\n"
"root.addHandler(queue_handler)\n"
"formatter = logging.Formatter('%(threadName)s: %(message)s')\n"
"handler.setFormatter(formatter)\n"
"listener.start()\n"
"# The log output will display the thread which generated\n"
"# the event (the main thread) rather than the internal\n"
"# thread which monitors the internal queue. This is what\n"
"# you want to happen.\n"
"root.warning('Look out!')\n"
"listener.stop()"
msgstr
""
#:
../../howto/logging-cookbook.rst:605
msgid
"which, when run, will produce:"
msgstr
""
#:
../../howto/logging-cookbook.rst:607
msgid
"MainThread: Look out!"
msgstr
""
#:
../../howto/logging-cookbook.rst:611
msgid
""
"Although the earlier discussion wasn't specifically talking about async "
"code, but rather about slow logging handlers, it should be noted that when "
"logging from async code, network and even file handlers could lead to "
"problems (blocking the event loop) because some logging is done from :mod:"
"`asyncio` internals. It might be best, if any async code is used in an "
"application, to use the above approach for logging, so that any blocking "
"code runs only in the ``QueueListener`` thread."
msgstr
""
#:
../../howto/logging-cookbook.rst:619
msgid
""
"Prior to Python 3.5, the :class:`QueueListener` always passed every message "
"received from the queue to every handler it was initialized with. (This was "
"because it was assumed that level filtering was all done on the other side, "
"where the queue is filled.) From 3.5 onwards, this behaviour can be changed "
"by passing a keyword argument ``respect_handler_level=True`` to the "
"listener's constructor. When this is done, the listener compares the level "
"of each message with the handler's level, and only passes a message to a "
"handler if it's appropriate to do so."
msgstr
""
#:
../../howto/logging-cookbook.rst:629
msgid
""
"The :class:`QueueListener` can be started (and stopped) via the :keyword:"
"`with` statement. For example:"
msgstr
""
#:
../../howto/logging-cookbook.rst:633
msgid
""
"with QueueListener(que, handler) as listener:\n"
" # The queue listener automatically starts\n"
" # when the 'with' block is entered.\n"
" pass\n"
"# The queue listener automatically stops once\n"
"# the 'with' block is exited."
msgstr
""
#:
../../howto/logging-cookbook.rst:645
msgid
"Sending and receiving logging events across a network"
msgstr
""
#:
../../howto/logging-cookbook.rst:647
msgid
""
"Let's say you want to send logging events across a network, and handle them "
"at the receiving end. A simple way of doing this is attaching a :class:"
"`SocketHandler` instance to the root logger at the sending end::"
msgstr
""
#:
../../howto/logging-cookbook.rst:651
msgid
""
"import logging, logging.handlers\n"
"\n"
"rootLogger = logging.getLogger()\n"
"rootLogger.setLevel(logging.DEBUG)\n"
"socketHandler = logging.handlers.SocketHandler('localhost',\n"
" logging.handlers.DEFAULT_TCP_LOGGING_PORT)\n"
"# don't bother with a formatter, since a socket handler sends the event as\n"
"# an unformatted pickle\n"
"rootLogger.addHandler(socketHandler)\n"
"\n"
"# Now, we can log to the root logger, or any other logger. First the "
"root...\n"
"logging.info('Jackdaws love my big sphinx of quartz.')\n"
"\n"
"# Now, define a couple of other loggers which might represent areas in your\n"
"# application:\n"
"\n"
"logger1 = logging.getLogger('myapp.area1')\n"
"logger2 = logging.getLogger('myapp.area2')\n"
"\n"
"logger1.debug('Quick zephyrs blow, vexing daft Jim.')\n"
"logger1.info('How quickly daft jumping zebras vex.')\n"
"logger2.warning('Jail zesty vixen who grabbed pay from quack.')\n"
"logger2.error('The five boxing wizards jump quickly.')"
msgstr
""
#:
../../howto/logging-cookbook.rst:675
msgid
""
"At the receiving end, you can set up a receiver using the :mod:"
"`socketserver` module. Here is a basic working example::"
msgstr
""
#:
../../howto/logging-cookbook.rst:678
msgid
""
"import pickle\n"
"import logging\n"
"import logging.handlers\n"
"import socketserver\n"
"import struct\n"
"\n"
"\n"
"class LogRecordStreamHandler(socketserver.StreamRequestHandler):\n"
"
\"\"\"
Handler for a streaming logging request.\n"
"\n"
" This basically logs the record using whatever logging policy is\n"
" configured locally.\n"
"
\"\"\"
\n"
"\n"
" def handle(self):\n"
"
\"\"\"
\n"
" Handle multiple requests - each expected to be a 4-byte length,\n"
" followed by the LogRecord in pickle format. Logs the record\n"
" according to whatever policy is configured locally.\n"
"
\"\"\"
\n"
" while True:\n"
" chunk = self.connection.recv(4)\n"
" if len(chunk) < 4:\n"
" break\n"
" slen = struct.unpack('>L', chunk)[0]\n"
" chunk = self.connection.recv(slen)\n"
" while len(chunk) < slen:\n"
" chunk = chunk + self.connection.recv(slen - len(chunk))\n"
" obj = self.unPickle(chunk)\n"
" record = logging.makeLogRecord(obj)\n"
" self.handleLogRecord(record)\n"
"\n"
" def unPickle(self, data):\n"
" return pickle.loads(data)\n"
"\n"
" def handleLogRecord(self, record):\n"
" # if a name is specified, we use the named logger rather than the "
"one\n"
" # implied by the record.\n"
" if self.server.logname is not None:\n"
" name = self.server.logname\n"
" else:\n"
" name = record.name\n"
" logger = logging.getLogger(name)\n"
" # N.B. EVERY record gets logged. This is because Logger.handle\n"
" # is normally called AFTER logger-level filtering. If you want\n"
" # to do filtering, do it at the client end to save wasting\n"
" # cycles and network bandwidth!\n"
" logger.handle(record)\n"
"\n"
"class LogRecordSocketReceiver(socketserver.ThreadingTCPServer):\n"
"
\"\"\"
\n"
" Simple TCP socket-based logging receiver suitable for testing.\n"
"
\"\"\"
\n"
"\n"
" allow_reuse_address = True\n"
"\n"
" def __init__(self, host='localhost',\n"
" port=logging.handlers.DEFAULT_TCP_LOGGING_PORT,\n"
" handler=LogRecordStreamHandler):\n"
" socketserver.ThreadingTCPServer.__init__(self, (host, port), "
"handler)\n"
" self.abort = 0\n"
" self.timeout = 1\n"
" self.logname = None\n"
"\n"
" def serve_until_stopped(self):\n"
" import select\n"
" abort = 0\n"
" while not abort:\n"
" rd, wr, ex = select.select([self.socket.fileno()],\n"
" [], [],\n"
" self.timeout)\n"
" if rd:\n"
" self.handle_request()\n"
" abort = self.abort\n"
"\n"
"def main():\n"
" logging.basicConfig(\n"
" format='%(relativeCreated)5d %(name)-15s %(levelname)-8s "
"%(message)s')\n"
" tcpserver = LogRecordSocketReceiver()\n"
" print('About to start TCP server...')\n"
" tcpserver.serve_until_stopped()\n"
"\n"
"if __name__ == '__main__':\n"
" main()"
msgstr
""
#:
../../howto/logging-cookbook.rst:763
msgid
""
"First run the server, and then the client. On the client side, nothing is "
"printed on the console; on the server side, you should see something like:"
msgstr
""
#:
../../howto/logging-cookbook.rst:766
msgid
""
"About to start TCP server...\n"
" 59 root INFO Jackdaws love my big sphinx of quartz.\n"
" 59 myapp.area1 DEBUG Quick zephyrs blow, vexing daft Jim.\n"
" 69 myapp.area1 INFO How quickly daft jumping zebras vex.\n"
" 69 myapp.area2 WARNING Jail zesty vixen who grabbed pay from quack.\n"
" 69 myapp.area2 ERROR The five boxing wizards jump quickly."
msgstr
""
#:
../../howto/logging-cookbook.rst:775
msgid
""
"Note that there are some security issues with pickle in some scenarios. If "
"these affect you, you can use an alternative serialization scheme by "
"overriding the :meth:`~SocketHandler.makePickle` method and implementing "
"your alternative there, as well as adapting the above script to use your "
"alternative serialization."
msgstr
""
#:
../../howto/logging-cookbook.rst:783
msgid
"Running a logging socket listener in production"
msgstr
""
#:
../../howto/logging-cookbook.rst:787
msgid
""
"To run a logging listener in production, you may need to use a process-"
"management tool such as `Supervisor <http://supervisord.org/>`_. `Here is a "
"Gist <socket-listener-gist_>`__ which provides the bare-bones files to run "
"the above functionality using Supervisor. It consists of the following files:"
msgstr
""
#:
../../howto/logging-cookbook.rst:794
msgid
"File"
msgstr
""
#:
../../howto/logging-cookbook.rst:794
msgid
"Purpose"
msgstr
""
#:
../../howto/logging-cookbook.rst:796
msgid
":file:`prepare.sh`"
msgstr
""
#:
../../howto/logging-cookbook.rst:796
msgid
"A Bash script to prepare the environment for testing"
msgstr
""
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