Gecko [ v99win.today ]

Name	Size	Permission
2to3.html	63.71 KB	-rw-r--r--
__builtin__.html	11.79 KB	-rw-r--r--
__future__.html	15.58 KB	-rw-r--r--
__main__.html	8.33 KB	-rw-r--r--
_winreg.html	73.99 KB	-rw-r--r--
abc.html	26.82 KB	-rw-r--r--
aepack.html	15.47 KB	-rw-r--r--
aetools.html	18.79 KB	-rw-r--r--
aetypes.html	27.08 KB	-rw-r--r--
aifc.html	29.59 KB	-rw-r--r--
al.html	22.13 KB	-rw-r--r--
allos.html	35.48 KB	-rw-r--r--
anydbm.html	19.31 KB	-rw-r--r--
archiving.html	10.64 KB	-rw-r--r--
argparse.html	269.59 KB	-rw-r--r--
array.html	35.35 KB	-rw-r--r--
ast.html	42.42 KB	-rw-r--r--
asynchat.html	35.84 KB	-rw-r--r--
asyncore.html	43.22 KB	-rw-r--r--
atexit.html	19.23 KB	-rw-r--r--
audioop.html	41.32 KB	-rw-r--r--
autogil.html	9.77 KB	-rw-r--r--
base64.html	24.8 KB	-rw-r--r--
basehttpserver.html	40.6 KB	-rw-r--r--
bastion.html	13.02 KB	-rw-r--r--
bdb.html	50.06 KB	-rw-r--r--
binascii.html	26.64 KB	-rw-r--r--
binhex.html	12.66 KB	-rw-r--r--
bisect.html	28.52 KB	-rw-r--r--
bsddb.html	32.02 KB	-rw-r--r--
bz2.html	31.92 KB	-rw-r--r--
calendar.html	50.16 KB	-rw-r--r--
carbon.html	54.14 KB	-rw-r--r--
cd.html	35.24 KB	-rw-r--r--
cgi.html	58.4 KB	-rw-r--r--
cgihttpserver.html	15.12 KB	-rw-r--r--
cgitb.html	13.5 KB	-rw-r--r--
chunk.html	17.41 KB	-rw-r--r--
cmath.html	32.41 KB	-rw-r--r--
cmd.html	32.69 KB	-rw-r--r--
code.html	28.92 KB	-rw-r--r--
codecs.html	125.92 KB	-rw-r--r--
codeop.html	16.42 KB	-rw-r--r--
collections.html	150.36 KB	-rw-r--r--
colorpicker.html	9.02 KB	-rw-r--r--
colorsys.html	14.38 KB	-rw-r--r--
commands.html	16.63 KB	-rw-r--r--
compileall.html	21.18 KB	-rw-r--r--
compiler.html	78.14 KB	-rw-r--r--
configparser.html	73.92 KB	-rw-r--r--
constants.html	14.68 KB	-rw-r--r--
contextlib.html	22.91 KB	-rw-r--r--
cookie.html	45.38 KB	-rw-r--r--
cookielib.html	102.78 KB	-rw-r--r--
copy.html	14.21 KB	-rw-r--r--
copy_reg.html	15.82 KB	-rw-r--r--
crypt.html	11.62 KB	-rw-r--r--
crypto.html	8.35 KB	-rw-r--r--
csv.html	82.79 KB	-rw-r--r--
ctypes.html	280.57 KB	-rw-r--r--
curses.ascii.html	28.97 KB	-rw-r--r--
curses.html	200.94 KB	-rw-r--r--
curses.panel.html	18.43 KB	-rw-r--r--
custominterp.html	8.59 KB	-rw-r--r--
datatypes.html	18.84 KB	-rw-r--r--
datetime.html	261.02 KB	-rw-r--r--
dbhash.html	18.4 KB	-rw-r--r--
dbm.html	14.75 KB	-rw-r--r--
debug.html	11.28 KB	-rw-r--r--
decimal.html	239.14 KB	-rw-r--r--
development.html	15.27 KB	-rw-r--r--
difflib.html	96.93 KB	-rw-r--r--
dircache.html	13.66 KB	-rw-r--r--
dis.html	96.52 KB	-rw-r--r--
distribution.html	8.27 KB	-rw-r--r--
distutils.html	10.97 KB	-rw-r--r--
dl.html	19.27 KB	-rw-r--r--
doctest.html	193.18 KB	-rw-r--r--
docxmlrpcserver.html	20.02 KB	-rw-r--r--
dumbdbm.html	16.74 KB	-rw-r--r--
dummy_thread.html	11.04 KB	-rw-r--r--
dummy_threading.html	9.96 KB	-rw-r--r--
easydialogs.html	38.83 KB	-rw-r--r--
email-examples.html	47.2 KB	-rw-r--r--
email.charset.html	32.45 KB	-rw-r--r--
email.encoders.html	14.09 KB	-rw-r--r--
email.errors.html	19.2 KB	-rw-r--r--
email.generator.html	24.78 KB	-rw-r--r--
email.header.html	31.12 KB	-rw-r--r--
email.html	55.3 KB	-rw-r--r--
email.iterators.html	14.22 KB	-rw-r--r--
email.message.html	74.91 KB	-rw-r--r--
email.mime.html	34.51 KB	-rw-r--r--
email.parser.html	37.09 KB	-rw-r--r--
email.utils.html	30.04 KB	-rw-r--r--
ensurepip.html	20.21 KB	-rw-r--r--
errno.html	52.31 KB	-rw-r--r--
exceptions.html	73.4 KB	-rw-r--r--
fcntl.html	27.85 KB	-rw-r--r--
filecmp.html	26.49 KB	-rw-r--r--
fileformats.html	10.21 KB	-rw-r--r--
fileinput.html	29.36 KB	-rw-r--r--
filesys.html	11.55 KB	-rw-r--r--
fl.html	71.58 KB	-rw-r--r--
fm.html	15 KB	-rw-r--r--
fnmatch.html	17.78 KB	-rw-r--r--
formatter.html	43.91 KB	-rw-r--r--
fpectl.html	17.84 KB	-rw-r--r--
fpformat.html	12.65 KB	-rw-r--r--
fractions.html	27.17 KB	-rw-r--r--
framework.html	44.24 KB	-rw-r--r--
frameworks.html	8.11 KB	-rw-r--r--
ftplib.html	56.56 KB	-rw-r--r--
functions.html	216.84 KB	-rw-r--r--
functools.html	31.06 KB	-rw-r--r--
future_builtins.html	15.9 KB	-rw-r--r--
gc.html	30.74 KB	-rw-r--r--
gdbm.html	19.35 KB	-rw-r--r--
gensuitemodule.html	14.54 KB	-rw-r--r--
getopt.html	26.56 KB	-rw-r--r--
getpass.html	12.5 KB	-rw-r--r--
gettext.html	91.32 KB	-rw-r--r--
gl.html	26.71 KB	-rw-r--r--
glob.html	15.42 KB	-rw-r--r--
grp.html	12.33 KB	-rw-r--r--
gzip.html	21.95 KB	-rw-r--r--
hashlib.html	27.4 KB	-rw-r--r--
heapq.html	36.72 KB	-rw-r--r--
hmac.html	15.97 KB	-rw-r--r--
hotshot.html	22.69 KB	-rw-r--r--
htmllib.html	29.9 KB	-rw-r--r--
htmlparser.html	45.11 KB	-rw-r--r--
httplib.html	78.55 KB	-rw-r--r--
i18n.html	10.61 KB	-rw-r--r--
ic.html	22.03 KB	-rw-r--r--
idle.html	45.74 KB	-rw-r--r--
imageop.html	20.94 KB	-rw-r--r--
imaplib.html	69.9 KB	-rw-r--r--
imgfile.html	14.91 KB	-rw-r--r--
imghdr.html	13.43 KB	-rw-r--r--
imp.html	41.48 KB	-rw-r--r--
importlib.html	10.27 KB	-rw-r--r--
imputil.html	36.11 KB	-rw-r--r--
index.html	82.54 KB	-rw-r--r--
inspect.html	64.31 KB	-rw-r--r--
internet.html	26.77 KB	-rw-r--r--
intro.html	9.76 KB	-rw-r--r--
io.html	122.3 KB	-rw-r--r--
ipc.html	17.18 KB	-rw-r--r--
itertools.html	129.91 KB	-rw-r--r--
jpeg.html	15.36 KB	-rw-r--r--
json.html	79.09 KB	-rw-r--r--
keyword.html	9.27 KB	-rw-r--r--
language.html	12.35 KB	-rw-r--r--
linecache.html	12.7 KB	-rw-r--r--
locale.html	68.54 KB	-rw-r--r--
logging.config.html	82.23 KB	-rw-r--r--
logging.handlers.html	91.96 KB	-rw-r--r--
logging.html	123.15 KB	-rw-r--r--
mac.html	24.49 KB	-rw-r--r--
macos.html	18.51 KB	-rw-r--r--
macosa.html	14.55 KB	-rw-r--r--
macostools.html	19.67 KB	-rw-r--r--
macpath.html	9.19 KB	-rw-r--r--
mailbox.html	185.53 KB	-rw-r--r--
mailcap.html	15.3 KB	-rw-r--r--
markup.html	20.37 KB	-rw-r--r--
marshal.html	19.88 KB	-rw-r--r--
math.html	50.52 KB	-rw-r--r--
md5.html	16.65 KB	-rw-r--r--
mhlib.html	30.04 KB	-rw-r--r--
mimetools.html	23.84 KB	-rw-r--r--
mimetypes.html	35.82 KB	-rw-r--r--
mimewriter.html	18.19 KB	-rw-r--r--
mimify.html	16.96 KB	-rw-r--r--
miniaeframe.html	14.5 KB	-rw-r--r--
misc.html	7.77 KB	-rw-r--r--
mm.html	10.19 KB	-rw-r--r--
mmap.html	33.52 KB	-rw-r--r--
modulefinder.html	19.85 KB	-rw-r--r--
modules.html	9.68 KB	-rw-r--r--
msilib.html	72.78 KB	-rw-r--r--
msvcrt.html	24.1 KB	-rw-r--r--
multifile.html	28.82 KB	-rw-r--r--
multiprocessing.html	423.97 KB	-rw-r--r--
mutex.html	13.56 KB	-rw-r--r--
netdata.html	19.28 KB	-rw-r--r--
netrc.html	15.51 KB	-rw-r--r--
new.html	16.1 KB	-rw-r--r--
nis.html	13.19 KB	-rw-r--r--
nntplib.html	51.08 KB	-rw-r--r--
numbers.html	40.91 KB	-rw-r--r--
numeric.html	14.85 KB	-rw-r--r--
operator.html	118.32 KB	-rw-r--r--
optparse.html	251.08 KB	-rw-r--r--
os.html	270.49 KB	-rw-r--r--
os.path.html	48.87 KB	-rw-r--r--
ossaudiodev.html	49.79 KB	-rw-r--r--
othergui.html	9.98 KB	-rw-r--r--
parser.html	44.52 KB	-rw-r--r--
pdb.html	41.44 KB	-rw-r--r--
persistence.html	16.25 KB	-rw-r--r--
pickle.html	107.94 KB	-rw-r--r--
pickletools.html	13.21 KB	-rw-r--r--
pipes.html	21.85 KB	-rw-r--r--
pkgutil.html	30.59 KB	-rw-r--r--
platform.html	40.14 KB	-rw-r--r--
plistlib.html	20.96 KB	-rw-r--r--
popen2.html	30.13 KB	-rw-r--r--
poplib.html	27.93 KB	-rw-r--r--
posix.html	17.27 KB	-rw-r--r--
posixfile.html	23.68 KB	-rw-r--r--
pprint.html	36.42 KB	-rw-r--r--
profile.html	76.65 KB	-rw-r--r--
pty.html	11.42 KB	-rw-r--r--
pwd.html	13.53 KB	-rw-r--r--
py_compile.html	13.33 KB	-rw-r--r--
pyclbr.html	18.14 KB	-rw-r--r--
pydoc.html	14.33 KB	-rw-r--r--
pyexpat.html	93.28 KB	-rw-r--r--
python.html	13.53 KB	-rw-r--r--
queue.html	29.64 KB	-rw-r--r--
quopri.html	14.5 KB	-rw-r--r--
random.html	47.78 KB	-rw-r--r--
re.html	163.11 KB	-rw-r--r--
readline.html	41.2 KB	-rw-r--r--
repr.html	24.57 KB	-rw-r--r--
resource.html	30.86 KB	-rw-r--r--
restricted.html	12.69 KB	-rw-r--r--
rexec.html	43.59 KB	-rw-r--r--
rfc822.html	51.25 KB	-rw-r--r--
rlcompleter.html	15.29 KB	-rw-r--r--
robotparser.html	15.01 KB	-rw-r--r--
runpy.html	23.55 KB	-rw-r--r--
sched.html	21.76 KB	-rw-r--r--
scrolledtext.html	10.67 KB	-rw-r--r--
select.html	50.17 KB	-rw-r--r--
sets.html	39.92 KB	-rw-r--r--
sgi.html	11.09 KB	-rw-r--r--
sgmllib.html	38.77 KB	-rw-r--r--
sha.html	14.55 KB	-rw-r--r--
shelve.html	32.93 KB	-rw-r--r--
shlex.html	38.43 KB	-rw-r--r--
shutil.html	49.49 KB	-rw-r--r--
signal.html	36.52 KB	-rw-r--r--
simplehttpserver.html	21.57 KB	-rw-r--r--
simplexmlrpcserver.html	40.41 KB	-rw-r--r--
site.html	29 KB	-rw-r--r--
smtpd.html	15.64 KB	-rw-r--r--
smtplib.html	51.86 KB	-rw-r--r--
sndhdr.html	12.05 KB	-rw-r--r--
socket.html	126.94 KB	-rw-r--r--
socketserver.html	81.38 KB	-rw-r--r--
someos.html	17.09 KB	-rw-r--r--
spwd.html	12.25 KB	-rw-r--r--
sqlite3.html	154.12 KB	-rw-r--r--
ssl.html	214.5 KB	-rw-r--r--
stat.html	41.11 KB	-rw-r--r--
statvfs.html	13.24 KB	-rw-r--r--
stdtypes.html	309.83 KB	-rw-r--r--
string.html	129.58 KB	-rw-r--r--
stringio.html	21.1 KB	-rw-r--r--
stringprep.html	21.4 KB	-rw-r--r--
strings.html	16.42 KB	-rw-r--r--
struct.html	47.68 KB	-rw-r--r--
subprocess.html	117 KB	-rw-r--r--
sun.html	7.83 KB	-rw-r--r--
sunau.html	35.43 KB	-rw-r--r--
sunaudio.html	21.05 KB	-rw-r--r--
symbol.html	9.06 KB	-rw-r--r--
symtable.html	29.03 KB	-rw-r--r--
sys.html	118.12 KB	-rw-r--r--
sysconfig.html	28.8 KB	-rw-r--r--
syslog.html	21.29 KB	-rw-r--r--
tabnanny.html	12.78 KB	-rw-r--r--
tarfile.html	99.54 KB	-rw-r--r--
telnetlib.html	30.46 KB	-rw-r--r--
tempfile.html	35.02 KB	-rw-r--r--
termios.html	19.22 KB	-rw-r--r--
test.html	61.42 KB	-rw-r--r--
textwrap.html	32.28 KB	-rw-r--r--
thread.html	22.67 KB	-rw-r--r--
threading.html	92.04 KB	-rw-r--r--
time.html	65.55 KB	-rw-r--r--
timeit.html	44.38 KB	-rw-r--r--
tix.html	56.73 KB	-rw-r--r--
tk.html	26.76 KB	-rw-r--r--
tkinter.html	86.67 KB	-rw-r--r--
token.html	27.31 KB	-rw-r--r--
tokenize.html	21.69 KB	-rw-r--r--
trace.html	33.91 KB	-rw-r--r--
traceback.html	44.22 KB	-rw-r--r--
ttk.html	123.83 KB	-rw-r--r--
tty.html	10.95 KB	-rw-r--r--
turtle.html	246.17 KB	-rw-r--r--
types.html	33.66 KB	-rw-r--r--
undoc.html	25.54 KB	-rw-r--r--
unicodedata.html	22.64 KB	-rw-r--r--
unittest.html	246.75 KB	-rw-r--r--
unix.html	11.9 KB	-rw-r--r--
urllib.html	71.61 KB	-rw-r--r--
urllib2.html	128.77 KB	-rw-r--r--
urlparse.html	49.04 KB	-rw-r--r--
user.html	13.41 KB	-rw-r--r--
userdict.html	32.96 KB	-rw-r--r--
uu.html	13.25 KB	-rw-r--r--
uuid.html	33.55 KB	-rw-r--r--
warnings.html	51.86 KB	-rw-r--r--
wave.html	29.08 KB	-rw-r--r--
weakref.html	41.14 KB	-rw-r--r--
webbrowser.html	29.53 KB	-rw-r--r--
whichdb.html	10.44 KB	-rw-r--r--
windows.html	10.37 KB	-rw-r--r--
winsound.html	22.56 KB	-rw-r--r--
wsgiref.html	94.38 KB	-rw-r--r--
xdrlib.html	38.05 KB	-rw-r--r--
xml.dom.html	110.39 KB	-rw-r--r--
xml.dom.minidom.html	45.23 KB	-rw-r--r--
xml.dom.pulldom.html	16.32 KB	-rw-r--r--
xml.etree.elementtree.html	124.2 KB	-rw-r--r--
xml.html	18.76 KB	-rw-r--r--
xml.sax.handler.html	47.5 KB	-rw-r--r--
xml.sax.html	26.04 KB	-rw-r--r--
xml.sax.reader.html	51.4 KB	-rw-r--r--
xml.sax.utils.html	18.11 KB	-rw-r--r--
xmlrpclib.html	71.79 KB	-rw-r--r--
zipfile.html	67.26 KB	-rw-r--r--
zipimport.html	24.32 KB	-rw-r--r--
zlib.html	34.41 KB	-rw-r--r--

Code Editor : logging.html

<!DOCTYPE html>

<title>15.7. logging — Logging facility for Python &#8212; Python 2.7.18 documentation</title>
 <link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
 <link rel="stylesheet" type="text/css" href="../_static/classic.css" />
 
 <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
 <script src="../_static/jquery.js"></script>
 <script src="../_static/underscore.js"></script>
 <script src="../_static/doctools.js"></script>
 
 <script src="../_static/sidebar.js"></script>
 
 <link rel="search" type="application/opensearchdescription+xml"
 title="Search within Python 2.7.18 documentation"
 href="../_static/opensearch.xml"/>
 <link rel="author" title="About these documents" href="../about.html" />
 <link rel="index" title="Index" href="../genindex.html" />
 <link rel="search" title="Search" href="../search.html" />
 <link rel="copyright" title="Copyright" href="../copyright.html" />
 <link rel="next" title="15.8. logging.config — Logging configuration" href="logging.config.html" />
 <link rel="prev" title="15.6. getopt — C-style parser for command line options" href="getopt.html" />
 <link rel="shortcut icon" type="image/png" href="../_static/py.png" />
 <link rel="canonical" href="file:///usr/share/doc/python2.7/html/library/logging.html" />
 <script type="text/javascript" src="../_static/copybutton.js"></script>

</head><body>
<div id="outdated-warning" style="padding: .5em; text-align: center; background-color: #FFBABA; color: #6A0E0E;">
 This document is for an old version of Python that is <a href="https://devguide.python.org/devcycle/#end-of-life-branches">no longer supported</a>.
 You should install the python3 and python3-doc packages and read the 
 <a href="file:///usr/share/doc/python3-doc/html/library/logging.html"> Python documentation for the Python3 version packaged in this release</a>.
</div>
 
 <div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 accesskey="I">index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="logging.config.html" title="15.8. logging.config — Logging configuration"
 accesskey="N">next</a> |</li>
 <li class="right" >
 <a href="getopt.html" title="15.6. getopt — C-style parser for command line options"
 accesskey="P">previous</a> |</li>
 <li><img src="../_static/py.png" alt=""
 style="vertical-align: middle; margin-top: -1px"/></li>
 <li><a href="https://www.python.org/">Python</a> &#187;</li>
 <li>
 <a href="../index.html">Python 2.7.18 documentation</a> &#187;
 </li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="allos.html" accesskey="U">15. Generic Operating System Services</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href="">15.7. <code class="xref py py-mod docutils literal notranslate">logging</code> — Logging facility for Python</a></li> 
 </ul>
 </div>

<div class="document">
 <div class="documentwrapper">
 <div class="bodywrapper">
 <div class="body" role="main">
 
 <section id="module-logging">
<h1>15.7. <a class="reference internal" href="#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate">logging</code></a> — Logging facility for Python<a class="headerlink" href="#module-logging" title="Permalink to this headline">¶</a></h1>
<aside class="sidebar" id="index-0">
Important
This page contains the API reference information. For tutorial
information and discussion of more advanced topics, see
<ul class="simple">
<li><a class="reference internal" href="../howto/logging.html#logging-basic-tutorial">Basic Tutorial</a></li>
<li><a class="reference internal" href="../howto/logging.html#logging-advanced-tutorial">Advanced Tutorial</a></li>
<li><a class="reference internal" href="../howto/logging-cookbook.html#logging-cookbook">Logging Cookbook</a></li>
</ul>
</aside>
Source code: <a class="reference external" href="https://github.com/python/cpython/tree/2.7/Lib/logging/__init__.py">Lib/logging/__init__.py</a>
<hr class="docutils" />
<div class="versionadded">
New in version 2.3.
</div>
This module defines functions and classes which implement a flexible event
logging system for applications and libraries.
The key benefit of having the logging API provided by a standard library module
is that all Python modules can participate in logging, so your application log
can include your own messages integrated with messages from third-party
modules.
The module provides a lot of functionality and flexibility. If you are
unfamiliar with logging, the best way to get to grips with it is to see the
tutorials (see the links on the right).
The basic classes defined by the module, together with their functions, are
listed below.
<ul class="simple">
<li>Loggers expose the interface that application code directly uses.</li>
<li>Handlers send the log records (created by loggers) to the appropriate
destination.</li>
<li>Filters provide a finer grained facility for determining which log records
to output.</li>
<li>Formatters specify the layout of log records in the final output.</li>
</ul>
<section id="logger-objects">
<h2>15.7.1. Logger Objects<a class="headerlink" href="#logger-objects" title="Permalink to this headline">¶</a></h2>
Loggers have the following attributes and methods. Note that Loggers are never
instantiated directly, but always through the module-level function
<code class="docutils literal notranslate">logging.getLogger(name)</code>. Multiple calls to <a class="reference internal" href="#logging.getLogger" title="logging.getLogger"><code class="xref py py-func docutils literal notranslate">getLogger()</code></a> with the same
name will always return a reference to the same Logger object.
The <code class="docutils literal notranslate">name</code> is potentially a period-separated hierarchical value, like
<code class="docutils literal notranslate">foo.bar.baz</code> (though it could also be just plain <code class="docutils literal notranslate">foo</code>, for example).
Loggers that are further down in the hierarchical list are children of loggers
higher up in the list. For example, given a logger with a name of <code class="docutils literal notranslate">foo</code>,
loggers with names of <code class="docutils literal notranslate">foo.bar</code>, <code class="docutils literal notranslate">foo.bar.baz</code>, and <code class="docutils literal notranslate">foo.bam</code> are all
descendants of <code class="docutils literal notranslate">foo</code>. The logger name hierarchy is analogous to the Python
package hierarchy, and identical to it if you organise your loggers on a
per-module basis using the recommended construction
<code class="docutils literal notranslate">logging.getLogger(__name__)</code>. That’s because in a module, <code class="docutils literal notranslate">__name__</code>
is the module’s name in the Python package namespace.
<dl class="py class">
<dt class="sig sig-object py" id="logging.Logger">
class logging.Logger<a class="headerlink" href="#logging.Logger" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="logging.Logger.propagate">
Logger.propagate<a class="headerlink" href="#logging.Logger.propagate" title="Permalink to this definition">¶</a></dt>
<dd>If this evaluates to true, events logged to this logger will be passed to the
handlers of higher level (ancestor) loggers, in addition to any handlers
attached to this logger. Messages are passed directly to the ancestor
loggers’ handlers - neither the level nor filters of the ancestor loggers in
question are considered.
If this evaluates to false, logging messages are not passed to the handlers
of ancestor loggers.
The constructor sets this attribute to <code class="docutils literal notranslate">True</code>.
<div class="admonition note">
Note
If you attach a handler to a logger and one or more of its
ancestors, it may emit the same record multiple times. In general, you
should not need to attach a handler to more than one logger - if you just
attach it to the appropriate logger which is highest in the logger
hierarchy, then it will see all events logged by all descendant loggers,
provided that their propagate setting is left set to <code class="docutils literal notranslate">True</code>. A common
scenario is to attach handlers only to the root logger, and to let
propagation take care of the rest.
</div>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.setLevel">
Logger.setLevel(level)<a class="headerlink" href="#logging.Logger.setLevel" title="Permalink to this definition">¶</a></dt>
<dd>Sets the threshold for this logger to level. Logging messages which are less
severe than level will be ignored. When a logger is created, the level is set to
<code class="xref py py-const docutils literal notranslate">NOTSET</code> (which causes all messages to be processed when the logger is
the root logger, or delegation to the parent when the logger is a non-root
logger). Note that the root logger is created with level <code class="xref py py-const docutils literal notranslate">WARNING</code>.
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.
See <a class="reference internal" href="#levels">Logging Levels</a> for a list of levels.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.isEnabledFor">
Logger.isEnabledFor(lvl)<a class="headerlink" href="#logging.Logger.isEnabledFor" title="Permalink to this definition">¶</a></dt>
<dd>Indicates if a message of severity lvl would be processed by this logger.
This method checks first the module-level level set by
<code class="docutils literal notranslate">logging.disable(lvl)</code> and then the logger’s effective level as determined
by <a class="reference internal" href="#logging.Logger.getEffectiveLevel" title="logging.Logger.getEffectiveLevel"><code class="xref py py-meth docutils literal notranslate">getEffectiveLevel()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.getEffectiveLevel">
Logger.getEffectiveLevel()<a class="headerlink" href="#logging.Logger.getEffectiveLevel" title="Permalink to this definition">¶</a></dt>
<dd>Indicates the effective level for this logger. If a value other than
<code class="xref py py-const docutils literal notranslate">NOTSET</code> has been set using <a class="reference internal" href="#logging.Logger.setLevel" title="logging.Logger.setLevel"><code class="xref py py-meth docutils literal notranslate">setLevel()</code></a>, it is returned. Otherwise,
the hierarchy is traversed towards the root until a value other than
<code class="xref py py-const docutils literal notranslate">NOTSET</code> is found, and that value is returned. The value returned is
an integer, typically one of <code class="xref py py-const docutils literal notranslate">logging.DEBUG</code>, <code class="xref py py-const docutils literal notranslate">logging.INFO</code>
etc.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.getChild">
Logger.getChild(suffix)<a class="headerlink" href="#logging.Logger.getChild" title="Permalink to this definition">¶</a></dt>
<dd>Returns a logger which is a descendant to this logger, as determined by the suffix.
Thus, <code class="docutils literal notranslate">logging.getLogger('abc').getChild('def.ghi')</code> would return the same
logger as would be returned by <code class="docutils literal notranslate">logging.getLogger('abc.def.ghi')</code>. This is a
convenience method, useful when the parent logger is named using e.g. <code class="docutils literal notranslate">__name__</code>
rather than a literal string.
<div class="versionadded">
New in version 2.7.
</div>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.debug">
Logger.debug(msg, *args, **kwargs)<a class="headerlink" href="#logging.Logger.debug" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">DEBUG</code> on this logger. The msg is the
message format string, and the args are the arguments which are merged into
msg using the string formatting operator. (Note that this means that you can
use keywords in the format string, together with a single dictionary argument.)
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
<a class="reference internal" href="sys.html#sys.exc_info" title="sys.exc_info"><code class="xref py py-func docutils literal notranslate">sys.exc_info()</code></a>) is provided, it is used; otherwise, <a class="reference internal" href="sys.html#sys.exc_info" title="sys.exc_info"><code class="xref py py-func docutils literal notranslate">sys.exc_info()</code></a>
is called to get the exception information.
The second 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:
<div class="highlight-default notranslate"><div class="highlight"><pre>FORMAT = &#39;%(asctime)-15s %(clientip)s %(user)-8s %(message)s&#39;
logging.basicConfig(format=FORMAT)
d = {&#39;clientip&#39;: &#39;192.168.0.1&#39;, &#39;user&#39;: &#39;fbloggs&#39;}
logger = logging.getLogger(&#39;tcpserver&#39;)
logger.warning(&#39;Protocol problem: %s&#39;, &#39;connection reset&#39;, extra=d)
</pre></div>
</div>
would print something like
<div class="highlight-default notranslate"><div class="highlight"><pre>2006-02-08 22:20:02,165 192.168.0.1 fbloggs Protocol problem: connection reset
</pre></div>
</div>
The keys in the dictionary passed in extra should not clash with the keys used
by the logging system. (See the <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> 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 <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> 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
<a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a>s would be used with particular <code class="xref py py-class docutils literal notranslate">Handler</code>s.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.info">
Logger.info(msg, *args, **kwargs)<a class="headerlink" href="#logging.Logger.info" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">INFO</code> on this logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.warning">
Logger.warning(msg, *args, **kwargs)<a class="headerlink" href="#logging.Logger.warning" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">WARNING</code> on this logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.error">
Logger.error(msg, *args, **kwargs)<a class="headerlink" href="#logging.Logger.error" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">ERROR</code> on this logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.critical">
Logger.critical(msg, *args, **kwargs)<a class="headerlink" href="#logging.Logger.critical" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">CRITICAL</code> on this logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.log">
Logger.log(lvl, msg, *args, **kwargs)<a class="headerlink" href="#logging.Logger.log" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with integer level lvl on this logger. The other arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.exception">
Logger.exception(msg, *args, **kwargs)<a class="headerlink" href="#logging.Logger.exception" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">ERROR</code> on this logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>, except that any passed exc_info is not
inspected. Exception info is always added to the logging message. This method
should only be called from an exception handler.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.addFilter">
Logger.addFilter(filter)<a class="headerlink" href="#logging.Logger.addFilter" title="Permalink to this definition">¶</a></dt>
<dd>Adds the specified filter filter to this logger.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.removeFilter">
Logger.removeFilter(filter)<a class="headerlink" href="#logging.Logger.removeFilter" title="Permalink to this definition">¶</a></dt>
<dd>Removes the specified filter filter from this logger.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.filter">
Logger.filter(record)<a class="headerlink" href="#logging.Logger.filter" title="Permalink to this definition">¶</a></dt>
<dd>Applies this logger’s filters to the record and returns a true value if the
record is to be processed. The filters are consulted in turn, until one of
them returns a false value. If none of them return a false value, the record
will be processed (passed to handlers). If one returns a false value, no
further processing of the record occurs.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.addHandler">
Logger.addHandler(hdlr)<a class="headerlink" href="#logging.Logger.addHandler" title="Permalink to this definition">¶</a></dt>
<dd>Adds the specified handler hdlr to this logger.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.removeHandler">
Logger.removeHandler(hdlr)<a class="headerlink" href="#logging.Logger.removeHandler" title="Permalink to this definition">¶</a></dt>
<dd>Removes the specified handler hdlr from this logger.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.findCaller">
Logger.findCaller()<a class="headerlink" href="#logging.Logger.findCaller" title="Permalink to this definition">¶</a></dt>
<dd>Finds the caller’s source filename and line number. Returns the filename, line
number and function name as a 3-element tuple.
<div class="versionchanged">
Changed in version 2.4: The function name was added. In earlier versions, the filename and line
number were returned as a 2-element tuple.
</div>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.handle">
Logger.handle(record)<a class="headerlink" href="#logging.Logger.handle" title="Permalink to this definition">¶</a></dt>
<dd>Handles a record by passing it to all handlers associated with this logger and
its ancestors (until a false value of propagate is found). This method is used
for unpickled records received from a socket, as well as those created locally.
Logger-level filtering is applied using <a class="reference internal" href="#logging.Logger.filter" title="logging.Logger.filter"><code class="xref py py-meth docutils literal notranslate">filter()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Logger.makeRecord">
Logger.makeRecord(name, lvl, fn, lno, msg, args, exc_info, func=None, extra=None)<a class="headerlink" href="#logging.Logger.makeRecord" title="Permalink to this definition">¶</a></dt>
<dd>This is a factory method which can be overridden in subclasses to create
specialized <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> instances.
<div class="versionchanged">
Changed in version 2.5: func and extra were added.
</div>
</dd></dl>

</section>
<section id="logging-levels">
<h2>15.7.2. Logging Levels<a class="headerlink" href="#logging-levels" title="Permalink to this headline">¶</a></h2>
The numeric values of logging levels are given in the following table. These are
primarily of interest if you want to define your own levels, and need them to
have specific values relative to the predefined levels. If you define a level
with the same numeric value, it overwrites the predefined value; the predefined
name is lost.
<table class="docutils align-default">
<colgroup>
<col style="width: 48%" />
<col style="width: 52%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head">Level</th>
<th class="head">Numeric value</th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><code class="docutils literal notranslate">CRITICAL</code></td>
<td>50</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate">ERROR</code></td>
<td>40</td>
</tr>
<tr class="row-even"><td><code class="docutils literal notranslate">WARNING</code></td>
<td>30</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate">INFO</code></td>
<td>20</td>
</tr>
<tr class="row-even"><td><code class="docutils literal notranslate">DEBUG</code></td>
<td>10</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate">NOTSET</code></td>
<td>0</td>
</tr>
</tbody>
</table>
</section>
<section id="handler-objects">
<h2>15.7.3. Handler Objects<a class="headerlink" href="#handler-objects" title="Permalink to this headline">¶</a></h2>
Handlers have the following attributes and methods. Note that <code class="xref py py-class docutils literal notranslate">Handler</code>
is never instantiated directly; this class acts as a base for more useful
subclasses. However, the <code class="xref py py-meth docutils literal notranslate">__init__()</code> method in subclasses needs to call
<a class="reference internal" href="#logging.Handler.__init__" title="logging.Handler.__init__"><code class="xref py py-meth docutils literal notranslate">Handler.__init__()</code></a>.
<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.__init__">
Handler.__init__(level=NOTSET)<a class="headerlink" href="#logging.Handler.__init__" title="Permalink to this definition">¶</a></dt>
<dd>Initializes the <code class="xref py py-class docutils literal notranslate">Handler</code> instance by setting its level, setting the list
of filters to the empty list and creating a lock (using <a class="reference internal" href="#logging.Handler.createLock" title="logging.Handler.createLock"><code class="xref py py-meth docutils literal notranslate">createLock()</code></a>) for
serializing access to an I/O mechanism.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.createLock">
Handler.createLock()<a class="headerlink" href="#logging.Handler.createLock" title="Permalink to this definition">¶</a></dt>
<dd>Initializes a thread lock which can be used to serialize access to underlying
I/O functionality which may not be threadsafe.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.acquire">
Handler.acquire()<a class="headerlink" href="#logging.Handler.acquire" title="Permalink to this definition">¶</a></dt>
<dd>Acquires the thread lock created with <a class="reference internal" href="#logging.Handler.createLock" title="logging.Handler.createLock"><code class="xref py py-meth docutils literal notranslate">createLock()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.release">
Handler.release()<a class="headerlink" href="#logging.Handler.release" title="Permalink to this definition">¶</a></dt>
<dd>Releases the thread lock acquired with <a class="reference internal" href="#logging.Handler.acquire" title="logging.Handler.acquire"><code class="xref py py-meth docutils literal notranslate">acquire()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.setLevel">
Handler.setLevel(level)<a class="headerlink" href="#logging.Handler.setLevel" title="Permalink to this definition">¶</a></dt>
<dd>Sets the threshold for this handler to level. Logging messages which are less
severe than level will be ignored. When a handler is created, the level is set
to <code class="xref py py-const docutils literal notranslate">NOTSET</code> (which causes all messages to be processed).
See <a class="reference internal" href="#levels">Logging Levels</a> for a list of levels.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.setFormatter">
Handler.setFormatter(fmt)<a class="headerlink" href="#logging.Handler.setFormatter" title="Permalink to this definition">¶</a></dt>
<dd>Sets the <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> for this handler to fmt.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.addFilter">
Handler.addFilter(filter)<a class="headerlink" href="#logging.Handler.addFilter" title="Permalink to this definition">¶</a></dt>
<dd>Adds the specified filter filter to this handler.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.removeFilter">
Handler.removeFilter(filter)<a class="headerlink" href="#logging.Handler.removeFilter" title="Permalink to this definition">¶</a></dt>
<dd>Removes the specified filter filter from this handler.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.filter">
Handler.filter(record)<a class="headerlink" href="#logging.Handler.filter" title="Permalink to this definition">¶</a></dt>
<dd>Applies this handler’s filters to the record and returns a true value if the
record is to be processed. The filters are consulted in turn, until one of
them returns a false value. If none of them return a false value, the record
will be emitted. If one returns a false value, the handler will not emit the
record.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.flush">
Handler.flush()<a class="headerlink" href="#logging.Handler.flush" title="Permalink to this definition">¶</a></dt>
<dd>Ensure all logging output has been flushed. This version does nothing and is
intended to be implemented by subclasses.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.close">
Handler.close()<a class="headerlink" href="#logging.Handler.close" title="Permalink to this definition">¶</a></dt>
<dd>Tidy up any resources used by the handler. This version does no output but
removes the handler from an internal list of handlers which is closed when
<a class="reference internal" href="#logging.shutdown" title="logging.shutdown"><code class="xref py py-func docutils literal notranslate">shutdown()</code></a> is called. Subclasses should ensure that this gets called
from overridden <a class="reference internal" href="#logging.Handler.close" title="logging.Handler.close"><code class="xref py py-meth docutils literal notranslate">close()</code></a> methods.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.handle">
Handler.handle(record)<a class="headerlink" href="#logging.Handler.handle" title="Permalink to this definition">¶</a></dt>
<dd>Conditionally emits the specified logging record, depending on filters which may
have been added to the handler. Wraps the actual emission of the record with
acquisition/release of the I/O thread lock.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.handleError">
Handler.handleError(record)<a class="headerlink" href="#logging.Handler.handleError" title="Permalink to this definition">¶</a></dt>
<dd>This method should be called from handlers when an exception is encountered
during an <a class="reference internal" href="#logging.Handler.emit" title="logging.Handler.emit"><code class="xref py py-meth docutils literal notranslate">emit()</code></a> call. If the module-level attribute
<code class="docutils literal notranslate">raiseExceptions</code> is <code class="docutils literal notranslate">False</code>, exceptions get silently ignored. This is
what is mostly wanted for a logging system - most users will not care about
errors in the logging system, they are more interested in application
errors. You could, however, replace this with a custom handler if you wish.
The specified record is the one which was being processed when the exception
occurred. (The default value of <code class="docutils literal notranslate">raiseExceptions</code> is <code class="docutils literal notranslate">True</code>, as that is
more useful during development).
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.format">
Handler.format(record)<a class="headerlink" href="#logging.Handler.format" title="Permalink to this definition">¶</a></dt>
<dd>Do formatting for a record - if a formatter is set, use it. Otherwise, use the
default formatter for the module.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Handler.emit">
Handler.emit(record)<a class="headerlink" href="#logging.Handler.emit" title="Permalink to this definition">¶</a></dt>
<dd>Do whatever it takes to actually log the specified logging record. This version
is intended to be implemented by subclasses and so raises a
<code class="xref py py-exc docutils literal notranslate">NotImplementedError</code>.
</dd></dl>

For a list of handlers included as standard, see <a class="reference internal" href="logging.handlers.html#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate">logging.handlers</code></a>.
</section>
<section id="formatter-objects">
<h2>15.7.4. Formatter Objects<a class="headerlink" href="#formatter-objects" title="Permalink to this headline">¶</a></h2>
<a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> objects have the following attributes and methods. They are
responsible for converting a <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> to (usually) a string which can
be interpreted by either a human or an external system. The base
<a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> allows a formatting string to be specified. If none is
supplied, the default value of <code class="docutils literal notranslate">'%(message)s'</code> is used, which just includes
the message in the logging call. To have additional items of information in the
formatted output (such as a timestamp), keep reading.
A Formatter can be initialized with a format string which makes use of knowledge
of the <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> attributes - such as the default value mentioned above
making use of the fact that the user’s message and arguments are pre-formatted
into a <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a>’s message attribute. This format string contains
standard Python %-style mapping keys. See section <a class="reference internal" href="stdtypes.html#string-formatting">String Formatting Operations</a>
for more information on string formatting.
The useful mapping keys in a <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> are given in the section on
<a class="reference internal" href="#logrecord-attributes">LogRecord attributes</a>.
<dl class="py class">
<dt class="sig sig-object py" id="logging.Formatter">
class logging.Formatter(fmt=None, datefmt=None)<a class="headerlink" href="#logging.Formatter" title="Permalink to this definition">¶</a></dt>
<dd>Returns a new instance of the <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> class. The instance is
initialized with a format string for the message as a whole, as well as a
format string for the date/time portion of a message. If no fmt is
specified, <code class="docutils literal notranslate">'%(message)s'</code> is used. If no datefmt is specified, the
ISO8601 date format is used.
<dl class="py method">
<dt class="sig sig-object py" id="logging.Formatter.format">
format(record)<a class="headerlink" href="#logging.Formatter.format" title="Permalink to this definition">¶</a></dt>
<dd>The record’s attribute dictionary is used as the operand to a string
formatting operation. Returns the resulting string. Before formatting the
dictionary, a couple of preparatory steps are carried out. The message
attribute of the record is computed using msg % args. If the
formatting string contains <code class="docutils literal notranslate">'(asctime)'</code>, <a class="reference internal" href="#logging.Formatter.formatTime" title="logging.Formatter.formatTime"><code class="xref py py-meth docutils literal notranslate">formatTime()</code></a> is called
to format the event time. If there is exception information, it is
formatted using <a class="reference internal" href="#logging.Formatter.formatException" title="logging.Formatter.formatException"><code class="xref py py-meth docutils literal notranslate">formatException()</code></a> and appended to the message. Note
that the formatted exception information is cached in attribute
exc_text. This is useful because the exception information can be
pickled and sent across the wire, but you should be careful if you have
more than one <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> subclass which customizes the formatting
of exception information. In this case, you will have to clear the cached
value after a formatter has done its formatting, so that the next
formatter to handle the event doesn’t use the cached value but
recalculates it afresh.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Formatter.formatTime">
formatTime(record, datefmt=None)<a class="headerlink" href="#logging.Formatter.formatTime" title="Permalink to this definition">¶</a></dt>
<dd>This method should be called from <a class="reference internal" href="functions.html#format" title="format"><code class="xref py py-meth docutils literal notranslate">format()</code></a> by a formatter which
wants to make use of a formatted time. This method can be overridden in
formatters to provide for any specific requirement, but the basic behavior
is as follows: if datefmt (a string) is specified, it is used with
<a class="reference internal" href="time.html#time.strftime" title="time.strftime"><code class="xref py py-func docutils literal notranslate">time.strftime()</code></a> to format the creation time of the
record. Otherwise, the ISO8601 format is used. The resulting string is
returned.
This function uses a user-configurable function to convert the creation
time to a tuple. By default, <a class="reference internal" href="time.html#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate">time.localtime()</code></a> is used; to change
this for a particular formatter instance, set the <code class="docutils literal notranslate">converter</code> attribute
to a function with the same signature as <a class="reference internal" href="time.html#time.localtime" title="time.localtime"><code class="xref py py-func docutils literal notranslate">time.localtime()</code></a> or
<a class="reference internal" href="time.html#time.gmtime" title="time.gmtime"><code class="xref py py-func docutils literal notranslate">time.gmtime()</code></a>. To change it for all formatters, for example if you
want all logging times to be shown in GMT, set the <code class="docutils literal notranslate">converter</code>
attribute in the <code class="docutils literal notranslate">Formatter</code> class.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="logging.Formatter.formatException">
formatException(exc_info)<a class="headerlink" href="#logging.Formatter.formatException" title="Permalink to this definition">¶</a></dt>
<dd>Formats the specified exception information (a standard exception tuple as
returned by <a class="reference internal" href="sys.html#sys.exc_info" title="sys.exc_info"><code class="xref py py-func docutils literal notranslate">sys.exc_info()</code></a>) as a string. This default implementation
just uses <a class="reference internal" href="traceback.html#traceback.print_exception" title="traceback.print_exception"><code class="xref py py-func docutils literal notranslate">traceback.print_exception()</code></a>. The resulting string is
returned.
</dd></dl>

</dd></dl>

</section>
<section id="filter-objects">
<h2>15.7.5. Filter Objects<a class="headerlink" href="#filter-objects" title="Permalink to this headline">¶</a></h2>
<code class="docutils literal notranslate">Filters</code> can be used by <code class="docutils literal notranslate">Handlers</code> and <code class="docutils literal notranslate">Loggers</code> for more sophisticated
filtering than is provided by levels. The base filter class only allows events
which are below a certain point in the logger hierarchy. For example, a filter
initialized with ‘A.B’ will allow events logged by loggers ‘A.B’, ‘A.B.C’,
‘A.B.C.D’, ‘A.B.D’ etc. but not ‘A.BB’, ‘B.A.B’ etc. If initialized with the
empty string, all events are passed.
<dl class="py class">
<dt class="sig sig-object py" id="logging.Filter">
class logging.Filter(name='')<a class="headerlink" href="#logging.Filter" title="Permalink to this definition">¶</a></dt>
<dd>Returns an instance of the <a class="reference internal" href="#logging.Filter" title="logging.Filter"><code class="xref py py-class docutils literal notranslate">Filter</code></a> class. If name is specified, it
names a logger which, together with its children, will have its events allowed
through the filter. If name is the empty string, allows every event.
<dl class="py method">
<dt class="sig sig-object py" id="logging.Filter.filter">
filter(record)<a class="headerlink" href="#logging.Filter.filter" title="Permalink to this definition">¶</a></dt>
<dd>Is the specified record to be logged? Returns zero for no, nonzero for
yes. If deemed appropriate, the record may be modified in-place by this
method.
</dd></dl>

</dd></dl>

Note that filters attached to handlers are consulted before an event is
emitted by the handler, whereas filters attached to loggers are consulted
whenever an event is logged (using <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>, <a class="reference internal" href="#logging.info" title="logging.info"><code class="xref py py-meth docutils literal notranslate">info()</code></a>,
etc.), before sending an event to handlers. This means that events which have
been generated by descendant loggers will not be filtered by a logger’s filter
setting, unless the filter has also been applied to those descendant loggers.
You don’t actually need to subclass <code class="docutils literal notranslate">Filter</code>: you can pass any instance
which has a <code class="docutils literal notranslate">filter</code> method with the same semantics.
Although filters are used primarily to filter records based on more
sophisticated criteria than levels, they get to see every record which is
processed by the handler or logger they’re attached to: this can be useful if
you want to do things like counting how many records were processed by a
particular logger or handler, or adding, changing or removing attributes in
the LogRecord being processed. Obviously changing the LogRecord needs to be
done with some care, but it does allow the injection of contextual information
into logs (see <a class="reference internal" href="../howto/logging-cookbook.html#filters-contextual">Using Filters to impart contextual information</a>).
</section>
<section id="logrecord-objects">
<h2>15.7.6. LogRecord Objects<a class="headerlink" href="#logrecord-objects" title="Permalink to this headline">¶</a></h2>
<a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> instances are created automatically by the <a class="reference internal" href="#logging.Logger" title="logging.Logger"><code class="xref py py-class docutils literal notranslate">Logger</code></a>
every time something is logged, and can be created manually via
<a class="reference internal" href="#logging.makeLogRecord" title="logging.makeLogRecord"><code class="xref py py-func docutils literal notranslate">makeLogRecord()</code></a> (for example, from a pickled event received over the
wire).
<dl class="py class">
<dt class="sig sig-object py" id="logging.LogRecord">
class logging.LogRecord(name, level, pathname, lineno, msg, args, exc_info, func=None)<a class="headerlink" href="#logging.LogRecord" title="Permalink to this definition">¶</a></dt>
<dd>Contains all the information pertinent to the event being logged.
The primary information is passed in <code class="xref py py-attr docutils literal notranslate">msg</code> and <code class="xref py py-attr docutils literal notranslate">args</code>, which
are combined using <code class="docutils literal notranslate">msg % args</code> to create the <code class="xref py py-attr docutils literal notranslate">message</code> field of the
record.
<dl class="field-list simple">
<dt class="field-odd">Parameters</dt>
<dd class="field-odd"><ul class="simple">
<li>name – The name of the logger used to log the event represented by
this LogRecord. Note that this name will always have this
value, even though it may be emitted by a handler attached to
a different (ancestor) logger.</li>
<li>level – The numeric level of the logging event (one of DEBUG, INFO etc.)
Note that this is converted to two attributes of the LogRecord:
<code class="docutils literal notranslate">levelno</code> for the numeric value and <code class="docutils literal notranslate">levelname</code> for the
corresponding level name.</li>
<li>pathname – The full pathname of the source file where the logging call
was made.</li>
<li>lineno – The line number in the source file where the logging call was
made.</li>
<li>msg – The event description message, possibly a format string with
placeholders for variable data.</li>
<li>args – Variable data to merge into the msg argument to obtain the
event description.</li>
<li>exc_info – An exception tuple with the current exception information,
or <code class="docutils literal notranslate">None</code> if no exception information is available.</li>
<li>func – The name of the function or method from which the logging call
was invoked.</li>
</ul>
</dd>
</dl>
<div class="versionchanged">
Changed in version 2.5: func was added.
</div>
<dl class="py method">
<dt class="sig sig-object py" id="logging.LogRecord.getMessage">
getMessage()<a class="headerlink" href="#logging.LogRecord.getMessage" title="Permalink to this definition">¶</a></dt>
<dd>Returns the message for this <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> instance after merging any
user-supplied arguments with the message. If the user-supplied message
argument to the logging call is not a string, <a class="reference internal" href="functions.html#str" title="str"><code class="xref py py-func docutils literal notranslate">str()</code></a> is called on it to
convert it to a string. This allows use of user-defined classes as
messages, whose <code class="docutils literal notranslate">__str__</code> method can return the actual format string to
be used.
</dd></dl>

</dd></dl>

</section>
<section id="logrecord-attributes">
<h2>15.7.7. LogRecord attributes<a class="headerlink" href="#logrecord-attributes" title="Permalink to this headline">¶</a></h2>
The LogRecord has a number of attributes, most of which are derived from the
parameters to the constructor. (Note that the names do not always correspond
exactly between the LogRecord constructor parameters and the LogRecord
attributes.) These attributes can be used to merge data from the record into
the format string. The following table lists (in alphabetical order) the
attribute names, their meanings and the corresponding placeholder in a %-style
format string.
<table class="docutils align-default">
<colgroup>
<col style="width: 18%" />
<col style="width: 28%" />
<col style="width: 53%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head">Attribute name</th>
<th class="head">Format</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td>args</td>
<td>You shouldn’t need to
format this yourself.</td>
<td>The tuple of arguments merged into <code class="docutils literal notranslate">msg</code> to
produce <code class="docutils literal notranslate">message</code>, or a dict whose values
are used for the merge (when there is only one
argument, and it is a dictionary).</td>
</tr>
<tr class="row-odd"><td>asctime</td>
<td><code class="docutils literal notranslate">%(asctime)s</code></td>
<td>Human-readable time when the
<a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> was created. By default
this is of the form ‘2003-07-08 16:49:45,896’
(the numbers after the comma are millisecond
portion of the time).</td>
</tr>
<tr class="row-even"><td>created</td>
<td><code class="docutils literal notranslate">%(created)f</code></td>
<td>Time when the <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> was created
(as returned by <a class="reference internal" href="time.html#time.time" title="time.time"><code class="xref py py-func docutils literal notranslate">time.time()</code></a>).</td>
</tr>
<tr class="row-odd"><td>exc_info</td>
<td>You shouldn’t need to
format this yourself.</td>
<td>Exception tuple (à la <code class="docutils literal notranslate">sys.exc_info</code>) or,
if no exception has occurred, <code class="docutils literal notranslate">None</code>.</td>
</tr>
<tr class="row-even"><td>filename</td>
<td><code class="docutils literal notranslate">%(filename)s</code></td>
<td>Filename portion of <code class="docutils literal notranslate">pathname</code>.</td>
</tr>
<tr class="row-odd"><td>funcName</td>
<td><code class="docutils literal notranslate">%(funcName)s</code></td>
<td>Name of function containing the logging call.</td>
</tr>
<tr class="row-even"><td>levelname</td>
<td><code class="docutils literal notranslate">%(levelname)s</code></td>
<td>Text logging level for the message
(<code class="docutils literal notranslate">'DEBUG'</code>, <code class="docutils literal notranslate">'INFO'</code>, <code class="docutils literal notranslate">'WARNING'</code>,
<code class="docutils literal notranslate">'ERROR'</code>, <code class="docutils literal notranslate">'CRITICAL'</code>).</td>
</tr>
<tr class="row-odd"><td>levelno</td>
<td><code class="docutils literal notranslate">%(levelno)s</code></td>
<td>Numeric logging level for the message
(<code class="xref py py-const docutils literal notranslate">DEBUG</code>, <code class="xref py py-const docutils literal notranslate">INFO</code>,
<code class="xref py py-const docutils literal notranslate">WARNING</code>, <code class="xref py py-const docutils literal notranslate">ERROR</code>,
<code class="xref py py-const docutils literal notranslate">CRITICAL</code>).</td>
</tr>
<tr class="row-even"><td>lineno</td>
<td><code class="docutils literal notranslate">%(lineno)d</code></td>
<td>Source line number where the logging call was
issued (if available).</td>
</tr>
<tr class="row-odd"><td>module</td>
<td><code class="docutils literal notranslate">%(module)s</code></td>
<td>Module (name portion of <code class="docutils literal notranslate">filename</code>).</td>
</tr>
<tr class="row-even"><td>msecs</td>
<td><code class="docutils literal notranslate">%(msecs)d</code></td>
<td>Millisecond portion of the time when the
<a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> was created.</td>
</tr>
<tr class="row-odd"><td>message</td>
<td><code class="docutils literal notranslate">%(message)s</code></td>
<td>The logged message, computed as <code class="docutils literal notranslate">msg %
args</code>. This is set when
<a class="reference internal" href="#logging.Formatter.format" title="logging.Formatter.format"><code class="xref py py-meth docutils literal notranslate">Formatter.format()</code></a> is invoked.</td>
</tr>
<tr class="row-even"><td>msg</td>
<td>You shouldn’t need to
format this yourself.</td>
<td>The format string passed in the original
logging call. Merged with <code class="docutils literal notranslate">args</code> to
produce <code class="docutils literal notranslate">message</code>, or an arbitrary object
(see <a class="reference internal" href="../howto/logging.html#arbitrary-object-messages">Using arbitrary objects as messages</a>).</td>
</tr>
<tr class="row-odd"><td>name</td>
<td><code class="docutils literal notranslate">%(name)s</code></td>
<td>Name of the logger used to log the call.</td>
</tr>
<tr class="row-even"><td>pathname</td>
<td><code class="docutils literal notranslate">%(pathname)s</code></td>
<td>Full pathname of the source file where the
logging call was issued (if available).</td>
</tr>
<tr class="row-odd"><td>process</td>
<td><code class="docutils literal notranslate">%(process)d</code></td>
<td>Process ID (if available).</td>
</tr>
<tr class="row-even"><td>processName</td>
<td><code class="docutils literal notranslate">%(processName)s</code></td>
<td>Process name (if available).</td>
</tr>
<tr class="row-odd"><td>relativeCreated</td>
<td><code class="docutils literal notranslate">%(relativeCreated)d</code></td>
<td>Time in milliseconds when the LogRecord was
created, relative to the time the logging
module was loaded.</td>
</tr>
<tr class="row-even"><td>thread</td>
<td><code class="docutils literal notranslate">%(thread)d</code></td>
<td>Thread ID (if available).</td>
</tr>
<tr class="row-odd"><td>threadName</td>
<td><code class="docutils literal notranslate">%(threadName)s</code></td>
<td>Thread name (if available).</td>
</tr>
</tbody>
</table>
<div class="versionchanged">
Changed in version 2.5: funcName was added.
</div>
<div class="versionchanged">
Changed in version 2.6: processName was added.
</div>
</section>
<section id="loggeradapter-objects">
<h2>15.7.8. LoggerAdapter Objects<a class="headerlink" href="#loggeradapter-objects" title="Permalink to this headline">¶</a></h2>
<a class="reference internal" href="#logging.LoggerAdapter" title="logging.LoggerAdapter"><code class="xref py py-class docutils literal notranslate">LoggerAdapter</code></a> instances are used to conveniently pass contextual
information into logging calls. For a usage example, see the section on
<a class="reference internal" href="../howto/logging-cookbook.html#context-info">adding contextual information to your logging output</a>.
<div class="versionadded">
New in version 2.6.
</div>
<dl class="py class">
<dt class="sig sig-object py" id="logging.LoggerAdapter">
class logging.LoggerAdapter(logger, extra)<a class="headerlink" href="#logging.LoggerAdapter" title="Permalink to this definition">¶</a></dt>
<dd>Returns an instance of <a class="reference internal" href="#logging.LoggerAdapter" title="logging.LoggerAdapter"><code class="xref py py-class docutils literal notranslate">LoggerAdapter</code></a> initialized with an
underlying <a class="reference internal" href="#logging.Logger" title="logging.Logger"><code class="xref py py-class docutils literal notranslate">Logger</code></a> instance and a dict-like object.
<dl class="py method">
<dt class="sig sig-object py" id="logging.LoggerAdapter.process">
process(msg, kwargs)<a class="headerlink" href="#logging.LoggerAdapter.process" title="Permalink to this definition">¶</a></dt>
<dd>Modifies the message and/or keyword arguments passed to a logging call in
order to insert contextual information. This implementation takes the object
passed as extra to the constructor and adds it to kwargs using key
‘extra’. The return value is a (msg, kwargs) tuple which has the
(possibly modified) versions of the arguments passed in.
</dd></dl>

</dd></dl>

In addition to the above, <a class="reference internal" href="#logging.LoggerAdapter" title="logging.LoggerAdapter"><code class="xref py py-class docutils literal notranslate">LoggerAdapter</code></a> supports the following
methods of <a class="reference internal" href="#logging.Logger" title="logging.Logger"><code class="xref py py-class docutils literal notranslate">Logger</code></a>: <a class="reference internal" href="#logging.Logger.debug" title="logging.Logger.debug"><code class="xref py py-meth docutils literal notranslate">debug()</code></a>, <a class="reference internal" href="#logging.Logger.info" title="logging.Logger.info"><code class="xref py py-meth docutils literal notranslate">info()</code></a>,
<a class="reference internal" href="#logging.Logger.warning" title="logging.Logger.warning"><code class="xref py py-meth docutils literal notranslate">warning()</code></a>, <a class="reference internal" href="#logging.Logger.error" title="logging.Logger.error"><code class="xref py py-meth docutils literal notranslate">error()</code></a>, <a class="reference internal" href="#logging.Logger.exception" title="logging.Logger.exception"><code class="xref py py-meth docutils literal notranslate">exception()</code></a>,
<a class="reference internal" href="#logging.Logger.critical" title="logging.Logger.critical"><code class="xref py py-meth docutils literal notranslate">critical()</code></a>, <a class="reference internal" href="#logging.Logger.log" title="logging.Logger.log"><code class="xref py py-meth docutils literal notranslate">log()</code></a> and <a class="reference internal" href="#logging.Logger.isEnabledFor" title="logging.Logger.isEnabledFor"><code class="xref py py-meth docutils literal notranslate">isEnabledFor()</code></a>.
These methods have the same signatures as their counterparts in <a class="reference internal" href="#logging.Logger" title="logging.Logger"><code class="xref py py-class docutils literal notranslate">Logger</code></a>,
so you can use the two types of instances interchangeably for these calls.
<div class="versionchanged">
Changed in version 2.7: The <a class="reference internal" href="#logging.Logger.isEnabledFor" title="logging.Logger.isEnabledFor"><code class="xref py py-meth docutils literal notranslate">isEnabledFor()</code></a> method was added to <a class="reference internal" href="#logging.LoggerAdapter" title="logging.LoggerAdapter"><code class="xref py py-class docutils literal notranslate">LoggerAdapter</code></a>.
This method delegates to the underlying logger.
</div>
</section>
<section id="thread-safety">
<h2>15.7.9. Thread Safety<a class="headerlink" href="#thread-safety" title="Permalink to this headline">¶</a></h2>
The logging module is intended to be thread-safe without any special work
needing to be done by its clients. It achieves this though using threading
locks; there is one lock to serialize access to the module’s shared data, and
each handler also creates a lock to serialize access to its underlying I/O.
If you are implementing asynchronous signal handlers using the <a class="reference internal" href="signal.html#module-signal" title="signal: Set handlers for asynchronous events."><code class="xref py py-mod docutils literal notranslate">signal</code></a>
module, you may not be able to use logging from within such handlers. This is
because lock implementations in the <a class="reference internal" href="threading.html#module-threading" title="threading: Higher-level threading interface."><code class="xref py py-mod docutils literal notranslate">threading</code></a> module are not always
re-entrant, and so cannot be invoked from such signal handlers.
</section>
<section id="module-level-functions">
<h2>15.7.10. Module-Level Functions<a class="headerlink" href="#module-level-functions" title="Permalink to this headline">¶</a></h2>
In addition to the classes described above, there are a number of module- level
functions.
<dl class="py function">
<dt class="sig sig-object py" id="logging.getLogger">
logging.getLogger([name])<a class="headerlink" href="#logging.getLogger" title="Permalink to this definition">¶</a></dt>
<dd>Return a logger with the specified name or, if no name is specified, return a
logger which is the root logger of the hierarchy. If specified, the name is
typically a dot-separated hierarchical name like “a”, “a.b” or “a.b.c.d”.
Choice of these names is entirely up to the developer who is using logging.
All calls to this function with a given name return the same logger instance.
This means that logger instances never need to be passed between different parts
of an application.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.getLoggerClass">
logging.getLoggerClass()<a class="headerlink" href="#logging.getLoggerClass" title="Permalink to this definition">¶</a></dt>
<dd>Return either the standard <a class="reference internal" href="#logging.Logger" title="logging.Logger"><code class="xref py py-class docutils literal notranslate">Logger</code></a> class, or the last class passed to
<a class="reference internal" href="#logging.setLoggerClass" title="logging.setLoggerClass"><code class="xref py py-func docutils literal notranslate">setLoggerClass()</code></a>. This function may be called from within a new class
definition, to ensure that installing a customized <a class="reference internal" href="#logging.Logger" title="logging.Logger"><code class="xref py py-class docutils literal notranslate">Logger</code></a> class will
not undo customizations already applied by other code. For example:
<div class="highlight-default notranslate"><div class="highlight"><pre>class MyLogger(logging.getLoggerClass()):
 # ... override behaviour here
</pre></div>
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.debug">
logging.debug(msg[, *args[, **kwargs]])<a class="headerlink" href="#logging.debug" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">DEBUG</code> on the root logger. The msg is the
message format string, and the args are the arguments which are merged into
msg using the string formatting operator. (Note that this means that you can
use keywords in the format string, together with a single dictionary argument.)
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
<a class="reference internal" href="sys.html#sys.exc_info" title="sys.exc_info"><code class="xref py py-func docutils literal notranslate">sys.exc_info()</code></a>) is provided, it is used; otherwise, <a class="reference internal" href="sys.html#sys.exc_info" title="sys.exc_info"><code class="xref py py-func docutils literal notranslate">sys.exc_info()</code></a>
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:
<div class="highlight-default notranslate"><div class="highlight"><pre>FORMAT = &quot;%(asctime)-15s %(clientip)s %(user)-8s %(message)s&quot;
logging.basicConfig(format=FORMAT)
d = {&#39;clientip&#39;: &#39;192.168.0.1&#39;, &#39;user&#39;: &#39;fbloggs&#39;}
logging.warning(&quot;Protocol problem: %s&quot;, &quot;connection reset&quot;, extra=d)
</pre></div>
</div>
would print something like:
<div class="highlight-default notranslate"><div class="highlight"><pre>2006-02-08 22:20:02,165 192.168.0.1 fbloggs Protocol problem: connection reset
</pre></div>
</div>
The keys in the dictionary passed in extra should not clash with the keys used
by the logging system. (See the <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> 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 <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> 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
<a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a>s would be used with particular <code class="xref py py-class docutils literal notranslate">Handler</code>s.
<div class="versionchanged">
Changed in version 2.5: extra was added.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.info">
logging.info(msg[, *args[, **kwargs]])<a class="headerlink" href="#logging.info" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">INFO</code> on the root logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-func docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.warning">
logging.warning(msg[, *args[, **kwargs]])<a class="headerlink" href="#logging.warning" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">WARNING</code> on the root logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-func docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.error">
logging.error(msg[, *args[, **kwargs]])<a class="headerlink" href="#logging.error" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">ERROR</code> on the root logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-func docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.critical">
logging.critical(msg[, *args[, **kwargs]])<a class="headerlink" href="#logging.critical" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">CRITICAL</code> on the root logger. The arguments
are interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-func docutils literal notranslate">debug()</code></a>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.exception">
logging.exception(msg[, *args[, **kwargs]])<a class="headerlink" href="#logging.exception" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level <code class="xref py py-const docutils literal notranslate">ERROR</code> on the root logger. The arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-func docutils literal notranslate">debug()</code></a>, except that any passed exc_info is not
inspected. Exception info is always added to the logging message. This
function should only be called from an exception handler.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.log">
logging.log(level, msg[, *args[, **kwargs]])<a class="headerlink" href="#logging.log" title="Permalink to this definition">¶</a></dt>
<dd>Logs a message with level level on the root logger. The other arguments are
interpreted as for <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-func docutils literal notranslate">debug()</code></a>.
<div class="admonition note">
Note
The above module-level convenience functions, which delegate to the
root logger, call <a class="reference internal" href="#logging.basicConfig" title="logging.basicConfig"><code class="xref py py-func docutils literal notranslate">basicConfig()</code></a> to ensure that at least one handler
is available. Because of this, they should not be used in threads,
in versions of Python earlier than 2.7.1 and 3.2, unless at least one
handler has been added to the root logger before the threads are
started. In earlier versions of Python, due to a thread safety shortcoming
in <a class="reference internal" href="#logging.basicConfig" title="logging.basicConfig"><code class="xref py py-func docutils literal notranslate">basicConfig()</code></a>, this can (under rare circumstances) lead to
handlers being added multiple times to the root logger, which can in turn
lead to multiple messages for the same event.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.disable">
logging.disable(lvl)<a class="headerlink" href="#logging.disable" title="Permalink to this definition">¶</a></dt>
<dd>Provides an overriding level lvl for all loggers which takes precedence over
the logger’s own level. When the need arises to temporarily throttle logging
output down across the whole application, this function can be useful. Its
effect is to disable all logging calls of severity lvl and below, so that
if you call it with a value of INFO, then all INFO and DEBUG events would be
discarded, whereas those of severity WARNING and above would be processed
according to the logger’s effective level. If
<code class="docutils literal notranslate">logging.disable(logging.NOTSET)</code> is called, it effectively removes this
overriding level, so that logging output again depends on the effective
levels of individual loggers.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.addLevelName">
logging.addLevelName(lvl, levelName)<a class="headerlink" href="#logging.addLevelName" title="Permalink to this definition">¶</a></dt>
<dd>Associates level lvl with text levelName in an internal dictionary, which is
used to map numeric levels to a textual representation, for example when a
<a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> formats a message. This function can also be used to define
your own levels. The only constraints are that all levels used must be
registered using this function, levels should be positive integers and they
should increase in increasing order of severity.
<div class="admonition note">
Note
If you are thinking of defining your own levels, please see the
section on <a class="reference internal" href="../howto/logging.html#custom-levels">Custom Levels</a>.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.getLevelName">
logging.getLevelName(lvl)<a class="headerlink" href="#logging.getLevelName" title="Permalink to this definition">¶</a></dt>
<dd>Returns the textual representation of logging level lvl. If the level is one
of the predefined levels <code class="xref py py-const docutils literal notranslate">CRITICAL</code>, <code class="xref py py-const docutils literal notranslate">ERROR</code>, <code class="xref py py-const docutils literal notranslate">WARNING</code>,
<code class="xref py py-const docutils literal notranslate">INFO</code> or <code class="xref py py-const docutils literal notranslate">DEBUG</code> then you get the corresponding string. If you
have associated levels with names using <a class="reference internal" href="#logging.addLevelName" title="logging.addLevelName"><code class="xref py py-func docutils literal notranslate">addLevelName()</code></a> then the name you
have associated with lvl is returned. If a numeric value corresponding to one
of the defined levels is passed in, the corresponding string representation is
returned. Otherwise, the string “Level %s” % lvl is returned.
<div class="admonition note">
Note
Integer levels should be used when e.g. setting levels on instances
of <a class="reference internal" href="#logging.Logger" title="logging.Logger"><code class="xref py py-class docutils literal notranslate">Logger</code></a> and handlers. This function is used to convert between
an integer level and the level name displayed in the formatted log output
by means of the <code class="docutils literal notranslate">%(levelname)s</code> format specifier (see
<a class="reference internal" href="#logrecord-attributes">LogRecord attributes</a>).
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.makeLogRecord">
logging.makeLogRecord(attrdict)<a class="headerlink" href="#logging.makeLogRecord" title="Permalink to this definition">¶</a></dt>
<dd>Creates and returns a new <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> instance whose attributes are
defined by attrdict. This function is useful for taking a pickled
<a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> attribute dictionary, sent over a socket, and reconstituting
it as a <a class="reference internal" href="#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate">LogRecord</code></a> instance at the receiving end.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.basicConfig">
logging.basicConfig([**kwargs])<a class="headerlink" href="#logging.basicConfig" title="Permalink to this definition">¶</a></dt>
<dd>Does basic configuration for the logging system by creating a
<a class="reference internal" href="logging.handlers.html#logging.StreamHandler" title="logging.StreamHandler"><code class="xref py py-class docutils literal notranslate">StreamHandler</code></a> with a default <a class="reference internal" href="#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate">Formatter</code></a> and adding it to the
root logger. The functions <a class="reference internal" href="#logging.debug" title="logging.debug"><code class="xref py py-func docutils literal notranslate">debug()</code></a>, <a class="reference internal" href="#logging.info" title="logging.info"><code class="xref py py-func docutils literal notranslate">info()</code></a>, <a class="reference internal" href="#logging.warning" title="logging.warning"><code class="xref py py-func docutils literal notranslate">warning()</code></a>,
<a class="reference internal" href="#logging.error" title="logging.error"><code class="xref py py-func docutils literal notranslate">error()</code></a> and <a class="reference internal" href="#logging.critical" title="logging.critical"><code class="xref py py-func docutils literal notranslate">critical()</code></a> will call <a class="reference internal" href="#logging.basicConfig" title="logging.basicConfig"><code class="xref py py-func docutils literal notranslate">basicConfig()</code></a> automatically
if no handlers are defined for the root logger.
This function does nothing if the root logger already has handlers
configured for it.
<div class="versionchanged">
Changed in version 2.4: Formerly, <a class="reference internal" href="#logging.basicConfig" title="logging.basicConfig"><code class="xref py py-func docutils literal notranslate">basicConfig()</code></a> did not take any keyword arguments.
</div>
<div class="admonition note">
Note
This function should be called from the main thread before other
threads are started. In versions of Python prior to 2.7.1 and 3.2, if
this function is called from multiple threads, it is possible (in rare
circumstances) that a handler will be added to the root logger more than
once, leading to unexpected results such as messages being duplicated in
the log.
</div>
The following keyword arguments are supported.
<table class="docutils align-default">
<colgroup>
<col style="width: 24%" />
<col style="width: 76%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head">Format</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td>filename</td>
<td>Specifies that a FileHandler be created,
using the specified filename, rather than a
StreamHandler.</td>
</tr>
<tr class="row-odd"><td>filemode</td>
<td>If filename is specified, open the file
in this mode. Defaults to <code class="docutils literal notranslate">'a'</code>.</td>
</tr>
<tr class="row-even"><td>format</td>
<td>Use the specified format string for the
handler.</td>
</tr>
<tr class="row-odd"><td>datefmt</td>
<td>Use the specified date/time format, as
accepted by <a class="reference internal" href="time.html#time.strftime" title="time.strftime"><code class="xref py py-func docutils literal notranslate">time.strftime()</code></a>.</td>
</tr>
<tr class="row-even"><td>level</td>
<td>Set the root logger level to the specified
<a class="reference internal" href="#levels">level</a>.</td>
</tr>
<tr class="row-odd"><td>stream</td>
<td>Use the specified stream to initialize the
StreamHandler. Note that this argument is
incompatible with filename - if both are
present, stream is ignored.</td>
</tr>
</tbody>
</table>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.shutdown">
logging.shutdown()<a class="headerlink" href="#logging.shutdown" title="Permalink to this definition">¶</a></dt>
<dd>Informs the logging system to perform an orderly shutdown by flushing and
closing all handlers. This should be called at application exit and no
further use of the logging system should be made after this call.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="logging.setLoggerClass">
logging.setLoggerClass(klass)<a class="headerlink" href="#logging.setLoggerClass" title="Permalink to this definition">¶</a></dt>
<dd>Tells the logging system to use the class klass when instantiating a logger.
The class should define <code class="xref py py-meth docutils literal notranslate">__init__()</code> such that only a name argument is
required, and the <code class="xref py py-meth docutils literal notranslate">__init__()</code> should call <code class="xref py py-meth docutils literal notranslate">Logger.__init__()</code>. This
function is typically called before any loggers are instantiated by applications
which need to use custom logger behavior.
</dd></dl>

</section>
<section id="integration-with-the-warnings-module">
<h2>15.7.11. Integration with the warnings module<a class="headerlink" href="#integration-with-the-warnings-module" title="Permalink to this headline">¶</a></h2>
The <a class="reference internal" href="#logging.captureWarnings" title="logging.captureWarnings"><code class="xref py py-func docutils literal notranslate">captureWarnings()</code></a> function can be used to integrate <a class="reference internal" href="#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate">logging</code></a>
with the <a class="reference internal" href="warnings.html#module-warnings" title="warnings: Issue warning messages and control their disposition."><code class="xref py py-mod docutils literal notranslate">warnings</code></a> module.
<dl class="py function">
<dt class="sig sig-object py" id="logging.captureWarnings">
logging.captureWarnings(capture)<a class="headerlink" href="#logging.captureWarnings" title="Permalink to this definition">¶</a></dt>
<dd>This function is used to turn the capture of warnings by logging on and
off.
If capture is <code class="docutils literal notranslate">True</code>, warnings issued by the <a class="reference internal" href="warnings.html#module-warnings" title="warnings: Issue warning messages and control their disposition."><code class="xref py py-mod docutils literal notranslate">warnings</code></a> module will
be redirected to the logging system. Specifically, a warning will be
formatted using <a class="reference internal" href="warnings.html#warnings.formatwarning" title="warnings.formatwarning"><code class="xref py py-func docutils literal notranslate">warnings.formatwarning()</code></a> and the resulting string
logged to a logger named <code class="docutils literal notranslate">'py.warnings'</code> with a severity of <code class="xref py py-const docutils literal notranslate">WARNING</code>.
If capture is <code class="docutils literal notranslate">False</code>, the redirection of warnings to the logging system
will stop, and warnings will be redirected to their original destinations
(i.e. those in effect before <code class="docutils literal notranslate">captureWarnings(True)</code> was called).
</dd></dl>

<div class="admonition seealso">
See also
<dl class="simple">
<dt>Module <a class="reference internal" href="logging.config.html#module-logging.config" title="logging.config: Configuration of the logging module."><code class="xref py py-mod docutils literal notranslate">logging.config</code></a></dt><dd>Configuration API for the logging module.
</dd>
<dt>Module <a class="reference internal" href="logging.handlers.html#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate">logging.handlers</code></a></dt><dd>Useful handlers included with the logging module.
</dd>
<dt><a class="pep reference external" href="https://www.python.org/dev/peps/pep-0282">PEP 282</a> - A Logging System</dt><dd>The proposal which described this feature for inclusion in the Python standard
library.
</dd>
<dt><a class="reference external" href="https://www.red-dove.com/python_logging.html">Original Python logging package</a></dt><dd>This is the original source for the <a class="reference internal" href="#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate">logging</code></a> package. The version of the
package available from this site is suitable for use with Python 1.5.2, 2.1.x
and 2.2.x, which do not include the <a class="reference internal" href="#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate">logging</code></a> package in the standard
library.
</dd>
</dl>
</div>
</section>
</section>

<div class="clearer"></div>
 </div>
 </div>
 </div>
 <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
 <div class="sphinxsidebarwrapper">
 <h3><a href="../contents.html">Table of Contents</a></h3>
 <ul>
<li><a class="reference internal" href="#">15.7. <code class="xref py py-mod docutils literal notranslate">logging</code> — Logging facility for Python</a><ul>
<li><a class="reference internal" href="#logger-objects">15.7.1. Logger Objects</a></li>
<li><a class="reference internal" href="#logging-levels">15.7.2. Logging Levels</a></li>
<li><a class="reference internal" href="#handler-objects">15.7.3. Handler Objects</a></li>
<li><a class="reference internal" href="#formatter-objects">15.7.4. Formatter Objects</a></li>
<li><a class="reference internal" href="#filter-objects">15.7.5. Filter Objects</a></li>
<li><a class="reference internal" href="#logrecord-objects">15.7.6. LogRecord Objects</a></li>
<li><a class="reference internal" href="#logrecord-attributes">15.7.7. LogRecord attributes</a></li>
<li><a class="reference internal" href="#loggeradapter-objects">15.7.8. LoggerAdapter Objects</a></li>
<li><a class="reference internal" href="#thread-safety">15.7.9. Thread Safety</a></li>
<li><a class="reference internal" href="#module-level-functions">15.7.10. Module-Level Functions</a></li>
<li><a class="reference internal" href="#integration-with-the-warnings-module">15.7.11. Integration with the warnings module</a></li>
</ul>
</li>
</ul>

<h4>Previous topic</h4>
 <a href="getopt.html"
 title="previous chapter">15.6. <code class="xref py py-mod docutils literal notranslate">getopt</code> — C-style parser for command line options</a>
 <h4>Next topic</h4>
 <a href="logging.config.html"
 title="next chapter">15.8. <code class="xref py py-mod docutils literal notranslate">logging.config</code> — Logging configuration</a>
 <div role="note" aria-label="source link">
 <h3>This Page</h3>
 <ul class="this-page-menu">
 <li><a href="../_sources/library/logging.rst.txt"
 rel="nofollow">Show Source</a></li>
 </ul>
 </div>
<div id="searchbox" style="display: none" role="search">
 <h3 id="searchlabel">Quick search</h3>
 <div class="searchformwrapper">
 <form class="search" action="../search.html" method="get">
 <input type="text" name="q" aria-labelledby="searchlabel" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"/>
 <input type="submit" value="Go" />
 </form>
 </div>
</div>
<script>$('#searchbox').show(0);</script>
 </div>
 </div>
 <div class="clearer"></div>
 </div> 
 <div class="related" role="navigation" aria-label="related navigation">
 <h3>Navigation</h3>
 <ul>
 <li class="right" style="margin-right: 10px">
 <a href="../genindex.html" title="General Index"
 >index</a></li>
 <li class="right" >
 <a href="../py-modindex.html" title="Python Module Index"
 >modules</a> |</li>
 <li class="right" >
 <a href="logging.config.html" title="15.8. logging.config — Logging configuration"
 >next</a> |</li>
 <li class="right" >
 <a href="getopt.html" title="15.6. getopt — C-style parser for command line options"
 >previous</a> |</li>
 <li><img src="../_static/py.png" alt=""
 style="vertical-align: middle; margin-top: -1px"/></li>
 <li><a href="https://www.python.org/">Python</a> &#187;</li>
 <li>
 <a href="../index.html">Python 2.7.18 documentation</a> &#187;
 </li>

<li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> &#187;</li>
 <li class="nav-item nav-item-2"><a href="allos.html" >15. Generic Operating System Services</a> &#187;</li>
 <li class="nav-item nav-item-this"><a href="">15.7. <code class="xref py py-mod docutils literal notranslate">logging</code> — Logging facility for Python</a></li> 
 </ul>
 </div> 
 <div class="footer">
 &copy; <a href="../copyright.html">Copyright</a> 1990-2024, Python Software Foundation.
 
 The Python Software Foundation is a non-profit corporation.
 <a href="https://www.python.org/psf/donations/">Please donate.</a>
 
 Last updated on December 09, 2024.
 <a href="../bugs.html">Found a bug</a>?
 
 Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 4.3.2.
 </div>

</body>
</html>

${this.title}

Code Editor : logging.html