<!DOCTYPE html> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8" /> <title>logging.handlers — Logging handlers — Python 3.7.4 documentation</title> <link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <script type="text/javascript" src="../_static/language_data.js"></script> <script type="text/javascript" src="../_static/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 3.7.4 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="getpass — Portable password input" href="getpass.html" /> <link rel="prev" title="logging.config — Logging configuration" href="logging.config.html" /> <link rel="shortcut icon" type="image/png" href="../_static/py.png" /> <link rel="canonical" href="https://docs.python.org/3/library/logging.handlers.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> <script type="text/javascript" src="../_static/switchers.js"></script> <style> @media only screen { table.full-width-table { width: 100%; } } </style> </head><body> <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="getpass.html" title="getpass — Portable password input" accesskey="N">next</a> |</li> <li class="right" > <a href="logging.config.html" title="logging.config — Logging configuration" 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> »</li> <li> <span class="language_switcher_placeholder">en</span> <span class="version_switcher_placeholder">3.7.4</span> <a href="../index.html">Documentation </a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="allos.html" accesskey="U">Generic Operating System Services</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body" role="main"> <div class="section" id="module-logging.handlers"> <span id="logging-handlers-logging-handlers"></span><h1><a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> — Logging handlers<a class="headerlink" href="#module-logging.handlers" title="Permalink to this headline">¶</a></h1> <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.7/Lib/logging/handlers.py">Lib/logging/handlers.py</a></p> <div class="sidebar"> <p class="sidebar-title">Important</p> <p>This page contains only reference information. For tutorials, please see</p> <ul class="simple"> <li><p><a class="reference internal" href="../howto/logging.html#logging-basic-tutorial"><span class="std std-ref">Basic Tutorial</span></a></p></li> <li><p><a class="reference internal" href="../howto/logging.html#logging-advanced-tutorial"><span class="std std-ref">Advanced Tutorial</span></a></p></li> <li><p><a class="reference internal" href="../howto/logging-cookbook.html#logging-cookbook"><span class="std std-ref">Logging Cookbook</span></a></p></li> </ul> </div> <hr class="docutils" /> <p>The following useful handlers are provided in the package. Note that three of the handlers (<a class="reference internal" href="#logging.StreamHandler" title="logging.StreamHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamHandler</span></code></a>, <a class="reference internal" href="#logging.FileHandler" title="logging.FileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">FileHandler</span></code></a> and <a class="reference internal" href="#logging.NullHandler" title="logging.NullHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">NullHandler</span></code></a>) are actually defined in the <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging</span></code></a> module itself, but have been documented here along with the other handlers.</p> <div class="section" id="streamhandler"> <span id="stream-handler"></span><h2>StreamHandler<a class="headerlink" href="#streamhandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.StreamHandler" title="logging.StreamHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamHandler</span></code></a> class, located in the core <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging</span></code></a> package, sends logging output to streams such as <em>sys.stdout</em>, <em>sys.stderr</em> or any file-like object (or, more precisely, any object which supports <code class="xref py py-meth docutils literal notranslate"><span class="pre">write()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code> methods).</p> <dl class="class"> <dt id="logging.StreamHandler"> <em class="property">class </em><code class="descclassname">logging.</code><code class="descname">StreamHandler</code><span class="sig-paren">(</span><em>stream=None</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.StreamHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.StreamHandler" title="logging.StreamHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamHandler</span></code></a> class. If <em>stream</em> is specified, the instance will use it for logging output; otherwise, <em>sys.stderr</em> will be used.</p> <dl class="method"> <dt id="logging.StreamHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.StreamHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>If a formatter is specified, it is used to format the record. The record is then written to the stream with a terminator. If exception information is present, it is formatted using <a class="reference internal" href="traceback.html#traceback.print_exception" title="traceback.print_exception"><code class="xref py py-func docutils literal notranslate"><span class="pre">traceback.print_exception()</span></code></a> and appended to the stream.</p> </dd></dl> <dl class="method"> <dt id="logging.StreamHandler.flush"> <code class="descname">flush</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.StreamHandler.flush" title="Permalink to this definition">¶</a></dt> <dd><p>Flushes the stream by calling its <a class="reference internal" href="#logging.StreamHandler.flush" title="logging.StreamHandler.flush"><code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code></a> method. Note that the <code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code> method is inherited from <a class="reference internal" href="logging.html#logging.Handler" title="logging.Handler"><code class="xref py py-class docutils literal notranslate"><span class="pre">Handler</span></code></a> and so does no output, so an explicit <a class="reference internal" href="#logging.StreamHandler.flush" title="logging.StreamHandler.flush"><code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code></a> call may be needed at times.</p> </dd></dl> <dl class="method"> <dt id="logging.StreamHandler.setStream"> <code class="descname">setStream</code><span class="sig-paren">(</span><em>stream</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.StreamHandler.setStream" title="Permalink to this definition">¶</a></dt> <dd><p>Sets the instance’s stream to the specified value, if it is different. The old stream is flushed before the new stream is set.</p> <dl class="field-list simple"> <dt class="field-odd">Parameters</dt> <dd class="field-odd"><p><strong>stream</strong> – The stream that the handler should use.</p> </dd> <dt class="field-even">Returns</dt> <dd class="field-even"><p>the old stream, if the stream was changed, or <em>None</em> if it wasn’t.</p> </dd> </dl> </dd></dl> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.7.</span></p> </div> </dd></dl> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.2: </span>The <code class="docutils literal notranslate"><span class="pre">StreamHandler</span></code> class now has a <code class="docutils literal notranslate"><span class="pre">terminator</span></code> attribute, default value <code class="docutils literal notranslate"><span class="pre">'\n'</span></code>, which is used as the terminator when writing a formatted record to a stream. If you don’t want this newline termination, you can set the handler instance’s <code class="docutils literal notranslate"><span class="pre">terminator</span></code> attribute to the empty string. In earlier versions, the terminator was hardcoded as <code class="docutils literal notranslate"><span class="pre">'\n'</span></code>.</p> </div> </div> <div class="section" id="filehandler"> <span id="file-handler"></span><h2>FileHandler<a class="headerlink" href="#filehandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.FileHandler" title="logging.FileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">FileHandler</span></code></a> class, located in the core <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging</span></code></a> package, sends logging output to a disk file. It inherits the output functionality from <a class="reference internal" href="#logging.StreamHandler" title="logging.StreamHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">StreamHandler</span></code></a>.</p> <dl class="class"> <dt id="logging.FileHandler"> <em class="property">class </em><code class="descclassname">logging.</code><code class="descname">FileHandler</code><span class="sig-paren">(</span><em>filename</em>, <em>mode='a'</em>, <em>encoding=None</em>, <em>delay=False</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.FileHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.FileHandler" title="logging.FileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">FileHandler</span></code></a> class. The specified file is opened and used as the stream for logging. If <em>mode</em> is not specified, <code class="xref py py-const docutils literal notranslate"><span class="pre">'a'</span></code> is used. If <em>encoding</em> is not <code class="docutils literal notranslate"><span class="pre">None</span></code>, it is used to open the file with that encoding. If <em>delay</em> is true, then file opening is deferred until the first call to <a class="reference internal" href="#logging.FileHandler.emit" title="logging.FileHandler.emit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">emit()</span></code></a>. By default, the file grows indefinitely.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.6: </span>As well as string values, <a class="reference internal" href="pathlib.html#pathlib.Path" title="pathlib.Path"><code class="xref py py-class docutils literal notranslate"><span class="pre">Path</span></code></a> objects are also accepted for the <em>filename</em> argument.</p> </div> <dl class="method"> <dt id="logging.FileHandler.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.FileHandler.close" title="Permalink to this definition">¶</a></dt> <dd><p>Closes the file.</p> </dd></dl> <dl class="method"> <dt id="logging.FileHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.FileHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Outputs the record to the file.</p> </dd></dl> </dd></dl> </div> <div class="section" id="nullhandler"> <span id="null-handler"></span><h2>NullHandler<a class="headerlink" href="#nullhandler" title="Permalink to this headline">¶</a></h2> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.1.</span></p> </div> <p>The <a class="reference internal" href="#logging.NullHandler" title="logging.NullHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">NullHandler</span></code></a> class, located in the core <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging</span></code></a> package, does not do any formatting or output. It is essentially a ‘no-op’ handler for use by library developers.</p> <dl class="class"> <dt id="logging.NullHandler"> <em class="property">class </em><code class="descclassname">logging.</code><code class="descname">NullHandler</code><a class="headerlink" href="#logging.NullHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.NullHandler" title="logging.NullHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">NullHandler</span></code></a> class.</p> <dl class="method"> <dt id="logging.NullHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.NullHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>This method does nothing.</p> </dd></dl> <dl class="method"> <dt id="logging.NullHandler.handle"> <code class="descname">handle</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.NullHandler.handle" title="Permalink to this definition">¶</a></dt> <dd><p>This method does nothing.</p> </dd></dl> <dl class="method"> <dt id="logging.NullHandler.createLock"> <code class="descname">createLock</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.NullHandler.createLock" title="Permalink to this definition">¶</a></dt> <dd><p>This method returns <code class="docutils literal notranslate"><span class="pre">None</span></code> for the lock, since there is no underlying I/O to which access needs to be serialized.</p> </dd></dl> </dd></dl> <p>See <a class="reference internal" href="../howto/logging.html#library-config"><span class="std std-ref">Configuring Logging for a Library</span></a> for more information on how to use <a class="reference internal" href="#logging.NullHandler" title="logging.NullHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">NullHandler</span></code></a>.</p> </div> <div class="section" id="watchedfilehandler"> <span id="watched-file-handler"></span><h2>WatchedFileHandler<a class="headerlink" href="#watchedfilehandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.WatchedFileHandler" title="logging.handlers.WatchedFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">WatchedFileHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, is a <code class="xref py py-class docutils literal notranslate"><span class="pre">FileHandler</span></code> which watches the file it is logging to. If the file changes, it is closed and reopened using the file name.</p> <p>A file change can happen because of usage of programs such as <em>newsyslog</em> and <em>logrotate</em> which perform log file rotation. This handler, intended for use under Unix/Linux, watches the file to see if it has changed since the last emit. (A file is deemed to have changed if its device or inode have changed.) If the file has changed, the old file stream is closed, and the file opened to get a new stream.</p> <p>This handler is not appropriate for use under Windows, because under Windows open log files cannot be moved or renamed - logging opens the files with exclusive locks - and so there is no need for such a handler. Furthermore, <em>ST_INO</em> is not supported under Windows; <a class="reference internal" href="os.html#os.stat" title="os.stat"><code class="xref py py-func docutils literal notranslate"><span class="pre">stat()</span></code></a> always returns zero for this value.</p> <dl class="class"> <dt id="logging.handlers.WatchedFileHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">WatchedFileHandler</code><span class="sig-paren">(</span><em>filename</em>, <em>mode='a'</em>, <em>encoding=None</em>, <em>delay=False</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.WatchedFileHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.WatchedFileHandler" title="logging.handlers.WatchedFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">WatchedFileHandler</span></code></a> class. The specified file is opened and used as the stream for logging. If <em>mode</em> is not specified, <code class="xref py py-const docutils literal notranslate"><span class="pre">'a'</span></code> is used. If <em>encoding</em> is not <code class="docutils literal notranslate"><span class="pre">None</span></code>, it is used to open the file with that encoding. If <em>delay</em> is true, then file opening is deferred until the first call to <a class="reference internal" href="#logging.handlers.WatchedFileHandler.emit" title="logging.handlers.WatchedFileHandler.emit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">emit()</span></code></a>. By default, the file grows indefinitely.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.6: </span>As well as string values, <a class="reference internal" href="pathlib.html#pathlib.Path" title="pathlib.Path"><code class="xref py py-class docutils literal notranslate"><span class="pre">Path</span></code></a> objects are also accepted for the <em>filename</em> argument.</p> </div> <dl class="method"> <dt id="logging.handlers.WatchedFileHandler.reopenIfNeeded"> <code class="descname">reopenIfNeeded</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.WatchedFileHandler.reopenIfNeeded" title="Permalink to this definition">¶</a></dt> <dd><p>Checks to see if the file has changed. If it has, the existing stream is flushed and closed and the file opened again, typically as a precursor to outputting the record to the file.</p> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.6.</span></p> </div> </dd></dl> <dl class="method"> <dt id="logging.handlers.WatchedFileHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.WatchedFileHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Outputs the record to the file, but first calls <a class="reference internal" href="#logging.handlers.WatchedFileHandler.reopenIfNeeded" title="logging.handlers.WatchedFileHandler.reopenIfNeeded"><code class="xref py py-meth docutils literal notranslate"><span class="pre">reopenIfNeeded()</span></code></a> to reopen the file if it has changed.</p> </dd></dl> </dd></dl> </div> <div class="section" id="baserotatinghandler"> <span id="base-rotating-handler"></span><h2>BaseRotatingHandler<a class="headerlink" href="#baserotatinghandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.BaseRotatingHandler" title="logging.handlers.BaseRotatingHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">BaseRotatingHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, is the base class for the rotating file handlers, <a class="reference internal" href="#logging.handlers.RotatingFileHandler" title="logging.handlers.RotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">RotatingFileHandler</span></code></a> and <a class="reference internal" href="#logging.handlers.TimedRotatingFileHandler" title="logging.handlers.TimedRotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">TimedRotatingFileHandler</span></code></a>. You should not need to instantiate this class, but it has attributes and methods you may need to override.</p> <dl class="class"> <dt id="logging.handlers.BaseRotatingHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">BaseRotatingHandler</code><span class="sig-paren">(</span><em>filename</em>, <em>mode</em>, <em>encoding=None</em>, <em>delay=False</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.BaseRotatingHandler" title="Permalink to this definition">¶</a></dt> <dd><p>The parameters are as for <code class="xref py py-class docutils literal notranslate"><span class="pre">FileHandler</span></code>. The attributes are:</p> <dl class="attribute"> <dt id="logging.handlers.BaseRotatingHandler.namer"> <code class="descname">namer</code><a class="headerlink" href="#logging.handlers.BaseRotatingHandler.namer" title="Permalink to this definition">¶</a></dt> <dd><p>If this attribute is set to a callable, the <a class="reference internal" href="#logging.handlers.BaseRotatingHandler.rotation_filename" title="logging.handlers.BaseRotatingHandler.rotation_filename"><code class="xref py py-meth docutils literal notranslate"><span class="pre">rotation_filename()</span></code></a> method delegates to this callable. The parameters passed to the callable are those passed to <a class="reference internal" href="#logging.handlers.BaseRotatingHandler.rotation_filename" title="logging.handlers.BaseRotatingHandler.rotation_filename"><code class="xref py py-meth docutils literal notranslate"><span class="pre">rotation_filename()</span></code></a>.</p> <div class="admonition note"> <p class="admonition-title">Note</p> <p>The namer function is called quite a few times during rollover, so it should be as simple and as fast as possible. It should also return the same output every time for a given input, otherwise the rollover behaviour may not work as expected.</p> </div> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.3.</span></p> </div> </dd></dl> <dl class="attribute"> <dt id="logging.handlers.BaseRotatingHandler.rotator"> <code class="descname">rotator</code><a class="headerlink" href="#logging.handlers.BaseRotatingHandler.rotator" title="Permalink to this definition">¶</a></dt> <dd><p>If this attribute is set to a callable, the <a class="reference internal" href="#logging.handlers.BaseRotatingHandler.rotate" title="logging.handlers.BaseRotatingHandler.rotate"><code class="xref py py-meth docutils literal notranslate"><span class="pre">rotate()</span></code></a> method delegates to this callable. The parameters passed to the callable are those passed to <a class="reference internal" href="#logging.handlers.BaseRotatingHandler.rotate" title="logging.handlers.BaseRotatingHandler.rotate"><code class="xref py py-meth docutils literal notranslate"><span class="pre">rotate()</span></code></a>.</p> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.3.</span></p> </div> </dd></dl> <dl class="method"> <dt id="logging.handlers.BaseRotatingHandler.rotation_filename"> <code class="descname">rotation_filename</code><span class="sig-paren">(</span><em>default_name</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.BaseRotatingHandler.rotation_filename" title="Permalink to this definition">¶</a></dt> <dd><p>Modify the filename of a log file when rotating.</p> <p>This is provided so that a custom filename can be provided.</p> <p>The default implementation calls the ‘namer’ attribute of the handler, if it’s callable, passing the default name to it. If the attribute isn’t callable (the default is <code class="docutils literal notranslate"><span class="pre">None</span></code>), the name is returned unchanged.</p> <dl class="field-list simple"> <dt class="field-odd">Parameters</dt> <dd class="field-odd"><p><strong>default_name</strong> – The default name for the log file.</p> </dd> </dl> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.3.</span></p> </div> </dd></dl> <dl class="method"> <dt id="logging.handlers.BaseRotatingHandler.rotate"> <code class="descname">rotate</code><span class="sig-paren">(</span><em>source</em>, <em>dest</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.BaseRotatingHandler.rotate" title="Permalink to this definition">¶</a></dt> <dd><p>When rotating, rotate the current log.</p> <p>The default implementation calls the ‘rotator’ attribute of the handler, if it’s callable, passing the source and dest arguments to it. If the attribute isn’t callable (the default is <code class="docutils literal notranslate"><span class="pre">None</span></code>), the source is simply renamed to the destination.</p> <dl class="field-list simple"> <dt class="field-odd">Parameters</dt> <dd class="field-odd"><ul class="simple"> <li><p><strong>source</strong> – The source filename. This is normally the base filename, e.g. ‘test.log’.</p></li> <li><p><strong>dest</strong> – The destination filename. This is normally what the source is rotated to, e.g. ‘test.log.1’.</p></li> </ul> </dd> </dl> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.3.</span></p> </div> </dd></dl> </dd></dl> <p>The reason the attributes exist is to save you having to subclass - you can use the same callables for instances of <a class="reference internal" href="#logging.handlers.RotatingFileHandler" title="logging.handlers.RotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">RotatingFileHandler</span></code></a> and <a class="reference internal" href="#logging.handlers.TimedRotatingFileHandler" title="logging.handlers.TimedRotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">TimedRotatingFileHandler</span></code></a>. If either the namer or rotator callable raises an exception, this will be handled in the same way as any other exception during an <code class="xref py py-meth docutils literal notranslate"><span class="pre">emit()</span></code> call, i.e. via the <code class="xref py py-meth docutils literal notranslate"><span class="pre">handleError()</span></code> method of the handler.</p> <p>If you need to make more significant changes to rotation processing, you can override the methods.</p> <p>For an example, see <a class="reference internal" href="../howto/logging-cookbook.html#cookbook-rotator-namer"><span class="std std-ref">Using a rotator and namer to customize log rotation processing</span></a>.</p> </div> <div class="section" id="rotatingfilehandler"> <span id="rotating-file-handler"></span><h2>RotatingFileHandler<a class="headerlink" href="#rotatingfilehandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.RotatingFileHandler" title="logging.handlers.RotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">RotatingFileHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports rotation of disk log files.</p> <dl class="class"> <dt id="logging.handlers.RotatingFileHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">RotatingFileHandler</code><span class="sig-paren">(</span><em>filename</em>, <em>mode='a'</em>, <em>maxBytes=0</em>, <em>backupCount=0</em>, <em>encoding=None</em>, <em>delay=False</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.RotatingFileHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.RotatingFileHandler" title="logging.handlers.RotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">RotatingFileHandler</span></code></a> class. The specified file is opened and used as the stream for logging. If <em>mode</em> is not specified, <code class="docutils literal notranslate"><span class="pre">'a'</span></code> is used. If <em>encoding</em> is not <code class="docutils literal notranslate"><span class="pre">None</span></code>, it is used to open the file with that encoding. If <em>delay</em> is true, then file opening is deferred until the first call to <a class="reference internal" href="#logging.handlers.RotatingFileHandler.emit" title="logging.handlers.RotatingFileHandler.emit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">emit()</span></code></a>. By default, the file grows indefinitely.</p> <p>You can use the <em>maxBytes</em> and <em>backupCount</em> values to allow the file to <em class="dfn">rollover</em> at a predetermined size. When the size is about to be exceeded, the file is closed and a new file is silently opened for output. Rollover occurs whenever the current log file is nearly <em>maxBytes</em> in length; but if either of <em>maxBytes</em> or <em>backupCount</em> is zero, rollover never occurs, so you generally want to set <em>backupCount</em> to at least 1, and have a non-zero <em>maxBytes</em>. When <em>backupCount</em> is non-zero, the system will save old log files by appending the extensions ‘.1’, ‘.2’ etc., to the filename. For example, with a <em>backupCount</em> of 5 and a base file name of <code class="file docutils literal notranslate"><span class="pre">app.log</span></code>, you would get <code class="file docutils literal notranslate"><span class="pre">app.log</span></code>, <code class="file docutils literal notranslate"><span class="pre">app.log.1</span></code>, <code class="file docutils literal notranslate"><span class="pre">app.log.2</span></code>, up to <code class="file docutils literal notranslate"><span class="pre">app.log.5</span></code>. The file being written to is always <code class="file docutils literal notranslate"><span class="pre">app.log</span></code>. When this file is filled, it is closed and renamed to <code class="file docutils literal notranslate"><span class="pre">app.log.1</span></code>, and if files <code class="file docutils literal notranslate"><span class="pre">app.log.1</span></code>, <code class="file docutils literal notranslate"><span class="pre">app.log.2</span></code>, etc. exist, then they are renamed to <code class="file docutils literal notranslate"><span class="pre">app.log.2</span></code>, <code class="file docutils literal notranslate"><span class="pre">app.log.3</span></code> etc. respectively.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.6: </span>As well as string values, <a class="reference internal" href="pathlib.html#pathlib.Path" title="pathlib.Path"><code class="xref py py-class docutils literal notranslate"><span class="pre">Path</span></code></a> objects are also accepted for the <em>filename</em> argument.</p> </div> <dl class="method"> <dt id="logging.handlers.RotatingFileHandler.doRollover"> <code class="descname">doRollover</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.RotatingFileHandler.doRollover" title="Permalink to this definition">¶</a></dt> <dd><p>Does a rollover, as described above.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.RotatingFileHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.RotatingFileHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Outputs the record to the file, catering for rollover as described previously.</p> </dd></dl> </dd></dl> </div> <div class="section" id="timedrotatingfilehandler"> <span id="timed-rotating-file-handler"></span><h2>TimedRotatingFileHandler<a class="headerlink" href="#timedrotatingfilehandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.TimedRotatingFileHandler" title="logging.handlers.TimedRotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">TimedRotatingFileHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports rotation of disk log files at certain timed intervals.</p> <dl class="class"> <dt id="logging.handlers.TimedRotatingFileHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">TimedRotatingFileHandler</code><span class="sig-paren">(</span><em>filename</em>, <em>when='h'</em>, <em>interval=1</em>, <em>backupCount=0</em>, <em>encoding=None</em>, <em>delay=False</em>, <em>utc=False</em>, <em>atTime=None</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.TimedRotatingFileHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.TimedRotatingFileHandler" title="logging.handlers.TimedRotatingFileHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">TimedRotatingFileHandler</span></code></a> class. The specified file is opened and used as the stream for logging. On rotating it also sets the filename suffix. Rotating happens based on the product of <em>when</em> and <em>interval</em>.</p> <p>You can use the <em>when</em> to specify the type of <em>interval</em>. The list of possible values is below. Note that they are not case sensitive.</p> <table class="docutils align-center"> <colgroup> <col style="width: 23%" /> <col style="width: 41%" /> <col style="width: 36%" /> </colgroup> <thead> <tr class="row-odd"><th class="head"><p>Value</p></th> <th class="head"><p>Type of interval</p></th> <th class="head"><p>If/how <em>atTime</em> is used</p></th> </tr> </thead> <tbody> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'S'</span></code></p></td> <td><p>Seconds</p></td> <td><p>Ignored</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'M'</span></code></p></td> <td><p>Minutes</p></td> <td><p>Ignored</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'H'</span></code></p></td> <td><p>Hours</p></td> <td><p>Ignored</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'D'</span></code></p></td> <td><p>Days</p></td> <td><p>Ignored</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">'W0'-'W6'</span></code></p></td> <td><p>Weekday (0=Monday)</p></td> <td><p>Used to compute initial rollover time</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">'midnight'</span></code></p></td> <td><p>Roll over at midnight, if <em>atTime</em> not specified, else at time <em>atTime</em></p></td> <td><p>Used to compute initial rollover time</p></td> </tr> </tbody> </table> <p>When using weekday-based rotation, specify ‘W0’ for Monday, ‘W1’ for Tuesday, and so on up to ‘W6’ for Sunday. In this case, the value passed for <em>interval</em> isn’t used.</p> <p>The system will save old log files by appending extensions to the filename. The extensions are date-and-time based, using the strftime format <code class="docutils literal notranslate"><span class="pre">%Y-%m-%d_%H-%M-%S</span></code> or a leading portion thereof, depending on the rollover interval.</p> <p>When computing the next rollover time for the first time (when the handler is created), the last modification time of an existing log file, or else the current time, is used to compute when the next rotation will occur.</p> <p>If the <em>utc</em> argument is true, times in UTC will be used; otherwise local time is used.</p> <p>If <em>backupCount</em> is nonzero, at most <em>backupCount</em> files will be kept, and if more would be created when rollover occurs, the oldest one is deleted. The deletion logic uses the interval to determine which files to delete, so changing the interval may leave old files lying around.</p> <p>If <em>delay</em> is true, then file opening is deferred until the first call to <a class="reference internal" href="#logging.handlers.TimedRotatingFileHandler.emit" title="logging.handlers.TimedRotatingFileHandler.emit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">emit()</span></code></a>.</p> <p>If <em>atTime</em> is not <code class="docutils literal notranslate"><span class="pre">None</span></code>, it must be a <code class="docutils literal notranslate"><span class="pre">datetime.time</span></code> instance which specifies the time of day when rollover occurs, for the cases where rollover is set to happen “at midnight” or “on a particular weekday”. Note that in these cases, the <em>atTime</em> value is effectively used to compute the <em>initial</em> rollover, and subsequent rollovers would be calculated via the normal interval calculation.</p> <div class="admonition note"> <p class="admonition-title">Note</p> <p>Calculation of the initial rollover time is done when the handler is initialised. Calculation of subsequent rollover times is done only when rollover occurs, and rollover occurs only when emitting output. If this is not kept in mind, it might lead to some confusion. For example, if an interval of “every minute” is set, that does not mean you will always see log files with times (in the filename) separated by a minute; if, during application execution, logging output is generated more frequently than once a minute, <em>then</em> you can expect to see log files with times separated by a minute. If, on the other hand, logging messages are only output once every five minutes (say), then there will be gaps in the file times corresponding to the minutes where no output (and hence no rollover) occurred.</p> </div> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.4: </span><em>atTime</em> parameter was added.</p> </div> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.6: </span>As well as string values, <a class="reference internal" href="pathlib.html#pathlib.Path" title="pathlib.Path"><code class="xref py py-class docutils literal notranslate"><span class="pre">Path</span></code></a> objects are also accepted for the <em>filename</em> argument.</p> </div> <dl class="method"> <dt id="logging.handlers.TimedRotatingFileHandler.doRollover"> <code class="descname">doRollover</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.TimedRotatingFileHandler.doRollover" title="Permalink to this definition">¶</a></dt> <dd><p>Does a rollover, as described above.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.TimedRotatingFileHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.TimedRotatingFileHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Outputs the record to the file, catering for rollover as described above.</p> </dd></dl> </dd></dl> </div> <div class="section" id="sockethandler"> <span id="socket-handler"></span><h2>SocketHandler<a class="headerlink" href="#sockethandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.SocketHandler" title="logging.handlers.SocketHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SocketHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, sends logging output to a network socket. The base class uses a TCP socket.</p> <dl class="class"> <dt id="logging.handlers.SocketHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">SocketHandler</code><span class="sig-paren">(</span><em>host</em>, <em>port</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.SocketHandler" title="logging.handlers.SocketHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SocketHandler</span></code></a> class intended to communicate with a remote machine whose address is given by <em>host</em> and <em>port</em>.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.4: </span>If <code class="docutils literal notranslate"><span class="pre">port</span></code> is specified as <code class="docutils literal notranslate"><span class="pre">None</span></code>, a Unix domain socket is created using the value in <code class="docutils literal notranslate"><span class="pre">host</span></code> - otherwise, a TCP socket is created.</p> </div> <dl class="method"> <dt id="logging.handlers.SocketHandler.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler.close" title="Permalink to this definition">¶</a></dt> <dd><p>Closes the socket.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SocketHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Pickles the record’s attribute dictionary and writes it to the socket in binary format. If there is an error with the socket, silently drops the packet. If the connection was previously lost, re-establishes the connection. To unpickle the record at the receiving end into a <a class="reference internal" href="logging.html#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate"><span class="pre">LogRecord</span></code></a>, use the <a class="reference internal" href="logging.html#logging.makeLogRecord" title="logging.makeLogRecord"><code class="xref py py-func docutils literal notranslate"><span class="pre">makeLogRecord()</span></code></a> function.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SocketHandler.handleError"> <code class="descname">handleError</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler.handleError" title="Permalink to this definition">¶</a></dt> <dd><p>Handles an error which has occurred during <a class="reference internal" href="#logging.handlers.SocketHandler.emit" title="logging.handlers.SocketHandler.emit"><code class="xref py py-meth docutils literal notranslate"><span class="pre">emit()</span></code></a>. The most likely cause is a lost connection. Closes the socket so that we can retry on the next event.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SocketHandler.makeSocket"> <code class="descname">makeSocket</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler.makeSocket" title="Permalink to this definition">¶</a></dt> <dd><p>This is a factory method which allows subclasses to define the precise type of socket they want. The default implementation creates a TCP socket (<a class="reference internal" href="socket.html#socket.SOCK_STREAM" title="socket.SOCK_STREAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">socket.SOCK_STREAM</span></code></a>).</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SocketHandler.makePickle"> <code class="descname">makePickle</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler.makePickle" title="Permalink to this definition">¶</a></dt> <dd><p>Pickles the record’s attribute dictionary in binary format with a length prefix, and returns it ready for transmission across the socket. The details of this operation are equivalent to:</p> <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">data</span> <span class="o">=</span> <span class="n">pickle</span><span class="o">.</span><span class="n">dumps</span><span class="p">(</span><span class="n">record_attr_dict</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span> <span class="n">datalen</span> <span class="o">=</span> <span class="n">struct</span><span class="o">.</span><span class="n">pack</span><span class="p">(</span><span class="s1">'>L'</span><span class="p">,</span> <span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">))</span> <span class="k">return</span> <span class="n">datalen</span> <span class="o">+</span> <span class="n">data</span> </pre></div> </div> <p>Note that pickles aren’t completely secure. If you are concerned about security, you may want to override this method to implement a more secure mechanism. For example, you can sign pickles using HMAC and then verify them on the receiving end, or alternatively you can disable unpickling of global objects on the receiving end.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SocketHandler.send"> <code class="descname">send</code><span class="sig-paren">(</span><em>packet</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler.send" title="Permalink to this definition">¶</a></dt> <dd><p>Send a pickled byte-string <em>packet</em> to the socket. The format of the sent byte-string is as described in the documentation for <a class="reference internal" href="#logging.handlers.SocketHandler.makePickle" title="logging.handlers.SocketHandler.makePickle"><code class="xref py py-meth docutils literal notranslate"><span class="pre">makePickle()</span></code></a>.</p> <p>This function allows for partial sends, which can happen when the network is busy.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SocketHandler.createSocket"> <code class="descname">createSocket</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SocketHandler.createSocket" title="Permalink to this definition">¶</a></dt> <dd><p>Tries to create a socket; on failure, uses an exponential back-off algorithm. On initial failure, the handler will drop the message it was trying to send. When subsequent messages are handled by the same instance, it will not try connecting until some time has passed. The default parameters are such that the initial delay is one second, and if after that delay the connection still can’t be made, the handler will double the delay each time up to a maximum of 30 seconds.</p> <p>This behaviour is controlled by the following handler attributes:</p> <ul class="simple"> <li><p><code class="docutils literal notranslate"><span class="pre">retryStart</span></code> (initial delay, defaulting to 1.0 seconds).</p></li> <li><p><code class="docutils literal notranslate"><span class="pre">retryFactor</span></code> (multiplier, defaulting to 2.0).</p></li> <li><p><code class="docutils literal notranslate"><span class="pre">retryMax</span></code> (maximum delay, defaulting to 30.0 seconds).</p></li> </ul> <p>This means that if the remote listener starts up <em>after</em> the handler has been used, you could lose messages (since the handler won’t even attempt a connection until the delay has elapsed, but just silently drop messages during the delay period).</p> </dd></dl> </dd></dl> </div> <div class="section" id="datagramhandler"> <span id="datagram-handler"></span><h2>DatagramHandler<a class="headerlink" href="#datagramhandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.DatagramHandler" title="logging.handlers.DatagramHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">DatagramHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, inherits from <a class="reference internal" href="#logging.handlers.SocketHandler" title="logging.handlers.SocketHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SocketHandler</span></code></a> to support sending logging messages over UDP sockets.</p> <dl class="class"> <dt id="logging.handlers.DatagramHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">DatagramHandler</code><span class="sig-paren">(</span><em>host</em>, <em>port</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.DatagramHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.DatagramHandler" title="logging.handlers.DatagramHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">DatagramHandler</span></code></a> class intended to communicate with a remote machine whose address is given by <em>host</em> and <em>port</em>.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.4: </span>If <code class="docutils literal notranslate"><span class="pre">port</span></code> is specified as <code class="docutils literal notranslate"><span class="pre">None</span></code>, a Unix domain socket is created using the value in <code class="docutils literal notranslate"><span class="pre">host</span></code> - otherwise, a UDP socket is created.</p> </div> <dl class="method"> <dt id="logging.handlers.DatagramHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.DatagramHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Pickles the record’s attribute dictionary and writes it to the socket in binary format. If there is an error with the socket, silently drops the packet. To unpickle the record at the receiving end into a <a class="reference internal" href="logging.html#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate"><span class="pre">LogRecord</span></code></a>, use the <a class="reference internal" href="logging.html#logging.makeLogRecord" title="logging.makeLogRecord"><code class="xref py py-func docutils literal notranslate"><span class="pre">makeLogRecord()</span></code></a> function.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.DatagramHandler.makeSocket"> <code class="descname">makeSocket</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.DatagramHandler.makeSocket" title="Permalink to this definition">¶</a></dt> <dd><p>The factory method of <a class="reference internal" href="#logging.handlers.SocketHandler" title="logging.handlers.SocketHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SocketHandler</span></code></a> is here overridden to create a UDP socket (<a class="reference internal" href="socket.html#socket.SOCK_DGRAM" title="socket.SOCK_DGRAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">socket.SOCK_DGRAM</span></code></a>).</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.DatagramHandler.send"> <code class="descname">send</code><span class="sig-paren">(</span><em>s</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.DatagramHandler.send" title="Permalink to this definition">¶</a></dt> <dd><p>Send a pickled byte-string to a socket. The format of the sent byte-string is as described in the documentation for <a class="reference internal" href="#logging.handlers.SocketHandler.makePickle" title="logging.handlers.SocketHandler.makePickle"><code class="xref py py-meth docutils literal notranslate"><span class="pre">SocketHandler.makePickle()</span></code></a>.</p> </dd></dl> </dd></dl> </div> <div class="section" id="sysloghandler"> <span id="syslog-handler"></span><h2>SysLogHandler<a class="headerlink" href="#sysloghandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.SysLogHandler" title="logging.handlers.SysLogHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SysLogHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports sending logging messages to a remote or local Unix syslog.</p> <dl class="class"> <dt id="logging.handlers.SysLogHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">SysLogHandler</code><span class="sig-paren">(</span><em>address=('localhost'</em>, <em>SYSLOG_UDP_PORT)</em>, <em>facility=LOG_USER</em>, <em>socktype=socket.SOCK_DGRAM</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SysLogHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.SysLogHandler" title="logging.handlers.SysLogHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SysLogHandler</span></code></a> class intended to communicate with a remote Unix machine whose address is given by <em>address</em> in the form of a <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port)</span></code> tuple. If <em>address</em> is not specified, <code class="docutils literal notranslate"><span class="pre">('localhost',</span> <span class="pre">514)</span></code> is used. The address is used to open a socket. An alternative to providing a <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port)</span></code> tuple is providing an address as a string, for example ‘/dev/log’. In this case, a Unix domain socket is used to send the message to the syslog. If <em>facility</em> is not specified, <code class="xref py py-const docutils literal notranslate"><span class="pre">LOG_USER</span></code> is used. The type of socket opened depends on the <em>socktype</em> argument, which defaults to <a class="reference internal" href="socket.html#socket.SOCK_DGRAM" title="socket.SOCK_DGRAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">socket.SOCK_DGRAM</span></code></a> and thus opens a UDP socket. To open a TCP socket (for use with the newer syslog daemons such as rsyslog), specify a value of <a class="reference internal" href="socket.html#socket.SOCK_STREAM" title="socket.SOCK_STREAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">socket.SOCK_STREAM</span></code></a>.</p> <p>Note that if your server is not listening on UDP port 514, <a class="reference internal" href="#logging.handlers.SysLogHandler" title="logging.handlers.SysLogHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SysLogHandler</span></code></a> may appear not to work. In that case, check what address you should be using for a domain socket - it’s system dependent. For example, on Linux it’s usually ‘/dev/log’ but on OS/X it’s ‘/var/run/syslog’. You’ll need to check your platform and use the appropriate address (you may need to do this check at runtime if your application needs to run on several platforms). On Windows, you pretty much have to use the UDP option.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.2: </span><em>socktype</em> was added.</p> </div> <dl class="method"> <dt id="logging.handlers.SysLogHandler.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SysLogHandler.close" title="Permalink to this definition">¶</a></dt> <dd><p>Closes the socket to the remote host.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SysLogHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SysLogHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>The record is formatted, and then sent to the syslog server. If exception information is present, it is <em>not</em> sent to the server.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.2.1: </span>(See: <a class="reference external" href="https://bugs.python.org/issue12168">bpo-12168</a>.) In earlier versions, the message sent to the syslog daemons was always terminated with a NUL byte, because early versions of these daemons expected a NUL terminated message - even though it’s not in the relevant specification (<span class="target" id="index-0"></span><a class="rfc reference external" href="https://tools.ietf.org/html/rfc5424.html"><strong>RFC 5424</strong></a>). More recent versions of these daemons don’t expect the NUL byte but strip it off if it’s there, and even more recent daemons (which adhere more closely to RFC 5424) pass the NUL byte on as part of the message.</p> <p>To enable easier handling of syslog messages in the face of all these differing daemon behaviours, the appending of the NUL byte has been made configurable, through the use of a class-level attribute, <code class="docutils literal notranslate"><span class="pre">append_nul</span></code>. This defaults to <code class="docutils literal notranslate"><span class="pre">True</span></code> (preserving the existing behaviour) but can be set to <code class="docutils literal notranslate"><span class="pre">False</span></code> on a <code class="docutils literal notranslate"><span class="pre">SysLogHandler</span></code> instance in order for that instance to <em>not</em> append the NUL terminator.</p> </div> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.3: </span>(See: <a class="reference external" href="https://bugs.python.org/issue12419">bpo-12419</a>.) In earlier versions, there was no facility for an “ident” or “tag” prefix to identify the source of the message. This can now be specified using a class-level attribute, defaulting to <code class="docutils literal notranslate"><span class="pre">""</span></code> to preserve existing behaviour, but which can be overridden on a <code class="docutils literal notranslate"><span class="pre">SysLogHandler</span></code> instance in order for that instance to prepend the ident to every message handled. Note that the provided ident must be text, not bytes, and is prepended to the message exactly as is.</p> </div> </dd></dl> <dl class="method"> <dt id="logging.handlers.SysLogHandler.encodePriority"> <code class="descname">encodePriority</code><span class="sig-paren">(</span><em>facility</em>, <em>priority</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SysLogHandler.encodePriority" title="Permalink to this definition">¶</a></dt> <dd><p>Encodes the facility and priority into an integer. You can pass in strings or integers - if strings are passed, internal mapping dictionaries are used to convert them to integers.</p> <p>The symbolic <code class="docutils literal notranslate"><span class="pre">LOG_</span></code> values are defined in <a class="reference internal" href="#logging.handlers.SysLogHandler" title="logging.handlers.SysLogHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SysLogHandler</span></code></a> and mirror the values defined in the <code class="docutils literal notranslate"><span class="pre">sys/syslog.h</span></code> header file.</p> <p><strong>Priorities</strong></p> <table class="docutils align-center"> <colgroup> <col style="width: 63%" /> <col style="width: 37%" /> </colgroup> <thead> <tr class="row-odd"><th class="head"><p>Name (string)</p></th> <th class="head"><p>Symbolic value</p></th> </tr> </thead> <tbody> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">alert</span></code></p></td> <td><p>LOG_ALERT</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">crit</span></code> or <code class="docutils literal notranslate"><span class="pre">critical</span></code></p></td> <td><p>LOG_CRIT</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">debug</span></code></p></td> <td><p>LOG_DEBUG</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">emerg</span></code> or <code class="docutils literal notranslate"><span class="pre">panic</span></code></p></td> <td><p>LOG_EMERG</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">err</span></code> or <code class="docutils literal notranslate"><span class="pre">error</span></code></p></td> <td><p>LOG_ERR</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">info</span></code></p></td> <td><p>LOG_INFO</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">notice</span></code></p></td> <td><p>LOG_NOTICE</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">warn</span></code> or <code class="docutils literal notranslate"><span class="pre">warning</span></code></p></td> <td><p>LOG_WARNING</p></td> </tr> </tbody> </table> <p><strong>Facilities</strong></p> <table class="docutils align-center"> <colgroup> <col style="width: 50%" /> <col style="width: 50%" /> </colgroup> <thead> <tr class="row-odd"><th class="head"><p>Name (string)</p></th> <th class="head"><p>Symbolic value</p></th> </tr> </thead> <tbody> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">auth</span></code></p></td> <td><p>LOG_AUTH</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">authpriv</span></code></p></td> <td><p>LOG_AUTHPRIV</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">cron</span></code></p></td> <td><p>LOG_CRON</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">daemon</span></code></p></td> <td><p>LOG_DAEMON</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">ftp</span></code></p></td> <td><p>LOG_FTP</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">kern</span></code></p></td> <td><p>LOG_KERN</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">lpr</span></code></p></td> <td><p>LOG_LPR</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">mail</span></code></p></td> <td><p>LOG_MAIL</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">news</span></code></p></td> <td><p>LOG_NEWS</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">syslog</span></code></p></td> <td><p>LOG_SYSLOG</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">user</span></code></p></td> <td><p>LOG_USER</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">uucp</span></code></p></td> <td><p>LOG_UUCP</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">local0</span></code></p></td> <td><p>LOG_LOCAL0</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">local1</span></code></p></td> <td><p>LOG_LOCAL1</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">local2</span></code></p></td> <td><p>LOG_LOCAL2</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">local3</span></code></p></td> <td><p>LOG_LOCAL3</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">local4</span></code></p></td> <td><p>LOG_LOCAL4</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">local5</span></code></p></td> <td><p>LOG_LOCAL5</p></td> </tr> <tr class="row-even"><td><p><code class="docutils literal notranslate"><span class="pre">local6</span></code></p></td> <td><p>LOG_LOCAL6</p></td> </tr> <tr class="row-odd"><td><p><code class="docutils literal notranslate"><span class="pre">local7</span></code></p></td> <td><p>LOG_LOCAL7</p></td> </tr> </tbody> </table> </dd></dl> <dl class="method"> <dt id="logging.handlers.SysLogHandler.mapPriority"> <code class="descname">mapPriority</code><span class="sig-paren">(</span><em>levelname</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SysLogHandler.mapPriority" title="Permalink to this definition">¶</a></dt> <dd><p>Maps a logging level name to a syslog priority name. You may need to override this if you are using custom levels, or if the default algorithm is not suitable for your needs. The default algorithm maps <code class="docutils literal notranslate"><span class="pre">DEBUG</span></code>, <code class="docutils literal notranslate"><span class="pre">INFO</span></code>, <code class="docutils literal notranslate"><span class="pre">WARNING</span></code>, <code class="docutils literal notranslate"><span class="pre">ERROR</span></code> and <code class="docutils literal notranslate"><span class="pre">CRITICAL</span></code> to the equivalent syslog names, and all other level names to ‘warning’.</p> </dd></dl> </dd></dl> </div> <div class="section" id="nteventloghandler"> <span id="nt-eventlog-handler"></span><h2>NTEventLogHandler<a class="headerlink" href="#nteventloghandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.NTEventLogHandler" title="logging.handlers.NTEventLogHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">NTEventLogHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports sending logging messages to a local Windows NT, Windows 2000 or Windows XP event log. Before you can use it, you need Mark Hammond’s Win32 extensions for Python installed.</p> <dl class="class"> <dt id="logging.handlers.NTEventLogHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">NTEventLogHandler</code><span class="sig-paren">(</span><em>appname</em>, <em>dllname=None</em>, <em>logtype='Application'</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.NTEventLogHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.NTEventLogHandler" title="logging.handlers.NTEventLogHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">NTEventLogHandler</span></code></a> class. The <em>appname</em> is used to define the application name as it appears in the event log. An appropriate registry entry is created using this name. The <em>dllname</em> should give the fully qualified pathname of a .dll or .exe which contains message definitions to hold in the log (if not specified, <code class="docutils literal notranslate"><span class="pre">'win32service.pyd'</span></code> is used - this is installed with the Win32 extensions and contains some basic placeholder message definitions. Note that use of these placeholders will make your event logs big, as the entire message source is held in the log. If you want slimmer logs, you have to pass in the name of your own .dll or .exe which contains the message definitions you want to use in the event log). The <em>logtype</em> is one of <code class="docutils literal notranslate"><span class="pre">'Application'</span></code>, <code class="docutils literal notranslate"><span class="pre">'System'</span></code> or <code class="docutils literal notranslate"><span class="pre">'Security'</span></code>, and defaults to <code class="docutils literal notranslate"><span class="pre">'Application'</span></code>.</p> <dl class="method"> <dt id="logging.handlers.NTEventLogHandler.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.NTEventLogHandler.close" title="Permalink to this definition">¶</a></dt> <dd><p>At this point, you can remove the application name from the registry as a source of event log entries. However, if you do this, you will not be able to see the events as you intended in the Event Log Viewer - it needs to be able to access the registry to get the .dll name. The current version does not do this.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.NTEventLogHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.NTEventLogHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Determines the message ID, event category and event type, and then logs the message in the NT event log.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.NTEventLogHandler.getEventCategory"> <code class="descname">getEventCategory</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.NTEventLogHandler.getEventCategory" title="Permalink to this definition">¶</a></dt> <dd><p>Returns the event category for the record. Override this if you want to specify your own categories. This version returns 0.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.NTEventLogHandler.getEventType"> <code class="descname">getEventType</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.NTEventLogHandler.getEventType" title="Permalink to this definition">¶</a></dt> <dd><p>Returns the event type for the record. Override this if you want to specify your own types. This version does a mapping using the handler’s typemap attribute, which is set up in <a class="reference internal" href="../reference/datamodel.html#object.__init__" title="object.__init__"><code class="xref py py-meth docutils literal notranslate"><span class="pre">__init__()</span></code></a> to a dictionary which contains mappings for <code class="xref py py-const docutils literal notranslate"><span class="pre">DEBUG</span></code>, <code class="xref py py-const docutils literal notranslate"><span class="pre">INFO</span></code>, <code class="xref py py-const docutils literal notranslate"><span class="pre">WARNING</span></code>, <code class="xref py py-const docutils literal notranslate"><span class="pre">ERROR</span></code> and <code class="xref py py-const docutils literal notranslate"><span class="pre">CRITICAL</span></code>. If you are using your own levels, you will either need to override this method or place a suitable dictionary in the handler’s <em>typemap</em> attribute.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.NTEventLogHandler.getMessageID"> <code class="descname">getMessageID</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.NTEventLogHandler.getMessageID" title="Permalink to this definition">¶</a></dt> <dd><p>Returns the message ID for the record. If you are using your own messages, you could do this by having the <em>msg</em> passed to the logger being an ID rather than a format string. Then, in here, you could use a dictionary lookup to get the message ID. This version returns 1, which is the base message ID in <code class="file docutils literal notranslate"><span class="pre">win32service.pyd</span></code>.</p> </dd></dl> </dd></dl> </div> <div class="section" id="smtphandler"> <span id="smtp-handler"></span><h2>SMTPHandler<a class="headerlink" href="#smtphandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.SMTPHandler" title="logging.handlers.SMTPHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SMTPHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports sending logging messages to an email address via SMTP.</p> <dl class="class"> <dt id="logging.handlers.SMTPHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">SMTPHandler</code><span class="sig-paren">(</span><em>mailhost</em>, <em>fromaddr</em>, <em>toaddrs</em>, <em>subject</em>, <em>credentials=None</em>, <em>secure=None</em>, <em>timeout=1.0</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SMTPHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.SMTPHandler" title="logging.handlers.SMTPHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SMTPHandler</span></code></a> class. The instance is initialized with the from and to addresses and subject line of the email. The <em>toaddrs</em> should be a list of strings. To specify a non-standard SMTP port, use the (host, port) tuple format for the <em>mailhost</em> argument. If you use a string, the standard SMTP port is used. If your SMTP server requires authentication, you can specify a (username, password) tuple for the <em>credentials</em> argument.</p> <p>To specify the use of a secure protocol (TLS), pass in a tuple to the <em>secure</em> argument. This will only be used when authentication credentials are supplied. The tuple should be either an empty tuple, or a single-value tuple with the name of a keyfile, or a 2-value tuple with the names of the keyfile and certificate file. (This tuple is passed to the <a class="reference internal" href="smtplib.html#smtplib.SMTP.starttls" title="smtplib.SMTP.starttls"><code class="xref py py-meth docutils literal notranslate"><span class="pre">smtplib.SMTP.starttls()</span></code></a> method.)</p> <p>A timeout can be specified for communication with the SMTP server using the <em>timeout</em> argument.</p> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.3: </span>The <em>timeout</em> argument was added.</p> </div> <dl class="method"> <dt id="logging.handlers.SMTPHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SMTPHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Formats the record and sends it to the specified addressees.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.SMTPHandler.getSubject"> <code class="descname">getSubject</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.SMTPHandler.getSubject" title="Permalink to this definition">¶</a></dt> <dd><p>If you want to specify a subject line which is record-dependent, override this method.</p> </dd></dl> </dd></dl> </div> <div class="section" id="memoryhandler"> <span id="memory-handler"></span><h2>MemoryHandler<a class="headerlink" href="#memoryhandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.MemoryHandler" title="logging.handlers.MemoryHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">MemoryHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports buffering of logging records in memory, periodically flushing them to a <em class="dfn">target</em> handler. Flushing occurs whenever the buffer is full, or when an event of a certain severity or greater is seen.</p> <p><a class="reference internal" href="#logging.handlers.MemoryHandler" title="logging.handlers.MemoryHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">MemoryHandler</span></code></a> is a subclass of the more general <a class="reference internal" href="#logging.handlers.BufferingHandler" title="logging.handlers.BufferingHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">BufferingHandler</span></code></a>, which is an abstract class. This buffers logging records in memory. Whenever each record is added to the buffer, a check is made by calling <code class="xref py py-meth docutils literal notranslate"><span class="pre">shouldFlush()</span></code> to see if the buffer should be flushed. If it should, then <code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code> is expected to do the flushing.</p> <dl class="class"> <dt id="logging.handlers.BufferingHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">BufferingHandler</code><span class="sig-paren">(</span><em>capacity</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.BufferingHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Initializes the handler with a buffer of the specified capacity. Here, <em>capacity</em> means the number of logging records buffered.</p> <dl class="method"> <dt id="logging.handlers.BufferingHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.BufferingHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Appends the record to the buffer. If <a class="reference internal" href="#logging.handlers.BufferingHandler.shouldFlush" title="logging.handlers.BufferingHandler.shouldFlush"><code class="xref py py-meth docutils literal notranslate"><span class="pre">shouldFlush()</span></code></a> returns true, calls <a class="reference internal" href="#logging.handlers.BufferingHandler.flush" title="logging.handlers.BufferingHandler.flush"><code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code></a> to process the buffer.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.BufferingHandler.flush"> <code class="descname">flush</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.BufferingHandler.flush" title="Permalink to this definition">¶</a></dt> <dd><p>You can override this to implement custom flushing behavior. This version just zaps the buffer to empty.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.BufferingHandler.shouldFlush"> <code class="descname">shouldFlush</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.BufferingHandler.shouldFlush" title="Permalink to this definition">¶</a></dt> <dd><p>Returns true if the buffer is up to capacity. This method can be overridden to implement custom flushing strategies.</p> </dd></dl> </dd></dl> <dl class="class"> <dt id="logging.handlers.MemoryHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">MemoryHandler</code><span class="sig-paren">(</span><em>capacity</em>, <em>flushLevel=ERROR</em>, <em>target=None</em>, <em>flushOnClose=True</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.MemoryHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.MemoryHandler" title="logging.handlers.MemoryHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">MemoryHandler</span></code></a> class. The instance is initialized with a buffer size of <em>capacity</em> (number of records buffered). If <em>flushLevel</em> is not specified, <code class="xref py py-const docutils literal notranslate"><span class="pre">ERROR</span></code> is used. If no <em>target</em> is specified, the target will need to be set using <a class="reference internal" href="#logging.handlers.MemoryHandler.setTarget" title="logging.handlers.MemoryHandler.setTarget"><code class="xref py py-meth docutils literal notranslate"><span class="pre">setTarget()</span></code></a> before this handler does anything useful. If <em>flushOnClose</em> is specified as <code class="docutils literal notranslate"><span class="pre">False</span></code>, then the buffer is <em>not</em> flushed when the handler is closed. If not specified or specified as <code class="docutils literal notranslate"><span class="pre">True</span></code>, the previous behaviour of flushing the buffer will occur when the handler is closed.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.6: </span>The <em>flushOnClose</em> parameter was added.</p> </div> <dl class="method"> <dt id="logging.handlers.MemoryHandler.close"> <code class="descname">close</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.MemoryHandler.close" title="Permalink to this definition">¶</a></dt> <dd><p>Calls <a class="reference internal" href="#logging.handlers.MemoryHandler.flush" title="logging.handlers.MemoryHandler.flush"><code class="xref py py-meth docutils literal notranslate"><span class="pre">flush()</span></code></a>, sets the target to <code class="docutils literal notranslate"><span class="pre">None</span></code> and clears the buffer.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.MemoryHandler.flush"> <code class="descname">flush</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.MemoryHandler.flush" title="Permalink to this definition">¶</a></dt> <dd><p>For a <a class="reference internal" href="#logging.handlers.MemoryHandler" title="logging.handlers.MemoryHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">MemoryHandler</span></code></a>, flushing means just sending the buffered records to the target, if there is one. The buffer is also cleared when this happens. Override if you want different behavior.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.MemoryHandler.setTarget"> <code class="descname">setTarget</code><span class="sig-paren">(</span><em>target</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.MemoryHandler.setTarget" title="Permalink to this definition">¶</a></dt> <dd><p>Sets the target handler for this handler.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.MemoryHandler.shouldFlush"> <code class="descname">shouldFlush</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.MemoryHandler.shouldFlush" title="Permalink to this definition">¶</a></dt> <dd><p>Checks for buffer full or a record at the <em>flushLevel</em> or higher.</p> </dd></dl> </dd></dl> </div> <div class="section" id="httphandler"> <span id="http-handler"></span><h2>HTTPHandler<a class="headerlink" href="#httphandler" title="Permalink to this headline">¶</a></h2> <p>The <a class="reference internal" href="#logging.handlers.HTTPHandler" title="logging.handlers.HTTPHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">HTTPHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports sending logging messages to a Web server, using either <code class="docutils literal notranslate"><span class="pre">GET</span></code> or <code class="docutils literal notranslate"><span class="pre">POST</span></code> semantics.</p> <dl class="class"> <dt id="logging.handlers.HTTPHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">HTTPHandler</code><span class="sig-paren">(</span><em>host</em>, <em>url</em>, <em>method='GET'</em>, <em>secure=False</em>, <em>credentials=None</em>, <em>context=None</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.HTTPHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.HTTPHandler" title="logging.handlers.HTTPHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">HTTPHandler</span></code></a> class. The <em>host</em> can be of the form <code class="docutils literal notranslate"><span class="pre">host:port</span></code>, should you need to use a specific port number. If no <em>method</em> is specified, <code class="docutils literal notranslate"><span class="pre">GET</span></code> is used. If <em>secure</em> is true, a HTTPS connection will be used. The <em>context</em> parameter may be set to a <a class="reference internal" href="ssl.html#ssl.SSLContext" title="ssl.SSLContext"><code class="xref py py-class docutils literal notranslate"><span class="pre">ssl.SSLContext</span></code></a> instance to configure the SSL settings used for the HTTPS connection. If <em>credentials</em> is specified, it should be a 2-tuple consisting of userid and password, which will be placed in a HTTP ‘Authorization’ header using Basic authentication. If you specify credentials, you should also specify secure=True so that your userid and password are not passed in cleartext across the wire.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.5: </span>The <em>context</em> parameter was added.</p> </div> <dl class="method"> <dt id="logging.handlers.HTTPHandler.mapLogRecord"> <code class="descname">mapLogRecord</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.HTTPHandler.mapLogRecord" title="Permalink to this definition">¶</a></dt> <dd><p>Provides a dictionary, based on <code class="docutils literal notranslate"><span class="pre">record</span></code>, which is to be URL-encoded and sent to the web server. The default implementation just returns <code class="docutils literal notranslate"><span class="pre">record.__dict__</span></code>. This method can be overridden if e.g. only a subset of <a class="reference internal" href="logging.html#logging.LogRecord" title="logging.LogRecord"><code class="xref py py-class docutils literal notranslate"><span class="pre">LogRecord</span></code></a> is to be sent to the web server, or if more specific customization of what’s sent to the server is required.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.HTTPHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.HTTPHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Sends the record to the Web server as a URL-encoded dictionary. The <a class="reference internal" href="#logging.handlers.HTTPHandler.mapLogRecord" title="logging.handlers.HTTPHandler.mapLogRecord"><code class="xref py py-meth docutils literal notranslate"><span class="pre">mapLogRecord()</span></code></a> method is used to convert the record to the dictionary to be sent.</p> </dd></dl> <div class="admonition note"> <p class="admonition-title">Note</p> <p>Since preparing a record for sending it to a Web server is not the same as a generic formatting operation, using <a class="reference internal" href="logging.html#logging.Handler.setFormatter" title="logging.Handler.setFormatter"><code class="xref py py-meth docutils literal notranslate"><span class="pre">setFormatter()</span></code></a> to specify a <a class="reference internal" href="logging.html#logging.Formatter" title="logging.Formatter"><code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code></a> for a <a class="reference internal" href="#logging.handlers.HTTPHandler" title="logging.handlers.HTTPHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">HTTPHandler</span></code></a> has no effect. Instead of calling <a class="reference internal" href="logging.html#logging.Handler.format" title="logging.Handler.format"><code class="xref py py-meth docutils literal notranslate"><span class="pre">format()</span></code></a>, this handler calls <a class="reference internal" href="#logging.handlers.HTTPHandler.mapLogRecord" title="logging.handlers.HTTPHandler.mapLogRecord"><code class="xref py py-meth docutils literal notranslate"><span class="pre">mapLogRecord()</span></code></a> and then <a class="reference internal" href="urllib.parse.html#urllib.parse.urlencode" title="urllib.parse.urlencode"><code class="xref py py-func docutils literal notranslate"><span class="pre">urllib.parse.urlencode()</span></code></a> to encode the dictionary in a form suitable for sending to a Web server.</p> </div> </dd></dl> </div> <div class="section" id="queuehandler"> <span id="queue-handler"></span><h2>QueueHandler<a class="headerlink" href="#queuehandler" title="Permalink to this headline">¶</a></h2> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.2.</span></p> </div> <p>The <a class="reference internal" href="#logging.handlers.QueueHandler" title="logging.handlers.QueueHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueHandler</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports sending logging messages to a queue, such as those implemented in the <a class="reference internal" href="queue.html#module-queue" title="queue: A synchronized queue class."><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code></a> or <a class="reference internal" href="multiprocessing.html#module-multiprocessing" title="multiprocessing: Process-based parallelism."><code class="xref py py-mod docutils literal notranslate"><span class="pre">multiprocessing</span></code></a> modules.</p> <p>Along with the <a class="reference internal" href="#logging.handlers.QueueListener" title="logging.handlers.QueueListener"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueListener</span></code></a> class, <a class="reference internal" href="#logging.handlers.QueueHandler" title="logging.handlers.QueueHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueHandler</span></code></a> can be used to let handlers do their work on a separate thread from the one which does the logging. This is important in Web applications and also other service applications where threads servicing clients need to respond as quickly as possible, while any potentially slow operations (such as sending an email via <a class="reference internal" href="#logging.handlers.SMTPHandler" title="logging.handlers.SMTPHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SMTPHandler</span></code></a>) are done on a separate thread.</p> <dl class="class"> <dt id="logging.handlers.QueueHandler"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">QueueHandler</code><span class="sig-paren">(</span><em>queue</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueHandler" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.QueueHandler" title="logging.handlers.QueueHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueHandler</span></code></a> class. The instance is initialized with the queue to send messages to. The <em>queue</em> can be any queue-like object; it’s used as-is by the <a class="reference internal" href="#logging.handlers.QueueHandler.enqueue" title="logging.handlers.QueueHandler.enqueue"><code class="xref py py-meth docutils literal notranslate"><span class="pre">enqueue()</span></code></a> method, which needs to know how to send messages to it. The queue is not <em>required</em> to have the task tracking API, which means that you can use <a class="reference internal" href="queue.html#queue.SimpleQueue" title="queue.SimpleQueue"><code class="xref py py-class docutils literal notranslate"><span class="pre">SimpleQueue</span></code></a> instances for <em>queue</em>.</p> <dl class="method"> <dt id="logging.handlers.QueueHandler.emit"> <code class="descname">emit</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueHandler.emit" title="Permalink to this definition">¶</a></dt> <dd><p>Enqueues the result of preparing the LogRecord. Should an exception occur (e.g. because a bounded queue has filled up), the <a class="reference internal" href="logging.html#logging.Handler.handleError" title="logging.Handler.handleError"><code class="xref py py-meth docutils literal notranslate"><span class="pre">handleError()</span></code></a> method is called to handle the error. This can result in the record silently being dropped (if <code class="xref py py-attr docutils literal notranslate"><span class="pre">logging.raiseExceptions</span></code> is <code class="docutils literal notranslate"><span class="pre">False</span></code>) or a message printed to <code class="docutils literal notranslate"><span class="pre">sys.stderr</span></code> (if <code class="xref py py-attr docutils literal notranslate"><span class="pre">logging.raiseExceptions</span></code> is <code class="docutils literal notranslate"><span class="pre">True</span></code>).</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.QueueHandler.prepare"> <code class="descname">prepare</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueHandler.prepare" title="Permalink to this definition">¶</a></dt> <dd><p>Prepares a record for queuing. The object returned by this method is enqueued.</p> <p>The base implementation formats the record to merge the message, arguments, and exception information, if present. It also removes unpickleable items from the record in-place.</p> <p>You might want to override this method if you want to convert the record to a dict or JSON string, or send a modified copy of the record while leaving the original intact.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.QueueHandler.enqueue"> <code class="descname">enqueue</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueHandler.enqueue" title="Permalink to this definition">¶</a></dt> <dd><p>Enqueues the record on the queue using <code class="docutils literal notranslate"><span class="pre">put_nowait()</span></code>; you may want to override this if you want to use blocking behaviour, or a timeout, or a customized queue implementation.</p> </dd></dl> </dd></dl> </div> <div class="section" id="queuelistener"> <span id="queue-listener"></span><h2>QueueListener<a class="headerlink" href="#queuelistener" title="Permalink to this headline">¶</a></h2> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.2.</span></p> </div> <p>The <a class="reference internal" href="#logging.handlers.QueueListener" title="logging.handlers.QueueListener"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueListener</span></code></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code></a> module, supports receiving logging messages from a queue, such as those implemented in the <a class="reference internal" href="queue.html#module-queue" title="queue: A synchronized queue class."><code class="xref py py-mod docutils literal notranslate"><span class="pre">queue</span></code></a> or <a class="reference internal" href="multiprocessing.html#module-multiprocessing" title="multiprocessing: Process-based parallelism."><code class="xref py py-mod docutils literal notranslate"><span class="pre">multiprocessing</span></code></a> modules. The messages are received from a queue in an internal thread and passed, on the same thread, to one or more handlers for processing. While <a class="reference internal" href="#logging.handlers.QueueListener" title="logging.handlers.QueueListener"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueListener</span></code></a> is not itself a handler, it is documented here because it works hand-in-hand with <a class="reference internal" href="#logging.handlers.QueueHandler" title="logging.handlers.QueueHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueHandler</span></code></a>.</p> <p>Along with the <a class="reference internal" href="#logging.handlers.QueueHandler" title="logging.handlers.QueueHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueHandler</span></code></a> class, <a class="reference internal" href="#logging.handlers.QueueListener" title="logging.handlers.QueueListener"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueListener</span></code></a> can be used to let handlers do their work on a separate thread from the one which does the logging. This is important in Web applications and also other service applications where threads servicing clients need to respond as quickly as possible, while any potentially slow operations (such as sending an email via <a class="reference internal" href="#logging.handlers.SMTPHandler" title="logging.handlers.SMTPHandler"><code class="xref py py-class docutils literal notranslate"><span class="pre">SMTPHandler</span></code></a>) are done on a separate thread.</p> <dl class="class"> <dt id="logging.handlers.QueueListener"> <em class="property">class </em><code class="descclassname">logging.handlers.</code><code class="descname">QueueListener</code><span class="sig-paren">(</span><em>queue</em>, <em>*handlers</em>, <em>respect_handler_level=False</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueListener" title="Permalink to this definition">¶</a></dt> <dd><p>Returns a new instance of the <a class="reference internal" href="#logging.handlers.QueueListener" title="logging.handlers.QueueListener"><code class="xref py py-class docutils literal notranslate"><span class="pre">QueueListener</span></code></a> class. The instance is initialized with the queue to send messages to and a list of handlers which will handle entries placed on the queue. The queue can be any queue-like object; it’s passed as-is to the <a class="reference internal" href="#logging.handlers.QueueListener.dequeue" title="logging.handlers.QueueListener.dequeue"><code class="xref py py-meth docutils literal notranslate"><span class="pre">dequeue()</span></code></a> method, which needs to know how to get messages from it. The queue is not <em>required</em> to have the task tracking API (though it’s used if available), which means that you can use <a class="reference internal" href="queue.html#queue.SimpleQueue" title="queue.SimpleQueue"><code class="xref py py-class docutils literal notranslate"><span class="pre">SimpleQueue</span></code></a> instances for <em>queue</em>.</p> <p>If <code class="docutils literal notranslate"><span class="pre">respect_handler_level</span></code> is <code class="docutils literal notranslate"><span class="pre">True</span></code>, a handler’s level is respected (compared with the level for the message) when deciding whether to pass messages to that handler; otherwise, the behaviour is as in previous Python versions - to always pass each message to each handler.</p> <div class="versionchanged"> <p><span class="versionmodified changed">Changed in version 3.5: </span>The <code class="docutils literal notranslate"><span class="pre">respect_handler_levels</span></code> argument was added.</p> </div> <dl class="method"> <dt id="logging.handlers.QueueListener.dequeue"> <code class="descname">dequeue</code><span class="sig-paren">(</span><em>block</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueListener.dequeue" title="Permalink to this definition">¶</a></dt> <dd><p>Dequeues a record and return it, optionally blocking.</p> <p>The base implementation uses <code class="docutils literal notranslate"><span class="pre">get()</span></code>. You may want to override this method if you want to use timeouts or work with custom queue implementations.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.QueueListener.prepare"> <code class="descname">prepare</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueListener.prepare" title="Permalink to this definition">¶</a></dt> <dd><p>Prepare a record for handling.</p> <p>This implementation just returns the passed-in record. You may want to override this method if you need to do any custom marshalling or manipulation of the record before passing it to the handlers.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.QueueListener.handle"> <code class="descname">handle</code><span class="sig-paren">(</span><em>record</em><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueListener.handle" title="Permalink to this definition">¶</a></dt> <dd><p>Handle a record.</p> <p>This just loops through the handlers offering them the record to handle. The actual object passed to the handlers is that which is returned from <a class="reference internal" href="#logging.handlers.QueueListener.prepare" title="logging.handlers.QueueListener.prepare"><code class="xref py py-meth docutils literal notranslate"><span class="pre">prepare()</span></code></a>.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.QueueListener.start"> <code class="descname">start</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueListener.start" title="Permalink to this definition">¶</a></dt> <dd><p>Starts the listener.</p> <p>This starts up a background thread to monitor the queue for LogRecords to process.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.QueueListener.stop"> <code class="descname">stop</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueListener.stop" title="Permalink to this definition">¶</a></dt> <dd><p>Stops the listener.</p> <p>This asks the thread to terminate, and then waits for it to do so. Note that if you don’t call this before your application exits, there may be some records still left on the queue, which won’t be processed.</p> </dd></dl> <dl class="method"> <dt id="logging.handlers.QueueListener.enqueue_sentinel"> <code class="descname">enqueue_sentinel</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#logging.handlers.QueueListener.enqueue_sentinel" title="Permalink to this definition">¶</a></dt> <dd><p>Writes a sentinel to the queue to tell the listener to quit. This implementation uses <code class="docutils literal notranslate"><span class="pre">put_nowait()</span></code>. You may want to override this method if you want to use timeouts or work with custom queue implementations.</p> <div class="versionadded"> <p><span class="versionmodified added">New in version 3.3.</span></p> </div> </dd></dl> </dd></dl> <div class="admonition seealso"> <p class="admonition-title">See also</p> <dl class="simple"> <dt>Module <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging</span></code></a></dt><dd><p>API reference for the logging module.</p> </dd> <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"><span class="pre">logging.config</span></code></a></dt><dd><p>Configuration API for the logging module.</p> </dd> </dl> </div> </div> </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="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.handlers</span></code> — Logging handlers</a><ul> <li><a class="reference internal" href="#streamhandler">StreamHandler</a></li> <li><a class="reference internal" href="#filehandler">FileHandler</a></li> <li><a class="reference internal" href="#nullhandler">NullHandler</a></li> <li><a class="reference internal" href="#watchedfilehandler">WatchedFileHandler</a></li> <li><a class="reference internal" href="#baserotatinghandler">BaseRotatingHandler</a></li> <li><a class="reference internal" href="#rotatingfilehandler">RotatingFileHandler</a></li> <li><a class="reference internal" href="#timedrotatingfilehandler">TimedRotatingFileHandler</a></li> <li><a class="reference internal" href="#sockethandler">SocketHandler</a></li> <li><a class="reference internal" href="#datagramhandler">DatagramHandler</a></li> <li><a class="reference internal" href="#sysloghandler">SysLogHandler</a></li> <li><a class="reference internal" href="#nteventloghandler">NTEventLogHandler</a></li> <li><a class="reference internal" href="#smtphandler">SMTPHandler</a></li> <li><a class="reference internal" href="#memoryhandler">MemoryHandler</a></li> <li><a class="reference internal" href="#httphandler">HTTPHandler</a></li> <li><a class="reference internal" href="#queuehandler">QueueHandler</a></li> <li><a class="reference internal" href="#queuelistener">QueueListener</a></li> </ul> </li> </ul> <h4>Previous topic</h4> <p class="topless"><a href="logging.config.html" title="previous chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">logging.config</span></code> — Logging configuration</a></p> <h4>Next topic</h4> <p class="topless"><a href="getpass.html" title="next chapter"><code class="xref py py-mod docutils literal notranslate"><span class="pre">getpass</span></code> — Portable password input</a></p> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../bugs.html">Report a Bug</a></li> <li> <a href="https://github.com/python/cpython/blob/3.7/Doc/library/logging.handlers.rst" rel="nofollow">Show Source </a> </li> </ul> </div> </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="getpass.html" title="getpass — Portable password input" >next</a> |</li> <li class="right" > <a href="logging.config.html" title="logging.config — Logging configuration" >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> »</li> <li> <span class="language_switcher_placeholder">en</span> <span class="version_switcher_placeholder">3.7.4</span> <a href="../index.html">Documentation </a> » </li> <li class="nav-item nav-item-1"><a href="index.html" >The Python Standard Library</a> »</li> <li class="nav-item nav-item-2"><a href="allos.html" >Generic Operating System Services</a> »</li> <li class="right"> <div class="inline-search" style="display: none" role="search"> <form class="inline-search" action="../search.html" method="get"> <input placeholder="Quick search" type="text" name="q" /> <input type="submit" value="Go" /> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('.inline-search').show(0);</script> | </li> </ul> </div> <div class="footer"> © <a href="../copyright.html">Copyright</a> 2001-2019, Python Software Foundation. <br /> The Python Software Foundation is a non-profit corporation. <a href="https://www.python.org/psf/donations/">Please donate.</a> <br /> Last updated on Jul 13, 2019. <a href="../bugs.html">Found a bug</a>? <br /> Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.0.1. </div> </body> </html>