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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>15.9. logging.handlers — Logging handlers — Python 2.7.16 documentation</title> <link rel="stylesheet" href="../_static/classic.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/sidebar.js"></script> <link rel="search" type="application/opensearchdescription+xml" title="Search within Python 2.7.16 documentation" href="../_static/opensearch.xml"/> <link rel="author" title="About these documents" href="../about.html" /> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="copyright" title="Copyright" href="../copyright.html" /> <link rel="next" title="15.10. getpass — Portable password input" href="getpass.html" /> <link rel="prev" title="15.8. 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/2/library/logging.handlers.html" /> <script type="text/javascript" src="../_static/copybutton.js"></script> </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="15.10. getpass — Portable password input" accesskey="N">next</a> |</li> <li class="right" > <a href="logging.config.html" title="15.8. 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> <a href="../index.html">Python 2.7.16 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">15. Generic Operating System Services</a> »</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>15.9. <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> <div class="sidebar"> <p class="first sidebar-title">Important</p> <p>This page contains only reference information. For tutorials, please see</p> <ul class="last simple"> <li><a class="reference internal" href="../howto/logging.html#logging-basic-tutorial"><span class="std std-ref">Basic Tutorial</span></a></li> <li><a class="reference internal" href="../howto/logging.html#logging-advanced-tutorial"><span class="std std-ref">Advanced Tutorial</span></a></li> <li><a class="reference internal" href="../howto/logging-cookbook.html#logging-cookbook"><span class="std std-ref">Logging Cookbook</span></a></li> </ul> </div> <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/2.7/Lib/logging/handlers.py">Lib/logging/handlers.py</a></p> <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>15.9.1. 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 newline 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 <code class="xref py py-class docutils literal notranslate"><span class="pre">Handler</span></code> 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> </dd></dl> </div> <div class="section" id="filehandler"> <span id="file-handler"></span><h2>15.9.2. 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 in version 2.6: </span><em>delay</em> was added.</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>15.9.3. NullHandler<a class="headerlink" href="#nullhandler" title="Permalink to this headline">¶</a></h2> <div class="versionadded"> <p><span class="versionmodified">New in version 2.7.</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>15.9.4. WatchedFileHandler<a class="headerlink" href="#watchedfilehandler" title="Permalink to this headline">¶</a></h2> <div class="versionadded"> <p><span class="versionmodified">New in version 2.6.</span></p> </div> <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><span class="optional">[</span>, <em>mode</em><span class="optional">[</span>, <em>encoding</em><span class="optional">[</span>, <em>delay</em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><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> <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 checks to see if the file has changed. If it has, the existing stream is flushed and closed and the file opened again, before outputting the record to the file.</p> </dd></dl> </dd></dl> </div> <div class="section" id="rotatingfilehandler"> <span id="rotating-file-handler"></span><h2>15.9.5. 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=0</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; if either of <em>maxBytes</em> or <em>backupCount</em> is zero, rollover never occurs. If <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 in version 2.6: </span><em>delay</em> was added.</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>15.9.6. 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><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 border="1" class="docutils"> <colgroup> <col width="41%" /> <col width="59%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Value</th> <th class="head">Type of interval</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">'S'</span></code></td> <td>Seconds</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">'M'</span></code></td> <td>Minutes</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">'H'</span></code></td> <td>Hours</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">'D'</span></code></td> <td>Days</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">'W0'-'W6'</span></code></td> <td>Weekday (0=Monday)</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">'midnight'</span></code></td> <td>Roll over at midnight</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> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.6: </span><em>delay</em> and <em>utc</em> were added.</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>15.9.7. 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> <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.</p> <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 string <em>packet</em> to the socket. 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><code class="docutils literal notranslate"><span class="pre">retryStart</span></code> (initial delay, defaulting to 1.0 seconds).</li> <li><code class="docutils literal notranslate"><span class="pre">retryFactor</span></code> (multiplier, defaulting to 2.0).</li> <li><code class="docutils literal notranslate"><span class="pre">retryMax</span></code> (maximum delay, defaulting to 30.0 seconds).</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>15.9.8. 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> <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 string to a socket.</p> </dd></dl> </dd></dl> </div> <div class="section" id="sysloghandler"> <span id="syslog-handler"></span><h2>15.9.9. 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 in version 2.7: </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> </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 border="1" class="docutils"> <colgroup> <col width="63%" /> <col width="37%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Name (string)</th> <th class="head">Symbolic value</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">alert</span></code></td> <td>LOG_ALERT</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">crit</span></code> or <code class="docutils literal notranslate"><span class="pre">critical</span></code></td> <td>LOG_CRIT</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">debug</span></code></td> <td>LOG_DEBUG</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">emerg</span></code> or <code class="docutils literal notranslate"><span class="pre">panic</span></code></td> <td>LOG_EMERG</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">err</span></code> or <code class="docutils literal notranslate"><span class="pre">error</span></code></td> <td>LOG_ERR</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">info</span></code></td> <td>LOG_INFO</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">notice</span></code></td> <td>LOG_NOTICE</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">warn</span></code> or <code class="docutils literal notranslate"><span class="pre">warning</span></code></td> <td>LOG_WARNING</td> </tr> </tbody> </table> <p><strong>Facilities</strong></p> <table border="1" class="docutils"> <colgroup> <col width="50%" /> <col width="50%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Name (string)</th> <th class="head">Symbolic value</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">auth</span></code></td> <td>LOG_AUTH</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">authpriv</span></code></td> <td>LOG_AUTHPRIV</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">cron</span></code></td> <td>LOG_CRON</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">daemon</span></code></td> <td>LOG_DAEMON</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">ftp</span></code></td> <td>LOG_FTP</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">kern</span></code></td> <td>LOG_KERN</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">lpr</span></code></td> <td>LOG_LPR</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">mail</span></code></td> <td>LOG_MAIL</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">news</span></code></td> <td>LOG_NEWS</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">syslog</span></code></td> <td>LOG_SYSLOG</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">user</span></code></td> <td>LOG_USER</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">uucp</span></code></td> <td>LOG_UUCP</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">local0</span></code></td> <td>LOG_LOCAL0</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">local1</span></code></td> <td>LOG_LOCAL1</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">local2</span></code></td> <td>LOG_LOCAL2</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">local3</span></code></td> <td>LOG_LOCAL3</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">local4</span></code></td> <td>LOG_LOCAL4</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">local5</span></code></td> <td>LOG_LOCAL5</td> </tr> <tr class="row-even"><td><code class="docutils literal notranslate"><span class="pre">local6</span></code></td> <td>LOG_LOCAL6</td> </tr> <tr class="row-odd"><td><code class="docutils literal notranslate"><span class="pre">local7</span></code></td> <td>LOG_LOCAL7</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>15.9.10. 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>15.9.11. 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><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> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.6: </span><em>credentials</em> was added.</p> </div> <div class="versionchanged"> <p><span class="versionmodified">Changed in version 2.7: </span><em>secure</em> 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>15.9.12. 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.</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><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>. 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.</p> <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 <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a> 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>15.9.13. 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><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 <code class="docutils literal notranslate"><span class="pre">host</span></code> 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.</p> <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="first admonition-title">Note</p> <p class="last">Since preparing a record for sending it to a Web server is not the same as a generic formatting operation, using <code class="xref py py-meth docutils literal notranslate"><span class="pre">setFormatter()</span></code> to specify a <code class="xref py py-class docutils literal notranslate"><span class="pre">Formatter</span></code> 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="functions.html#format" title="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.html#urllib.urlencode" title="urllib.urlencode"><code class="xref py py-func docutils literal notranslate"><span class="pre">urllib.urlencode()</span></code></a> to encode the dictionary in a form suitable for sending to a Web server.</p> </div> </dd></dl> <div class="admonition seealso"> <p class="first admonition-title">See also</p> <dl class="last docutils"> <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>API reference for the logging module.</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>Configuration API for the logging module.</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="#">15.9. <code class="docutils literal notranslate"><span class="pre">logging.handlers</span></code> — Logging handlers</a><ul> <li><a class="reference internal" href="#streamhandler">15.9.1. StreamHandler</a></li> <li><a class="reference internal" href="#filehandler">15.9.2. FileHandler</a></li> <li><a class="reference internal" href="#nullhandler">15.9.3. NullHandler</a></li> <li><a class="reference internal" href="#watchedfilehandler">15.9.4. WatchedFileHandler</a></li> <li><a class="reference internal" href="#rotatingfilehandler">15.9.5. RotatingFileHandler</a></li> <li><a class="reference internal" href="#timedrotatingfilehandler">15.9.6. TimedRotatingFileHandler</a></li> <li><a class="reference internal" href="#sockethandler">15.9.7. SocketHandler</a></li> <li><a class="reference internal" href="#datagramhandler">15.9.8. DatagramHandler</a></li> <li><a class="reference internal" href="#sysloghandler">15.9.9. SysLogHandler</a></li> <li><a class="reference internal" href="#nteventloghandler">15.9.10. NTEventLogHandler</a></li> <li><a class="reference internal" href="#smtphandler">15.9.11. SMTPHandler</a></li> <li><a class="reference internal" href="#memoryhandler">15.9.12. MemoryHandler</a></li> <li><a class="reference internal" href="#httphandler">15.9.13. 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