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<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."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></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"><em>Basic Tutorial</em></a></li>
<li><a class="reference internal" href="../howto/logging.html#logging-advanced-tutorial"><em>Advanced Tutorial</em></a></li>
<li><a class="reference internal" href="../howto/logging-cookbook.html#logging-cookbook"><em>Logging Cookbook</em></a></li>
</ul>
</div>
<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"><tt class="xref py py-class docutils literal"><span class="pre">StreamHandler</span></tt></a>, <a class="reference internal" href="#logging.FileHandler" title="logging.FileHandler"><tt class="xref py py-class docutils literal"><span class="pre">FileHandler</span></tt></a> and
<a class="reference internal" href="#logging.NullHandler" title="logging.NullHandler"><tt class="xref py py-class docutils literal"><span class="pre">NullHandler</span></tt></a>) are actually defined in the <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><tt class="xref py py-mod docutils literal"><span class="pre">logging</span></tt></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"><tt class="xref py py-class docutils literal"><span class="pre">StreamHandler</span></tt></a> class, located in the core <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><tt class="xref py py-mod docutils literal"><span class="pre">logging</span></tt></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 <tt class="xref py py-meth docutils literal"><span class="pre">write()</span></tt>
and <tt class="xref py py-meth docutils literal"><span class="pre">flush()</span></tt> methods).</p>
<dl class="class">
<dt id="logging.StreamHandler">
<em class="property">class </em><tt class="descclassname">logging.</tt><tt class="descname">StreamHandler</tt><big>(</big><em>stream=None</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">StreamHandler</span></tt></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">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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"><tt class="xref py py-func docutils literal"><span class="pre">traceback.print_exception()</span></tt></a> and appended to the stream.</p>
</dd></dl>
<dl class="method">
<dt id="logging.StreamHandler.flush">
<tt class="descname">flush</tt><big>(</big><big>)</big><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"><tt class="xref py py-meth docutils literal"><span class="pre">flush()</span></tt></a> method. Note that the
<tt class="xref py py-meth docutils literal"><span class="pre">close()</span></tt> method is inherited from <tt class="xref py py-class docutils literal"><span class="pre">Handler</span></tt> and so does
no output, so an explicit <a class="reference internal" href="#logging.StreamHandler.flush" title="logging.StreamHandler.flush"><tt class="xref py py-meth docutils literal"><span class="pre">flush()</span></tt></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"><tt class="xref py py-class docutils literal"><span class="pre">FileHandler</span></tt></a> class, located in the core <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><tt class="xref py py-mod docutils literal"><span class="pre">logging</span></tt></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"><tt class="xref py py-class docutils literal"><span class="pre">StreamHandler</span></tt></a>.</p>
<dl class="class">
<dt id="logging.FileHandler">
<em class="property">class </em><tt class="descclassname">logging.</tt><tt class="descname">FileHandler</tt><big>(</big><em>filename</em>, <em>mode='a'</em>, <em>encoding=None</em>, <em>delay=False</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">FileHandler</span></tt></a> class. The specified file is
opened and used as the stream for logging. If <em>mode</em> is not specified,
<tt class="xref py py-const docutils literal"><span class="pre">'a'</span></tt> is used. If <em>encoding</em> is not <em>None</em>, 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"><tt class="xref py py-meth docutils literal"><span class="pre">emit()</span></tt></a>. By default, the file grows indefinitely.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.6: </span><em>delay</em> was added.</p>
<dl class="method">
<dt id="logging.FileHandler.close">
<tt class="descname">close</tt><big>(</big><big>)</big><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">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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>
<p class="versionadded">
<span class="versionmodified">New in version 2.7.</span></p>
<p>The <a class="reference internal" href="#logging.NullHandler" title="logging.NullHandler"><tt class="xref py py-class docutils literal"><span class="pre">NullHandler</span></tt></a> class, located in the core <a class="reference internal" href="logging.html#module-logging" title="logging: Flexible event logging system for applications."><tt class="xref py py-mod docutils literal"><span class="pre">logging</span></tt></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><tt class="descclassname">logging.</tt><tt class="descname">NullHandler</tt><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"><tt class="xref py py-class docutils literal"><span class="pre">NullHandler</span></tt></a> class.</p>
<dl class="method">
<dt id="logging.NullHandler.emit">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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">
<tt class="descname">handle</tt><big>(</big><em>record</em><big>)</big><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">
<tt class="descname">createLock</tt><big>(</big><big>)</big><a class="headerlink" href="#logging.NullHandler.createLock" title="Permalink to this definition">¶</a></dt>
<dd><p>This method returns <tt class="docutils literal"><span class="pre">None</span></tt> 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"><em>Configuring Logging for a Library</em></a> for more information on how to use
<a class="reference internal" href="#logging.NullHandler" title="logging.NullHandler"><tt class="xref py py-class docutils literal"><span class="pre">NullHandler</span></tt></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>
<p class="versionadded">
<span class="versionmodified">New in version 2.6.</span></p>
<p>The <a class="reference internal" href="#logging.handlers.WatchedFileHandler" title="logging.handlers.WatchedFileHandler"><tt class="xref py py-class docutils literal"><span class="pre">WatchedFileHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></a>
module, is a <tt class="xref py py-class docutils literal"><span class="pre">FileHandler</span></tt> 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="stat.html#module-stat" title="stat: Utilities for interpreting the results of os.stat(), os.lstat() and os.fstat()."><tt class="xref py py-func docutils literal"><span class="pre">stat()</span></tt></a> always returns zero for
this value.</p>
<dl class="class">
<dt id="logging.handlers.WatchedFileHandler">
<em class="property">class </em><tt class="descclassname">logging.handlers.</tt><tt class="descname">WatchedFileHandler</tt><big>(</big><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><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">WatchedFileHandler</span></tt></a> class. The specified
file is opened and used as the stream for logging. If <em>mode</em> is not specified,
<tt class="xref py py-const docutils literal"><span class="pre">'a'</span></tt> is used. If <em>encoding</em> is not <em>None</em>, 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"><tt class="xref py py-meth docutils literal"><span class="pre">emit()</span></tt></a>. By default, the file grows indefinitely.</p>
<dl class="method">
<dt id="logging.handlers.WatchedFileHandler.emit">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">RotatingFileHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></a>
module, supports rotation of disk log files.</p>
<dl class="class">
<dt id="logging.handlers.RotatingFileHandler">
<em class="property">class </em><tt class="descclassname">logging.handlers.</tt><tt class="descname">RotatingFileHandler</tt><big>(</big><em>filename</em>, <em>mode='a'</em>, <em>maxBytes=0</em>, <em>backupCount=0</em>, <em>encoding=None</em>, <em>delay=0</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">RotatingFileHandler</span></tt></a> class. The specified
file is opened and used as the stream for logging. If <em>mode</em> is not specified,
<tt class="docutils literal"><span class="pre">'a'</span></tt> is used. If <em>encoding</em> is not <em>None</em>, 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"><tt class="xref py py-meth docutils literal"><span class="pre">emit()</span></tt></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 <em>maxBytes</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 <tt class="file docutils literal"><span class="pre">app.log</span></tt>, you
would get <tt class="file docutils literal"><span class="pre">app.log</span></tt>, <tt class="file docutils literal"><span class="pre">app.log.1</span></tt>, <tt class="file docutils literal"><span class="pre">app.log.2</span></tt>, up to
<tt class="file docutils literal"><span class="pre">app.log.5</span></tt>. The file being written to is always <tt class="file docutils literal"><span class="pre">app.log</span></tt>. When
this file is filled, it is closed and renamed to <tt class="file docutils literal"><span class="pre">app.log.1</span></tt>, and if files
<tt class="file docutils literal"><span class="pre">app.log.1</span></tt>, <tt class="file docutils literal"><span class="pre">app.log.2</span></tt>, etc. exist, then they are renamed to
<tt class="file docutils literal"><span class="pre">app.log.2</span></tt>, <tt class="file docutils literal"><span class="pre">app.log.3</span></tt> etc. respectively.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.6: </span><em>delay</em> was added.</p>
<dl class="method">
<dt id="logging.handlers.RotatingFileHandler.doRollover">
<tt class="descname">doRollover</tt><big>(</big><big>)</big><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">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">TimedRotatingFileHandler</span></tt></a> class, located in the
<a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></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><tt class="descclassname">logging.handlers.</tt><tt class="descname">TimedRotatingFileHandler</tt><big>(</big><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><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">TimedRotatingFileHandler</span></tt></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><tt class="docutils literal"><span class="pre">'S'</span></tt></td>
<td>Seconds</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">'M'</span></tt></td>
<td>Minutes</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">'H'</span></tt></td>
<td>Hours</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">'D'</span></tt></td>
<td>Days</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">'W0'-'W6'</span></tt></td>
<td>Weekday (0=Monday)</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">'midnight'</span></tt></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
<tt class="docutils literal"><span class="pre">%Y-%m-%d_%H-%M-%S</span></tt> 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"><tt class="xref py py-meth docutils literal"><span class="pre">emit()</span></tt></a>.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.6: </span><em>delay</em> and <em>utc</em> were added.</p>
<dl class="method">
<dt id="logging.handlers.TimedRotatingFileHandler.doRollover">
<tt class="descname">doRollover</tt><big>(</big><big>)</big><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">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">SocketHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></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><tt class="descclassname">logging.handlers.</tt><tt class="descname">SocketHandler</tt><big>(</big><em>host</em>, <em>port</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">SocketHandler</span></tt></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">
<tt class="descname">close</tt><big>(</big><big>)</big><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">
<tt class="descname">emit</tt><big>(</big><big>)</big><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
<tt class="xref py py-class docutils literal"><span class="pre">LogRecord</span></tt>, use the <tt class="xref py py-func docutils literal"><span class="pre">makeLogRecord()</span></tt> function.</p>
</dd></dl>
<dl class="method">
<dt id="logging.handlers.SocketHandler.handleError">
<tt class="descname">handleError</tt><big>(</big><big>)</big><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"><tt class="xref py py-meth docutils literal"><span class="pre">emit()</span></tt></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">
<tt class="descname">makeSocket</tt><big>(</big><big>)</big><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"><tt class="xref py py-const docutils literal"><span class="pre">socket.SOCK_STREAM</span></tt></a>).</p>
</dd></dl>
<dl class="method">
<dt id="logging.handlers.SocketHandler.makePickle">
<tt class="descname">makePickle</tt><big>(</big><em>record</em><big>)</big><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">
<tt class="descname">send</tt><big>(</big><em>packet</em><big>)</big><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">
<tt class="descname">createSocket</tt><big>(</big><big>)</big><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 intial 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><tt class="docutils literal"><span class="pre">retryStart</span></tt> (initial delay, defaulting to 1.0 seconds).</li>
<li><tt class="docutils literal"><span class="pre">retryFactor</span></tt> (multiplier, defaulting to 2.0).</li>
<li><tt class="docutils literal"><span class="pre">retryMax</span></tt> (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"><tt class="xref py py-class docutils literal"><span class="pre">DatagramHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></a>
module, inherits from <a class="reference internal" href="#logging.handlers.SocketHandler" title="logging.handlers.SocketHandler"><tt class="xref py py-class docutils literal"><span class="pre">SocketHandler</span></tt></a> to support sending logging messages
over UDP sockets.</p>
<dl class="class">
<dt id="logging.handlers.DatagramHandler">
<em class="property">class </em><tt class="descclassname">logging.handlers.</tt><tt class="descname">DatagramHandler</tt><big>(</big><em>host</em>, <em>port</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">DatagramHandler</span></tt></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">
<tt class="descname">emit</tt><big>(</big><big>)</big><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
<tt class="xref py py-class docutils literal"><span class="pre">LogRecord</span></tt>, use the <tt class="xref py py-func docutils literal"><span class="pre">makeLogRecord()</span></tt> function.</p>
</dd></dl>
<dl class="method">
<dt id="logging.handlers.DatagramHandler.makeSocket">
<tt class="descname">makeSocket</tt><big>(</big><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">SocketHandler</span></tt></a> is here overridden to create
a UDP socket (<a class="reference internal" href="socket.html#socket.SOCK_DGRAM" title="socket.SOCK_DGRAM"><tt class="xref py py-const docutils literal"><span class="pre">socket.SOCK_DGRAM</span></tt></a>).</p>
</dd></dl>
<dl class="method">
<dt id="logging.handlers.DatagramHandler.send">
<tt class="descname">send</tt><big>(</big><em>s</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">SysLogHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></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><tt class="descclassname">logging.handlers.</tt><tt class="descname">SysLogHandler</tt><big>(</big><em>address=('localhost'</em>, <em>SYSLOG_UDP_PORT)</em>, <em>facility=LOG_USER</em>, <em>socktype=socket.SOCK_DGRAM</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">SysLogHandler</span></tt></a> class intended to
communicate with a remote Unix machine whose address is given by <em>address</em> in
the form of a <tt class="docutils literal"><span class="pre">(host,</span> <span class="pre">port)</span></tt> tuple. If <em>address</em> is not specified,
<tt class="docutils literal"><span class="pre">('localhost',</span> <span class="pre">514)</span></tt> is used. The address is used to open a socket. An
alternative to providing a <tt class="docutils literal"><span class="pre">(host,</span> <span class="pre">port)</span></tt> 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,
<tt class="xref py py-const docutils literal"><span class="pre">LOG_USER</span></tt> 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"><tt class="xref py py-const docutils literal"><span class="pre">socket.SOCK_DGRAM</span></tt></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"><tt class="xref py py-const docutils literal"><span class="pre">socket.SOCK_STREAM</span></tt></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"><tt class="xref py py-class docutils literal"><span class="pre">SysLogHandler</span></tt></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>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.7: </span><em>socktype</em> was added.</p>
<dl class="method">
<dt id="logging.handlers.SysLogHandler.close">
<tt class="descname">close</tt><big>(</big><big>)</big><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">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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">
<tt class="descname">encodePriority</tt><big>(</big><em>facility</em>, <em>priority</em><big>)</big><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 <tt class="docutils literal"><span class="pre">LOG_</span></tt> values are defined in <a class="reference internal" href="#logging.handlers.SysLogHandler" title="logging.handlers.SysLogHandler"><tt class="xref py py-class docutils literal"><span class="pre">SysLogHandler</span></tt></a> and
mirror the values defined in the <tt class="docutils literal"><span class="pre">sys/syslog.h</span></tt> 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><tt class="docutils literal"><span class="pre">alert</span></tt></td>
<td>LOG_ALERT</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">crit</span></tt> or <tt class="docutils literal"><span class="pre">critical</span></tt></td>
<td>LOG_CRIT</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">debug</span></tt></td>
<td>LOG_DEBUG</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">emerg</span></tt> or <tt class="docutils literal"><span class="pre">panic</span></tt></td>
<td>LOG_EMERG</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">err</span></tt> or <tt class="docutils literal"><span class="pre">error</span></tt></td>
<td>LOG_ERR</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">info</span></tt></td>
<td>LOG_INFO</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">notice</span></tt></td>
<td>LOG_NOTICE</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">warn</span></tt> or <tt class="docutils literal"><span class="pre">warning</span></tt></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><tt class="docutils literal"><span class="pre">auth</span></tt></td>
<td>LOG_AUTH</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">authpriv</span></tt></td>
<td>LOG_AUTHPRIV</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">cron</span></tt></td>
<td>LOG_CRON</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">daemon</span></tt></td>
<td>LOG_DAEMON</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">ftp</span></tt></td>
<td>LOG_FTP</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">kern</span></tt></td>
<td>LOG_KERN</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">lpr</span></tt></td>
<td>LOG_LPR</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">mail</span></tt></td>
<td>LOG_MAIL</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">news</span></tt></td>
<td>LOG_NEWS</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">syslog</span></tt></td>
<td>LOG_SYSLOG</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">user</span></tt></td>
<td>LOG_USER</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">uucp</span></tt></td>
<td>LOG_UUCP</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">local0</span></tt></td>
<td>LOG_LOCAL0</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">local1</span></tt></td>
<td>LOG_LOCAL1</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">local2</span></tt></td>
<td>LOG_LOCAL2</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">local3</span></tt></td>
<td>LOG_LOCAL3</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">local4</span></tt></td>
<td>LOG_LOCAL4</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">local5</span></tt></td>
<td>LOG_LOCAL5</td>
</tr>
<tr class="row-even"><td><tt class="docutils literal"><span class="pre">local6</span></tt></td>
<td>LOG_LOCAL6</td>
</tr>
<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">local7</span></tt></td>
<td>LOG_LOCAL7</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="method">
<dt id="logging.handlers.SysLogHandler.mapPriority">
<tt class="descname">mapPriority</tt><big>(</big><em>levelname</em><big>)</big><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 <tt class="docutils literal"><span class="pre">DEBUG</span></tt>, <tt class="docutils literal"><span class="pre">INFO</span></tt>, <tt class="docutils literal"><span class="pre">WARNING</span></tt>, <tt class="docutils literal"><span class="pre">ERROR</span></tt> and
<tt class="docutils literal"><span class="pre">CRITICAL</span></tt> 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"><tt class="xref py py-class docutils literal"><span class="pre">NTEventLogHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></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><tt class="descclassname">logging.handlers.</tt><tt class="descname">NTEventLogHandler</tt><big>(</big><em>appname</em>, <em>dllname=None</em>, <em>logtype='Application'</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">NTEventLogHandler</span></tt></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, <tt class="docutils literal"><span class="pre">'win32service.pyd'</span></tt> 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 <tt class="docutils literal"><span class="pre">'Application'</span></tt>, <tt class="docutils literal"><span class="pre">'System'</span></tt> or <tt class="docutils literal"><span class="pre">'Security'</span></tt>, and
defaults to <tt class="docutils literal"><span class="pre">'Application'</span></tt>.</p>
<dl class="method">
<dt id="logging.handlers.NTEventLogHandler.close">
<tt class="descname">close</tt><big>(</big><big>)</big><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">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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">
<tt class="descname">getEventCategory</tt><big>(</big><em>record</em><big>)</big><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">
<tt class="descname">getEventType</tt><big>(</big><em>record</em><big>)</big><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__"><tt class="xref py py-meth docutils literal"><span class="pre">__init__()</span></tt></a> to a dictionary
which contains mappings for <tt class="xref py py-const docutils literal"><span class="pre">DEBUG</span></tt>, <tt class="xref py py-const docutils literal"><span class="pre">INFO</span></tt>,
<tt class="xref py py-const docutils literal"><span class="pre">WARNING</span></tt>, <tt class="xref py py-const docutils literal"><span class="pre">ERROR</span></tt> and <tt class="xref py py-const docutils literal"><span class="pre">CRITICAL</span></tt>. 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">
<tt class="descname">getMessageID</tt><big>(</big><em>record</em><big>)</big><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 <tt class="file docutils literal"><span class="pre">win32service.pyd</span></tt>.</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"><tt class="xref py py-class docutils literal"><span class="pre">SMTPHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></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><tt class="descclassname">logging.handlers.</tt><tt class="descname">SMTPHandler</tt><big>(</big><em>mailhost</em>, <em>fromaddr</em>, <em>toaddrs</em>, <em>subject</em>, <em>credentials=None</em>, <em>secure=None</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">SMTPHandler</span></tt></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"><tt class="xref py py-meth docutils literal"><span class="pre">smtplib.SMTP.starttls()</span></tt></a> method.)</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.6: </span><em>credentials</em> was added.</p>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.7: </span><em>secure</em> was added.</p>
<dl class="method">
<dt id="logging.handlers.SMTPHandler.emit">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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">
<tt class="descname">getSubject</tt><big>(</big><em>record</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">MemoryHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></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"><tt class="xref py py-class docutils literal"><span class="pre">MemoryHandler</span></tt></a> is a subclass of the more general
<a class="reference internal" href="#logging.handlers.BufferingHandler" title="logging.handlers.BufferingHandler"><tt class="xref py py-class docutils literal"><span class="pre">BufferingHandler</span></tt></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 <tt class="xref py py-meth docutils literal"><span class="pre">shouldFlush()</span></tt> to see if the buffer should be flushed. If it
should, then <tt class="xref py py-meth docutils literal"><span class="pre">flush()</span></tt> is expected to do the flushing.</p>
<dl class="class">
<dt id="logging.handlers.BufferingHandler">
<em class="property">class </em><tt class="descclassname">logging.handlers.</tt><tt class="descname">BufferingHandler</tt><big>(</big><em>capacity</em><big>)</big><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">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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"><tt class="xref py py-meth docutils literal"><span class="pre">shouldFlush()</span></tt></a> returns true,
calls <a class="reference internal" href="#logging.handlers.BufferingHandler.flush" title="logging.handlers.BufferingHandler.flush"><tt class="xref py py-meth docutils literal"><span class="pre">flush()</span></tt></a> to process the buffer.</p>
</dd></dl>
<dl class="method">
<dt id="logging.handlers.BufferingHandler.flush">
<tt class="descname">flush</tt><big>(</big><big>)</big><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">
<tt class="descname">shouldFlush</tt><big>(</big><em>record</em><big>)</big><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><tt class="descclassname">logging.handlers.</tt><tt class="descname">MemoryHandler</tt><big>(</big><em>capacity</em>, <em>flushLevel=ERROR</em>, <em>target=None</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">MemoryHandler</span></tt></a> class. The instance is
initialized with a buffer size of <em>capacity</em>. If <em>flushLevel</em> is not specified,
<tt class="xref py py-const docutils literal"><span class="pre">ERROR</span></tt> 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"><tt class="xref py py-meth docutils literal"><span class="pre">setTarget()</span></tt></a> before this handler does anything useful.</p>
<dl class="method">
<dt id="logging.handlers.MemoryHandler.close">
<tt class="descname">close</tt><big>(</big><big>)</big><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"><tt class="xref py py-meth docutils literal"><span class="pre">flush()</span></tt></a>, sets the target to <a class="reference internal" href="constants.html#None" title="None"><tt class="xref py py-const docutils literal"><span class="pre">None</span></tt></a> and clears the
buffer.</p>
</dd></dl>
<dl class="method">
<dt id="logging.handlers.MemoryHandler.flush">
<tt class="descname">flush</tt><big>(</big><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">MemoryHandler</span></tt></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">
<tt class="descname">setTarget</tt><big>(</big><em>target</em><big>)</big><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">
<tt class="descname">shouldFlush</tt><big>(</big><em>record</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">HTTPHandler</span></tt></a> class, located in the <a class="reference internal" href="#module-logging.handlers" title="logging.handlers: Handlers for the logging module."><tt class="xref py py-mod docutils literal"><span class="pre">logging.handlers</span></tt></a> module,
supports sending logging messages to a Web server, using either <tt class="docutils literal"><span class="pre">GET</span></tt> or
<tt class="docutils literal"><span class="pre">POST</span></tt> semantics.</p>
<dl class="class">
<dt id="logging.handlers.HTTPHandler">
<em class="property">class </em><tt class="descclassname">logging.handlers.</tt><tt class="descname">HTTPHandler</tt><big>(</big><em>host</em>, <em>url</em>, <em>method='GET'</em><big>)</big><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"><tt class="xref py py-class docutils literal"><span class="pre">HTTPHandler</span></tt></a> class. The <em>host</em> can be
of the form <tt class="docutils literal"><span class="pre">host:port</span></tt>, should you need to use a specific port number.
If no <em>method</em> is specified, <tt class="docutils literal"><span class="pre">GET</span></tt> is used.</p>
<dl class="method">
<dt id="logging.handlers.HTTPHandler.emit">
<tt class="descname">emit</tt><big>(</big><em>record</em><big>)</big><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 percent-encoded dictionary.</p>
</dd></dl>
</dd></dl>
<div class="admonition-see-also 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."><tt class="xref py py-mod docutils literal"><span class="pre">logging</span></tt></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."><tt class="xref py py-mod docutils literal"><span class="pre">logging.config</span></tt></a></dt>
<dd>Configuration API for the logging module.</dd>
</dl>
</div>
</div>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar">
<div class="sphinxsidebarwrapper">
<h3><a href="../contents.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">15.9. <tt class="docutils literal"><span class="pre">logging.handlers</span></tt> — 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. HTTPHandler</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="logging.config.html"
title="previous chapter">15.8. <tt class="docutils literal"><span class="pre">logging.config</span></tt> — Logging configuration</a></p>
<h4>Next topic</h4>
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title="next chapter">15.10. <tt class="docutils literal"><span class="pre">getpass</span></tt> — Portable password input</a></p>
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