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<H2><A NAME="SECTION0082920000000000000000"></A><A NAME="minimal-example"></A>
<BR>
6.29.2 Basic example
</H2>

<P>

<span class="versionnote">Changed in version 2.4:
formerly <tt class="function">basicConfig</tt> did not take any keyword
arguments.</span>

<P>
The <tt class="module">logging</tt> package provides a lot of flexibility, and its
configuration can appear daunting.  This section demonstrates that simple
use of the logging package is possible.

<P>
The simplest example shows logging to the console:

<P>
<div class="verbatim"><pre>
import logging

logging.debug('A debug message')
logging.info('Some information')
logging.warning('A shot across the bows')
</pre></div>

<P>
If you run the above script, you'll see this:
<div class="verbatim"><pre>
WARNING:root:A shot across the bows
</pre></div>

<P>
Because no particular logger was specified, the system used the root logger.
The debug and info messages didn't appear because by default, the root
logger is configured to only handle messages with a severity of WARNING
or above. The message format is also a configuration default, as is the output
destination of the messages - <code>sys.stderr</code>. The severity level,
the message format and destination can be easily changed, as shown in
the example below:

<P>
<div class="verbatim"><pre>
import logging

logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s %(levelname)s %(message)s',
                    filename='/tmp/myapp.log',
                    filemode='w')
logging.debug('A debug message')
logging.info('Some information')
logging.warning('A shot across the bows')
</pre></div>

<P>
The <tt class="method">basicConfig()</tt> method is used to change the configuration
defaults, which results in output (written to <code>/tmp/myapp.log</code>)
which should look something like the following:

<P>
<div class="verbatim"><pre>
2004-07-02 13:00:08,743 DEBUG A debug message
2004-07-02 13:00:08,743 INFO Some information
2004-07-02 13:00:08,743 WARNING A shot across the bows
</pre></div>

<P>
This time, all messages with a severity of DEBUG or above were handled,
and the format of the messages was also changed, and output went to the
specified file rather than the console.

<P>
Formatting uses standard Python string formatting - see section
<A href="typesseq-strings.html#typesseq-strings">2.3.6</A>. The format string takes the following
common specifiers. For a complete list of specifiers, consult the
<tt class="class">Formatter</tt> documentation.

<P>
<div class="center"><table class="realtable">
  <thead>
    <tr>
      <th class="left"  >Format</th>
      <th class="left"  >Description</th>
      </tr>
    </thead>
  <tbody>
    <tr><td class="left"   valign="baseline"><code>%(name)s</code></td>
        <td class="left"  >Name of the logger (logging channel).</td></tr>
    <tr><td class="left"   valign="baseline"><code>%(levelname)s</code></td>
        <td class="left"  >Text logging level for the message
                        (<code>'DEBUG'</code>, <code>'INFO'</code>,
                        <code>'WARNING'</code>, <code>'ERROR'</code>,
                        <code>'CRITICAL'</code>).</td></tr>
    <tr><td class="left"   valign="baseline"><code>%(asctime)s</code></td>
        <td class="left"  >Human-readable time when the <tt class="class">LogRecord</tt>
                        was created.  By default this is of the form
                        ``2003-07-08 16:49:45,896'' (the numbers after the
                        comma are millisecond portion of the time).</td></tr>
    <tr><td class="left"   valign="baseline"><code>%(message)s</code></td>
        <td class="left"  >The logged message.</td></tr></tbody>
</table></div>

<P>
To change the date/time format, you can pass an additional keyword parameter,
<var>datefmt</var>, as in the following:

<P>
<div class="verbatim"><pre>
import logging

logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s %(levelname)-8s %(message)s',
                    datefmt='%a, %d %b %Y %H:%M:%S',
                    filename='/temp/myapp.log',
                    filemode='w')
logging.debug('A debug message')
logging.info('Some information')
logging.warning('A shot across the bows')
</pre></div>

<P>
which would result in output like

<P>
<div class="verbatim"><pre>
Fri, 02 Jul 2004 13:06:18 DEBUG    A debug message
Fri, 02 Jul 2004 13:06:18 INFO     Some information
Fri, 02 Jul 2004 13:06:18 WARNING  A shot across the bows
</pre></div>

<P>
The date format string follows the requirements of <tt class="function">strftime()</tt> -
see the documentation for the <tt class="module"><a href="module-time.html">time</a></tt> module.

<P>
If, instead of sending logging output to the console or a file, you'd rather
use a file-like object which you have created separately, you can pass it
to <tt class="function">basicConfig()</tt> using the <var>stream</var> keyword argument. Note
that if both <var>stream</var> and <var>filename</var> keyword arguments are passed,
the <var>stream</var> argument is ignored.

<P>
Of course, you can put variable information in your output. To do this,
simply have the message be a format string and pass in additional arguments
containing the variable information, as in the following example:

<P>
<div class="verbatim"><pre>
import logging

logging.basicConfig(level=logging.DEBUG,
                    format='%(asctime)s %(levelname)-8s %(message)s',
                    datefmt='%a, %d %b %Y %H:%M:%S',
                    filename='/temp/myapp.log',
                    filemode='w')
logging.error('Pack my box with %d dozen %s', 5, 'liquor jugs')
</pre></div>

<P>
which would result in

<P>
<div class="verbatim"><pre>
Wed, 21 Jul 2004 15:35:16 ERROR    Pack my box with 5 dozen liquor jugs
</pre></div>

<P>

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<span class="release-info">Release 2.4.2, documentation updated on 28 September 2005.</span>
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