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<title>6.29.5.3 RotatingFileHandler
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<H3><A NAME=
"SECTION0082953000000000000000">
6.29.5.3 RotatingFileHandler
</A>
The
<tt class=
"class">RotatingFileHandler
</tt> class supports rotation of disk log files.
<dl><dt><table cellpadding=
"0" cellspacing=
"0"><tr valign=
"baseline">
<td><nobr><b><span class=
"typelabel">class
</span> <tt id='l2h-
2513' xml:id='l2h-
2513'
class=
"class">RotatingFileHandler
</tt></b>(
</nobr></td>
<td><var>filename
</var><big>[
</big><var>, mode
</var><big>[
</big><var>,
maxBytes
</var><big>[
</big><var>, backupCount
</var><big>]
</big><var></var><big>]
</big><var></var><big>]
</big><var></var>)
</td></tr></table></dt>
Returns a new instance of the
<tt class=
"class">RotatingFileHandler
</tt> class. The
specified file is opened and used as the stream for logging. If
<var>mode
</var> is not specified,
<code>'a'
</code> is used. By default, the
You can use the
<var>maxBytes
</var> and
<var>backupCount
</var> values to allow the file to
<i class=
"dfn">rollover
</i> 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
<var>maxBytes
</var> in length; if
<var>maxBytes
</var> is zero, rollover never occurs. If
<var>backupCount
</var>
is non-zero, the system will save old log files by appending the
extensions
".1",
".2" etc., to the filename. For example, with
a
<var>backupCount
</var> of
5 and a base file name of
<span class=
"file">app.log
</span>, you would get
<span class=
"file">app.log
</span>,
<span class=
"file">app.log
.1</span>,
<span class=
"file">app.log
.2</span>, up to
<span class=
"file">app.log
.5</span>. The file being
written to is always
<span class=
"file">app.log
</span>. When this file is filled, it is
closed and renamed to
<span class=
"file">app.log
.1</span>, and if files
<span class=
"file">app.log
.1</span>,
<span class=
"file">app.log
.2</span>, etc. exist, then they are renamed to
<span class=
"file">app.log
.2</span>,
<span class=
"file">app.log
.3</span> etc. respectively.
<dl><dt><table cellpadding=
"0" cellspacing=
"0"><tr valign=
"baseline">
<td><nobr><b><tt id='l2h-
2514' xml:id='l2h-
2514'
class=
"method">doRollover
</tt></b>(
</nobr></td>
<td><var></var>)
</td></tr></table></dt>
Does a rollover, as described above.
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"0" cellspacing=
"0"><tr valign=
"baseline">
<td><nobr><b><tt id='l2h-
2515' xml:id='l2h-
2515'
class=
"method">emit
</tt></b>(
</nobr></td>
<td><var>record
</var>)
</td></tr></table></dt>
Outputs the record to the file, catering for rollover as described previously.
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<span class=
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2.4.2, documentation updated on
28 September
2005.
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