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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head>
<meta http-equiv="Content-Language" content="en"><title>Text File Input Monitor</title></head>
<body>
<a href="rsyslog_conf_modules.html">back</a>
<h1>Text File Input Module</h1>
<p><b>Module Name: imfile</b></p>
<p><b>Author: </b>Rainer Gerhards
<rgerhards@adiscon.com></p>
<p><b>Description</b>:</p>
<p>Provides the ability to convert any standard text file into
a syslog message. A standard
text file is a file consisting of printable characters with lines
being delimited by LF.</p>
<p>The file is read line-by-line and any line read is passed to
rsyslog's rule engine. The rule engine applies filter conditons and
selects which actions needs to be carried out.</p>
<p>As new lines are written they are taken from the file and
processed. Please note that this happens based on a polling interval
and not immediately. The file monitor support file rotation. To fully
work, rsyslogd must run while the file is rotated. Then, any remaining
lines from the old file are read and processed and when done with that,
the new file is being processed from the beginning. If rsyslogd is
stopped during rotation, the new file is read, but any not-yet-reported
lines from the previous file can no longer be obtained.</p>
<p>When rsyslogd is stopped while monitoring a text file, it
records the last processed location and continues to work from there
upon restart. So no data is lost during a restart (except, as noted
above, if the file is rotated just in this very moment).</p>
<p>Currently, the file must have a fixed name and location
(directory). It is planned to add support for dynamically generating
file names in the future.</p>
<p>Multiple files may be monitored by specifying
$InputRunFileMonitor multiple times.
</p>
<p><b>Configuration Directives</b>:</p>
<ul>
<li><strong>$InputFileName /path/to/file</strong><br>
The file being monitored. So far, this must be an absolute name (no
macros or templates)</li>
<li><span style="font-weight: bold;">$InputFileTag
tag:</span><br>
The tag to be used for messages that originate from this file. If you
would like to see the colon after the tag, you need to specify it here
(as shown above).</li>
<li><span style="font-weight: bold;">$InputFileStateFile
<name-of-state-file></span><br>
Rsyslog must keep track of which parts of the to be monitored file it
already processed. This is done in the state file. This file always is
created in the rsyslog working directory (configurable via
$WorkDirectory). Be careful to use unique names for different files
being monitored. If there are duplicates, all sorts of "interesting"
things may happen. Rsyslog currently does not check if a name is
specified multiple times.</li>
<li><span style="font-weight: bold;">$InputFileFacility
facility</span><br>
The syslog facility to be assigned to lines read. Can be specified in
textual form (e.g. "local0", "local1", ...) or as numbers (e.g. 128 for
"local0"). Textual form is suggested. <span style="font-weight: bold;">Default</span> is
"local0".<span style="font-weight: bold;"></span></li>
<li><span style="font-weight: bold;">$InputFileSeverity</span><br>
The
syslog severity to be assigned to lines read. Can be specified in
textual form (e.g. "info", "warning", ...) or as numbers (e.g. 4 for
"info"). Textual form is suggested. <span style="font-weight: bold;">Default</span>
is "notice".</li>
<li><span style="font-weight: bold;">$InputRunFileMonitor</span><br>
This <span style="font-weight: bold;">activates</span>
the current monitor. It has no parameters. If you forget this
directive, no file monitoring will take place.</li>
<li><span style="font-weight: bold;">$InputFilePollInterval
seconds</span><br>
This is a global setting. It specifies how often files are to be polled
for new data. The time specified is in seconds. The <span style="font-weight: bold;">default value</span> is 10
seconds. Please note that future
releases of imfile may support per-file polling intervals, but
currently this is not the case. If multiple $InputFilePollInterval
statements are present in rsyslog.conf, only the last one is used.<br>
A short poll interval provides more rapid message forwarding, but
requires more system ressources. While it is possible, we stongly
recommend not to set the polling interval to 0 seconds. That will make
rsyslogd become a CPU hog, taking up considerable ressources. It is
supported, however, for the few very unusual situations where this
level may be needed. Even if you need quick response, 1 seconds should
be well enough. Please note that imfile keeps reading files as long as
there is any data in them. So a "polling sleep" will only happen when
nothing is left to be processed.</li>
<li><b>$InputFilePersistStateInterval</b> [lines]</b><br>
Available in 4.7.3+, 5.6.2+<br>
Specifies how often the state file shall be written when processing the input
file. The default value is 0, which means a new state file is only written when
the monitored files is being closed (end of rsyslogd execution). Any other
value n means that the state file is written every time n file lines have
been processed. This setting can be used to guard against message duplication due
to fatal errors (like power fail). Note that this setting affects imfile
performance, especially when set to a low value. Frequently writing the state
file is very time consuming.
<li><b>$InputFileReadMode</b> [mode]</b><br>
Available in 5.7.3+
<br>
Mode to be used when reading lines. 0 (the default) means that each line is forwarded
as its own log message.
</ul>
<b>Caveats/Known Bugs:</b>
<p>So far, only 100 files can be monitored. If more are needed,
the source needs to be patched. See define MAX_INPUT_FILES in imfile.c</p><p>Powertop
users may want to notice that imfile utilizes polling. Thus, it is no
good citizen when it comes to conserving system power consumption. We
are currently evaluating to move to inotify(). However, there are a
number of subtle issues, which needs to be worked out first. We will
make the change as soon as we can. If you can afford it, we recommend
using a long polling interval in the mean time.
</p>
<p><b>Sample:</b></p>
<p>The following sample monitors two files. If you need just one,
remove the second one. If you need more, add them according to the
sample ;). This code must be placed in /etc/rsyslog.conf (or wherever
your distro puts rsyslog's config files). Note that only commands
actually needed need to be specified. The second file uses less
commands and uses defaults instead.<br>
</p>
<textarea rows="15" cols="60">$ModLoad imfile #
needs to be done just once
# File 1
$InputFileName /path/to/file1
$InputFileTag tag1:
$InputFileStateFile stat-file1
$InputFileSeverity error
$InputFileFacility local7
$InputRunFileMonitor
# File 2
$InputFileName /path/to/file2
$InputFileTag tag2:
$InputFileStateFile stat-file2
$InputRunFileMonitor
# ... and so on ...
#
# check for new lines every 10 seconds
$InputFilePollingInterval 10
</textarea>
<p>[<a href="rsyslog_conf.html">rsyslog.conf overview</a>]
[<a href="manual.html">manual index</a>] [<a href="http://www.rsyslog.com/">rsyslog site</a>]</p>
<p><font size="2">This documentation is part of the
<a href="http://www.rsyslog.com/">rsyslog</a> project.<br>
Copyright © 2008 by <a href="http://www.gerhards.net/rainer">Rainer
Gerhards</a> and <a href="http://www.adiscon.com/">Adiscon</a>.
Released under the GNU GPL version 3 or higher.</font></p>
</body></html>
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