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| author | Rainer Gerhards <rgerhards@adiscon.com> | 2008-11-11 11:00:37 +0100 |
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| committer | Rainer Gerhards <rgerhards@adiscon.com> | 2008-11-11 11:00:37 +0100 |
| commit | 170d0d6f375241e0d0ca85a1327df82165fec439 (patch) | |
| tree | 4c68c10812c13819d1eede393905601cc3e553c2 /doc/rsyslog_conf_templates.html | |
| parent | 3c615c60beb851f3a42cea3fcc31f4a2243cedaa (diff) | |
| download | rsyslog-170d0d6f375241e0d0ca85a1327df82165fec439.tar.gz rsyslog-170d0d6f375241e0d0ca85a1327df82165fec439.tar.xz rsyslog-170d0d6f375241e0d0ca85a1327df82165fec439.zip | |
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diff --git a/doc/rsyslog_conf_templates.html b/doc/rsyslog_conf_templates.html new file mode 100644 index 00000000..90b5fafe --- /dev/null +++ b/doc/rsyslog_conf_templates.html @@ -0,0 +1,150 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html><head><title>Templates - rsyslog.conf</title></head> +<body> +<p>This is a part of the rsyslog.conf - documentation.</p> +<a href="rsyslog_conf.html">back</a> +<h2>Templates</h2> +<p>Templates are a key feature of rsyslog. They allow to specify +any +format a user might want. They are also used for dynamic file name +generation. Every output in rsyslog uses templates - this holds true +for files, user messages and so on. The database writer expects its +template to be a proper SQL statement - so this is highly customizable +too. You might ask how does all of this work when no templates at all +are specified. Good question ;) The answer is simple, though. Templates +compatible with the stock syslogd formats are hardcoded into rsyslogd. +So if no template is specified, we use one of these hardcoded +templates. Search for "template_" in syslogd.c and you will find the +hardcoded ones.</p> +<p>A template consists of a template directive, a name, the +actual template text and optional options. A sample is:</p> +<blockquote><code>$template MyTemplateName,"\7Text +%property% some more text\n",<options></code></blockquote> +<p>The "$template" is the template directive. It tells rsyslog +that this line contains a template. "MyTemplateName" is the template +name. All +other config lines refer to this name. The text within quotes is the +actual template text. The backslash is an escape character, much as it +is in C. It does all these "cool" things. For example, \7 rings the +bell (this is an ASCII value), \n is a new line. C programmers and perl +coders have the advantage of knowing this, but the set in rsyslog is a +bit restricted currently. +</p> +<p>All text in the template is used literally, except for things +within percent signs. These are properties and allow you access to the +contents of the syslog message. Properties are accessed via the +property replacer (nice name, huh) and it can do cool things, too. For +example, it can pick a substring or do date-specific formatting. More +on this is below, on some lines of the property replacer.<br> +<br> +The <options> part is optional. It carries options +influencing the template as whole. See details below. Be sure NOT to +mistake template options with property options - the later ones are +processed by the property replacer and apply to a SINGLE property, only +(and not the whole template).<br> +<br> +Template options are case-insensitive. Currently defined are: </p> +<p><b>sql</b> - format the string suitable for a SQL +statement in MySQL format. This will replace single quotes ("'") and +the backslash character by their backslash-escaped counterpart ("\'" +and "\\") inside each field. Please note that in MySQL configuration, +the <code class="literal">NO_BACKSLASH_ESCAPES</code> +mode must be turned off for this format to work (this is the default).</p> +<p><b>stdsql</b> - format the string suitable for a +SQL statement that is to be sent to a standards-compliant sql server. +This will replace single quotes ("'") by two single quotes ("''") +inside each field. You must use stdsql together with MySQL if in MySQL +configuration the +<code class="literal">NO_BACKSLASH_ESCAPES</code> is +turned on.</p> +<p>Either the <b>sql</b> or <b>stdsql</b> +option <b>must</b> be specified when a template is used +for writing to a database, otherwise injection might occur. Please note +that due to the unfortunate fact that several vendors have violated the +sql standard and introduced their own escape methods, it is impossible +to have a single option doing all the work. So you yourself +must make sure you are using the right format. <b>If you choose +the wrong one, you are still vulnerable to sql injection.</b><br> +<br> +Please note that the database writer *checks* that the sql option is +present in the template. If it is not present, the write database +action is disabled. This is to guard you against accidental forgetting +it and then becoming vulnerable to SQL injection. The sql option can +also be useful with files - especially if you want to import them into +a database on another machine for performance reasons. However, do NOT +use it if you do not have a real need for it - among others, it takes +some toll on the processing time. Not much, but on a really busy system +you might notice it ;)</p> +<p>The default template for the write to database action has the +sql option set. As we currently support only MySQL and the sql option +matches the default MySQL configuration, this is a good choice. +However, if you have turned on +<code class="literal">NO_BACKSLASH_ESCAPES</code> in +your MySQL config, you need to supply a template with the stdsql +option. Otherwise you will become vulnerable to SQL injection. <br> +<br> +To escape:<br> +% = \%<br> +\ = \\ --> '\' is used to escape (as in C)<br> +$template TraditionalFormat,%timegenerated% %HOSTNAME% +%syslogtag%%msg%\n"<br> +<br> +Properties can be accessed by the <a href="property_replacer.html">property +replacer</a> (see there for details).</p> +<p><b>Please note that templates can also by +used to generate selector lines with dynamic file names.</b> For +example, if you would like to split syslog messages from different +hosts to different files (one per host), you can define the following +template:</p> +<blockquote><code>$template +DynFile,"/var/log/system-%HOSTNAME%.log"</code></blockquote> +<p>This template can then be used when defining an output +selector line. It will result in something like +"/var/log/system-localhost.log"</p> +<p>Template +names beginning with "RSYSLOG_" are reserved for rsyslog use. Do NOT +use them if, otherwise you may receive a conflict in the future (and +quite unpredictable behaviour). There is a small set of pre-defined +templates that you can use without the need to define it:</p> +<ul> +<li><span style="font-weight: bold;">RSYSLOG_TraditionalFileFormat</span> +- the "old style" default log file format with low-precision timestamps</li> +<li><span style="font-weight: bold;">RSYSLOG_FileFormat</span> +- a modern-style logfile format similar to TraditionalFileFormat, buth +with high-precision timestamps and timezone information</li> +<li><span style="font-weight: bold;">RSYSLOG_TraditionalForwardFormat</span> +- the traditional forwarding format with low-precision timestamps. Most +useful if you send messages to other syslogd's or rsyslogd +below +version 3.12.5.</li> +<li><span style="font-weight: bold;">RSYSLOG_ForwardFormat</span> +- a new high-precision forwarding format very similar to the +traditional one, but with high-precision timestamps and timezone +information. Recommended to be used when sending messages to rsyslog +3.12.5 or above.</li> +<li><span style="font-weight: bold;">RSYSLOG_SyslogProtocol23Format</span> +- the format specified in IETF's internet-draft +ietf-syslog-protocol-23, which is assumed to be come the new syslog +standard RFC. This format includes several improvements. The rsyslog +message parser understands this format, so you can use it together with +all relatively recent versions of rsyslog. Other syslogd's may get +hopelessly confused if receiving that format, so check before you use +it. Note that the format is unlikely to change when the final RFC comes +out, but this may happen.</li> +<li><span style="font-weight: bold;">RSYSLOG_DebugFormat</span> +- a special format used for troubleshooting property problems. This format +is meant to be written to a log file. Do <b>not</b> use for production or remote +forwarding.</li> +</ul> + +<p>[<a href="manual.html">manual index</a>] +[<a href="rsyslog_conf.html">rsyslog.conf</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 2 or higher.</font></p> +</body> +</html> + |