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   rsyslog.conf    ( 5 )

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PROPERTY REPLACER

The property replacer is a core component in rsyslogd's output system. A syslog message has a number of well-defined properties (see below). Each of this properties can be accessed and manipulated by the property replacer. With it, it is easy to use only part of a property value or manipulate the value, e.g. by converting all characters to lower case.

Accessing Properties Syslog message properties are used inside templates. They are accessed by putting them between percent signs. Properties can be modified by the property replacer. The full syntax is as follows:

%propname:fromChar:toChar:options%

propname is the name of the property to access. It is case- sensitive.

Available Properties msg the MSG part of the message (aka "the message" ;))

rawmsg the message exactly as it was received from the socket. Should be useful for debugging.

HOSTNAME hostname from the message

FROMHOST hostname of the system the message was received from (in a relay chain, this is the system immediately in front of us and not necessarily the original sender)

syslogtag TAG from the message

programname the "static" part of the tag, as defined by BSD syslogd. For example, when TAG is "named[12345]", programname is "named".

PRI PRI part of the message - undecoded (single value)

PRI-text the PRI part of the message in a textual form (e.g. "syslog.info")

IUT the monitorware InfoUnitType - used when talking to a MonitorWare backend (also for phpLogCon)

syslogfacility the facility from the message - in numerical form

syslogfacility-text the facility from the message - in text form

syslogseverity severity from the message - in numerical form

syslogseverity-text severity from the message - in text form

timegenerated timestamp when the message was RECEIVED. Always in high resolution

timereported timestamp from the message. Resolution depends on what was provided in the message (in most cases, only seconds)

TIMESTAMP alias for timereported

PROTOCOL-VERSION The contents of the PROTOCOL-VERSION field from IETF draft draft-ietf-syslog-protocol

STRUCTURED-DATA The contents of the STRUCTURED-DATA field from IETF draft draft-ietf-syslog-protocol

APP-NAME The contents of the APP-NAME field from IETF draft draft- ietf-syslog-protocol

PROCID The contents of the PROCID field from IETF draft draft- ietf-syslog-protocol

MSGID The contents of the MSGID field from IETF draft draft- ietf-syslog-protocol

$NOW The current date stamp in the format YYYY-MM-DD

$YEAR The current year (4-digit)

$MONTH The current month (2-digit)

$DAY The current day of the month (2-digit)

$HOUR The current hour in military (24 hour) time (2-digit)

$MINUTE The current minute (2-digit)

Properties starting with a $-sign are so-called system properties. These do NOT stem from the message but are rather internally-generated.

Character Positions FromChar and toChar are used to build substrings. They specify the offset within the string that should be copied. Offset counting starts at 1, so if you need to obtain the first 2 characters of the message text, you can use this syntax: "%msg:1:2%". If you do not wish to specify from and to, but you want to specify options, you still need to include the colons. For example, if you would like to convert the full message text to lower case, use "%msg:::lowercase%". If you would like to extract from a position until the end of the string, you can place a dollar-sign ("$") in toChar (e.g. %msg:10:$%, which will extract from position 10 to the end of the string).

There is also support for regular expressions. To use them, you need to place a "R" into FromChar. This tells rsyslog that a regular expression instead of position-based extraction is desired. The actual regular expression must then be provided in toChar. The regular expression must be followed by the string "--end". It denotes the end of the regular expression and will not become part of it. If you are using regular expressions, the property replacer will return the part of the property text that matches the regular expression. An example for a property replacer sequence with a regular expression is: "%msg:R:.*Sev:. \(.*\) \[.*--end%"

Also, extraction can be done based on so-called "fields". To do so, place a "F" into FromChar. A field in its current definition is anything that is delimited by a delimiter character. The delimiter by default is TAB (US-ASCII value 9). However, if can be changed to any other US-ASCII character by specifying a comma and the decimal US-ASCII value of the delimiter immediately after the "F". For example, to use comma (",") as a delimiter, use this field specifier: "F,44". If your syslog data is delimited, this is a quicker way to extract than via regular expressions (actually, a *much* quicker way). Field counting starts at 1. Field zero is accepted, but will always lead to a "field not found" error. The same happens if a field number higher than the number of fields in the property is requested. The field number must be placed in the "ToChar" parameter. An example where the 3rd field (delimited by TAB) from the msg property is extracted is as follows: "%msg:F:3%". The same example with semicolon as delimiter is "%msg:F,59:3%".

Please note that the special characters "F" and "R" are case- sensitive. Only upper case works, lower case will return an error. There are no white spaces permitted inside the sequence (that will lead to error messages and will NOT provide the intended result).

Property Options Property options are case-insensitive. Currently, the following options are defined:

uppercase convert property to lowercase only

lowercase convert property text to uppercase only

drop-last-lf The last LF in the message (if any), is dropped. Especially useful for PIX.

date-mysql format as mysql date

date-rfc3164 format as RFC 3164 date

date-rfc3339 format as RFC 3339 date

escape-cc replace control characters (ASCII value 127 and values less then 32) with an escape sequence. The sequence is "#<charval>" where charval is the 3-digit decimal value of the control character. For example, a tabulator would be replaced by "#009".

space-cc replace control characters by spaces

drop-cc drop control characters - the resulting string will neither contain control characters, escape sequences nor any other replacement character like space.