Home / server / Questions / 502932
In Process
shylent
Asked: 2013-04-27 07:33:54 +0800 CST

Rsyslog: Difference between logging to a UNIX domain socket or an INET socket (UDP)

  • 772

I am observing the following behaviour when logging to syslog from an external application: if I send a well-formed syslog message to a UDP socket, rsyslog correctly parses it, however if the very same message is sent to a UNIX domain socket (/dev/log), it is not parsed at all (rsyslog basically assumes, that everything, that he received, is a message, so no timestamp, no anything).

The message in question is

<142>1 2010-12-29T11:11:11Z foo bar 123 baz - A Message

which is parsed as

Dec 29 11:11:11 foo bar[123] A Message

unless it isn't.

logging

2 Answers

  1. Probably you should send the message without the hostname (foo) and in rfc3164 format (not rfc5424 as the above) to get it parsed.

    • 1

  2. When parsing messages rsyslog does its best to make sense of it.

    For a message received from an Unix socket, rsyslog accepts RFC 3164-like messages, using these fields: pri, timestamp, tag, and content.

    It accepts various message formats, like :

    • just a message
    • <pri>message
    • <pri>tag: msg

    About the message timestamps:

    1. They must be RFC3164 formatted.
    2. Since the SysSock.IgnoreTimestamp option is enabled by default, your timestamps will be ignored until you disable this option.

    The hostname field cannot be overridden. rsyslog will always get it from its configuration.

    • 0