Cfengine; fixes syslog-ng's wagon good

We just finished implementing syslog-ng to send all logs from the nodes in the TIER2 to a single logging server.

Seems simple at first, unfortunately most of the grid services do not log via the standard logging interface and make their own log files. This gets even worse when syslog-ng will not start if a log file it is supposed to track does not exist.

After a bit of pain we realised that cfengine could detect the presence of the gLite log files, rewrite the syslog-ng server config and restart syslog-ng.

A couple of shell scripts and we are away, for each log file they produce something like:

classes:
s_var_log_gridftp_session = ( FileExists("/var/log/gridftp-session.log") )

editfiles:
# /var/log/gridftp-session.log
###################################
s_var_log_gridftp_session::
{ /etc/syslog-ng.conf
DefineClasses "newsyslog_ng"
BeginGroupIfNoLineContaining "# s_var_log_gridftp_session v15"
DeleteLinesContaining "s_var_log_gridftp_session"
Append "# s_var_log_gridftp_session v15"
Append "source s_var_log_gridftp_session { file ('/var/log/gridftp-session.log' follow_freq(30) log_prefix('log_gridftp_session: ')); };"
Append "log { source(s_var_log_gridftp_session); destination(d_stunnel); };"
EndGroup
}
!s_var_log_gridftp_session::
{ /etc/syslog-ng.conf
DefineClasses "newsyslog_ng"
DeleteLinesContaining "s_var_log_gridftp_session"
}

shellcommands:

any::

newsyslog_ng::
"/sbin/service syslog stop" umask=022
"/sbin/chkconfig --level 2345 syslog off"
"/sbin/chkconfig --add syslog-ng"
"/sbin/chkconfig --add syslog-ng-stunnel"
"/etc/init.d/syslog-ng-stunnel restart" umask=022
"/sbin/service syslog-ng restart" umask=022

So central logging is a go, and there is only one master config file for all nodes. Even better if you start a new service, its logs get added automatically.