SyslogLogger is a Logger work-alike that logs via syslog instead of to a file. You can add SyslogLogger to your Rails production environment to aggregate logs between multiple machines.

By default, SyslogLogger uses the program name ‘rails’, but this can be changed via the first argument to ::new.

NOTE! You can only set the SyslogLogger program name when you initialize SyslogLogger for the first time. This is a limitation of the way SyslogLogger uses syslog (and in some ways, a limitation of the way syslog(3) works). Attempts to change SyslogLogger’s program name after the first initialization will be ignored.

Sample usage with Rails

config/environment/production.rb

Add the following lines:

require 'syslog_logger'
RAILS_DEFAULT_LOGGER = SyslogLogger.new

config/environment.rb

In 0.10.0, change this line:

RAILS_DEFAULT_LOGGER = Logger.new("#{RAILS_ROOT}/log/#{RAILS_ENV}.log")

to:

RAILS_DEFAULT_LOGGER ||= Logger.new("#{RAILS_ROOT}/log/#{RAILS_ENV}.log")

Other versions of Rails should have a similar change.

BSD syslog setup

/etc/syslog.conf

Add the following lines:

!rails
*.*                                             /var/log/production.log

Then touch /var/log/production.log and signal syslogd with a HUP (killall -HUP syslogd, on FreeBSD).

/etc/newsyslog.conf

Add the following line:

/var/log/production.log                 640  7     *    @T00  Z

This creates a log file that is rotated every day at midnight, gzip’d, then kept for 7 days. Consult newsyslog.conf(5) for more details.

syslog-ng setup

syslog-ng.conf

destination rails_log { file("/var/log/production.log"); };
filter f_rails { program("rails.*"); };
log { source(src); filter(f_rails); destination(rails_log); };

Starting

Now restart your Rails app. Your production logs should now be showing up in /var/log/production.log. If you have mulitple machines, you can log them all to a central machine with remote syslog logging for analysis. Consult your syslogd(8) manpage for further details.