This is a syslog backend for Lager. It allows you to send messages out of lager and into the local syslog daemon.
Configure a Lager handler like the following:
{lager_syslog_backend, [Identity, Facility, Level]}
The Identity is the string to tag all messages with in syslog, usually the application’s name. The facility is the facility to log to (see the syslog documentation for a list of these). The Level is the lager level at which the backend accepts messages (eg. using ‘info’ would send all messages at info level or above into syslog). While you can filter messages at the syslog level, it will improve performance if you filter in lager instead.
An example for riak would look something like this:
{lager_syslog_backend, ["riak", local7, info]}
Refer to Lager’s documentation for futher information on configuring handlers.
There’s not a lot to go wrong, but if you are not receiving messages, check your syslog config and read its manpage for more information. OS X, in particular, has a very strange default config where it drops messages below the ‘info’ level by default.