Syslog

Syslog is an Elixir port of the erlang Twig logger. It is an Elixir logger backend providing UDP support to a syslog server.

Configuration

Elixir Project

Syslog's behavior is controlled using the application configuration environment:

• host (127.0.0.1): the hostname of the syslog server
• port (514): the port of the syslog server
• facility (:local2): syslog facility to be used
• level (:info): logging threshold. Messages "above" this threshold (in syslog parlance) will be discarded. Acceptable values are debug, info, notice, warn, err, crit, alert, and emerg.
• appid (:elixir): inserted as the APPID in the syslog message

For example, the following config/config.exs file sets up syslog using level debug, facility local1, and appid myproj

use Mix.Config
config :logger, [
  level: :debug,
  backends: [Logger.Backends.Syslog],
  syslog: [facility: :local1, appid: "myproj"]
]

Add the application

You should also add the syslog application in the mix.exs file as shown below:

defmodule MyMod.Mixfile do
  # ...
  def application do
    [applications: [:logger, :syslog],
     mod: {MyMod, []}]
  end
  # ...
end

Syslog Server

The syslog server must be configured to support remote logging. On a Redhat based Linux distribution, you can setup remote logging by editing /etc/sysconfig/syslog and add the -r option as shown below:

# /etc/sysconfig/syslog
...
SYSLOGD_OPTIONS="-m 0 -r"
...

If your system uses rsyslog you should add or uncomment the following lines in your /etc/rsyslog.conf:

$ModLoad imudp
$UDPServerRun 514

The facility also needs to be configured. Again, for Redhat distributions, edit /etc/syslog.conf, edit the first line below and and add the second:

#/etc/syslog.conf
...
*.info;local1.none;mail.none;authpriv.none;cron.none            /var/log/messages
...
local2.*                    /var/log/my_elixir_project.log

Then restart the syslog service after making the configuration changes

root@ucx20 ~]# service syslog restart
Shutting down kernel logger:                               [  OK  ]
Shutting down system logger:                               [  OK  ]
Starting system logger:                                    [  OK  ]
Starting kernel logger:                                    [  OK  ]
[root@ucx20 ~]#

Example Project

Checkout the following test project for a working example.

License

syslog is copyright (c) 2014-2018 E-MetroTel.

The source code is released under the MIT License.

Check LICENSE for more information.