peburrows/json_logger

Simple JSON Logger for Elixir apps.

Elixir JSON Logger

JSON Logger is a logger backend that outputs elixir logs in JSON format.

This project is originally designed to make Elixir apps work with Logstash easily. It aims at providing as much information for the log is possible, so the logs can be more easily analyzed by backend services like Elasticsearch.

Issues and PRs are welcome.

Dependencies

This project requires json.

Configuration

Elixir Project

JSON Logger currently provides very few options:

• level: The minimal level of logging. There's no default of this option. Example: level: :warn
• output: The output of the log. Must be either :console or {:udp, host, port} or {:tcp, host, port}. Example: output: {:udp, "localhost", 514}`
• metadata: Whatever else you want in the log. Example: metadata: "Some very important project"

Example configuration: config :logger, :json_logger, level: :info, output: {:udp, "localhost", 514}

TCP support is still experimental, please submit issues that you encounter.

In your application

You should add json_logger to your mix.exs as well. This step may not be necessary (if you know why please tell me).

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

Adding the logger backend

You need to add this backend to your Logger, preferably put this in your Application's start/2.

Logger.add_backend Logger.Backends.JSON

If you wish to use Logstash with this library

Here is an example logstash configuration:

input {
  udp {
    port => 514
    type => "elixir_json_logging"
  }
}

filter {
  json {
    source => "message"
  }
}

output {
  stdout {
    codec => rubydebug
  }
}

Note that this configuration will probably break on your system (listening to a <1024 port). You should change the "port" to a larger value.