We could not cover all languages or examples for many applications in the documentation. But to give a brief overview, we created this page.

Ruby on Rails

This is easy: You just need to combine a few components.

Log All Requests and Logger Calls into Graylog

The recommended way to send structured information (i.e. HTTP return code, action, controller, … in additional fields) about every request and explicit Rails.logger calls is easily accomplished using the GELF gem and lograge. Lograge builds one combined log entry for every request (instead of several lines like the standard Rails logger) and has a Graylog output since version 0.2.0.

Start by adding Lograge and the GELF gem to your Gemfile:

gem "gelf"
gem "lograge"

Now configure both in your Rails application. Usually  config/environments/production.rb  is a good place for that:

config.lograge.enabled = true
config.lograge.formatter = Lograge::Formatters::Graylog2.new
config.logger = GELF::Logger.new("graylog.example.org", 12201, "WAN", { :host => "hostname-of-this-app", :facility => "heroku" })

This configuration will also send all explicit  Rails.logger  calls (e.g. Rails.logger.error "Something went wrong") to Graylog.

Log only explicit logger calls into Graylog

If you don’t want to log information about every request, but only explicit  Rails.logger  calls, it is enough to only configure the Rails logger.

Add the GELF gem to your Gemfile:

gem "gelf"

…and configure it in your Rails application. Usually  config/environments/production.rb  is a good place for that:

config.logger = GELF::Logger.new("graylog.example.org", 12201, "WAN", { :host => "hostname-of-this-app", :facility => "heroku" })

Heroku

You need to apply a workaround if you want custom logging on Heroku. The reason for this is that Heroku injects its own logger (rails_log_stdout), that overwrites your custom one. The workaround is to add a file that makes Heroku think that the logger is already in your application:

$ touch vendor/plugins/rails_log_stdout/heroku_fix