Loggery Gem

Make your Rails app produce Logstash compatible log files that can be used for structured, centralized logging in Kibana.

This is a convenience gem that heavily builds on previous work by Lograge by roidrage and logstash-logger by dwbutler. It mainly connects these gems and sets some useful defaults.

Add this line to your application's Gemfile:

gem 'loggery'

And then execute:

$ bundle

To enable, add

config.loggery.enabled = true

to your config/application.rb or to the environment specific config/staging.rb and/or config/production.rb.

In this basic setup, Loggery will save your log output to log/logstash-<rails-env>.log in JSON format. It will also:

• use lograge to create a single-line log entry for every Rails request including the db / view / total duration, controller name, action, http status, etc...
• add the process PID to every log line
• add the request ID to every HTTP request, to easily follow the log trace of any single request.

In addition to logging strings like any normal Rails app

Rails.logger.info "OMG something just happened!"

You can now also log hashes with additional information:

Rails.logger.info message: "OMG something just happened!", reason: "Foo servive not available", context:
some_hash.inspect, attempt: attempt_counter, time_taken: your_time_measurement

This allows you to give your logs more context about the thing you were trying to do, the state of input variables, etc...

The following context attribute names should be avoided, because they are used by other tools in the chain. Using those will result in an exception to make sure you notice during development and testing:

• type
• uid
• _id
• _type
• _source
• _all
• _parent
• _fieldnames
• _routing
• _index
• _size
• _timestamp
• _ttl

If you would like to enrich your log records with information about the active user, add this to your ApplicationController:

include Loggery::Controller::LoggingContext

def loggery_log_context
  {
    user_id: current_user&.id,
    user_email: current_user&.email
  }
end

The above example assumes you would like to log the id and email of your user. You can provide a method loggery_log_context to include whichever additional information from your controllers you would like to add to your log records.

If you're using Sidekiq you can enable structured logging in sidekiq by adding these lines to config/initializers/sidekiq.rb:

Loggery.setup_sidekiq(config)

This will make sure that useful sidekiq-metadata is added to your log lines to make tracing job executions easier. The added info is:

• sidekiq job-id
• sidekiq queue
• thread-id
• worker name
• worker arguments
• retry count
• process PID

Bug reports and pull requests are welcome on GitHub at https://github.com/liefery/loggery-gem. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.