Logging.md

Logging

The Infinum Rails Team uses Graylog for logging all requests that are processed by our apps.

Setup

To use Graylog in a Rails project, you need to do the following:

• Append your Gemfile with the following gems:

  • Example

      gem 'gelf'
      gem 'rails_semantic_logger'

  • Gelf gem allows you to send GELF messages to the Graylog server instances.

  • The rails_semantic_logger gem replaces the default Rails logger with Semantic Logger. It also reduces the Rails logging output in production to almost a single line for every Controller-Action call. Basically, it is a full-fledged logging framework with numerous options.

• Add graylog_host in config for all environments.

  • production.rb and staging.rb

      config.graylog_host = Rails.application.secrets.graylog_host
      config.rails_semantic_logger.add_file_appender = false  # if you want to disable logging to files

  • development.rb and test.rb

      config.graylog_host = nil

• Add semantic_logger.rb in the initializers folder.

  • Example

      if Rails.application.config.graylog_host.present?
        SemanticLogger.add_appender(
          appender:    :graylog,
          url:         Rails.application.config.graylog_host,
          application: "#{application_name}-#{Rails.env}",
          level:       :info,
          gelf_options: {
            tls: {
              cert: '/etc/ssl/private/graylog/graylog.crt',
              key: '/etc/ssl/private/graylog/graylog.key'
            }
          }
        )
      end

  • With these settings, you need to use TCP. Keep that in mind when defining the URL (ask the DevOps team).

• Customize payload

  • Add the following code in the controllers whose logs you wish to alter:

      def append_info_to_payload(payload)
        super
        payload[:ip_address] = request.remote_ip if request.remote_ip.present?
        payload[:user] = current_user.username if current_user.present?
      end

• Consult with your PM and define the time range for keeping historical data.

• Notify our devops before turning the logging on because they should handle streams, permissions, backup options, etc.