RequestIdLogging

RequestIdLogging provides a Rack middleware and a logger formatter to prepend X-Request-Id to log messages in your Rails app.

Installation

Add this line to your application's Gemfile:

gem 'request_id_logging'

And then execute:

$ bundle

Or install it yourself as:

$ gem install request_id_logging

Usage

First, add RequestIdLogging::Middleware to rack middlewares. In your application.rb or environments/xxx.rb, insert RequestIdLogging::Middleware after ActionDispatch::RequestId.

module MyApp
  class Application < Rails::Application
    # some configurations
    # :

    config.middleware.insert_after ActionDispatch::RequestId, RequestIdLogging::Middleware
  end
end

Next, set RequestIdLogging::Formatter instance to your logger's formatter.

module MyApp
  class Application < Rails::Application
    # Set to Rails logger.
    config.logger = ActiveSupport::Logger.new("log/#{Rails.env}.log")
    config.logger.formatter = RequestIdLogging::Formatter.new
    config.logger.formatter.datetime_format = '%Y-%m-%d %H:%M:%S.%L '.freeze

    # And/Or set to your original logger's formatter.
    config.x.my_app_logger = Logger.new('log/my_app.log')
    config.x.my_app_logger.formatter = RequestIdLogging::Formatter.new
    config.x.my_app_logger.formatter.datetime_format = '%Y-%m-%d %H:%M:%S.%L '.freeze
  end
end

Then, loggers write logs with request id.

Rails.logger.info 'test'
# => I, [2016-12-03 20:52:59.879 #106]  INFO -- : [aca576f4-f4fa-4c2a-b172-d8fb5cc37681] test

Rails.configuration.x.my_app_logger.info 'test my_app'
# => I, [2016-12-03 20:53:00.184 #106]  INFO -- : [aca576f4-f4fa-4c2a-b172-d8fb5cc37681] test my_app

Request id customization

You can customize request id using :request_id_proc option.

Following example extracts first 8 characters from request id and uses it as request id.

logger = Logger.new('log/my_app.log')
logger.formatter = RequestIdLogging::Formatter.new(request_id_proc: ->(id) { id&.first(8) }) # &. operator requires >= Ruby 2.3.0

logger.info 'customize request id'
# => I, [2016-12-03 20:46:31.399 #83]  INFO -- : [4a966ef6] customize request id

Formatter delegation

You can use your original formatter using :formatter option.

If this option is specified, RequestIdLogging::Formatter prepends request id to msg and calls your formatter#call.

original_formatter = Logger::Formatter.new
def original_formatter.call(severity, time, progname, msg)
  "MyFormatter: #{severity}, #{time}, #{progname}, #{msg}\n"
end

logger = Logger.new('log/my_app.log')
logger.formatter = RequestIdLogging::Formatter.new(formatter: original_formatter)

logger.info 'formatter delegation'
# => MyFormatter: INFO, 2016-12-04 10:47, , [6a8ef6bb-cf75-4ddf-a111-72c285c3ebda] test my_app

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ryu39/request_id_logging. 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.

License

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