MLogger

MLogger is a simple logger featuring an alternative log rotation strategy, specially designed to handle high traffic loads and transient environments.

To use MLogger, initiate a new logger with MLogger.new('log/production.log', shift_period_suffix: '%Y%m%d_%H').

Here's how ordinary log rotation strategy works:

1. Logs are consistently written to the same file (e.g., production.log).
2. The file is renamed once a specified time or size limit is reached (e.g., production.log becomes production.log.20230701).

In contrast, MLogger employs a different log rotation strategy:

1. Each log message is written to a time-stamped file (e.g., production.log.20230701_11).
2. Upon reaching a time threshold, logging is switched to a new file with the updated timestamp (e.g., production.log.20230701_12).

Key advantages of using MLogger include:

1. Support for hourly and shorter shift periods, accommodating heavy traffic loads.
2. Log lines always exist within the appropriately time-stamped path, even in cases where there are no logs or when there is an overflow of logs beyond shift periods.

1. For systems expecting an IO-like interface, you can utilize MLogger::LoggerDevice (MLogger::LoggerDevice#write).
2. To facilitate line-based operations, MLogger skips writing a log header (e.g., # Logfile created on %s by %s).

Install the gem and add to the application's Gemfile by executing:

$ bundle add m_logger

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install m_logger

# Log to File
hourly_logger = MLogger.new('log/my_log', shift_period_suffix: '%Y%m%d_%H') # hourly rotate
hourly_logger.debug('fuga')

daily_logger = MLogger.new('log/my_log', shift_period_suffix: '%Y%m%d') # daily rotate
daily_logger.debug('fuga')

# Log in Rack::Middleware
logger_device = MLogger::Device.new('log/rack_ltsv', shift_period_suffix: '%Y%m%d_%H')
Rails.configuration.middleware.insert(0, Rack::LtsvLogger, logger_device)

# Log to Stdout (You don't have to change logger class.)
logger = MLogger.new(STDOUT)
logger.info('hoge')

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 the created tag, and push the .gem file to rubygems.org.

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

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

Everyone interacting in the MLogger project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

External log file specification originates from Mobage and Sakasho series in DeNA. Thanks for those who have contributed to these products.