AwesomeFluentLogger

This library can mimic Ruby's built-in Logger class to forward logs to Fluentd. You can use this library not only for Rails but also for pure-Ruby apps.

Commentary: シンプルに Fluentd にログ転送ができる RubyGem "awesome_fluent_logger" をつくった (日本語/Japanese)

Installation

Add this line to your application's Gemfile:

gem 'awesome_fluent_logger'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install awesome_fluent_logger

Usage

Tiny example

Your Ruby program:

require 'awesome_fluent_logger'

logger = AwesomeFluentLogger.new(fluent: { host: 'localhost', port: 24224 })
logger.info('information logging')

Fluentd output:

2021-01-23 13:28:46.000000000 +0000 info: {"severity":"INFO","time":"2021-01-23 13:28:46.336397 +0000","progname":null,"message":"information logging"}

Rails example

Rails configure file (config/application.rb or config/environments/{RAILS_ENV}.rb):

logger = AwesomeFluentLogger.new(fluent: { host: 'localhost', port: 24224 })
config.logger = ActiveSupport::TaggedLogging.new(logger)

Can be set fluent-logger instance in initialize parameters

:fluent of initialize argument can be set an instance of Fluent::Logger::FluentLogger class.

fluent = Fluent::Logger::FluentLogger.new(nil, socket_path: '/tmp/fluent.sock')
logger = AwesomeFluentLogger.new(fluent: fluent)

Fluent tags

If the initialize parameter [:fluent][:tag_prefix] is specified, it will be inserted at the beginning of the Fluentd tag.

logger = AwesomeFluentLogger.new(fluent: { tag_prefix: 'kanan', host: 'localhost', port: 24224 })
logger.info('ご機嫌いかがかなん？')

2021-01-23 13:28:46.000000000 +0000 kanan.info: {"severity":"INFO", ...

The same effect is given by specifying progname.

logger = AwesomeFluentLogger.new(fluent: { host: 'localhost', port: 24224 }, progname: 'chika')
logger.info('かんかんみかん')

2021-01-23 13:28:46.000000000 +0000 chika.info: {"severity":"INFO", ...

If both are specified, they will be nested. In this case, tag_prefix will be added first.

logger = AwesomeFluentLogger.new(fluent: { tag_prefix: 'kanan', host: 'localhost', port: 24224 }, progname: 'chika')
logger.info('2人は幼馴染です')

2021-01-23 13:28:46.000000000 +0000 kanan.chika.info: {"severity":"INFO", ...

Initialize parameters

Other initialization parameters are based on the Logger class of the Ruby standard library.

Key	Default	Descriptions
fluent	(none)	Fluent::Logger::FluentLogger initialize paramater hash or Fluent::Logger::FluentLogger class instance
level	Logger::DEBUG	Logger severity level constant
progname	nil	Program name to include in log messages and Fluentd tag
formatter	AwesomeFluentLogger::Formatter	Inherited Logger::Formatter class instance
datetime_format	%Y-%m-%d %H:%M:%S.%6N %z	%iso8601 or Time#strftime formatted text

Contributing

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

License

MIT License