evanescent

Description

This gem provides an IO like object, that can be used with any logging class (such as Ruby's native Logger). This object will save its input to a file, and allows:

Hourly or daily rotation.
Compression of rotated files.
Removal of old compressed files.

This functionality supplement logging classes, allowing everything related to logging management, to be done within Ruby, without relying on external tools (such as logrotate).

Install

gem install evanescent

This gem uses Semantic Versioning, so you should add to your .gemspec something like:

  s.add_runtime_dependency 'evanescent', '~> 1.0'

Please, always check latest available version!

Example

Logger

require 'evanescent'
require 'timecop'

logger = Evanescent.logger(
  path: 'test.log',
  rotation: :hourly,
  keep: '2 hours',
)

logger.class # => Logger

# Within first hour, only test.log will exist.
Timecop.freeze(Time.now)
logger.info 'first message'
Dir.entries('.') # => [".", "..", "test.log"]

# One hour later, rotation and compression will happen.
Timecop.freeze(Time.now + 3600)
logger.info 'second message'
Dir.entries('.') # => [".", "..", "test.log", "test.log.2015122315.gz"]

# Another hour later, we'll have 2 compressed files.
Timecop.freeze(Time.now + 3600)
logger.info 'third message'
Dir.entries('.') # => [".", "..", "test.log", "test.log.2015122315.gz", "test.log.2015122316.gz"]

# At last, after keep period, old compressed files are purged.
Timecop.freeze(Time.now + 3600)
logger.info 'fourth message'
Dir.entries('.') # => [".", "..", "test.log", "test.log.2015122316.gz", "test.log.2015122317.gz"]

Generic usage

Evanescent is an IO like object: it responds to :write and :close:

io = Evanescent.new(
  path: 'test.log',
  rotation: :hourly,
  keep: '2 hours',
)
io.write('message') # writes message to test.log
io.close

Limitations

Although Evanescent supports mult-thread operation, inter-process locking is not currently implemented, and behavior is unpredicted in this situation.