NyplLogFormatter

This is a logger that logs according to NYPL's agreed-upon format.
It is a subclass of the stdlib Logger class, so it works exactly as a regular Logger does. The only advantage to subclassing is that we can bake in custom formatting.

Our .travis.yml tests against multiple Ruby versions. Feel free to add more.

Add this line to your application's Gemfile:

gem 'nypl_log_formatter'

And then execute:

$ bundle

Or install it yourself as:

$ gem install nypl_log_formatter

require 'nypl_log_formatter'

my_logger = NyplLogFormatter.new('path/to/file.log')
my_logger.info('this will log JSON')
my_logger.warn('So will this')

# Contents of file.log
  # Logfile created on 2018-01-17 15:51:31 -0500 by logger.rb/61378
  #{"level":"INFO","message":"this will log JSON","timestamp":"2018-01-17T15:51:53.481-0500"}
  #{"level":"WARN","message":"So will this","timestamp":"2018-01-17T15:51:54.279-0500"}

The constructor (and all other methods, really) of NyplLogFormatter are the same as a Logger. Which means you can do EVERYTHING you can with a Logger, in the same way. That includes:

• Setting Log level
• Using STDOUT instead of a file.
• Setting log rotation.

For more info see your ruby version's documentation for the Logger class.

You can pass a second argument, a Hash that will end up as keys/values in the logged JSON.

logger = NyplLogFormatter.new('path/to/file.log')

logger.error(
  'Something went wrong',
  user: {email: 'simon@example.com', name: 'simon'},
  permissions: ['admin', 'good-boy']
)

# Contents of file.log
  # Logfile created on 2018-01-17 15:51:31 -0500 by logger.rb/61378
  #{"level":"ERROR","message":"Something went wrong","timestamp":"2018-02-07T16:47:22.017-0500","user":{"email":"simon@example.com","name":"simon"},"permissions":["admin","good-boy"]}

You can set logging threshold to control what severity of log is written either in the initializer:

Application.logger = NyplLogFormatter.new(STDOUT, level: 'info')

Or using the level= setter:

Application.logger.level = 'info'

See Logger notes on supported levels

After checking out the repo, run bin/setup to install dependencies. 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.

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