DVLA::Herodotus

A Gem that produces loggers that are pre-formatted into an agreed log format

Add this line to your application's Gemfile:

gem 'dvla-herodotus'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install dvla-herodotus

You can get a logger by calling the following once Herodotus is installed:

logger = DVLA::Herodotus.logger('<system-name>')

You can also log out to a file. If you want all the logs in a single file, provide a string of the path to that output file and it will be logged to simultaneously with standard console logger.

Note: Log messages are stripped of colour codes before being saved to file.

logger = DVLA::Herodotus.logger('<system-name>', output_path: 'logs.txt')

Alternatively, if you want each scenario to log out to a separate file based on the scenario name, pass in a lambda that returns a string that attempts to interpolate @scenario.

logger = DVLA::Herodotus.logger('<system-name>', output_path: -> { "#{@scenario}_log.txt" })

This is a standard Ruby logger, so anything that would work on a logger acquired the traditional way will also work here, however it is formatted such that all logs will be output in the following format:

[SystemName CurrentDate CurrentTime CorrelationId] Level : -- Message

You can configure Herodotus in the following way to add a Process Id to the output:

config = DVLA::Herodotus.config do |config|
  config.display_pid = true
end
logger = DVLA::Herodotus.logger('<system-name>', config: config)

This would result in logs in the following format:

[SystemName CurrentDate CurrentTime CorrelationId PID] Level : -- Message

Herodotus allows you to Sync correlation_ids between instantiated HerodotusLogger objects.

The HerodotusLogger flagged as main will be used as the source.

config = DVLA::Herodotus.config do |config|
  config.main = true
end
main_logger = DVLA::Herodotus.logger('<system-name>', config: config)

You can call new_scenario with the identifier just before each scenario to create a unique correlation_id per scenario.

logger.new_scenario('Scenario Id')

Also included is a series of additional methods on String that allow you to modify the colour and style of logs. You can stack multiple method calls to add additional styling and use string interpolation to style different parts of the string

  example_string = "#{'H'.red}#{'E'.bright_red}#{'R'.yellow}#{'O'.green}#{'D'.blue}#{'O'.bright_blue}#{'T'.magenta}#{'U'.bright_magenta}#{'S'.cyan}".bold.reverse_colour

Herodotus is very lightweight. Currently, all code to generate a new logger can be found in herodotus.rb and the code for the logger is in herodotus_logger.rb so that is the best place to start with any modifications