DVLA::Herodotus

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

Installation

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

---

Usage

Logger

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

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

Configuration

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

Syncing logs

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)

new_scenario method

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')

Strings

Also included is a series of additional methods on String that allow you to modify the colour and style of logs. As these exist on String, you can call them on any string such as:

example_string = 'Multicoloured String'.blue.bg_red.bold

Method	Function
blue	Sets the string's colour to blue
red	Sets the string's colour to red
green	Sets the string's colour to green
brown	Sets the string's colour to brown
blue	Sets the string's colour to blue
magenta	Sets the string's colour to magenta
cyan	Sets the string's colour to cyan
gray	Sets the string's colour to gray
bg_blue	Sets the string's background colour to blue
bg_red	Sets the string's background colour to red
bg_green	Sets the string's background colour to green
bg_brown	Sets the string's background colour to brown
bg_blue	Sets the string's background colour to blue
bg_magenta	Sets the string's background colour to magenta
bg_cyan	Sets the string's background colour to cyan
bg_gray	Sets the string's background colour to gray
bold	Sets the string to be bold
italic	Sets the string to be italic
underline	Sets the string to be underline
blink	Sets the string to blink
reverse_color	Reverses the colour of the string

Development

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