Drudge

A gem that enables you to write command line automation tools using Ruby 2.0.

Given a binary file called cli:

#!/usr/bin/env ruby 

require 'drudge'

class Cli < Drudge

  desc "Greets people"
  def greet(from, opening = 'Hi', *messages,  to)
    puts "#{from} says #{opening}, #{messages.join(', ')} to #{to}"
  end
end

Cli.dispatch

Running:

$ ./cli greet Santa 'good day to you' Joe
Santa says Hi, good day to you to Joe

$ ./cli greet Santa Greetings 'how do you do?' Joe
Santa says Greetings, how do you do? to Joe

$ ./cli
error: expected a command:

  cli
      ^

$ ./cli great Santa Joe
error: unknown command 'great':

    cli great Santa Joe
        ~~~~~

$ ./cli greet
error: expected a value for <from>:

    cli greet
              ^

$ ./cli greet Santa
error: expected a value for <to>:

    cli greet Santa
                    ^

The philosphy of Drudge is to provide a very thin layer over normal Ruby constructs such as classes and methods that exposes them via a command line interface.

This layer interprets the command line instruction and invokes the identifed ruby method using a very simple resolution method. From then on, it's just normal Ruby! No special life-cycles, etc.

Even though this layer is simple, it is built to produce excellent error messages on wrong command line input.

Drudge is built for Ruby 2 with keyword arguments in mind.

Drudge was inspired by the great work folks did in Thor.

The problem with Thor is that it tries to be two things at once: a build tool (aimed on replacing rake) and an automation tool.

This introduces a number of unnecessary complexities:

• there are rake-like namespaces but also sub commands for automation. These two concepts have a number of nasty interactions which result in many small but annoying bugs

• it is meant to be used a a stand-alone tool (by invoking thor which will look for a Thorfile) but also as a library for building your own tools. This too produces complexities and unwanted interactions in the Thor codebase

• Thor skews the normal Ruby class/method model towards the command line interface and introduces some 'suprises' for the user (e.g. the Thor-subclass gets instantieated every time a method/command is called, something that is not usually expected)

In contrast, Drudge's aim is simple: a library for building command-line automation tools with the aim of transferring you (conceptionally) from the command line interface into Ruby and then letting you use build your tool in a familiar environement.

Released under the MIT License. See the LICENSE file for further details.