DOCKER_HOST env support

Author: h0tw1r3

tasks/docker.rb

@@ -2,6 +2,7 @@
 # frozen_string_literal: true
 
 require 'json'
+require 'uri'
 require 'yaml'
 require 'puppet_litmus'
 require_relative '../lib/task_helper'
@@ -152,7 +153,11 @@ def provision(image, inventory_location, vars)
   os_release_facts = get_image_os_release_facts(image)
   distro = os_release_facts['ID']
   version = os_release_facts['VERSION_ID']
-  hostname = 'localhost'
+  hostname = if ENV.key?('DOCKER_HOST') && !ENV['DOCKER_HOST'].empty?
+               URI.parse(ENV['DOCKER_HOST']).host || ENV['DOCKER_HOST']
+             else
+               'localhost'
+             end
   group_name = 'ssh_nodes'
   warn '!!! Using private port forwarding!!!'
   front_facing_port = random_ssh_forwarding_port