Issue #71 Making sure correct host IP is used for DNS redirect on guest

- Adding integration test

features/docker_provider.feature

@@ -0,0 +1,32 @@
+Feature: Landrush with Docker provider
+  Landrush should work with Docker provider
+
+  Scenario: Booting box with Docker provider
+    Given a file named "Vagrantfile" with:
+    """
+    Vagrant.configure(2) do |config|
+      config.vm.provider "docker" do |d|
+        # https://github.com/tknerr/vagrant-docker-baseimages
+        d.image = "tknerr/baseimage-ubuntu:18.04"
+        d.has_ssh = true
+        d.privileged = true
+      end
+
+      config.vm.provision "shell", inline: 'apt-get install -y net-tools dnsutils'
+
+      config.landrush.enabled = true
+      config.vm.hostname = "foo.vagrant.test"
+
+      config.landrush.host 'static1.example.com', '1.2.3.4'
+      config.landrush.host 'static2.example.com', '2.3.4.5'
+    end
+    """
+    When I successfully run `bundle exec vagrant up`
+    Then Landrush is running
+
+    When I successfully run `bundle exec vagrant ssh -- dig +noall +answer +nocomments static1.example.com`
+    Then stdout from "bundle exec vagrant ssh -- dig +noall +answer +nocomments static1.example.com" should match /.*1\.2\.3\.4/
+
+    When I successfully run `bundle exec vagrant landrush stop`
+    Then Landrush is not running
+

lib/landrush.rb

@@ -16,3 +16,4 @@
 require 'landrush/store'
 require 'landrush/version'
 require 'landrush-ip'
+require 'socket'

lib/landrush/action/redirect_dns.rb

@@ -29,6 +29,9 @@ def _target_host
           _gateway_for_ip(machine.guest.capability(:configured_dns_servers).first)
         when :parallels then
           machine.provider.capability(:host_address)
+        else
+          # As a fallthrough default use the first non loopback IP. This IP should be reachable from the guest as well
+          Socket.ip_address_list.find { |ai| ai.ipv4? && !ai.ipv4_loopback? }.ip_address
         end
       end
 

lib/landrush/plugin.rb

@@ -21,9 +21,11 @@ class Plugin < Vagrant.plugin('2')
       # Hooks for VirtualBox and HyperV providers
       hook.before(VagrantPlugins::ProviderVirtualBox::Action::Network, pre_boot_actions)
       hook.before(VagrantPlugins::HyperV::Action::WaitForIPAddress, pre_boot_actions)
-      hook.after(VagrantPlugins::DockerProvider::Action::Start, pre_boot_actions)
       hook.after(Vagrant::Action::Builtin::WaitForCommunicator, post_boot_actions)
 
+      # Hooks for Docker provider
+      hook.after(VagrantPlugins::DockerProvider::Action::Start, pre_boot_actions)
+
       # Hooks for Libvirt provider
       if defined?(VagrantPlugins::ProviderLibvirt)
         hook.after(VagrantPlugins::ProviderLibvirt::Action::CreateNetworks, pre_boot_actions)