providers/docker: implement port checker for remote machine

plugins/guests/linux/cap/port.rb

@@ -0,0 +1,11 @@
+module VagrantPlugins
+  module GuestLinux
+    module Cap
+      class Port
+        def self.port_open_check(machine, port)
+          machine.communicate.test("nc -z 127.0.0.1 #{port}")
+        end
+      end
+    end
+  end
+end

plugins/guests/linux/plugin.rb

@@ -51,6 +51,12 @@ module VagrantPlugins
         Cap::NFSClient
       end
 
+      # For the Docker provider
+      guest_capability("linux", "port_open_check") do
+        require_relative "cap/port"
+        Cap::Port
+      end
+
       guest_capability("linux", "read_ip_address") do
         require_relative "cap/read_ip_address"
         Cap::ReadIPAddress

plugins/providers/docker/action.rb

@@ -15,7 +15,7 @@ module VagrantPlugins
           b.use Call, IsState, :not_created do |env, b2|
             # If the VM is NOT created yet, then do the setup steps
             if env[:result]
-              b2.use EnvSet, :port_collision_repair => true
+              b2.use EnvSet, port_collision_repair: true
 
               b2.use Call, HasSSH do |env2, b3|
                 if env2[:result]
@@ -27,14 +27,8 @@ module VagrantPlugins
                 end
               end
 
-              b2.use Call, HostMachineRequired do |env2, b3|
+              b2.use HostMachinePortChecker
-                if !env[:result]
+              b2.use HandleForwardedPortCollisions
-                  # We're not using a proxy host VM, so just handle
-                  # port collisions like we would any other system.
-                  b3.use HandleForwardedPortCollisions
-                end
-              end
-
               b2.use PrepareNFSValidIds
               b2.use SyncedFolderCleanup
               b2.use SyncedFolders
@@ -225,6 +219,7 @@ module VagrantPlugins
       autoload :Destroy, action_root.join("destroy")
       autoload :HasSSH, action_root.join("has_ssh")
       autoload :HostMachine, action_root.join("host_machine")
+      autoload :HostMachinePortChecker, action_root.join("host_machine_port_checker")
       autoload :HostMachineRequired, action_root.join("host_machine_required")
       autoload :HostMachineSyncFolders, action_root.join("host_machine_sync_folders")
       autoload :HostMachineSyncFoldersDisable, action_root.join("host_machine_sync_folders_disable")

plugins/providers/docker/action/create.rb

@@ -59,7 +59,7 @@ module VagrantPlugins
         def forwarded_ports
           mappings = {}
           @machine.config.vm.networks.each do |type, options|
-            if type == :forwarded_port && options[:id] != 'ssh'
+            if type == :forwarded_port
               mappings[options[:host]] = options
             end
           end

plugins/providers/docker/action/host_machine_port_checker.rb

@@ -0,0 +1,31 @@
+require "log4r"
+
+module VagrantPlugins
+  module DockerProvider
+    module Action
+      # This sets up the middleware env var to check for ports in use.
+      class HostMachinePortChecker
+        def initialize(app, env)
+          @app    = app
+          @logger = Log4r::Logger.new("vagrant::docker::hostmachineportchecker")
+        end
+
+        def call(env)
+          return @app.call(env) if !env[:machine].provider.host_vm?
+
+          @machine = env[:machine]
+          env[:port_collision_port_check] = method(:port_check)
+
+          @app.call(env)
+        end
+
+        protected
+
+        def port_check(port)
+          host_machine = @machine.provider.host_vm
+          host_machine.guest.capability(:port_open_check, port)
+        end
+      end
+    end
+  end
+end