Feature flip provisioner's meta-args

Fix #248

README.md

@@ -275,6 +275,30 @@ chef, and puppet) to work!
 * `http.open_timeout` - Open timeout for any HTTP request. Default is `60`
 * `http.read_timeout` - Read timeout for any HTTP request. Default is `30`
 
+### Provisioners meta-args
+
+We call meta-args, dynamic arguments automatically injected by the vagrant OpenStack provider as
+a provisioner argument. The notation for a meta-arg is its name surrounded by double `@` character.
+
+The current implementation supports only shell provisioner.
+
+* `meta_args_support` - Whether meta-args injection is activated or not. Default is `false`
+
+__Available meta-args__
+
+* `@@ssh_ip@@` - The IP used by Vagrant to SSH into the machine
+
+__Usage example__
+
+```ruby
+config.vm.provision "shell", inline: 'echo "$1 : $2" > ~/provision', args: ['IP', '@@ssh_ip@@']
+```
+
+__N.B.__
+> Activate meta-args support causes Vagrant to wrap the built-in provisioning middleware into a custom
+  one provided by the OpenStack provider. As a consequence, hooks declared on the built-in provisioning
+  middleware will not be applied (see [#248](https://github.com/ggiamarchi/vagrant-openstack-provider/issues/248))
+
 
 ## Vagrant standard configuration
 

source/lib/vagrant-openstack-provider/action.rb

@@ -34,7 +34,11 @@ def self.action_provision
             if env[:machine_state_id] == :not_created
               b2.use Message, I18n.t('vagrant_openstack.not_created')
             else
-              b2.use ProvisionWrapper
+              if env[:machine].provider_config.meta_args_support
+                b2.use ProvisionWrapper
+              else
+                b2.use Provision
+              end
               b2.use SyncFolders
             end
           end
@@ -100,7 +104,13 @@ def self.action_up
             case env[:machine_state_id]
             when :not_created
               ssh_disabled = env[:machine].provider_config.ssh_disabled
-              b2.use ProvisionWrapper unless ssh_disabled
+              unless ssh_disabled
+                if env[:machine].provider_config.meta_args_support
+                  b2.use ProvisionWrapper
+                else
+                  b2.use Provision
+                end
+              end
               b2.use SyncFolders
               b2.use CreateStack
               b2.use CreateServer

source/lib/vagrant-openstack-provider/config.rb

@@ -195,6 +195,10 @@ class Config < Vagrant.plugin('2', :config)
       # @return [HttpConfig]
       attr_accessor :http
 
+      #
+      # @return [Boolean]
+      attr_accessor :meta_args_support
+
       def initialize
         @password = UNSET_VALUE
         @openstack_compute_url = UNSET_VALUE
@@ -236,6 +240,7 @@ def initialize
         @server_delete_timeout = UNSET_VALUE
         @stack_create_timeout = UNSET_VALUE
         @stack_delete_timeout = UNSET_VALUE
+        @meta_args_support = UNSET_VALUE
         @http = HttpConfig.new
       end
 
@@ -320,6 +325,7 @@ def finalize!
         @server_delete_timeout = 200 if @server_delete_timeout == UNSET_VALUE
         @stack_create_timeout = 200 if @stack_create_timeout == UNSET_VALUE
         @stack_delete_timeout = 200 if @stack_delete_timeout == UNSET_VALUE
+        @meta_args_support = false if @meta_args_support == UNSET_VALUE
         @networks = nil if @networks.empty?
         @volumes = nil if @volumes.empty?
         @stacks = nil if @stacks.empty?