Ansible: Improvements for 'extra_vars' argument

`extra_vars` argument can now:
- contains a hierarchical set of parameters (instead of flat Key-Value Pairs)
- alternatively refers to a configuration file (instead of embedded Hash)

See Ansible Documentation for version requirement details:
http://www.ansibleworks.com/docs/playbooks_variables.html#passing-variables-on-the-command-line

plugins/provisioners/ansible/config.rb

@@ -47,12 +47,6 @@ module VagrantPlugins
         @start_at_task     = nil if @start_at_task == UNSET_VALUE
         @raw_arguments     = nil if @raw_arguments == UNSET_VALUE
         @host_key_checking = nil if @host_key_checking == UNSET_VALUE
-
-        if @extra_vars && @extra_vars.is_a?(Hash)
-          @extra_vars.each do |k, v|
-            @extra_vars[k] = v.to_s
-          end
-        end
       end
 
       def validate(machine)
@@ -72,10 +66,26 @@ module VagrantPlugins
           end
         end
 
-        # Validate that extra_vars is a hash, if set
+        # Validate that extra_vars is either a hash, or a path to an existing file
         if extra_vars
-          if !extra_vars.kind_of?(Hash)
+          extra_vars_is_valid = (extra_vars.kind_of?(Hash) or extra_vars.kind_of?(String))
-            errors << I18n.t("vagrant.provisioners.ansible.extra_vars_not_hash")
+
+          if extra_vars.kind_of?(String)
+            # Accept the usage of '@' prefix in Vagrantfile (e.g. '@vars.yml' and 'vars.yml' are both supported)
+            extra_vars =~ /^@?(.+)$/
+            extra_vars_path = $1.to_s
+            expanded_path = Pathname.new(extra_vars_path).expand_path(machine.env.root_path)
+            extra_vars_is_valid = expanded_path.exist?
+            if extra_vars_is_valid
+              @extra_vars = '@' + extra_vars_path
+            end
+          end
+
+          if !extra_vars_is_valid
+            errors << I18n.t("vagrant.provisioners.ansible.extra_vars_invalid",
+                              :type  => extra_vars.class.to_s,
+                              :value => extra_vars.to_s
+                            )
           end
         end
 

plugins/provisioners/ansible/provisioner.rb

@@ -11,20 +11,8 @@ module VagrantPlugins
         options << "#{config.raw_arguments}" if config.raw_arguments
 
         # Append Provisioner options (highest precedence):
-        if config.extra_vars
-          extra_vars = config.extra_vars.map do |k,v|
-            v = v.gsub('"', '\\"')
-            if v.include?(' ')
-              v = v.gsub("'", "\\'")
-              v = "'#{v}'"
-            end
-
-            "#{k}=#{v}"
-          end
-          options << "--extra-vars=\"#{extra_vars.join(" ")}\""
-        end
-
         options << "--inventory-file=#{self.setup_inventory_file}"
+        options << "--extra-vars=#{self.get_extra_vars_argument}" if config.extra_vars
         options << "--sudo" if config.sudo
         options << "--sudo-user=#{config.sudo_user}" if config.sudo_user
         options << "#{self.get_verbosity_argument}" if config.verbose
@@ -83,6 +71,16 @@ module VagrantPlugins
         return generated_inventory_file.to_s
       end
 
+      def get_extra_vars_argument
+        if config.extra_vars.kind_of?(String) and config.extra_vars =~ /^@.+$/
+          # A JSON or YAML file is referenced (requires Ansible 1.3+)
+          return config.extra_vars
+        else
+          # Expected to be a Hash after config validation. (extra_vars as JSON requires Ansible 1.2+, while YAML requires Ansible 1.3+)
+          return config.extra_vars.to_json
+        end
+      end
+
       def get_verbosity_argument
         if config.verbose.to_s =~ /^v+$/
           # ansible-playbook accepts "silly" arguments like '-vvvvv' as '-vvvv' for now

templates/locales/en.yml

@@ -1246,4 +1246,4 @@ en:
         no_playbook: "`playbook` must be set for the Ansible provisioner."
         playbook_path_invalid: "`playbook` for the Ansible provisioner does not exist on the host system: %{path}"
         inventory_path_invalid: "`inventory_path` for the Ansible provisioner does not exist on the host system: %{path}"
-        extra_vars_not_hash: "`extra_vars` for the Ansible provisioner must be a hash"
+        extra_vars_invalid: "`extra_vars` for the Ansible provisioner must be a hash or a path to an existing file. Received: %{value} (as %{type})"

website/docs/source/v2/provisioning/ansible.html.md

@@ -119,11 +119,14 @@ end
 The Ansible provisioner also includes a number of additional options that can be set,
 all of which get passed to the `ansible-playbook` command that ships with Ansible.
 
-* `ansible.extra_vars` can be used to pass a hash of additional variables to the playbook. For example:
+* `ansible.extra_vars` can be used to pass additional variables (with highest priority) to the playbook. This parameter can be a path to a JSON or YAML file, or a hash. For example:
 ```
 ansible.extra_vars = {
   ntp_server: "pool.ntp.org",
-  nginx_workers: 4
+  nginx: {
+    port: 8008,
+    workers: 4
+  }
 }
 ```
 These variables take the highest precedence over any other variables.