providers/docker: build_args [GH-3684]

CHANGELOG.md

@@ -4,6 +4,8 @@ IMPROVEMENTS:
 
   - command/rdp: Args after "--" are passed directly through to the
       RDP client. [GH-3686]
+  - providers/docker: `build_args` config to specify extra args for
+      `docker build`. [GH-3684]
 
 ## 1.6.1 (May 7, 2014)
 

plugins/providers/docker/action/build.rb

@@ -35,7 +35,10 @@ module VagrantPlugins
           if !image || env[:build_rebuild]
             # Build it
             machine.ui.output(I18n.t("docker_provider.building"))
-            image = machine.provider.driver.build(build_dir)
+            image = machine.provider.driver.build(
+              build_dir,
+              extra_args: machine.provider_config.build_args,
+            )
             machine.ui.detail("Image: #{image}")
 
             # Store the image ID

plugins/providers/docker/config.rb

@@ -5,6 +5,12 @@ module VagrantPlugins
     class Config < Vagrant.plugin("2", :config)
       attr_accessor :image, :cmd, :ports, :volumes, :privileged
 
+      # Additional arguments to pass to `docker build` when creating
+      # an image using the build dir setting.
+      #
+      # @return [Array<String>]
+      attr_accessor :build_args
+
       # The directory with a Dockerfile to build and use as the basis
       # for this container. If this is set, "image" should not be set.
       #
@@ -73,6 +79,7 @@ module VagrantPlugins
       attr_accessor :vagrant_vagrantfile
 
       def initialize
+        @build_args = []
         @build_dir  = UNSET_VALUE
         @cmd        = UNSET_VALUE
         @create_args = []
@@ -126,6 +133,7 @@ module VagrantPlugins
       end
 
       def finalize!
+        @build_args = [] if @build_args == UNSET_VALUE
         @build_dir  = nil if @build_dir == UNSET_VALUE
         @cmd        = [] if @cmd == UNSET_VALUE
         @create_args = [] if @create_args == UNSET_VALUE

plugins/providers/docker/driver.rb

@@ -15,7 +15,9 @@ module VagrantPlugins
       end
 
       def build(dir, **opts)
-        result = execute('docker', 'build', dir)
+        args   = Array(opts[:extra_args])
+        args   << dir
+        result = execute('docker', 'build', *args)
         regexp = /Successfully built (.+)$/i
         match  = regexp.match(result)
         if !match