Docu changes for building Docker images from git

CHANGELOG.md

@@ -617,6 +617,7 @@ IMPROVEMENTS:
   - provisioners/puppet: Support custom environment variables [GH-7931, GH-7252, GH-2270]
   - util/safe_exec: Use subprocess for safe_exec on Windows [GH-7802]
   - util/subprocess: Allow closing STDIN [GH-7778]
+  - providers/docker: Support building containter images directly from git
 
 BUG FIXES:
 

plugins/providers/docker/config.rb

@@ -14,11 +14,19 @@ module VagrantPlugins
       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.
+      # for this container. If this is set, neither "image" nor "git_repo" 
+      # should be set.
       #
       # @return [String]
       attr_accessor :build_dir
       
+      # The URL for a git repository with a Dockerfile to build and use
+      # as the basis for this container. If this is set, neither "image"
+      # nor "build_dir" should be set.
+      #
+      # @return [String]
+      attr_accessor :git_repo
+
       # Use docker-compose to manage the lifecycle and environment for
       # containers instead of using docker directly.
       #

templates/locales/providers_docker.yml

@@ -138,15 +138,17 @@ en:
         "docker" provider.
       config:
         both_build_and_image: |-
-          Only one of "build_dir" or "image" can be set
+          Only one of "build_dir", "git_repo" or "image" can be set
         build_dir_invalid: |-
           "build_dir" must exist and contain a Dockerfile
         build_dir_or_image: |-
-          One of "build_dir" or "image" must be set
+          One of "build_dir", "git_repo" or "image" must be set
         compose_configuration_hash: |-
           "compose_configuration" must be a hash
         compose_force_vm: |-
           Docker compose is not currently supported from within proxy VM.
+        git_repo_invalid: |-
+          "git_repo" must be a valid git URL
         create_args_array: |-
           "create_args" must be an array
         invalid_link: |-

website/source/docs/docker/configuration.html.md

@@ -15,10 +15,15 @@ you may set. A complete reference is shown below.
 ### Required
 
   * `build_dir` (string) - The path to a directory containing a Dockerfile.
-    One of this or `image` is required.
+    One of this, `image` or `git_repo` is required.
 
   * `image` (string) - The image to launch, specified by the image ID or a name
-    such as `ubuntu:12.04`. One of this or `build_dir` is required.
+    such as `ubuntu:12.04`. One of this, `git_repo` or `build_dir` is required.
+    
+  * `git_repo` (string) - The URL of a git repository to build the image from.
+    Supports pulling specific tags, branches and revision, consult the 
+    [docker documenation](https://docs.docker.com/engine/reference/commandline/build/#/git-repositories)
+    for more information. One of this, `image` or `build_dir` is required.
 
 ### Optional