tar_dir attribute for the .tar output of r_library

README.md

@@ -151,14 +151,15 @@ r_library(
         "//path/to/packageA:r_pkg_target",
         "//path/to/packageB:r_pkg_target",
     ],
+    tar_dir = "r-libs",
 )  
 
 load("@io_bazel_rules_docker//container:container.bzl", "container_image")
 
 container_image(
     name = "image",
     base = "@r_base//image",
-    directory = "/r-libs",
+    directory = "/",
     env = {"R_LIBS_USER": "/r-libs"},
     tars = [":my_r_library.tar"],
     repository = "my_repo",
@@ -286,6 +287,9 @@ Executable rule to install the given packages and all dependencies to a user
 provided or system default R library. Run the target with --help for usage
 information.
 
+This rule also creates an invisible {name}.tar target which outputs the R
+library as a tar file; mainly for use with the Docker rules.
+
 <table class="table table-condensed table-bordered table-params">
   <colgroup>
     <col class="col-param" />
@@ -312,6 +316,14 @@ information.
         For runtime overrides, use bazel run [target] -- -l [path].</p>
       </td>
     </tr>
+    <tr>
+      <td><code>tar_dir</code></td>
+      <td>
+        <p><code>String; default "."</code></p>
+        <p>The root directory in the tar file under which the R library will be
+        copied.</p>
+      </td>
+    </tr>
   </tbody>
 </table>
 

tests/BUILD

@@ -20,14 +20,22 @@ r_library(
         "//exampleC",
         "@R_bitops//:bitops",
     ],
+    tar_dir = "r-libs",
 )
 
 load("@io_bazel_rules_docker//container:container.bzl", "container_image")
 
 container_image(
     name = "image",
     base = "@r_base//image",
-    directory = "/r-libs",
+    directory = "/",
     env = {"R_LIBS_USER": "/r-libs"},
     tars = [":library.tar"],
 )
+
+sh_test(
+    name = "image_test",
+    size = "small",
+    srcs = ["image_test.sh"],
+    data = [":image-layer.tar"],
+)

tests/image_test.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+
+# Copyright 2017 GRAIL, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eou pipefail
+
+readonly LAYER_TAR="image-layer.tar"
+readonly FILE_TO_CHECK="r-libs/exampleC/DESCRIPTION"
+
+tar -tf "${LAYER_TAR}" | grep "${FILE_TO_CHECK}"