implement container_layer rule.

README.md

@@ -988,11 +988,163 @@ An executable rule that pushes a Docker image to a Docker registry on `bazel run
   </tbody>
 </table>
 
+<a name="container_layer"></a>
+## container_layer
+
+```python
+container_layer(data_path, directory, files, mode, tars, debs, symlinks, env)
+```
+
+A rule that assembles data into a tarball which can be use as in `layers` attr in `container_image` rule.
+
+<table class="table table-condensed table-bordered table-implicit">
+  <colgroup>
+    <col class="col-param" />
+    <col class="param-description" />
+  </colgroup>
+  <thead>
+    <tr>
+      <th colspan="2">Implicit output targets</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code><i>name</i>-layer.tar</code></td>
+      <td>
+        <code>A tarball of current layer</code>
+        <p>
+            A data tarball corresponding to the layer.
+        </p>
+      </td>
+    </tr>
+  </tbody>
+</table>
+
+<table class="table table-condensed table-bordered table-params">
+  <colgroup>
+    <col class="col-param" />
+    <col class="param-description" />
+  </colgroup>
+  <thead>
+    <tr>
+      <th colspan="2">Attributes</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <td><code>name</code></td>
+      <td>
+        <code>Name, required</code>
+        <p>A unique name for this rule.</p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>data_path</code></td>
+      <td>
+        <code>String, optional</code>
+        <p>Root path of the files.</p>
+        <p>
+          The directory structure from the files is preserved inside the
+          Docker image, but a prefix path determined by `data_path`
+          is removed from the directory structure. This path can
+          be absolute from the workspace root if starting with a `/` or
+          relative to the rule's directory. A relative path may starts with "./"
+          (or be ".") but cannot use go up with "..". By default, the
+          `data_path` attribute is unused, and all files should have no prefix.
+        </p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>directory</code></td>
+      <td>
+        <code>String, optional</code>
+        <p>Target directory.</p>
+        <p>
+          The directory in which to expand the specified files, defaulting to '/'.
+          Only makes sense accompanying one of files/tars/debs.
+        </p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>files</code></td>
+      <td>
+        <code>List of files, optional</code>
+        <p>File to add to the layer.</p>
+        <p>
+          A list of files that should be included in the Docker image.
+        </p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>mode</code></td>
+      <td>
+        <code>String, default to 0555</code>
+        <p>
+          Set the mode of files added by the <code>files</code> attribute.
+        </p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>tars</code></td>
+      <td>
+        <code>List of files, optional</code>
+        <p>Tar file to extract in the layer.</p>
+        <p>
+          A list of tar files whose content should be in the Docker image.
+        </p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>debs</code></td>
+      <td>
+        <code>List of files, optional</code>
+        <p>Debian package to install.</p>
+        <p>
+          A list of debian packages that will be installed in the Docker image.
+        </p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>symlinks</code></td>
+      <td>
+        <code>Dictionary, optional</code>
+        <p>Symlinks to create in the Docker image.</p>
+        <p>
+          <code>
+          symlinks = {
+           "/path/to/link": "/path/to/target",
+           ...
+          },
+          </code>
+        </p>
+      </td>
+    </tr>
+    <tr>
+      <td><code>env</code></td>
+      <td>
+        <code>Dictionary from strings to strings, optional</code>
+        <p><a href="https://docs.docker.com/engine/reference/builder/#env">Dictionary
+               from environment variable names to their values when running the
+               Docker image.</a></p>
+        <p>
+          <code>
+          env = {
+            "FOO": "bar",
+            ...
+          },
+          </code>
+        </p>
+	<p>The values of this field support stamp variables.</p>
+      </td>
+    </tr>
+  </tbody>
+</table>
+
 <a name="container_image"></a>
 ## container_image
 
 ```python
-container_image(name, base, data_path, directory, files, legacy_repository_naming, mode, tars, debs, symlinks, entrypoint, cmd, env, labels, ports, volumes, workdir, repository)
+container_image(name, base, data_path, directory, files, legacy_repository_naming, mode, tars, debs, symlinks, entrypoint, cmd, env, labels, ports, volumes, workdir, layers, repository)
 ```
 
 <table class="table table-condensed table-bordered table-implicit">
@@ -1262,6 +1414,14 @@ container_image(name, base, data_path, directory, files, legacy_repository_namin
 	<p>This field supports stamp variables.</p>
       </td>
     </tr>
+    <tr>
+      <td><code>layers</code></td>
+      <td>
+        <code>Label list, optional</code>
+        <p>List of `container_layer` targets. </p>
+        <p>The data from each `container_layer` will be part of container image, and the environment variable will be available in the image as well.</p>
+      </td>
+    </tr>
     <tr>
       <td><code>repository</code></td>
       <td>

cc/image.bzl

@@ -83,5 +83,5 @@ def cc_image(name, base=None, deps=[], layers=[], binary=None, **kwargs):
     base = this_name
 
   visibility = kwargs.get('visibility', None)
-  app_layer(name=name, base=base, binary=binary, layers=layers,
+  app_layer(name=name, base=base, binary=binary, lang_layers=layers,
             visibility=visibility)

container/BUILD

@@ -84,14 +84,18 @@ TEST_TARGETS = [
     "directory_with_tar_base",
     "files_base",
     "files_with_files_base",
+    "files_in_layer_with_files_base",
     "files_with_tar_base",
     "tar_base",
     "tar_with_files_base",
     "tar_with_tar_base",
+    "tars_in_layer_with_tar_base",
     "docker_tarball_base",
+    "layers_with_docker_tarball_base",
     # TODO(mattmoor): Re-enable once archive is visible
     # "generated_tarball",
     "with_env",
+    "layers_with_env",
     "with_double_env",
     "with_label",
     "with_double_label",
@@ -145,7 +149,7 @@ skylark_library(
     name = "bundle",
     srcs = ["bundle.bzl"],
     deps = [
-        ":layers",
+        ":layer_tools",
         "//skylib:label",
     ],
 )
@@ -166,7 +170,7 @@ skylark_library(
     name = "flatten",
     srcs = ["flatten.bzl"],
     deps = [
-        ":layers",
+        ":layer_tools",
         "//skylib:label",
     ],
 )
@@ -175,7 +179,7 @@ skylark_library(
     name = "image",
     srcs = ["image.bzl"],
     deps = [
-        ":layers",
+        ":layer_tools",
         "//skylib:filetype",
         "//skylib:label",
         "//skylib:path",
@@ -189,7 +193,7 @@ skylark_library(
     name = "import",
     srcs = ["import.bzl"],
     deps = [
-        ":layers",
+        ":layer_tools",
         "//skylib:filetype",
         "//skylib:path",
         "//skylib:zip",
@@ -198,8 +202,8 @@ skylark_library(
 )
 
 skylark_library(
-    name = "layers",
-    srcs = ["layers.bzl"],
+    name = "layer_tools",
+    srcs = ["layer_tools.bzl"],
     deps = ["//skylib:path"],
 )
 
@@ -218,7 +222,7 @@ skylark_library(
     name = "push",
     srcs = ["push.bzl"],
     deps = [
-        ":layers",
+        ":layer_tools",
         "//skylib:path",
     ],
 )

container/bundle.bzl

@@ -18,7 +18,7 @@ load(
     _string_to_label = "string_to_label",
 )
 load(
-    "//container:layers.bzl",
+    "//container:layer_tools.bzl",
     _assemble_image = "assemble",
     _get_layers = "get_from_target",
     _incr_load = "incremental_load",

container/container.bzl

@@ -16,6 +16,7 @@
 load("//container:bundle.bzl", "container_bundle")
 load("//container:flatten.bzl", "container_flatten")
 load("//container:image.bzl", "container_image", "image")
+load("//container:layer.bzl", "container_layer")
 load("//container:import.bzl", "container_import")
 load("//container:load.bzl", "container_load")
 load("//container:pull.bzl", "container_pull")

container/flatten.bzl

@@ -14,7 +14,7 @@
 """A rule to flatten container images."""
 
 load(
-    "//container:layers.bzl",
+    "//container:layer_tools.bzl",
     _get_layers = "get_from_target",
     _layer_tools = "tools",
 )