1 files changed, 31 insertions, 0 deletions
diff --git a/images/defs.bzl b/images/defs.bzl
new file mode 100644
index 000000000..61d7bbf73
--- /dev/null
+++ b/images/defs.bzl
@@ -0,0 +1,31 @@
+"""Helpers for Docker image generation."""
+
+def _docker_image_impl(ctx):
+    importer = ctx.actions.declare_file(ctx.label.name)
+    importer_content = [
+        "#!/bin/bash",
+        "set -euo pipefail",
+        "exec docker import " + " ".join([
+            "-c '%s'" % attr
+            for attr in ctx.attr.statements
+        ]) + " " + " ".join([
+            "'%s'" % f.path
+            for f in ctx.files.data
+        ]) + " $1",
+        "",
+    ]
+    ctx.actions.write(importer, "\n".join(importer_content), is_executable = True)
+    return [DefaultInfo(
+        runfiles = ctx.runfiles(ctx.files.data),
+        executable = importer,
+    )]
+
+docker_image = rule(
+    implementation = _docker_image_impl,
+    doc = "Tool to load a Docker image; takes a single parameter (image name).",
+    attrs = {
+        "statements": attr.string_list(doc = "Extra Dockerfile directives."),
+        "data": attr.label_list(doc = "All image data."),
+    },
+    executable = True,
+)