bazel: refactor multi-arch container builds into starlark

build/container.bzl

+# Copyright 2019 The Kubernetes Authors.
+#
+# 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.
+
+load("@io_bazel_rules_docker//container:container.bzl", "container_bundle", "container_image")
+load("//build:platforms.bzl", "go_platform_constraint")
+
+# multi_arch_container produces a private internal container_image, multiple
+# arch-specific tagged container_bundles (named NAME-ARCH) and aliases
+# from NAME and NAME.tar to the appropriately NAME-ARCH container_bundle target
+# for the currently-configured architecture.
+# Args:
+#   name: name used for the alias; the internal container_image and
+#     container_bundles are based on this name
+#   architectures: list of architectures (in GOARCH naming parlance) to
+#     configure
+#   base: base image to use for the containers. The format string {ARCH} will
+#     be replaced with the configured GOARCH.
+#   docker_tags: list of docker tags to apply to the image. The format string
+#     {ARCH} will be replaced with the configured GOARCH; any stamping variables
+#     should be escaped, e.g. {{STABLE_MY_VAR}}.
+#   tags: will be applied to all rules
+#   visiblity: will be applied only to the container_bundles; the internal
+#     container_image is private
+#   All other args will be applied to the internal container_image.
+def multi_arch_container(
+        name,
+        architectures,
+        base,
+        docker_tags,
+        tags = None,
+        visibility = None,
+        **kwargs):
+    container_image(
+        name = "%s-internal" % name,
+        base = select({
+            go_platform_constraint(os = "linux", arch = arch): base.format(ARCH = arch)
+            for arch in architectures
+        }),
+        tags = tags,
+        visibility = ["//visibility:private"],
+        **kwargs
+    )
+
+    for arch in architectures:
+        container_bundle(
+            name = "%s-%s" % (name, arch),
+            images = {
+                docker_tag.format(ARCH = arch): ":%s-internal" % name
+                for docker_tag in docker_tags
+            },
+            tags = tags,
+            visibility = visibility,
+        )
+    for suffix in ["", ".tar"]:
+        native.alias(
+            name = "%s%s" % (name, suffix),
+            actual = select({
+                go_platform_constraint(os = "linux", arch = arch): "%s-%s%s" % (name, arch, suffix)
+                for arch in architectures
+            }),
+        )

cluster/images/conformance/BUILD

-load("@io_bazel_rules_docker//container:container.bzl", "container_bundle", "container_image", "container_layer")
-load("//build:platforms.bzl", "SERVER_PLATFORMS", "for_platforms")
+load("@io_bazel_rules_docker//container:container.bzl", "container_layer")
+load("//build:platforms.bzl", "SERVER_PLATFORMS")
+load("//build:container.bzl", "multi_arch_container")
 
 container_layer(
     name = "cluster-srcs",
@@ -18,17 +19,18 @@ container_layer(
     ],
 )
 
-container_image(
-    name = "conformance-internal",
-    base = select(for_platforms(
-        for_server = "@debian-hyperkube-base-{ARCH}//image",
-        only_os = "linux",
-    )),
+multi_arch_container(
+    name = "conformance",
+    architectures = SERVER_PLATFORMS["linux"],
+    base = "@debian-hyperkube-base-{ARCH}//image",
     cmd = [
         "/bin/bash",
         "-c",
         "/run_e2e.sh",
     ],
+    # {ARCH} is replaced by the macro, but STABLE_DOCKER_TAG is replaced by the
+    # build stamping, so we need to escape it
+    docker_tags = ["k8s.gcr.io/conformance-{ARCH}:{{STABLE_DOCKER_TAG}}"],
     env = {
         "E2E_FOCUS": "\[Conformance\]",
         "E2E_SKIP": "",
@@ -45,23 +47,10 @@ container_image(
         ":bins",
     ],
     stamp = True,
-    workdir = "/usr/local/bin",
-)
-
-[container_bundle(
-    name = "conformance-%s" % arch,
-    images = {"k8s.gcr.io/conformance-%s:{STABLE_DOCKER_TAG}" % arch: "conformance-internal"},
     tags = ["manual"],
     visibility = ["//visibility:public"],
-) for arch in SERVER_PLATFORMS["linux"]]
-
-[alias(
-    name = "conformance%s" % suffix,
-    actual = select(for_platforms(for_server = "conformance-{ARCH}%s" % suffix)),
-) for suffix in [
-    "",
-    ".tar",
-]]
+    workdir = "/usr/local/bin",
+)
 
 filegroup(
     name = "package-srcs",

cluster/images/hyperkube/BUILD

-load("@io_bazel_rules_docker//container:container.bzl", "container_bundle", "container_image")
-load("//build:platforms.bzl", "SERVER_PLATFORMS", "for_platforms")
+load("//build:container.bzl", "multi_arch_container")
+load("//build:platforms.bzl", "SERVER_PLATFORMS")
 
-container_image(
-    name = "hyperkube-internal",
-    base = select(for_platforms(
-        for_server = "@debian-hyperkube-base-{ARCH}//image",
-        only_os = "linux",
-    )),
+multi_arch_container(
+    name = "hyperkube",
+    architectures = SERVER_PLATFORMS["linux"],
+    base = "@debian-hyperkube-base-{ARCH}//image",
+    # {ARCH} is replaced by the macro, but STABLE_DOCKER_TAG is replaced by the
+    # build stamping, so we need to escape it
+    docker_tags = ["k8s.gcr.io/hyperkube-{ARCH}:{{STABLE_DOCKER_TAG}}"],
     files = [
         "//cmd/hyperkube",
     ],
     stamp = True,
-)
-
-[container_bundle(
-    name = "hyperkube-%s" % arch,
-    images = {"k8s.gcr.io/hyperkube-%s:{STABLE_DOCKER_TAG}" % arch: "hyperkube-internal"},
     tags = ["manual"],
     visibility = ["//visibility:public"],
-) for arch in SERVER_PLATFORMS["linux"]]
-
-[alias(
-    name = "hyperkube%s" % suffix,
-    actual = select(for_platforms(for_server = "hyperkube-{ARCH}%s" % suffix)),
-) for suffix in [
-    "",
-    ".tar",
-]]
+)
 
 filegroup(
     name = "package-srcs",