Create work-around wrappers for pure attribute on go_binary and go_test

This enables cgo when cross-compiling certain tests and binaries to
Linux, while disabling cgo for Windows and Darwin.

build/BUILD

@@ -143,8 +143,8 @@ filegroup(
         "//cmd/genyaml",
         "//cmd/kubemark",  # TODO: server platforms only
         "//cmd/linkcheck",
-        "//test/e2e:e2e.test",
+        "//test/e2e:e2e.test_binary",
-        "//test/e2e_node:e2e_node.test",  # TODO: server platforms only
+        "//test/e2e_node:e2e_node.test_binary",  # TODO: server platforms only
         "//vendor/github.com/onsi/ginkgo/ginkgo",
     ],
 )

build/go.bzl

@@ -0,0 +1,103 @@
+# 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_go//go:def.bzl", "go_binary", "go_test")
+
+# Defines several go_binary rules to work around a Bazel issue which makes
+# the pure attribute on go_binary not configurable.
+# The name provided will have cgo enabled if targeting Linux, and will
+# be a pure go binary otherwise. Additionally, if targeting Windows, the
+# output filename will have a .exe suffix.
+def go_binary_conditional_pure(name, tags = None, **kwargs):
+    tags = tags or []
+    tags.append("manual")
+    go_binary(
+        name = "_%s-cgo" % name,
+        out = name,
+        pure = "off",
+        tags = tags,
+        **kwargs
+    )
+
+    # Define a rule for both Unix and Windows exe suffixes.
+    [go_binary(
+        name = "_%s-pure" % out,
+        out = out,
+        pure = "on",
+        tags = tags,
+        **kwargs
+    ) for out in [name, name + ".exe"]]
+
+    # The real magic, where we work around the pure attribute not being
+    # configurable: select the appropriate go_binary rule above based on the
+    # configured platform.
+    native.alias(
+        name = name,
+        actual = select({
+            "@io_bazel_rules_go//go/platform:linux": ":_%s-cgo" % name,
+            "@io_bazel_rules_go//go/platform:windows": ":_%s.exe-pure" % name,
+            "//conditions:default": ":_%s-pure" % name,
+        }),
+    )
+
+# Defines several go_test rules to work around a Bazel issue which makes
+# the pure attribute on go_test not configurable.
+# This also defines genrules to produce test binaries named ${out} and
+# ${out}.exe, and an alias named ${out}_binary which automatically selects
+# the correct filename suffix (i.e. with a .exe on Windows).
+def go_test_conditional_pure(name, out, tags = None, **kwargs):
+    tags = tags or []
+    tags.append("manual")
+
+    go_test(
+        name = "_%s-cgo" % name,
+        pure = "off",
+        testonly = False,
+        tags = tags,
+        **kwargs
+    )
+
+    go_test(
+        name = "_%s-pure" % name,
+        pure = "on",
+        testonly = False,
+        tags = tags,
+        **kwargs
+    )
+
+    native.alias(
+        name = name,
+        actual = select({
+            "@io_bazel_rules_go//go/platform:linux": ":_%s-cgo" % name,
+            "//conditions:default": ":_%s-pure" % name,
+        }),
+    )
+
+    [native.genrule(
+        name = "gen_%s" % o,
+        srcs = [name],
+        outs = [o],
+        cmd = "cp $< $@;",
+        output_to_bindir = True,
+        executable = True,
+        tags = tags,
+    ) for o in [out, out + ".exe"]]
+
+    native.alias(
+        name = "%s_binary" % out,
+        actual = select({
+            "@io_bazel_rules_go//go/platform:windows": ":gen_%s.exe" % out,
+            "//conditions:default": ":gen_%s" % out,
+        }),
+    )

cluster/images/conformance/BUILD

@@ -12,7 +12,7 @@ container_layer(
     directory = "/usr/local/bin",
     files = [
         "//cmd/kubectl",
-        "//test/e2e:e2e.test",
+        "//test/e2e:e2e.test_binary",
         "//vendor/github.com/onsi/ginkgo/ginkgo",
     ],
 )

cmd/gendocs/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_binary(
     name = "gendocs",

cmd/genkubedocs/BUILD

@@ -1,8 +1,11 @@
 package(default_visibility = ["//visibility:public"])
 
+load(
+    "//build:go.bzl",
+    go_binary = "go_binary_conditional_pure",
+)
 load(
     "@io_bazel_rules_go//go:def.bzl",
-    "go_binary",
     "go_library",
     "go_test",
 )

cmd/genman/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_binary(
     name = "genman",

cmd/genswaggertypedocs/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_binary(
     name = "genswaggertypedocs",

cmd/genyaml/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_binary(
     name = "genyaml",

cmd/hyperkube/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 load("//pkg/version:def.bzl", "version_x_defs")
 
 go_binary(

cmd/kubelet/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 load("//pkg/version:def.bzl", "version_x_defs")
 
 go_binary(

cmd/kubemark/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_binary(
     name = "kubemark",

cmd/linkcheck/BUILD

@@ -1,10 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_binary",
+    go_binary = "go_binary_conditional_pure",
-    "go_library",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_binary(
     name = "linkcheck",

test/e2e/BUILD

@@ -1,14 +1,15 @@
 package(default_visibility = ["//visibility:public"])
 
 load(
-    "@io_bazel_rules_go//go:def.bzl",
+    "//build:go.bzl",
-    "go_library",
+    go_test = "go_test_conditional_pure",
-    "go_test",
 )
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_test(
     name = "go_default_test",
     srcs = ["e2e_test.go"],
+    out = "e2e.test",
     embed = [":go_default_library"],
     tags = ["e2e"],
     deps = [
@@ -78,17 +79,6 @@ go_library(
     ],
 )
 
-# This is a handwritten rule. Do not delete, it will not be regenerated by
-# update-bazel.sh.
-genrule(
-    name = "gen_e2e.test",
-    testonly = 1,
-    srcs = [":go_default_test"],
-    outs = ["e2e.test"],
-    cmd = "srcs=($(SRCS)); cp $$(dirname $${srcs[0]})/go_default_test $@;",
-    output_to_bindir = 1,
-)
-
 filegroup(
     name = "package-srcs",
     srcs = glob(["**"]),

test/e2e_kubeadm/BUILD

@@ -1,6 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
-load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+load(
+    "//build:go.bzl",
+    go_test = "go_test_conditional_pure",
+)
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_test(
     name = "go_default_test",
@@ -8,6 +12,7 @@ go_test(
         "e2e_kubeadm_suite_test.go",
         "kubeadm_test.go",
     ],
+    out = "e2e_kubeadm.test",
     embed = [":go_default_library"],
     tags = ["e2e"],
     deps = [
@@ -32,15 +37,6 @@ filegroup(
     visibility = ["//visibility:private"],
 )
 
-genrule(
-    name = "gen_e2e_kubeadm.test",
-    testonly = 1,
-    srcs = [":go_default_test"],
-    outs = ["e2e_kubeadm.test"],
-    cmd = "srcs=($(SRCS)); cp $$(dirname $${srcs[0]})/go_default_test $@;",
-    output_to_bindir = 1,
-)
-
 filegroup(
     name = "all-srcs",
     srcs = [

test/e2e_node/BUILD

@@ -1,6 +1,10 @@
 package(default_visibility = ["//visibility:public"])
 
-load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+load(
+    "//build:go.bzl",
+    go_test = "go_test_conditional_pure",
+)
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
 
 go_library(
     name = "go_default_library",
@@ -106,6 +110,7 @@ go_test(
         "summary_test.go",
         "volume_manager_test.go",
     ],
+    out = "e2e_node.test",
     embed = [":go_default_library"],
     tags = ["e2e"],
     deps = [
@@ -180,15 +185,6 @@ go_test(
     }),
 )
 
-genrule(
-    name = "gen_e2e_node.test",
-    testonly = 1,
-    srcs = [":go_default_test"],
-    outs = ["e2e_node.test"],
-    cmd = "srcs=($(SRCS)); cp $$(dirname $${srcs[0]})/go_default_test $@;",
-    output_to_bindir = 1,
-)
-
 filegroup(
     name = "package-srcs",
     srcs = glob(["**"]),