use python_version = PY2 for par_binary and py_binary targets

.bazelrc

@@ -0,0 +1,23 @@
+# Copyright 2017 The Bazel Authors. All rights reserved.
+#
+# 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.
+
+# Flags to explicitly use python toolchains to select appropriate py_runtime
+# Also, force host binaries to use py2.
+# Note these flags will only work with Bazel 0.25.0 or above.
+build --incompatible_use_python_toolchains
+build --host_force_python=PY2
+test --incompatible_use_python_toolchains
+test --host_force_python=PY2
+run --incompatible_use_python_toolchains
+run --host_force_python=PY2

container/BUILD

@@ -30,6 +30,7 @@ py_binary(
     name = "extract_config",
     srcs = ["extract_config.py"],
     legacy_create_init = False,
+    python_version = "PY2",
     visibility = ["//visibility:public"],
     deps = [
         "@containerregistry",
@@ -48,6 +49,7 @@ py_binary(
     name = "join_layers",
     srcs = ["join_layers.py"],
     legacy_create_init = False,
+    python_version = "PY2",
     visibility = ["//visibility:public"],
     deps = [
         ":utils",
@@ -60,6 +62,7 @@ py_binary(
     name = "create_image_config",
     srcs = ["create_image_config.py"],
     legacy_create_init = False,
+    python_version = "PY2",
     visibility = ["//visibility:public"],
     deps = [
         ":utils",
@@ -167,6 +170,7 @@ py_test(
     size = "medium",
     srcs = ["image_test.py"],
     data = TEST_DATA,
+    python_version = "PY2",
     deps = ["@containerregistry"],
 )
 

python/BUILD

@@ -27,3 +27,4 @@ py_runtime(
     files = [],
     interpreter_path = "/usr/bin/python2",
 )
+

tests/container/BUILD

@@ -3,5 +3,6 @@ package(default_visibility = ["//visibility:public"])
 py_test(
     name = "build_tar_test",
     srcs = ["build_tar_test.py"],
+    python_version = "PY2",
     deps = ["//container:build_tar_lib"],
 )

tools/BUILD

@@ -17,6 +17,7 @@ py_binary(
     name = "update_deps",
     srcs = ["update_deps.py"],
     legacy_create_init = False,
+    python_version = "PY2",
     deps = [
         "@containerregistry",
     ],