Implement dual testing

BUILD

@@ -65,7 +65,7 @@ config_setting(
 
 config_setting(
     name = "python3",
-    values = {"python_path": "python3"},
+    flag_values = {"@bazel_tools//tools/python:python_version": "PY3"},
 )
 
 config_setting(

bazel/grpc_python_deps.bzl

@@ -47,6 +47,15 @@ def grpc_python_deps():
             remote = "https://github.com/bazelbuild/rules_python.git",
         )
 
+
+    if "rules_python" not in native.existing_rules():
+        http_archive(
+            name = "rules_python",
+            url = "https://github.com/bazelbuild/rules_python/archive/9d68f24659e8ce8b736590ba1e4418af06ec2552.zip",
+            sha256 = "f7402f11691d657161f871e11968a984e5b48b023321935f5a55d7e56cf4758a",
+            strip_prefix = "rules_python-9d68f24659e8ce8b736590ba1e4418af06ec2552",
+        )
+
     python_configure(name = "local_config_python")
 
     native.bind(

bazel/python_rules.bzl

@@ -178,3 +178,29 @@ def py_grpc_library(
         deps = [Label("//src/python/grpcio/grpc:grpcio")] + deps,
         **kwargs
     )
+
+
+def py2and3_test(name,
+                 py_test = native.py_test,
+                 **kwargs):
+    if "python_version" in kwargs:
+        fail("Cannot specify 'python_version' in py2and3_test.")
+
+    names = [name + suffix for suffix in (".python2", ".python3")]
+    python_versions = ["PY2", "PY3"]
+    for case_name, python_version in zip(names, python_versions):
+        py_test(
+            name = case_name,
+            python_version = python_version,
+            **kwargs
+        )
+
+    suite_kwargs = {}
+    if "visibility" in kwargs:
+        suite_kwargs["visibility"] = kwargs["visibility"]
+
+    native.test_suite(
+        name = name,
+        tests = names,
+        **suite_kwargs
+    )

src/python/grpcio_tests/tests/unit/BUILD.bazel

@@ -1,3 +1,5 @@
+load("//bazel:python_rules.bzl", "py2and3_test")
+
 package(default_visibility = ["//visibility:public"])
 
 GRPCIO_TESTS_UNIT = [
@@ -80,7 +82,7 @@ py_library(
 )
 
 [
-    py_test(
+    py2and3_test(
         name=test_file_name[:-3],
         size="small",
         srcs=[test_file_name],

third_party/py/BUILD.tpl

@@ -2,35 +2,36 @@
 
 package(default_visibility=["//visibility:public"])
 
-# To build Python C/C++ extension on Windows, we need to link to python import library pythonXY.lib
-# See https://docs.python.org/3/extending/windows.html
-cc_import(
-    name="python_lib",
-    interface_library=select({
-        ":windows": ":python_import_lib",
-        # A placeholder for Unix platforms which makes --no_build happy.
-        "//conditions:default": "not-existing.lib",
-    }),
-    system_provided=1,
-)
-
-cc_library(
-    name="python_headers",
-    hdrs=[":python_include"],
-    deps=select({
-        ":windows": [":python_lib"],
-        "//conditions:default": [],
-    }),
-    includes=["python_include"],
-)
-
 config_setting(
     name="windows",
     values={"cpu": "x64_windows"},
     visibility=["//visibility:public"],
 )
 
-%{PYTHON_INCLUDE_GENRULE}
-%{PYTHON_IMPORT_LIB_GENRULE}
+config_setting(
+    name="python2",
+    flag_values = {"@rules_python//python:python_version": "PY2"}
+)
+
+config_setting(
+    name="python3",
+    flag_values = {"@rules_python//python:python_version": "PY3"}
+)
 
+cc_library(
+    name = "python_lib",
+    deps = select({
+        ":python2": ["//_python2:_python2_lib"],
+        ":python3": ["//_python3:_python3_lib"],
+        "//conditions:default": ["not-existing.lib"],
+    })
+)
 
+cc_library(
+    name = "python_headers",
+    deps = select({
+        ":python2": ["//_python2:_python2_headers"],
+        ":python3": ["//_python3:_python3_headers"],
+        "//conditions:default": ["not-existing.headers"],
+    })
+)

third_party/py/python_configure.bzl

@@ -3,14 +3,15 @@
 
 `python_configure` depends on the following environment variables:
 
-  * `PYTHON_BIN_PATH`: location of python binary.
-  * `PYTHON_LIB_PATH`: Location of python libraries.
+  * `PYTHON2_BIN_PATH`: location of python binary.
+  * `PYTHON2_LIB_PATH`: Location of python libraries.
 """
 
 _BAZEL_SH = "BAZEL_SH"
-_PYTHON_BIN_PATH = "PYTHON_BIN_PATH"
-_PYTHON_LIB_PATH = "PYTHON_LIB_PATH"
-_PYTHON_CONFIG_REPO = "PYTHON_CONFIG_REPO"
+_PYTHON2_BIN_PATH = "PYTHON2_BIN_PATH"
+_PYTHON2_LIB_PATH = "PYTHON2_LIB_PATH"
+_PYTHON3_BIN_PATH = "PYTHON3_BIN_PATH"
+_PYTHON3_LIB_PATH = "PYTHON3_LIB_PATH"
 
 
 def _tpl(repository_ctx, tpl, substitutions={}, out=None):
@@ -136,9 +137,9 @@ def _symlink_genrule_for_dir(repository_ctx,
                     "\n".join(outs))
 
 
-def _get_python_bin(repository_ctx):
+def _get_python_bin(repository_ctx, bin_path_key, default_bin_path):
     """Gets the python bin path."""
-    python_bin = repository_ctx.os.environ.get(_PYTHON_BIN_PATH, 'python')
+    python_bin = repository_ctx.os.environ.get(bin_path_key, default_bin_path)
     if not repository_ctx.path(python_bin).exists:
         # It's a command, use 'which' to find its path.
         python_bin_path = repository_ctx.which(python_bin)
@@ -150,7 +151,7 @@ def _get_python_bin(repository_ctx):
     _fail("Cannot find python in PATH, please make sure " +
           "python is installed and add its directory in PATH, or --define " +
           "%s='/something/else'.\nPATH=%s" %
-          (_PYTHON_BIN_PATH, repository_ctx.os.environ.get("PATH", "")))
+          (bin_path_key, repository_ctx.os.environ.get("PATH", "")))
 
 
 def _get_bash_bin(repository_ctx):
@@ -170,9 +171,9 @@ def _get_bash_bin(repository_ctx):
                 (_BAZEL_SH, repository_ctx.os.environ.get("PATH", "")))
 
 
-def _get_python_lib(repository_ctx, python_bin):
+def _get_python_lib(repository_ctx, python_bin, lib_path_key):
     """Gets the python lib path."""
-    python_lib = repository_ctx.os.environ.get(_PYTHON_LIB_PATH)
+    python_lib = repository_ctx.os.environ.get(lib_path_key)
     if python_lib != None:
         return python_lib
     print_lib = (
@@ -202,13 +203,13 @@ def _check_python_lib(repository_ctx, python_lib):
         _fail("Invalid python library path: %s" % python_lib)
 
 
-def _check_python_bin(repository_ctx, python_bin):
+def _check_python_bin(repository_ctx, python_bin, bin_path_key):
     """Checks the python bin path."""
     cmd = '[[ -x "%s" ]] && [[ ! -d "%s" ]]' % (python_bin, python_bin)
     result = repository_ctx.execute([_get_bash_bin(repository_ctx), "-c", cmd])
     if result.return_code == 1:
         _fail("--define %s='%s' is not executable. Is it the python binary?" %
-              (_PYTHON_BIN_PATH, python_bin))
+              (bin_path_key, python_bin))
 
 
 def _get_python_include(repository_ctx, python_bin):
@@ -222,11 +223,11 @@ def _get_python_include(repository_ctx, python_bin):
         error_msg="Problem getting python include path.",
         error_details=(
             "Is the Python binary path set up right? " + "(See ./configure or "
-            + _PYTHON_BIN_PATH + ".) " + "Is distutils installed?"))
+            + _PYTHON2_BIN_PATH + ".) " + "Is distutils installed?"))
     return result.stdout.splitlines()[0]
 
 
-def _get_python_import_lib_name(repository_ctx, python_bin):
+def _get_python_import_lib_name(repository_ctx, python_bin, bin_path_key):
     """Get Python import library name (pythonXY.lib) on Windows."""
     result = _execute(
         repository_ctx, [
@@ -236,66 +237,77 @@ def _get_python_import_lib_name(repository_ctx, python_bin):
         ],
         error_msg="Problem getting python import library.",
         error_details=("Is the Python binary path set up right? " +
-                       "(See ./configure or " + _PYTHON_BIN_PATH + ".) "))
+                       "(See ./configure or " + bin_path_key + ".) "))
     return result.stdout.splitlines()[0]
 
 
-def _create_local_python_repository(repository_ctx):
+# TODO(rbellevi): Rename.
+def _create_local_python_repository(repository_ctx,
+                                    variety_name,
+                                    bin_path_key,
+                                    default_bin_path,
+                                    lib_path_key):
     """Creates the repository containing files set up to build with Python."""
-    python_bin = _get_python_bin(repository_ctx)
-    _check_python_bin(repository_ctx, python_bin)
-    python_lib = _get_python_lib(repository_ctx, python_bin)
+    python_bin = _get_python_bin(repository_ctx, bin_path_key, default_bin_path)
+    _check_python_bin(repository_ctx, python_bin, bin_path_key)
+    python_lib = _get_python_lib(repository_ctx, python_bin, lib_path_key)
     _check_python_lib(repository_ctx, python_lib)
     python_include = _get_python_include(repository_ctx, python_bin)
     python_include_rule = _symlink_genrule_for_dir(
-        repository_ctx, python_include, 'python_include', 'python_include')
+        repository_ctx, python_include, '{}_include'.format(variety_name),
+        '{}_include'.format(variety_name))
     python_import_lib_genrule = ""
     # To build Python C/C++ extension on Windows, we need to link to python import library pythonXY.lib
     # See https://docs.python.org/3/extending/windows.html
     if _is_windows(repository_ctx):
         python_include = _normalize_path(python_include)
-        python_import_lib_name = _get_python_import_lib_name(
+        python_import_lib_name = _get_python_import_lib_name, bin_path_key(
             repository_ctx, python_bin)
         python_import_lib_src = python_include.rsplit(
             '/', 1)[0] + "/libs/" + python_import_lib_name
         python_import_lib_genrule = _symlink_genrule_for_dir(
-            repository_ctx, None, '', 'python_import_lib',
+            repository_ctx, None, '', '{}_import_lib'.format(variety_name),
             [python_import_lib_src], [python_import_lib_name])
     _tpl(
-        repository_ctx, "BUILD", {
+        repository_ctx, "variety", {
             "%{PYTHON_INCLUDE_GENRULE}": python_include_rule,
             "%{PYTHON_IMPORT_LIB_GENRULE}": python_import_lib_genrule,
-        })
-
-
-def _create_remote_python_repository(repository_ctx, remote_config_repo):
-    """Creates pointers to a remotely configured repo set up to build with Python.
-  """
-    _tpl(repository_ctx, "remote.BUILD", {
-        "%{REMOTE_PYTHON_REPO}": remote_config_repo,
-    }, "BUILD")
+            "%{VARIETY_NAME}": variety_name,
+        },
+        out="{}/BUILD".format(variety_name))
 
 
+# TODO(rbellevi): Remove
 def _python_autoconf_impl(repository_ctx):
     """Implementation of the python_autoconf repository rule."""
-    if _PYTHON_CONFIG_REPO in repository_ctx.os.environ:
-        _create_remote_python_repository(
-            repository_ctx, repository_ctx.os.environ[_PYTHON_CONFIG_REPO])
-    else:
-        _create_local_python_repository(repository_ctx)
+    _create_local_python_repository(repository_ctx,
+                                    "_python2",
+                                    _PYTHON2_BIN_PATH,
+                                    "python",
+                                    _PYTHON2_LIB_PATH)
+    _create_local_python_repository(repository_ctx,
+                                    "_python3",
+                                    _PYTHON3_BIN_PATH,
+                                    "python3",
+                                    _PYTHON3_LIB_PATH)
+    _tpl(repository_ctx, "BUILD")
 
 
 python_configure = repository_rule(
     implementation=_python_autoconf_impl,
     environ=[
         _BAZEL_SH,
-        _PYTHON_BIN_PATH,
-        _PYTHON_LIB_PATH,
-        _PYTHON_CONFIG_REPO,
+        _PYTHON2_BIN_PATH,
+        _PYTHON2_LIB_PATH,
+        _PYTHON3_BIN_PATH,
+        _PYTHON3_LIB_PATH,
     ],
 )
 """Detects and configures the local Python.
 
+It is expected that the system have both a working Python 2 and python 3
+installation
+
 Add the following to your WORKSPACE FILE:
 
 ```python

third_party/py/remote.BUILD.tpl

@@ -1,10 +0,0 @@
-# Adapted with modifications from tensorflow/third_party/py/
-
-package(default_visibility=["//visibility:public"])
-
-alias(
-    name="python_headers",
-    actual="%{REMOTE_PYTHON_REPO}:python_headers",
-)
-
-

third_party/py/variety.tpl

@@ -0,0 +1,26 @@
+package(default_visibility=["//visibility:public"])
+
+# To build Python C/C++ extension on Windows, we need to link to python import library pythonXY.lib
+# See https://docs.python.org/3/extending/windows.html
+cc_import(
+    name="%{VARIETY_NAME}_lib",
+    interface_library=select({
+        "//:windows": ":%{VARIETY_NAME}_import_lib",
+        # A placeholder for Unix platforms which makes --no_build happy.
+        "//conditions:default": "not-existing.lib",
+    }),
+    system_provided=1,
+)
+
+cc_library(
+    name="%{VARIETY_NAME}_headers",
+    hdrs=[":%{VARIETY_NAME}_include"],
+    deps=select({
+        "//:windows": [":%{VARIETY_NAME}_lib"],
+        "//conditions:default": [],
+    }),
+    includes=["%{VARIETY_NAME}_include"],
+)
+
+%{PYTHON_INCLUDE_GENRULE}
+%{PYTHON_IMPORT_LIB_GENRULE}

tools/bazel.rc

@@ -82,7 +82,3 @@ build:basicprof --copt=-DNDEBUG
 build:basicprof --copt=-O2
 build:basicprof --copt=-DGRPC_BASIC_PROFILER
 build:basicprof --copt=-DGRPC_TIMERS_RDTSC
-
-build:python3 --python_path=python3
-build:python3 --python_version=PY3
-build:python3 --action_env=PYTHON_BIN_PATH=python3