Make Python build standalone on Windows

PYTHON-MANIFEST.in

@@ -7,6 +7,7 @@ graft include/grpc
 graft third_party/boringssl
 graft third_party/nanopb
 graft third_party/zlib
+include src/python/grpcio/build.py
 include src/python/grpcio/commands.py
 include src/python/grpcio/grpc_version.py
 include src/python/grpcio/grpc_core_dependencies.py

setup.py

@@ -31,6 +31,7 @@
 
 import os
 import os.path
+import platform
 import shlex
 import shutil
 import sys
@@ -56,10 +57,15 @@
 sys.path.insert(0, os.path.abspath(PYTHON_STEM))
 
 # Break import-style to ensure we can actually find our in-repo dependencies.
+import build
 import commands
 import grpc_core_dependencies
 import grpc_version
 
+# TODO(atash) make this conditional on being on a mingw32 build
+build.monkeypatch_unix_compiler()
+
+
 LICENSE = '3-clause BSD'
 
 # Environment variable to determine whether or not the Cython extension should
@@ -72,6 +78,14 @@
 ENABLE_CYTHON_TRACING = os.environ.get(
     'GRPC_PYTHON_ENABLE_CYTHON_TRACING', False)
 
+# There are some situations (like on Windows) where CC, CFLAGS, and LDFLAGS are
+# entirely ignored/dropped/forgotten by distutils and its Cygwin/MinGW support.
+# We use these environment variables to thus get around that without locking
+# ourselves in w.r.t. the multitude of operating systems this ought to build on.
+# By default we assume a GCC-like compiler.
+EXTRA_COMPILE_ARGS = shlex.split(os.environ.get('GRPC_PYTHON_CFLAGS', ''))
+EXTRA_LINK_ARGS = shlex.split(os.environ.get('GRPC_PYTHON_LDFLAGS', ''))
+
 CYTHON_EXTENSION_PACKAGE_NAMES = ()
 
 CYTHON_EXTENSION_MODULE_NAMES = ('grpc._cython.cygrpc',)
@@ -81,9 +95,7 @@
     os.path.join(PYTHON_STEM, 'grpc/_cython/imports.generated.c'),
 )
 
-CORE_C_FILES = ()
-if not "win32" in sys.platform:
-  CORE_C_FILES += tuple(grpc_core_dependencies.CORE_SOURCE_FILES)
+CORE_C_FILES = tuple(grpc_core_dependencies.CORE_SOURCE_FILES)
 
 EXTENSION_INCLUDE_DIRECTORIES = (
     (PYTHON_STEM,) + CORE_INCLUDE + BORINGSSL_INCLUDE + ZLIB_INCLUDE)
@@ -93,12 +105,17 @@
   EXTENSION_LIBRARIES += ('rt',)
 if not "win32" in sys.platform:
   EXTENSION_LIBRARIES += ('m',)
+if "win32" in sys.platform:
+  EXTENSION_LIBRARIES += ('ws2_32',)
 
 DEFINE_MACROS = (('OPENSSL_NO_ASM', 1), ('_WIN32_WINNT', 0x600), ('GPR_BACKWARDS_COMPATIBILITY_MODE', 1),)
+if "win32" in sys.platform:
+  DEFINE_MACROS += (('OPENSSL_WINDOWS', 1), ('WIN32_LEAN_AND_MEAN', 1),)
+  if '64bit' in platform.architecture()[0]:
+    DEFINE_MACROS += (('MS_WIN64', 1),)
 
-LDFLAGS = shlex.split(os.environ.get('GRPC_PYTHON_LDFLAGS', ''))
-CFLAGS = shlex.split(os.environ.get('GRPC_PYTHON_CFLAGS', ''))
-
+LDFLAGS = tuple(EXTRA_LINK_ARGS)
+CFLAGS = tuple(EXTRA_COMPILE_ARGS)
 if "linux" in sys.platform:
   LDFLAGS += ('-Wl,-wrap,memcpy',)
 if "linux" in sys.platform or "darwin" in sys.platform:

src/python/grpcio/build.py

@@ -0,0 +1,117 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Covers inadequacies in distutils."""
+
+from distutils import ccompiler
+from distutils import errors
+from distutils import unixccompiler
+import os
+import os.path
+import shutil
+import sys
+import tempfile
+
+
+def _unix_piecemeal_link(
+    self, target_desc, objects, output_filename, output_dir=None,
+    libraries=None, library_dirs=None, runtime_library_dirs=None,
+    export_symbols=None, debug=0, extra_preargs=None, extra_postargs=None,
+    build_temp=None, target_lang=None):
+  """`link` externalized method taken almost verbatim from UnixCCompiler.
+
+  Modifies the link command for unix-like compilers by using a command file so
+  that long command line argument strings don't break the command shell's
+  ARG_MAX character limit.
+  """
+  objects, output_dir = self._fix_object_args(objects, output_dir)
+  libraries, library_dirs, runtime_library_dirs = self._fix_lib_args(
+      libraries, library_dirs, runtime_library_dirs)
+  # filter out standard library paths, which are not explicitely needed
+  # for linking
+  library_dirs = [dir for dir in library_dirs
+                  if not dir in ('/lib', '/lib64', '/usr/lib', '/usr/lib64')]
+  runtime_library_dirs = [dir for dir in runtime_library_dirs
+                          if not dir in ('/lib', '/lib64', '/usr/lib', '/usr/lib64')]
+  lib_opts = ccompiler.gen_lib_options(self, library_dirs, runtime_library_dirs,
+                             libraries)
+  if not isinstance(output_dir, basestring) and output_dir is not None:
+    raise TypeError, "'output_dir' must be a string or None"
+  if output_dir is not None:
+    output_filename = os.path.join(output_dir, output_filename)
+
+  if self._need_link(objects, output_filename):
+    ld_args = (objects + self.objects +
+               lib_opts + ['-o', output_filename])
+    if debug:
+      ld_args[:0] = ['-g']
+    if extra_preargs:
+      ld_args[:0] = extra_preargs
+    if extra_postargs:
+      ld_args.extend(extra_postargs)
+    self.mkpath(os.path.dirname(output_filename))
+    try:
+      if target_desc == ccompiler.CCompiler.EXECUTABLE:
+        linker = self.linker_exe[:]
+      else:
+        linker = self.linker_so[:]
+      if target_lang == "c++" and self.compiler_cxx:
+        # skip over environment variable settings if /usr/bin/env
+        # is used to set up the linker's environment.
+        # This is needed on OSX. Note: this assumes that the
+        # normal and C++ compiler have the same environment
+        # settings.
+        i = 0
+        if os.path.basename(linker[0]) == "env":
+          i = 1
+          while '=' in linker[i]:
+            i = i + 1
+
+        linker[i] = self.compiler_cxx[i]
+
+      if sys.platform == 'darwin':
+        import _osx_support
+        linker = _osx_support.compiler_fixup(linker, ld_args)
+
+      temporary_directory = tempfile.mkdtemp()
+      command_filename = os.path.abspath(
+          os.path.join(temporary_directory, 'command'))
+      with open(command_filename, 'w') as command_file:
+        escaped_ld_args = [arg.replace('\\', '\\\\') for arg in ld_args]
+        command_file.write(' '.join(escaped_ld_args))
+      self.spawn(linker + ['@{}'.format(command_filename)])
+    except errors.DistutilsExecError, msg:
+      raise ccompiler.LinkError, msg
+  else:
+    log.debug("skipping %s (up-to-date)", output_filename)
+
+def monkeypatch_unix_compiler():
+  """Monkeypatching is dumb, but it's either that or we become maintainers of
+     something much, much bigger."""
+  unixccompiler.UnixCCompiler.link = _unix_piecemeal_link