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"""Provides distutils command classes for the GRPC Python setup process."""

import distutils
import glob
import os
import os.path
import platform
import re
import shutil
import subprocess
import sys
import traceback

import setuptools
from setuptools.command import bdist_egg
from setuptools.command import build_ext
from setuptools.command import build_py
from setuptools.command import easy_install
from setuptools.command import install
from setuptools.command import test

import support

PYTHON_STEM = os.path.dirname(os.path.abspath(__file__))

BINARIES_REPOSITORY = os.environ.get(
    'GRPC_PYTHON_BINARIES_REPOSITORY',
    'https://storage.googleapis.com/grpc-precompiled-binaries/python')

USE_GRPC_CUSTOM_BDIST = bool(int(os.environ.get(
    'GRPC_PYTHON_USE_CUSTOM_BDIST', '1')))

CONF_PY_ADDENDUM = """
extensions.append('sphinx.ext.napoleon')
napoleon_google_docstring = True
napoleon_numpy_docstring = True

html_theme = 'sphinx_rtd_theme'
"""


class CommandError(Exception):
  """Simple exception class for GRPC custom commands."""


# TODO(atash): Remove this once PyPI has better Linux bdist support. See
# https://bitbucket.org/pypa/pypi/issues/120/binary-wheels-for-linux-are-not-supported
def _get_grpc_custom_bdist_egg(decorated_basename, target_egg_basename):
  """Returns a string path to a .egg file for Linux to install.

  If we can retrieve a pre-compiled egg from online, uses it. Else, emits a
  warning and builds from source.
  """
  # Break import style to ensure that setup.py has had a chance to install the
  # relevant package eggs.
  from six.moves.urllib import request
  decorated_path = decorated_basename + '.egg'
  try:
    url = BINARIES_REPOSITORY + '/{target}'.format(target=decorated_path)
    egg_data = request.urlopen(url).read()
  except IOError as error:
    raise CommandError(
        '{}\n\nCould not find the bdist egg {}: {}'
            .format(traceback.format_exc(), decorated_path, error.message))
  # Our chosen local egg path.
  egg_path = target_egg_basename + '.egg'
  try:
    with open(egg_path, 'w') as egg_file:
      egg_file.write(egg_data)
  except IOError as error:
    raise CommandError(
        '{}\n\nCould not write grpcio egg: {}'
            .format(traceback.format_exc(), error.message))
  return egg_path


class EggNameMixin(object):
  """Mixin for setuptools.Command classes to enable acquiring the egg name."""

  def egg_name(self, with_custom):
    """
    Args:
      with_custom: Boolean describing whether or not to decorate the egg name
        with custom gRPC-specific target information.
    """
    egg_command = self.get_finalized_command('bdist_egg')
    base = os.path.splitext(os.path.basename(egg_command.egg_output))[0]
    if with_custom:
      flavor = 'ucs2' if sys.maxunicode == 65535 else 'ucs4'
      return '{base}-{flavor}'.format(base=base, flavor=flavor)
    else:
      return base


class Install(install.install, EggNameMixin):
  """Custom Install command for gRPC Python.

  This is for bdist shims and whatever else we might need a custom install
  command for.
  """

  user_options = install.install.user_options + [
      # TODO(atash): remove this once PyPI has better Linux bdist support. See
      # https://bitbucket.org/pypa/pypi/issues/120/binary-wheels-for-linux-are-not-supported
      ('use-grpc-custom-bdist', None,
       'Whether to retrieve a binary from the gRPC binary repository instead '
       'of building from source.'),
  ]

  def initialize_options(self):
    install.install.initialize_options(self)
    self.use_grpc_custom_bdist = USE_GRPC_CUSTOM_BDIST

  def finalize_options(self):
    install.install.finalize_options(self)

  def run(self):
    if self.use_grpc_custom_bdist:
      try:
        try:
          egg_path = _get_grpc_custom_bdist_egg(self.egg_name(True),
                                                self.egg_name(False))
        except CommandError as error:
          sys.stderr.write(
              '\nWARNING: Failed to acquire grpcio prebuilt binary:\n'
              '{}.\n\n'.format(error.message))
          raise
        try:
          self._run_bdist_retrieval_install(egg_path)
        except Exception as error:
          # if anything else happens (and given how there's no way to really know
          # what's happening in setuptools here, I mean *anything*), warn the user
          # and fall back to building from source.
          sys.stderr.write(
              '{}\nWARNING: Failed to install grpcio prebuilt binary.\n\n'
                  .format(traceback.format_exc()))
          raise
      except Exception:
        install.install.run(self)
    else:
      install.install.run(self)

  # TODO(atash): Remove this once PyPI has better Linux bdist support. See
  # https://bitbucket.org/pypa/pypi/issues/120/binary-wheels-for-linux-are-not-supported
  def _run_bdist_retrieval_install(self, bdist_egg):
    easy_install = self.distribution.get_command_class('easy_install')
    easy_install_command = easy_install(
        self.distribution, args='x', root=self.root, record=self.record,
    )
    easy_install_command.ensure_finalized()
    easy_install_command.always_copy_from = '.'
    easy_install_command.package_index.scan(glob.glob('*.egg'))
    arguments = [bdist_egg]
    if setuptools.bootstrap_install_from:
      args.insert(0, setuptools.bootstrap_install_from)
    easy_install_command.args = arguments
    easy_install_command.run()
    setuptools.bootstrap_install_from = None


class BdistEggCustomName(bdist_egg.bdist_egg, EggNameMixin):
  """Thin wrapper around the bdist_egg command to build with our custom name."""

  def run(self):
    bdist_egg.bdist_egg.run(self)
    target = os.path.join(self.dist_dir, '{}.egg'.format(self.egg_name(True)))
    shutil.move(self.get_outputs()[0], target)


class SphinxDocumentation(setuptools.Command):
  """Command to generate documentation via sphinx."""

  description = 'generate sphinx documentation'
  user_options = []

  def initialize_options(self):
    pass

  def finalize_options(self):
    pass

  def run(self):
    # We import here to ensure that setup.py has had a chance to install the
    # relevant package eggs first.
    import sphinx
    import sphinx.apidoc
    metadata = self.distribution.metadata
    src_dir = os.path.join(
        PYTHON_STEM, self.distribution.package_dir[''], 'grpc')
    sys.path.append(src_dir)
    sphinx.apidoc.main([
        '', '--force', '--full', '-H', metadata.name, '-A', metadata.author,
        '-V', metadata.version, '-R', metadata.version,
        '-o', os.path.join('doc', 'src'), src_dir])
    conf_filepath = os.path.join('doc', 'src', 'conf.py')
    with open(conf_filepath, 'a') as conf_file:
      conf_file.write(CONF_PY_ADDENDUM)
    sphinx.main(['', os.path.join('doc', 'src'), os.path.join('doc', 'build')])


class BuildProtoModules(setuptools.Command):
  """Command to generate project *_pb2.py modules from proto files."""

  description = 'build protobuf modules'
  user_options = [
    ('include=', None, 'path patterns to include in protobuf generation'),
    ('exclude=', None, 'path patterns to exclude from protobuf generation')
  ]

  def initialize_options(self):
    self.exclude = None
    self.include = r'.*\.proto$'
    self.protoc_command = None
    self.grpc_python_plugin_command = None

  def finalize_options(self):
    self.protoc_command = distutils.spawn.find_executable('protoc')
    self.grpc_python_plugin_command = distutils.spawn.find_executable(
        'grpc_python_plugin')

  def run(self):
    if not self.protoc_command:
      raise CommandError('could not find protoc')
    if not self.grpc_python_plugin_command:
      raise CommandError('could not find grpc_python_plugin '
                         '(protoc plugin for GRPC Python)')
    include_regex = re.compile(self.include)
    exclude_regex = re.compile(self.exclude) if self.exclude else None
    paths = []
    root_directory = PYTHON_STEM
    for walk_root, directories, filenames in os.walk(root_directory):
      for filename in filenames:
        path = os.path.join(walk_root, filename)
        if include_regex.match(path) and not (
            exclude_regex and exclude_regex.match(path)):
          paths.append(path)
    command = [
        self.protoc_command,
        '--plugin=protoc-gen-python-grpc={}'.format(
            self.grpc_python_plugin_command),
        '-I {}'.format(root_directory),
        '--python_out={}'.format(root_directory),
        '--python-grpc_out={}'.format(root_directory),
    ] + paths
    try:
      subprocess.check_output(' '.join(command), cwd=root_directory, shell=True,
                              stderr=subprocess.STDOUT)
    except subprocess.CalledProcessError as e:
      raise CommandError('Command:\n{}\nMessage:\n{}\nOutput:\n{}'.format(
          command, e.message, e.output))


class BuildProjectMetadata(setuptools.Command):
  """Command to generate project metadata in a module."""

  description = 'build grpcio project metadata files'
  user_options = []

  def initialize_options(self):
    pass

  def finalize_options(self):
    pass

  def run(self):
    with open(os.path.join(PYTHON_STEM, 'grpc/_grpcio_metadata.py'), 'w') as module_file:
      module_file.write('__version__ = """{}"""'.format(
          self.distribution.get_version()))


class BuildPy(build_py.build_py):
  """Custom project build command."""

  def run(self):
    try:
      self.run_command('build_proto_modules')
    except CommandError as error:
      sys.stderr.write('warning: %s\n' % error.message)
    self.run_command('build_project_metadata')
    build_py.build_py.run(self)


class BuildExt(build_ext.build_ext):
  """Custom build_ext command to enable compiler-specific flags."""

  C_OPTIONS = {
      'unix': ('-pthread', '-std=gnu99'),
      'msvc': (),
  }
  LINK_OPTIONS = {}

  def build_extensions(self):
    compiler = self.compiler.compiler_type
    if compiler in BuildExt.C_OPTIONS:
      for extension in self.extensions:
        extension.extra_compile_args += list(BuildExt.C_OPTIONS[compiler])
    if compiler in BuildExt.LINK_OPTIONS:
      for extension in self.extensions:
        extension.extra_link_args += list(BuildExt.LINK_OPTIONS[compiler])
    try:
      build_ext.build_ext.build_extensions(self)
    except Exception as error:
      formatted_exception = traceback.format_exc()
      support.diagnose_build_ext_error(self, error, formatted_exception)
      raise CommandError(
          "Failed `build_ext` step:\n{}".format(formatted_exception))


class Gather(setuptools.Command):
  """Command to gather project dependencies."""

  description = 'gather dependencies for grpcio'
  user_options = [
    ('test', 't', 'flag indicating to gather test dependencies'),
    ('install', 'i', 'flag indicating to gather install dependencies')
  ]

  def initialize_options(self):
    self.test = False
    self.install = False

  def finalize_options(self):
    # distutils requires this override.
    pass

  def run(self):
    if self.install and self.distribution.install_requires:
      self.distribution.fetch_build_eggs(self.distribution.install_requires)
    if self.test and self.distribution.tests_require:
      self.distribution.fetch_build_eggs(self.distribution.tests_require)


class RunInterop(test.test):

  description = 'run interop test client/server'
  user_options = [
    ('args=', 'a', 'pass-thru arguments for the client/server'),
    ('client', 'c', 'flag indicating to run the client'),
    ('server', 's', 'flag indicating to run the server')
  ]

  def initialize_options(self):
    self.args = ''
    self.client = False
    self.server = False

  def finalize_options(self):
    if self.client and self.server:
      raise DistutilsOptionError('you may only specify one of client or server')

  def run(self):
    if self.distribution.install_requires:
      self.distribution.fetch_build_eggs(self.distribution.install_requires)
    if self.distribution.tests_require:
      self.distribution.fetch_build_eggs(self.distribution.tests_require)
    if self.client:
      self.run_client()
    elif self.server:
      self.run_server()

  def run_server(self):
    # We import here to ensure that our setuptools parent has had a chance to
    # edit the Python system path.
    from tests.interop import server
    sys.argv[1:] = self.args.split()
    server.serve()

  def run_client(self):
    # We import here to ensure that our setuptools parent has had a chance to
    # edit the Python system path.
    from tests.interop import client
    sys.argv[1:] = self.args.split()
    client.test_interoperability()
