def _create_binary(self, binary_tgt, results_dir):
    """Create a .pex file for the specified binary target."""
    # Note that we rebuild a chroot from scratch, instead of using the REQUIREMENTS_PEX
    # and PYTHON_SOURCES products, because those products are already-built pexes, and there's
    # no easy way to merge them into a single pex file (for example, they each have a __main__.py,
    # metadata, and so on, which the merging code would have to handle specially).
    interpreter = self.context.products.get_data(PythonInterpreter)
    with temporary_dir() as tmpdir:
      # Create the pex_info for the binary.
      run_info_dict = self.context.run_tracker.run_info.get_as_dict()
      build_properties = PexInfo.make_build_properties()
      build_properties.update(run_info_dict)
      pex_info = binary_tgt.pexinfo.copy()
      pex_info.build_properties = build_properties

      pex_builder = PexBuilderWrapper.Factory.create(
        builder=PEXBuilder(path=tmpdir, interpreter=interpreter, pex_info=pex_info, copy=True),
        log=self.context.log)

      if binary_tgt.shebang:
        self.context.log.info('Found Python binary target {} with customized shebang, using it: {}'
          .format(binary_tgt.name, binary_tgt.shebang))
        pex_builder.set_shebang(binary_tgt.shebang)
      else:
        self.context.log.debug('No customized shebang found for {}'.format(binary_tgt.name))

      # Find which targets provide sources and which specify requirements.
      source_tgts = []
      req_tgts = []
      constraint_tgts = []
      for tgt in binary_tgt.closure(exclude_scopes=Scopes.COMPILE):
        if has_python_sources(tgt) or has_resources(tgt):
          source_tgts.append(tgt)
        elif has_python_requirements(tgt):
          req_tgts.append(tgt)
        if is_python_target(tgt):
          constraint_tgts.append(tgt)

      # Add interpreter compatibility constraints to pex info. This will first check the targets for any
      # constraints, and if they do not have any will resort to the global constraints.
      pex_builder.add_interpreter_constraints_from(constraint_tgts)

      # Dump everything into the builder's chroot.
      for tgt in source_tgts:
        pex_builder.add_sources_from(tgt)

      # We need to ensure that we are resolving for only the current platform if we are
      # including local python dist targets that have native extensions.
      self._python_native_code_settings.check_build_for_current_platform_only(self.context.targets())
      pex_builder.add_requirement_libs_from(req_tgts, platforms=binary_tgt.platforms)

      # Build the .pex file.
      pex_path = os.path.join(results_dir, '{}.pex'.format(binary_tgt.name))
      pex_builder.build(pex_path)
      return pex_path
Create a .pex file for the specified binary target.