Construct pillar from file tree.

def _construct_pillar(top_dir,
                      follow_dir_links,
                      keep_newline=False,
                      render_default=None,
                      renderer_blacklist=None,
                      renderer_whitelist=None,
                      template=False):
    '''
    Construct pillar from file tree.
    '''
    pillar = {}
    renderers = salt.loader.render(__opts__, __salt__)

    norm_top_dir = os.path.normpath(top_dir)
    for dir_path, dir_names, file_names in salt.utils.path.os_walk(
            top_dir, topdown=True, onerror=_on_walk_error,
            followlinks=follow_dir_links):
        # Find current path in pillar tree
        pillar_node = pillar
        norm_dir_path = os.path.normpath(dir_path)
        prefix = os.path.relpath(norm_dir_path, norm_top_dir)
        if norm_dir_path != norm_top_dir:
            path_parts = []
            head = prefix
            while head:
                head, tail = os.path.split(head)
                path_parts.insert(0, tail)
            while path_parts:
                pillar_node = pillar_node[path_parts.pop(0)]

        # Create dicts for subdirectories
        for dir_name in dir_names:
            pillar_node[dir_name] = {}

        # Add files
        for file_name in file_names:
            file_path = os.path.join(dir_path, file_name)
            if not os.path.isfile(file_path):
                log.error('file_tree: %s: not a regular file', file_path)
                continue

            contents = b''
            try:
                with salt.utils.files.fopen(file_path, 'rb') as fhr:
                    buf = fhr.read(__opts__['file_buffer_size'])
                    while buf:
                        contents += buf
                        buf = fhr.read(__opts__['file_buffer_size'])
                    if contents.endswith(b'\n') \
                            and _check_newline(prefix,
                                               file_name,
                                               keep_newline):
                        contents = contents[:-1]
            except (IOError, OSError) as exc:
                log.error('file_tree: Error reading %s: %s',
                          file_path,
                          exc.strerror)
            else:
                data = contents
                if template is True:
                    data = salt.template.compile_template_str(template=salt.utils.stringutils.to_unicode(contents),
                                                              renderers=renderers,
                                                              default=render_default,
                                                              blacklist=renderer_blacklist,
                                                              whitelist=renderer_whitelist)
                if salt.utils.stringio.is_readable(data):
                    pillar_node[file_name] = data.getvalue()
                else:
                    pillar_node[file_name] = data

    return pillar