Retriever authorization and engine filesystem configuration.

def _get_engine_filesystem_config(file_types, args, conf_args):
    """Retriever authorization and engine filesystem configuration.
    """
    file_types = [x.replace("_container", "") for x in list(file_types)]
    out = ""
    if "gcp" in file_types:
        out += _AUTH_CONFIG_GOOGLE
    if "s3" in file_types:
        out += _AUTH_CONFIG_AWS % conf_args["cloud_region"]
    if "gcp" in file_types or "http" in file_types or "s3" in file_types:
        out += "engine {\n"
        out += "  filesystems {\n"
        if "gcp" in file_types:
            out += '    gcs {\n'
            out += '      auth = "gcp-auth"\n'
            if args.cloud_project:
                out += '      project = "%s"\n' % args.cloud_project
            out += '    }\n'
        if "http" in file_types:
            out += '    http {}\n'
        if "s3" in file_types:
            out += '    s3 { auth = "default" }'
        out += "  }\n"
        out += "}\n"

    return out