How to use the gnocchi.indexer.get_driver function in gnocchi

self.backends[name] = (
                            metricd.get_coordinator_and_start(
                                str(uuid.uuid4()).encode(),
                                self.conf.coordination_url)
                        )
                    elif name == "storage":
                        self.backends[name] = (
                            gnocchi_storage.get_driver(self.conf)
                        )
                    elif name == "incoming":
                        self.backends[name] = (
                            gnocchi_incoming.get_driver(self.conf)
                        )
                    elif name == "indexer":
                        self.backends[name] = (
                            gnocchi_indexer.get_driver(self.conf)
                        )
                    else:
                        raise RuntimeError("Unknown driver %s" % name)

        return self.backends[name]

sack_number_opt = copy.copy(_SACK_NUMBER_OPT)
    sack_number_opt.default = 128
    conf.register_cli_opts([
        cfg.BoolOpt("skip-index", default=False,
                    help="Skip index upgrade."),
        cfg.BoolOpt("skip-storage", default=False,
                    help="Skip storage upgrade."),
        cfg.BoolOpt("skip-incoming", default=False,
                    help="Skip incoming storage upgrade."),
        cfg.BoolOpt("skip-archive-policies-creation", default=False,
                    help="Skip default archive policies creation."),
        sack_number_opt,
    ])
    conf = service.prepare_service(conf=conf, log_to_std=True)
    if not conf.skip_index:
        index = indexer.get_driver(conf)
        LOG.info("Upgrading indexer %s", index)
        index.upgrade()
    if not conf.skip_storage:
        s = storage.get_driver(conf)
        LOG.info("Upgrading storage %s", s)
        s.upgrade()
    if not conf.skip_incoming:
        i = incoming.get_driver(conf)
        LOG.info("Upgrading incoming storage %s", i)
        i.upgrade(conf.sacks_number)

    if (not conf.skip_archive_policies_creation
            and not index.list_archive_policies()
            and not index.list_archive_policy_rules()):
        if conf.skip_index:
            index = indexer.get_driver(conf)

LOG.info("Upgrading indexer %s", index)
        index.upgrade()
    if not conf.skip_storage:
        s = storage.get_driver(conf)
        LOG.info("Upgrading storage %s", s)
        s.upgrade()
    if not conf.skip_incoming:
        i = incoming.get_driver(conf)
        LOG.info("Upgrading incoming storage %s", i)
        i.upgrade(conf.sacks_number)

    if (not conf.skip_archive_policies_creation
            and not index.list_archive_policies()
            and not index.list_archive_policy_rules()):
        if conf.skip_index:
            index = indexer.get_driver(conf)
        for name, ap in six.iteritems(archive_policy.DEFAULT_ARCHIVE_POLICIES):
            index.create_archive_policy(ap)
        index.create_archive_policy_rule("default", "*", "low")

def _configure(self):
        member_id = (
            "%s.%s.%s" % (socket.gethostname(),
                          self.worker_id,
                          # NOTE(jd) Still use a uuid here so we're
                          # sure there's no conflict in case of
                          # crash/restart
                          str(uuid.uuid4()))
        ).encode()
        self.coord = get_coordinator_and_start(member_id,
                                               self.conf.coordination_url)
        self.store = storage.get_driver(self.conf)
        self.incoming = incoming.get_driver(self.conf)
        self.index = indexer.get_driver(self.conf)
        self.chef = chef.Chef(self.coord, self.incoming,
                              self.index, self.store)

def injector():
    conf = cfg.ConfigOpts()
    conf.register_cli_opts([
        cfg.IntOpt("metrics", default=1, min=1),
        cfg.StrOpt("archive-policy-name", default="low"),
        cfg.StrOpt("creator", default="admin"),
        cfg.IntOpt("batch-of-measures", default=1000),
        cfg.IntOpt("measures-per-batch", default=10),
    ])
    conf = service.prepare_service(conf=conf)
    index = indexer.get_driver(conf)
    instore = incoming.get_driver(conf)

    def todo():
        metric = index.create_metric(
            uuid.uuid4(),
            creator=conf.creator,
            archive_policy_name=conf.archive_policy_name)

        for _ in six.moves.range(conf.batch_of_measures):
            measures = [
                incoming.Measure(
                    utils.dt_in_unix_ns(utils.utcnow()), random.random())
                for __ in six.moves.range(conf.measures_per_batch)]
            instore.add_measures(metric, measures)

    with futures.ThreadPoolExecutor(max_workers=conf.metrics) as executor:

def metricd_tester(conf):
    # NOTE(sileht): This method is designed to be profiled, we
    # want to avoid issues with profiler and os.fork(), that
    # why we don't use the MetricdServiceManager.
    index = indexer.get_driver(conf)
    s = storage.get_driver(conf)
    inc = incoming.get_driver(conf)
    c = chef.Chef(None, inc, index, s)
    metrics_count = 0
    for sack in inc.iter_sacks():
        try:
            metrics_count += c.process_new_measures_for_sack(s, True)
        except chef.SackAlreadyLocked:
            continue
        if metrics_count >= conf.stop_after_processing_metrics:
            break