 ```python
import argparse
import qlib
from qlib.backtest import Backtest, run_backtest
from qlib.data.dataset import Dataset
from qlib.data.register import register
from qlib.log import get_module_logger
from qlib.utils import init_instance_by_config
from dask.distributed import Client

class OnlineManager:
    def __init__(
        self,
        provider_uri,
        region,
        experiment_name,
        task_url,
        task_db_name,
        task_pool_name,
        rolling_step,
        start_time,
        end_time,
        tasks,
        trainer,
    ):
        self.provider_uri = provider_uri
        self.region = region
        self.experiment_name = experiment_name
        self.task_url = task_url
        self.task_db_name = task_db_name
        self.task_pool_name = task_pool_name
        self.rolling_step = rolling_step
        self.start_time = start_time
        self.end_time = end_time
        self.tasks = tasks
        self.trainer = trainer

    def reset_experiment(self):
        pass

    def run_workflow(self):
        pass

    def train_tasks(self):
        pass

    def main(self):
        self.reset_experiment()
        self.run_workflow()

        # collect results
        results = self.trainer.get_results()

        # get signals
        signals = self.trainer.get_signals()

        # perform backtesting
        bt_config = {
            "start_time": self.start_time,
            "end_time": self.end_time,
            "exchange": "QEX",
            "feature_pool": "pool_qlib",
            "label_dates": ["2020-01-01", "2020-06-30"],
            "instruments": ["000300.SZ"],
            "features": ["open", "high", "low", "close", "volume"],
            "calendar": "SH",
            "trading_cal": qlib.utils.get_trading_calendar("SH"),
            "fetch_data": True,
            "drop_na": True,
        }
        bt_engine = Backtest(**bt_config)
        runner = bt_engine.run(signals)

        # risk analysis
        risk_analysis = runner.analyze()

if __name__ == "__main__":
    logger = get_module_logger("online_manager")

    parser = argparse.ArgumentParser(description="Online Manager")
    parser.add_argument("--provider_uri", required=True, help="Provider URI")
    parser.add_argument("--region", required=True, help="Region")
    parser.add_argument("--experiment_name", required=True, help="Experiment Name")
    parser.add_argument("--task_url", required=True, help="Task URL")
    parser.add_argument("--task_db_name", required=True, help="Task Database Name")
    parser.add_argument("--task_pool_name", required=True, help="Task Pool Name")
    parser.add_argument("--rolling_step", required=True, help="Rolling Step")
    parser.add_argument("--start_time", required=True, help="Start Time")
    parser.add_argument("--end_time", required=True, help="End Time")
    parser.add_argument("--tasks", required=True, help="Tasks")
    parser.add_argument("--trainer", required=True, help="Trainer")

    args = parser.parse_args()

    online_manager = OnlineManager(
        provider_uri=args.provider_uri,
        region=args.region,
        experiment_name=args.experiment_name,
        task_url=args.task_url,
        task_db_name=args.task_db_name,
        task_pool_name=args.task_pool_name,
        rolling_step=args.rolling_step,
        start_time=args.start_time,
        end_time=args.end_time,
        tasks=args.tasks,
        trainer=args.trainer,
    )

    online_manager.main()
```