Adapters

The NautilusTrader design integrates data providers and/or trading venues through adapter implementations, these can be found in the top level adapters subpackage.

An integrations adapter is typically comprised of the following main components:

• HttpClient
• WebSocketClient
• InstrumentProvider
• DataClient
• ExecutionClient

Instrument providers

Instrument providers do as their name suggests - instantiating Nautilus Instrument objects by parsing the publisher or venues raw API.

The use cases for the instruments available from an InstrumentProvider are either:

• Used standalone to discover the instruments available for an integration, using these for research or backtesting purposes
• Used in a sandbox or live environment context for consumption by actors/strategies

Research and backtesting

Here is an example of discovering the current instruments for the Binance Futures testnet:

from nautilus_trader.adapters.binance.common.enums import BinanceAccountType
from nautilus_trader.adapters.binance.factories import get_cached_binance_http_client
from nautilus_trader.adapters.binance.futures.providers import BinanceFuturesInstrumentProvider
from nautilus_trader.common.component import LiveClock


clock = LiveClock()
account_type = BinanceAccountType.USDT_FUTURE

client = get_cached_binance_http_client(
    loop=asyncio.get_event_loop(),
    clock=clock,
    account_type=account_type,
    key=os.getenv("BINANCE_FUTURES_TESTNET_API_KEY"),
    secret=os.getenv("BINANCE_FUTURES_TESTNET_API_SECRET"),
    is_testnet=True,
)
await client.connect()

provider = BinanceFuturesInstrumentProvider(
    client=client,
    account_type=BinanceAccountType.USDT_FUTURE,
)

await provider.load_all_async()

Live trading

Each integration is implementation specific, and there are generally two options for the behavior of an InstrumentProvider within a TradingNode for live trading, as configured:

• All instruments are automatically loaded on start:

from nautilus_trader.config import InstrumentProviderConfig

InstrumentProviderConfig(load_all=True)

• Only those instruments explicitly specified in the configuration are loaded on start:

InstrumentProviderConfig(load_ids=["BTCUSDT-PERP.BINANCE", "ETHUSDT-PERP.BINANCE"])

Data clients

Requests

An Actor or Strategy can request custom data from a DataClient by sending a DataRequest. If the client that receives the DataRequest implements a handler for the request, data will be returned to the Actor or Strategy.

Example

An example of this is a DataRequest for an Instrument, which the Actor class implements (copied below). Any Actor or Strategy can call a request_instrument method with an InstrumentId to request the instrument from a DataClient.

In this particular case, the Actor implements a separate method request_instrument. A similar type of DataRequest could be instantiated and called from anywhere and/or anytime in the actor/strategy code.

A simplified version of request_instrument for an actor/strategy is:

# nautilus_trader/common/actor.pyx

cpdef void request_instrument(self, InstrumentId instrument_id, ClientId client_id=None):
    """
    Request `Instrument` data for the given instrument ID.

    Parameters
    ----------
    instrument_id : InstrumentId
        The instrument ID for the request.
    client_id : ClientId, optional
        The specific client ID for the command.
        If ``None`` then will be inferred from the venue in the instrument ID.
    """
    Condition.not_none(instrument_id, "instrument_id")

    cdef RequestInstrument request = RequestInstrument(
        instrument_id=instrument_id,
        start=None,
        end=None,
        client_id=client_id,
        venue=instrument_id.venue,
        callback=self._handle_instrument_response,
        request_id=UUID4(),
        ts_init=self._clock.timestamp_ns(),
        params=None,
    )

    self._send_data_req(request)

A simplified version of the request handler implemented in a LiveMarketDataClient that will retrieve the data and send it back to actors/strategies is for example:

# nautilus_trader/live/data_client.py

def request_instrument(self, request: RequestInstrument) -> None:
    self.create_task(self._request_instrument(request))

# nautilus_trader/adapters/binance/data.py

async def _request_instrument(self, request: RequestInstrument) -> None:
    instrument: Instrument | None = self._instrument_provider.find(request.instrument_id)

    if instrument is None:
        self._log.error(f"Cannot find instrument for {request.instrument_id}")
        return

    self._handle_instrument(instrument, request.id, request.params)

The DataEngine which is an important component in Nautilus links a request with a DataClient. For example a simplified version of handling an instrument request is:

# nautilus_trader/data/engine.pyx

self._msgbus.register(endpoint="DataEngine.request", handler=self.request)

cpdef void request(self, RequestData request):
    self._handle_request(request)

cpdef void _handle_request(self, RequestData request):
    cdef DataClient client = self._clients.get(request.client_id)

    if client is None:
        client = self._routing_map.get(request.venue, self._default_client)

    if isinstance(request, RequestInstrument):
        self._handle_request_instrument(client, request)

cpdef void _handle_request_instrument(self, DataClient client, RequestInstrument request):
    client.request_instrument(request)