stable/freqtrade/resolvers/exchange_resolver.py

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"""
This module loads custom exchanges
"""
import logging
from freqtrade.exchange import Exchange, MAP_EXCHANGE_CHILDCLASS
import freqtrade.exchange as exchanges
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from freqtrade.resolvers import IResolver
logger = logging.getLogger(__name__)
class ExchangeResolver(IResolver):
"""
This class contains all the logic to load a custom exchange class
"""
__slots__ = ['exchange']
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def __init__(self, exchange_name: str, config: dict, validate: bool = True) -> None:
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"""
Load the custom class from config parameter
:param config: configuration dictionary
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"""
# Map exchange name to avoid duplicate classes for identical exchanges
exchange_name = MAP_EXCHANGE_CHILDCLASS.get(exchange_name, exchange_name)
exchange_name = exchange_name.title()
try:
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self.exchange = self._load_exchange(exchange_name, kwargs={'config': config,
'validate': validate})
except ImportError:
logger.info(
f"No {exchange_name} specific subclass found. Using the generic class instead.")
if not hasattr(self, "exchange"):
self.exchange = Exchange(config, validate=validate)
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def _load_exchange(
self, exchange_name: str, kwargs: dict) -> Exchange:
"""
Loads the specified exchange.
Only checks for exchanges exported in freqtrade.exchanges
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:param exchange_name: name of the module to import
:return: Exchange instance or None
"""
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try:
ex_class = getattr(exchanges, exchange_name)
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exchange = ex_class(**kwargs)
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if exchange:
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logger.info(f"Using resolved exchange '{exchange_name}'...")
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return exchange
except AttributeError:
# Pass and raise ImportError instead
pass
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raise ImportError(
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f"Impossible to load Exchange '{exchange_name}'. This class does not exist "
"or contains Python code errors."
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)