Move exchange utilities into separate module

freqtrade/exchange/exchange_utils.py

@@ -0,0 +1,252 @@
+"""
+Exchange support utils
+"""
+from datetime import datetime, timedelta, timezone
+from math import ceil
+from typing import Any, Dict, List, Optional, Tuple
+
+import ccxt
+from ccxt import ROUND_DOWN, ROUND_UP, TICK_SIZE, TRUNCATE, decimal_to_precision
+
+from freqtrade.exchange.common import BAD_EXCHANGES, EXCHANGE_HAS_OPTIONAL, EXCHANGE_HAS_REQUIRED
+from freqtrade.util import FtPrecise
+
+
+CcxtModuleType = Any
+
+
+def is_exchange_known_ccxt(exchange_name: str, ccxt_module: CcxtModuleType = None) -> bool:
+    return exchange_name in ccxt_exchanges(ccxt_module)
+
+
+def ccxt_exchanges(ccxt_module: CcxtModuleType = None) -> List[str]:
+    """
+    Return the list of all exchanges known to ccxt
+    """
+    return ccxt_module.exchanges if ccxt_module is not None else ccxt.exchanges
+
+
+def available_exchanges(ccxt_module: CcxtModuleType = None) -> List[str]:
+    """
+    Return exchanges available to the bot, i.e. non-bad exchanges in the ccxt list
+    """
+    exchanges = ccxt_exchanges(ccxt_module)
+    return [x for x in exchanges if validate_exchange(x)[0]]
+
+
+def validate_exchange(exchange: str) -> Tuple[bool, str]:
+    ex_mod = getattr(ccxt, exchange.lower())()
+    if not ex_mod or not ex_mod.has:
+        return False, ''
+    missing = [k for k in EXCHANGE_HAS_REQUIRED if ex_mod.has.get(k) is not True]
+    if missing:
+        return False, f"missing: {', '.join(missing)}"
+
+    missing_opt = [k for k in EXCHANGE_HAS_OPTIONAL if not ex_mod.has.get(k)]
+
+    if exchange.lower() in BAD_EXCHANGES:
+        return False, BAD_EXCHANGES.get(exchange.lower(), '')
+    if missing_opt:
+        return True, f"missing opt: {', '.join(missing_opt)}"
+
+    return True, ''
+
+
+def validate_exchanges(all_exchanges: bool) -> List[Tuple[str, bool, str]]:
+    """
+    :return: List of tuples with exchangename, valid, reason.
+    """
+    exchanges = ccxt_exchanges() if all_exchanges else available_exchanges()
+    exchanges_valid = [
+        (e, *validate_exchange(e)) for e in exchanges
+    ]
+    return exchanges_valid
+
+
+def timeframe_to_seconds(timeframe: str) -> int:
+    """
+    Translates the timeframe interval value written in the human readable
+    form ('1m', '5m', '1h', '1d', '1w', etc.) to the number
+    of seconds for one timeframe interval.
+    """
+    return ccxt.Exchange.parse_timeframe(timeframe)
+
+
+def timeframe_to_minutes(timeframe: str) -> int:
+    """
+    Same as timeframe_to_seconds, but returns minutes.
+    """
+    return ccxt.Exchange.parse_timeframe(timeframe) // 60
+
+
+def timeframe_to_msecs(timeframe: str) -> int:
+    """
+    Same as timeframe_to_seconds, but returns milliseconds.
+    """
+    return ccxt.Exchange.parse_timeframe(timeframe) * 1000
+
+
+def timeframe_to_prev_date(timeframe: str, date: datetime = None) -> datetime:
+    """
+    Use Timeframe and determine the candle start date for this date.
+    Does not round when given a candle start date.
+    :param timeframe: timeframe in string format (e.g. "5m")
+    :param date: date to use. Defaults to now(utc)
+    :returns: date of previous candle (with utc timezone)
+    """
+    if not date:
+        date = datetime.now(timezone.utc)
+
+    new_timestamp = ccxt.Exchange.round_timeframe(timeframe, date.timestamp() * 1000,
+                                                  ROUND_DOWN) // 1000
+    return datetime.fromtimestamp(new_timestamp, tz=timezone.utc)
+
+
+def timeframe_to_next_date(timeframe: str, date: datetime = None) -> datetime:
+    """
+    Use Timeframe and determine next candle.
+    :param timeframe: timeframe in string format (e.g. "5m")
+    :param date: date to use. Defaults to now(utc)
+    :returns: date of next candle (with utc timezone)
+    """
+    if not date:
+        date = datetime.now(timezone.utc)
+    new_timestamp = ccxt.Exchange.round_timeframe(timeframe, date.timestamp() * 1000,
+                                                  ROUND_UP) // 1000
+    return datetime.fromtimestamp(new_timestamp, tz=timezone.utc)
+
+
+def date_minus_candles(
+        timeframe: str, candle_count: int, date: Optional[datetime] = None) -> datetime:
+    """
+    subtract X candles from a date.
+    :param timeframe: timeframe in string format (e.g. "5m")
+    :param candle_count: Amount of candles to subtract.
+    :param date: date to use. Defaults to now(utc)
+
+    """
+    if not date:
+        date = datetime.now(timezone.utc)
+
+    tf_min = timeframe_to_minutes(timeframe)
+    new_date = timeframe_to_prev_date(timeframe, date) - timedelta(minutes=tf_min * candle_count)
+    return new_date
+
+
+def market_is_active(market: Dict) -> bool:
+    """
+    Return True if the market is active.
+    """
+    # "It's active, if the active flag isn't explicitly set to false. If it's missing or
+    # true then it's true. If it's undefined, then it's most likely true, but not 100% )"
+    # See https://github.com/ccxt/ccxt/issues/4874,
+    # https://github.com/ccxt/ccxt/issues/4075#issuecomment-434760520
+    return market.get('active', True) is not False
+
+
+def amount_to_contracts(amount: float, contract_size: Optional[float]) -> float:
+    """
+    Convert amount to contracts.
+    :param amount: amount to convert
+    :param contract_size: contract size - taken from exchange.get_contract_size(pair)
+    :return: num-contracts
+    """
+    if contract_size and contract_size != 1:
+        return float(FtPrecise(amount) / FtPrecise(contract_size))
+    else:
+        return amount
+
+
+def contracts_to_amount(num_contracts: float, contract_size: Optional[float]) -> float:
+    """
+    Takes num-contracts and converts it to contract size
+    :param num_contracts: number of contracts
+    :param contract_size: contract size - taken from exchange.get_contract_size(pair)
+    :return: Amount
+    """
+
+    if contract_size and contract_size != 1:
+        return float(FtPrecise(num_contracts) * FtPrecise(contract_size))
+    else:
+        return num_contracts
+
+
+def amount_to_precision(amount: float, amount_precision: Optional[float],
+                        precisionMode: Optional[int]) -> float:
+    """
+    Returns the amount to buy or sell to a precision the Exchange accepts
+    Re-implementation of ccxt internal methods - ensuring we can test the result is correct
+    based on our definitions.
+    :param amount: amount to truncate
+    :param amount_precision: amount precision to use.
+                             should be retrieved from markets[pair]['precision']['amount']
+    :param precisionMode: precision mode to use. Should be used from precisionMode
+                          one of ccxt's DECIMAL_PLACES, SIGNIFICANT_DIGITS, or TICK_SIZE
+    :return: truncated amount
+    """
+    if amount_precision is not None and precisionMode is not None:
+        precision = int(amount_precision) if precisionMode != TICK_SIZE else amount_precision
+        # precision must be an int for non-ticksize inputs.
+        amount = float(decimal_to_precision(amount, rounding_mode=TRUNCATE,
+                                            precision=precision,
+                                            counting_mode=precisionMode,
+                                            ))
+
+    return amount
+
+
+def amount_to_contract_precision(
+        amount, amount_precision: Optional[float], precisionMode: Optional[int],
+        contract_size: Optional[float]) -> float:
+    """
+    Returns the amount to buy or sell to a precision the Exchange accepts
+    including calculation to and from contracts.
+    Re-implementation of ccxt internal methods - ensuring we can test the result is correct
+    based on our definitions.
+    :param amount: amount to truncate
+    :param amount_precision: amount precision to use.
+                             should be retrieved from markets[pair]['precision']['amount']
+    :param precisionMode: precision mode to use. Should be used from precisionMode
+                          one of ccxt's DECIMAL_PLACES, SIGNIFICANT_DIGITS, or TICK_SIZE
+    :param contract_size: contract size - taken from exchange.get_contract_size(pair)
+    :return: truncated amount
+    """
+    if amount_precision is not None and precisionMode is not None:
+        contracts = amount_to_contracts(amount, contract_size)
+        amount_p = amount_to_precision(contracts, amount_precision, precisionMode)
+        return contracts_to_amount(amount_p, contract_size)
+    return amount
+
+
+def price_to_precision(price: float, price_precision: Optional[float],
+                       precisionMode: Optional[int]) -> float:
+    """
+    Returns the price rounded up to the precision the Exchange accepts.
+    Partial Re-implementation of ccxt internal method decimal_to_precision(),
+    which does not support rounding up
+    TODO: If ccxt supports ROUND_UP for decimal_to_precision(), we could remove this and
+    align with amount_to_precision().
+    !!! Rounds up
+    :param price: price to convert
+    :param price_precision: price precision to use. Used from markets[pair]['precision']['price']
+    :param precisionMode: precision mode to use. Should be used from precisionMode
+                          one of ccxt's DECIMAL_PLACES, SIGNIFICANT_DIGITS, or TICK_SIZE
+    :return: price rounded up to the precision the Exchange accepts
+
+    """
+    if price_precision is not None and precisionMode is not None:
+        # price = float(decimal_to_precision(price, rounding_mode=ROUND,
+        #                                    precision=price_precision,
+        #                                    counting_mode=self.precisionMode,
+        #                                    ))
+        if precisionMode == TICK_SIZE:
+            precision = FtPrecise(price_precision)
+            price_str = FtPrecise(price)
+            missing = price_str % precision
+            if not missing == FtPrecise("0"):
+                price = round(float(str(price_str - missing + precision)), 14)
+        else:
+            symbol_prec = price_precision
+            big_price = price * pow(10, symbol_prec)
+            price = ceil(big_price) / pow(10, symbol_prec)
+    return price