Merge pull request #5756 from GluTbl/patch-1

add custom entry/exit price support to backtesting

docs/bot-basics.md

@@ -56,7 +56,11 @@ This loop will be repeated again and again until the bot is stopped.
 * Calculate buy / sell signals (calls `populate_buy_trend()` and `populate_sell_trend()` once per pair).
 * Loops per candle simulating entry and exit points.
   * Confirm trade buy / sell (calls `confirm_trade_entry()` and `confirm_trade_exit()` if implemented in the strategy).
+  * Call `custom_entry_price()` (if implemented in the strategy) to determine entry price (Prices are moved to be within the opening candle).
+  * Determine stake size by calling the `custom_stake_amount()` callback.
   * Call `custom_stoploss()` and `custom_sell()` to find custom exit points.
+  * For sells based on sell-signal and custom-sell: Call `custom_exit_price()` to determine exit price (Prices are moved to be within the closing candle).
+
 * Generate backtest report output
 
 !!! Note

docs/strategy-callbacks.md

@@ -387,8 +387,10 @@ class AwesomeStrategy(IStrategy):
     **Example**:  
     If the new_entryprice is 97, the proposed_rate is 100 and the `custom_price_max_distance_ratio` is set to 2%, The retained valid custom entry price will be 98, which is 2% below the current (proposed) rate.
 
-!!! Warning "No backtesting support"
-    Custom entry-prices are currently not supported during backtesting.
+!!! Warning "Backtesting"
+    While Custom prices are supported in backtesting (starting with 2021.12), prices will be moved to within the candle's high/low prices.
+    This behavior is currently being tested, and might be changed at a later point.
+    `custom_exit_price()` is only called for sells of type Sell_signal and Custom sell. All other sell-types will use regular backtesting prices.
 
 ## Custom order timeout rules
 

freqtrade/optimize/backtesting.py

@@ -342,10 +342,7 @@ class Backtesting:
                     # use Open rate if open_rate > calculated sell rate
                     return sell_row[OPEN_IDX]
 
-                # Use the maximum between close_rate and low as we
-                # cannot sell outside of a candle.
-                # Applies when a new ROI setting comes in place and the whole candle is above that.
-                return min(max(close_rate, sell_row[LOW_IDX]), sell_row[HIGH_IDX])
+                return close_rate
 
             else:
                 # This should not be reached...
@@ -366,6 +363,17 @@ class Backtesting:
 
             trade_dur = int((trade.close_date_utc - trade.open_date_utc).total_seconds() // 60)
             closerate = self._get_close_rate(sell_row, trade, sell, trade_dur)
+            # call the custom exit price,with default value as previous closerate
+            current_profit = trade.calc_profit_ratio(closerate)
+            if sell.sell_type in (SellType.SELL_SIGNAL, SellType.CUSTOM_SELL):
+                # Custom exit pricing only for sell-signals
+                closerate = strategy_safe_wrapper(self.strategy.custom_exit_price,
+                                                  default_retval=closerate)(
+                    pair=trade.pair, trade=trade,
+                    current_time=sell_row[DATE_IDX],
+                    proposed_rate=closerate, current_profit=current_profit)
+            # Use the maximum between close_rate and low as we cannot sell outside of a candle.
+            closerate = min(max(closerate, sell_row[LOW_IDX]), sell_row[HIGH_IDX])
 
             # Confirm trade exit:
             time_in_force = self.strategy.order_time_in_force['sell']
@@ -424,13 +432,21 @@ class Backtesting:
             stake_amount = self.wallets.get_trade_stake_amount(pair, None)
         except DependencyException:
             return None
+        # let's call the custom entry price, using the open price as default price
+        propose_rate = strategy_safe_wrapper(self.strategy.custom_entry_price,
+                                             default_retval=row[OPEN_IDX])(
+            pair=pair, current_time=row[DATE_IDX].to_pydatetime(),
+            proposed_rate=row[OPEN_IDX])  # default value is the open rate
 
-        min_stake_amount = self.exchange.get_min_pair_stake_amount(pair, row[OPEN_IDX], -0.05) or 0
+        # Move rate to within the candle's low/high rate
+        propose_rate = min(max(propose_rate, row[LOW_IDX]), row[HIGH_IDX])
+
+        min_stake_amount = self.exchange.get_min_pair_stake_amount(pair, propose_rate, -0.05) or 0
         max_stake_amount = self.wallets.get_available_stake_amount()
 
         stake_amount = strategy_safe_wrapper(self.strategy.custom_stake_amount,
                                              default_retval=stake_amount)(
-            pair=pair, current_time=row[DATE_IDX].to_pydatetime(), current_rate=row[OPEN_IDX],
+            pair=pair, current_time=row[DATE_IDX].to_pydatetime(), current_rate=propose_rate,
             proposed_stake=stake_amount, min_stake=min_stake_amount, max_stake=max_stake_amount)
         stake_amount = self.wallets.validate_stake_amount(pair, stake_amount, min_stake_amount)
 
@@ -441,7 +457,7 @@ class Backtesting:
         time_in_force = self.strategy.order_time_in_force['sell']
         # Confirm trade entry:
         if not strategy_safe_wrapper(self.strategy.confirm_trade_entry, default_retval=True)(
-                pair=pair, order_type=order_type, amount=stake_amount, rate=row[OPEN_IDX],
+                pair=pair, order_type=order_type, amount=stake_amount, rate=propose_rate,
                 time_in_force=time_in_force, current_time=row[DATE_IDX].to_pydatetime()):
             return None
 
@@ -450,10 +466,10 @@ class Backtesting:
             has_buy_tag = len(row) >= BUY_TAG_IDX + 1
             trade = LocalTrade(
                 pair=pair,
-                open_rate=row[OPEN_IDX],
+                open_rate=propose_rate,
                 open_date=row[DATE_IDX].to_pydatetime(),
                 stake_amount=stake_amount,
-                amount=round(stake_amount / row[OPEN_IDX], 8),
+                amount=round(stake_amount / propose_rate, 8),
                 fee_open=self.fee,
                 fee_close=self.fee,
                 is_open=True,