From e040c518cac73e6ee1ad551757eef93407fc6fdc Mon Sep 17 00:00:00 2001
From: Matthias <xmatthias@outlook.com>
Date: Sun, 28 Jun 2020 16:18:39 +0200
Subject: [PATCH] Dynamic backoff on DDos errors

---
 freqtrade/exchange/common.py    | 11 +++++++++--
 tests/exchange/test_exchange.py | 14 +++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/freqtrade/exchange/common.py b/freqtrade/exchange/common.py
index d931e1789..b0f6b14e3 100644
--- a/freqtrade/exchange/common.py
+++ b/freqtrade/exchange/common.py
@@ -91,6 +91,13 @@ MAP_EXCHANGE_CHILDCLASS = {
 }
 
 
+def calculate_backoff(retry, max_retries):
+    """
+    Calculate backoff
+    """
+    return retry ** 2 + 1
+
+
 def retrier_async(f):
     async def wrapper(*args, **kwargs):
         count = kwargs.pop('count', API_RETRY_COUNT)
@@ -125,13 +132,13 @@ def retrier(_func=None, retries=API_RETRY_COUNT):
                     kwargs.update({'count': count})
                     logger.warning('retrying %s() still for %s times', f.__name__, count)
                     if isinstance(ex, DDosProtection):
-                        time.sleep(1)
+                        time.sleep(calculate_backoff(count, retries))
                     return wrapper(*args, **kwargs)
                 else:
                     logger.warning('Giving up retrying: %s()', f.__name__)
                     raise ex
         return wrapper
-    # Support both @retrier and @retrier() syntax
+    # Support both @retrier and @retrier(retries=2) syntax
     if _func is None:
         return decorator
     else:
diff --git a/tests/exchange/test_exchange.py b/tests/exchange/test_exchange.py
index 64ea317aa..358452caf 100644
--- a/tests/exchange/test_exchange.py
+++ b/tests/exchange/test_exchange.py
@@ -14,7 +14,7 @@ from pandas import DataFrame
 from freqtrade.exceptions import (DependencyException, InvalidOrderException, DDosProtection,
                                   OperationalException, TemporaryError)
 from freqtrade.exchange import Binance, Exchange, Kraken
-from freqtrade.exchange.common import API_RETRY_COUNT
+from freqtrade.exchange.common import API_RETRY_COUNT, calculate_backoff
 from freqtrade.exchange.exchange import (market_is_active, symbol_is_pair,
                                          timeframe_to_minutes,
                                          timeframe_to_msecs,
@@ -2296,3 +2296,15 @@ def test_calculate_fee_rate(mocker, default_conf, order, expected) -> None:
 
     ex = get_patched_exchange(mocker, default_conf)
     assert ex.calculate_fee_rate(order) == expected
+
+
+@pytest.mark.parametrize('retry,max_retries,expected', [
+    (0, 3, 1),
+    (1, 3, 2),
+    (2, 3, 5),
+    (3, 3, 10),
+    (0, 1, 1),
+    (1, 1, 2),
+])
+def test_calculate_backoff(retry, max_retries, expected):
+    assert calculate_backoff(retry, max_retries) == expected