From aa3c1a953aa6c66c3c82dff5d489988a41d8d97a Mon Sep 17 00:00:00 2001
From: enenn <enenn@users.noreply.github.com>
Date: Sat, 24 Mar 2018 08:46:20 +0100
Subject: [PATCH] Add retrier decorator

---
 freqtrade/exchange/__init__.py            | 21 ++++++++++++++++++++-
 freqtrade/tests/exchange/test_exchange.py |  4 ++--
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/freqtrade/exchange/__init__.py b/freqtrade/exchange/__init__.py
index 5070e89b2..9a7cd08a5 100644
--- a/freqtrade/exchange/__init__.py
+++ b/freqtrade/exchange/__init__.py
@@ -16,6 +16,7 @@ logger = logging.getLogger(__name__)
 # Current selected exchange
 _API: ccxt.Exchange = None
 _CONF: dict = {}
+API_RETRY_COUNT = 4
 
 # Holds all open sell orders for dry_run
 _DRY_RUN_OPEN_ORDERS: Dict[str, Any] = {}
@@ -23,6 +24,23 @@ _DRY_RUN_OPEN_ORDERS: Dict[str, Any] = {}
 _TICKER_CACHE: dict = {}
 
 
+def retrier(f):
+    def wrapper(*args, **kwargs):
+        count = kwargs.pop('count', API_RETRY_COUNT)
+        try:
+            return f(*args, **kwargs)
+        except (NetworkException, DependencyException) as ex:
+            logger.warning('%s returned exception: "%s"', f, ex)
+            if count > 0:
+                count -= 1
+                kwargs.update({'count': count})
+                logger.warning('retrying %s still for %s times', f, count)
+                return wrapper(*args, **kwargs)
+            else:
+                raise OperationalException('Giving up retrying: %s', f)
+    return wrapper
+
+
 def init(config: dict) -> None:
     """
     Initializes this module with the given config,
@@ -192,6 +210,7 @@ def get_balances() -> dict:
         raise OperationalException(e)
 
 
+@retrier
 def get_ticker(pair: str, refresh: Optional[bool] = True) -> dict:
     global _TICKER_CACHE
     try:
@@ -208,7 +227,7 @@ def get_ticker(pair: str, refresh: Optional[bool] = True) -> dict:
         raise OperationalException(e)
 
 
-@cached(TTLCache(maxsize=100, ttl=30))
+@retrier
 def get_ticker_history(pair: str, tick_interval: str) -> List[Dict]:
     if 'fetchOHLCV' not in _API.has or not _API.has['fetchOHLCV']:
         raise OperationalException(
diff --git a/freqtrade/tests/exchange/test_exchange.py b/freqtrade/tests/exchange/test_exchange.py
index eacc641d5..8805cfab3 100644
--- a/freqtrade/tests/exchange/test_exchange.py
+++ b/freqtrade/tests/exchange/test_exchange.py
@@ -307,7 +307,7 @@ def test_get_ticker(default_conf, mocker):
     assert ticker['bid'] == 0.5
     assert ticker['ask'] == 1
 
-    with pytest.raises(NetworkException):
+    with pytest.raises(OperationalException):  # test retrier
         api_mock.fetch_ticker = MagicMock(side_effect=ccxt.NetworkError)
         mocker.patch('freqtrade.exchange._API', api_mock)
         get_ticker(pair='ETH/BTC', refresh=True)
@@ -365,7 +365,7 @@ def test_get_ticker_history(default_conf, mocker):
     assert ticks[0]['C'] == 4
     assert ticks[0]['V'] == 5
 
-    with pytest.raises(NetworkException):
+    with pytest.raises(OperationalException):  # test retrier
         api_mock.fetch_ohlcv = MagicMock(side_effect=ccxt.NetworkError)
         mocker.patch('freqtrade.exchange._API', api_mock)
         # new symbol to get around cache