Download using asyncio

freqtrade/exchange/__init__.py

@@ -142,6 +142,7 @@ class Exchange(object):
 
         try:
             markets = self._api.load_markets()
+            asyncio.get_event_loop().run_until_complete(self._api_async.load_markets())
         except ccxt.BaseError as e:
             logger.warning('Unable to validate pairs (assuming they are correct). Reason: %s', e)
             return
@@ -341,12 +342,43 @@ class Exchange(object):
             logger.info("returning cached ticker-data for %s", pair)
             return self._cached_ticker[pair]
 
+    def get_history(self, pair: str, tick_interval: str,
+                    since_ms: int) -> List:
+        """
+        Gets candle history using asyncio and returns the list of candles.
+        Handles all async doing.
+        """
+        return asyncio.get_event_loop().run_until_complete(
+            self._async_get_history(pair=pair, tick_interval=tick_interval,
+                                    since_ms=since_ms))
+
+    async def _async_get_history(self, pair: str,
+                                 tick_interval: str,
+                                 since_ms: int) -> List:
+        # Assume exchange returns 500 candles
+        _LIMIT = 500
+
+        one_call = constants.TICKER_INTERVAL_MINUTES[tick_interval] * 60 * _LIMIT * 1000
+        logger.debug("one_call: %s", one_call)
+        input_coroutines = [self.async_get_candle_history(
+            pair, tick_interval, since) for since in
+                range(since_ms, int(time.time() * 1000), one_call)]
+        tickers = await asyncio.gather(*input_coroutines, return_exceptions=True)
+
+        # Combine tickers
+        data = []
+        for tick in tickers:
+            if tick[0] == pair:
+                data.extend(tick[1])
+        logger.info("downloaded %s with length %s.", pair, len(data))
+        return data
+
     async def async_get_candles_history(self, pairs: List[str],
                                         tick_interval: str) -> List[Tuple[str, List]]:
         # COMMENTED CODE IS FOR DISCUSSION: where should we close the loop on async ?
         # loop = asyncio.new_event_loop()
         # asyncio.set_event_loop(loop)
-        await self._api_async.load_markets()
+        # await self._api_async.load_markets()
         input_coroutines = [self.async_get_candle_history(
             symbol, tick_interval) for symbol in pairs]
         tickers = await asyncio.gather(*input_coroutines, return_exceptions=True)
@@ -357,7 +389,7 @@ class Exchange(object):
                                        since_ms: Optional[int] = None) -> Tuple[str, List]:
         try:
             # fetch ohlcv asynchronously
-            logger.debug("fetching %s ...", pair)
+            logger.debug("fetching %s since %s ...", pair, since_ms)
 
             # Calculating ticker interval in second
             interval_in_sec = constants.TICKER_INTERVAL_MINUTES[tick_interval] * 60