Merge 24ab1b5be5 into 842b0c2270

docs/backtesting.md

@@ -36,7 +36,7 @@ python3 ./freqtrade/main.py backtesting --realistic-simulation
 python3 ./freqtrade/main.py backtesting --realistic-simulation --ticker-interval 1m
 ```
 
-**Reload your testdata files**
+**Update cached pairs with the latest data**
 ```bash
 python3 ./freqtrade/main.py backtesting --realistic-simulation --refresh-pairs-cached
 ```
@@ -80,12 +80,9 @@ The full timerange specification:
 - Use last 123 tickframes of data: `--timerange=-123`
 - Use first 123 tickframes of data: `--timerange=123-`
 - Use tickframes from line 123 through 456: `--timerange=123-456`
-
+- Use tickframes till 2018/01/31: `--timerange=-20180131`
-
+- Use tickframes since 2018/01/31: `--timerange=20180131-`
-Incoming feature, not implemented yet:
+- Use tickframes since 2018/01/31 till 2018/03/01 : `--timerange=20180131-20180301`
-- `--timerange=-20180131`
--  `--timerange=20180101-`
-- `--timerange=20180101-20181231`
 
 
 **Update testdata directory**

docs/bot-usage.md

@@ -124,7 +124,7 @@ optional arguments:
                         world limitations
   -r, --refresh-pairs-cached
                         refresh the pairs files in tests/testdata with 
-                        the latest data from Bittrex. Use it if you want
+                        the latest data from the exchange. Use it if you want
                         to run your backtesting with up-to-date data.
 ```
 

freqtrade/arguments.py

@@ -6,6 +6,7 @@ import argparse
 import logging
 import os
 import re
+import arrow
 from typing import List, Tuple, Optional
 
 from freqtrade import __version__
@@ -117,7 +118,7 @@ class Arguments(object):
         )
         parser.add_argument(
             '-r', '--refresh-pairs-cached',
-            help='refresh the pairs files in tests/testdata with the latest data from Bittrex. \
+            help='refresh the pairs files in tests/testdata with the latest data from the exchange. \
                   Use it if you want to run your backtesting with up-to-date data.',
             action='store_true',
             dest='refresh_pairs',
@@ -228,12 +229,16 @@ class Arguments(object):
                 stop = None
                 if stype[0]:
                     start = rvals[index]
-                    if stype[0] != 'date':
+                    if stype[0] == 'date':
+                        start = arrow.get(start, 'YYYYMMDD').timestamp
+                    else:
                         start = int(start)
                     index += 1
                 if stype[1]:
                     stop = rvals[index]
-                    if stype[1] != 'date':
+                    if stype[1] == 'date':
+                        stop = arrow.get(stop, 'YYYYMMDD').timestamp
+                    else:
                         stop = int(stop)
                 return stype, start, stop
         raise Exception('Incorrect syntax for timerange "%s"' % text)
@@ -265,3 +270,17 @@ class Arguments(object):
             help='Export files to given dir',
             dest='export',
             default=None)
+
+        self.parser.add_argument(
+            '--days',
+            help='Download data for number of days',
+            dest='days',
+            type=int,
+            default=None)
+
+        self.parser.add_argument(
+            '--exchange',
+            help='Exchange name',
+            dest='exchange',
+            type=str,
+            default='bittrex')

freqtrade/exchange/__init__.py

@@ -8,7 +8,7 @@ import ccxt
 import arrow
 
 from freqtrade import OperationalException, DependencyException, NetworkException
-
+from freqtrade.constants import Constants
 
 logger = logging.getLogger(__name__)
 
@@ -269,9 +269,34 @@ def get_ticker(pair: str, refresh: Optional[bool] = True) -> dict:
 
 
 @retrier
-def get_ticker_history(pair: str, tick_interval: str) -> List[Dict]:
+def get_ticker_history(pair: str, tick_interval: str, since_ms: Optional[int] = None) -> List[Dict]:
     try:
-        return _API.fetch_ohlcv(pair, timeframe=tick_interval)
+        # last item should be in the time interval [now - tick_interval, now]
+        till_time_ms = arrow.utcnow().shift(
+                        minutes=-Constants.TICKER_INTERVAL_MINUTES[tick_interval]
+                       ).timestamp * 1000
+        # it looks as if some exchanges return cached data
+        # and they update it one in several minute, so 10 mins interval
+        # is necessary to skeep downloading of an empty array when all
+        # chached data was already downloaded
+        till_time_ms = min(till_time_ms, arrow.utcnow().shift(minutes=-10).timestamp * 1000)
+
+        data = []
+        while not since_ms or since_ms < till_time_ms:
+            data_part = _API.fetch_ohlcv(pair, timeframe=tick_interval, since=since_ms)
+
+            if not data_part:
+                break
+
+            logger.info('Downloaded data for time range [%s, %s]',
+                        arrow.get(data_part[0][0] / 1000).format(),
+                        arrow.get(data_part[-1][0] / 1000).format())
+
+            data.extend(data_part)
+            since_ms = data[-1][0] + 1
+
+        return data
+
     except ccxt.NetworkError as e:
         raise NetworkException(
             'Could not load ticker history due to networking error. Message: {}'.format(e)

freqtrade/optimize/__init__.py

@@ -4,25 +4,47 @@ import gzip
 import json
 import logging
 import os
+import arrow
 from typing import Optional, List, Dict, Tuple
 
 from freqtrade import misc
 from freqtrade.exchange import get_ticker_history
+from freqtrade.constants import Constants
+
 from user_data.hyperopt_conf import hyperopt_optimize_conf
 
 logger = logging.getLogger(__name__)
 
 
 def trim_tickerlist(tickerlist: List[Dict], timerange: Tuple[Tuple, int, int]) -> List[Dict]:
-    stype, start, stop = timerange
+    if not tickerlist:
-    if stype == (None, 'line'):
+        return tickerlist
-        return tickerlist[stop:]
-    elif stype == ('line', None):
-        return tickerlist[0:start]
-    elif stype == ('index', 'index'):
-        return tickerlist[start:stop]
 
-    return tickerlist
+    stype, start, stop = timerange
+
+    start_index = 0
+    stop_index = len(tickerlist)
+
+    if stype[0] == 'line':
+        stop_index = start
+    if stype[0] == 'index':
+        start_index = start
+    elif stype[0] == 'date':
+        while tickerlist[start_index][0] < start * 1000:
+            start_index += 1
+
+    if stype[1] == 'line':
+        start_index = len(tickerlist) + stop
+    if stype[1] == 'index':
+        stop_index = stop
+    elif stype[1] == 'date':
+        while tickerlist[stop_index-1][0] > stop * 1000:
+            stop_index -= 1
+
+    if start_index > stop_index:
+        raise ValueError(f'The timerange [{start},{stop}] is incorrect')
+
+    return tickerlist[start_index:stop_index]
 
 
 def load_tickerdata_file(
@@ -75,13 +97,16 @@ def load_data(datadir: str,
     # If the user force the refresh of pairs
     if refresh_pairs:
         logger.info('Download data for all pairs and store them in %s', datadir)
-        download_pairs(datadir, _pairs, ticker_interval)
+        download_pairs(datadir, _pairs, ticker_interval, timerange=timerange)
 
     for pair in _pairs:
         pairdata = load_tickerdata_file(datadir, pair, ticker_interval, timerange=timerange)
         if not pairdata:
             # download the tickerdata from exchange
-            download_backtesting_testdata(datadir, pair=pair, interval=ticker_interval)
+            download_backtesting_testdata(datadir,
+                                          pair=pair,
+                                          tick_interval=ticker_interval,
+                                          timerange=timerange)
             # and retry reading the pair
             pairdata = load_tickerdata_file(datadir, pair, ticker_interval, timerange=timerange)
         result[pair] = pairdata
@@ -97,11 +122,16 @@ def make_testdata_path(datadir: str) -> str:
     )
 
 
-def download_pairs(datadir, pairs: List[str], ticker_interval: str) -> bool:
+def download_pairs(datadir, pairs: List[str],
+                   ticker_interval: str,
+                   timerange: Optional[Tuple[Tuple, int, int]] = None) -> bool:
     """For each pairs passed in parameters, download the ticker intervals"""
     for pair in pairs:
         try:
-            download_backtesting_testdata(datadir, pair=pair, interval=ticker_interval)
+            download_backtesting_testdata(datadir,
+                                          pair=pair,
+                                          tick_interval=ticker_interval,
+                                          timerange=timerange)
         except BaseException:
             logger.info(
                 'Failed to download the pair: "%s", Interval: %s',
@@ -112,45 +142,85 @@ def download_pairs(datadir, pairs: List[str], ticker_interval: str) -> bool:
     return True
 
 
-# FIX: 20180110, suggest rename interval to tick_interval
+def load_cached_data_for_updating(filename: str,
-def download_backtesting_testdata(datadir: str, pair: str, interval: str = '5m') -> bool:
+                                  tick_interval: str,
+                                  timerange: Optional[Tuple[Tuple, int, int]]) -> Tuple[list, int]:
     """
-    Download the latest 1 and 5 ticker intervals from Bittrex for the pairs passed in parameters
+    Load cached data and choose what part of the data should be updated
+    """
+
+    since_ms = None
+
+    # user sets timerange, so find the start time
+    if timerange:
+        if timerange[0][0] == 'date':
+            since_ms = timerange[1] * 1000
+        elif timerange[0][1] == 'line':
+            num_minutes = timerange[2] * Constants.TICKER_INTERVAL_MINUTES[tick_interval]
+            since_ms = arrow.utcnow().shift(minutes=num_minutes).timestamp * 1000
+
+    # read the cached file
+    if os.path.isfile(filename):
+        with open(filename, "rt") as file:
+            data = json.load(file)
+            # remove the last item, because we are not sure if it is correct
+            # it could be fetched when the candle was incompleted
+            if data:
+                data.pop()
+    else:
+        data = []
+
+    if data:
+        if since_ms and since_ms < data[0][0]:
+            # the data is requested for earlier period than the cache has
+            # so fully redownload all the data
+            data = []
+        else:
+            # a part of the data was already downloaded, so
+            # download unexist data only
+            since_ms = data[-1][0] + 1
+
+    return (data, since_ms)
+
+
+# FIX: 20180110, suggest rename interval to tick_interval
+def download_backtesting_testdata(datadir: str,
+                                  pair: str,
+                                  tick_interval: str = '5m',
+                                  timerange: Optional[Tuple[Tuple, int, int]] = None) -> bool:
+    """
+    Download the latest ticker intervals from the exchange for the pairs passed in parameters
+    The data is downloaded starting from the last correct ticker interval data that
+    esists in a cache. If timerange starts earlier than the data in the cache,
+    the full data will be redownloaded
+
     Based on @Rybolov work: https://github.com/rybolov/freqtrade-data
     :param pairs: list of pairs to download
+    :param tick_interval: ticker interval
+    :param timerange: range of time to download
     :return: bool
     """
 
     path = make_testdata_path(datadir)
+    filepair = pair.replace("/", "_")
+    filename = os.path.join(path, f'{filepair}-{tick_interval}.json')
+
     logger.info(
         'Download the pair: "%s", Interval: %s',
         pair,
-        interval
+        tick_interval
     )
 
-    filepair = pair.replace("/", "_")
+    data, since_ms = load_cached_data_for_updating(filename, tick_interval, timerange)
-    filename = os.path.join(path, '{pair}-{interval}.json'.format(
-        pair=filepair,
-        interval=interval,
-    ))
 
-    if os.path.isfile(filename):
+    logger.debug("Current Start: %s", misc.format_ms_time(data[1][0]) if data else 'None')
-        with open(filename, "rt") as file:
+    logger.debug("Current End: %s", misc.format_ms_time(data[-1][0]) if data else 'None')
-            data = json.load(file)
+
-        logger.debug("Current Start: %s", misc.format_ms_time(data[1][0]))
+    new_data = get_ticker_history(pair=pair, tick_interval=tick_interval, since_ms=since_ms)
-        logger.debug("Current End: %s", misc.format_ms_time(data[-1:][0][0]))
+    data.extend(new_data)
-    else:
-        data = []
-        logger.debug("Current Start: None")
-        logger.debug("Current End: None")
 
-    new_data = get_ticker_history(pair=pair, tick_interval=interval)
-    for row in new_data:
-        if row not in data:
-            data.append(row)
     logger.debug("New Start: %s", misc.format_ms_time(data[0][0]))
-    logger.debug("New End: %s", misc.format_ms_time(data[-1:][0][0]))
+    logger.debug("New End: %s", misc.format_ms_time(data[-1][0]))
-    data = sorted(data, key=lambda data: data[0])
 
     misc.file_dump_json(filename, data)
 

freqtrade/tests/exchange/test_exchange.py

@@ -321,6 +321,15 @@ def test_get_ticker(default_conf, mocker):
         get_ticker(pair='ETH/BTC', refresh=True)
 
 
+def make_fetch_ohlcv_mock(data):
+    def fetch_ohlcv_mock(pair, timeframe, since):
+        if since:
+            assert since > data[-1][0]
+            return []
+        return data
+    return fetch_ohlcv_mock
+
+
 def test_get_ticker_history(default_conf, mocker):
     api_mock = MagicMock()
     tick = [
@@ -334,7 +343,7 @@ def test_get_ticker_history(default_conf, mocker):
         ]
     ]
     type(api_mock).has = PropertyMock(return_value={'fetchOHLCV': True})
-    api_mock.fetch_ohlcv = MagicMock(return_value=tick)
+    api_mock.fetch_ohlcv = MagicMock(side_effect=make_fetch_ohlcv_mock(tick))
     mocker.patch('freqtrade.exchange._API', api_mock)
 
     # retrieve original ticker
@@ -357,7 +366,7 @@ def test_get_ticker_history(default_conf, mocker):
             10,  # volume (in quote currency)
         ]
     ]
-    api_mock.fetch_ohlcv = MagicMock(return_value=new_tick)
+    api_mock.fetch_ohlcv = MagicMock(side_effect=make_fetch_ohlcv_mock(new_tick))
     mocker.patch('freqtrade.exchange._API', api_mock)
 
     ticks = get_ticker_history('ETH/BTC', default_conf['ticker_interval'])

freqtrade/tests/optimize/test_optimize.py

@@ -3,12 +3,14 @@
 import json
 import os
 import uuid
+import arrow
 from shutil import copyfile
 
 from freqtrade import optimize
 from freqtrade.misc import file_dump_json
 from freqtrade.optimize.__init__ import make_testdata_path, download_pairs, \
-    download_backtesting_testdata, load_tickerdata_file, trim_tickerlist
+    download_backtesting_testdata, load_tickerdata_file, trim_tickerlist, \
+    load_cached_data_for_updating
 from freqtrade.tests.conftest import log_has
 
 # Change this if modifying UNITTEST/BTC testdatafile
@@ -145,6 +147,109 @@ def test_download_pairs(ticker_history, mocker) -> None:
     _clean_test_file(file2_5)
 
 
+def test_load_cached_data_for_updating(mocker) -> None:
+    datadir = os.path.join(os.path.dirname(__file__), '..', 'testdata')
+
+    test_data = None
+    test_filename = os.path.join(datadir, 'UNITTEST_BTC-1m.json')
+    with open(test_filename, "rt") as file:
+        test_data = json.load(file)
+
+    # change now time to test 'line' cases
+    # now = last cached item + 1 hour
+    now_ts = test_data[-1][0] / 1000 + 60 * 60
+    mocker.patch('arrow.utcnow', return_value=arrow.get(now_ts))
+
+    # timeframe starts earlier than the cached data
+    # should fully update data
+    timerange = (('date', None), test_data[0][0] / 1000 - 1, None)
+    data, start_ts = load_cached_data_for_updating(test_filename,
+                                                   '1m',
+                                                   timerange)
+    assert data == []
+    assert start_ts == test_data[0][0] - 1000
+
+    # same with 'line' timeframe
+    num_lines = (test_data[-1][0] - test_data[1][0]) / 1000 / 60 + 120
+    data, start_ts = load_cached_data_for_updating(test_filename,
+                                                   '1m',
+                                                   ((None, 'line'), None, -num_lines))
+    assert data == []
+    assert start_ts < test_data[0][0] - 1
+
+    # timeframe starts in the center of the cached data
+    # should return the chached data w/o the last item
+    timerange = (('date', None), test_data[0][0] / 1000 + 1, None)
+    data, start_ts = load_cached_data_for_updating(test_filename,
+                                                   '1m',
+                                                   timerange)
+    assert data == test_data[:-1]
+    assert test_data[-2][0] < start_ts < test_data[-1][0]
+
+    # same with 'line' timeframe
+    num_lines = (test_data[-1][0] - test_data[1][0]) / 1000 / 60 + 30
+    timerange = ((None, 'line'), None, -num_lines)
+    data, start_ts = load_cached_data_for_updating(test_filename,
+                                                   '1m',
+                                                   timerange)
+    assert data == test_data[:-1]
+    assert test_data[-2][0] < start_ts < test_data[-1][0]
+
+    # timeframe starts after the chached data
+    # should return the chached data w/o the last item
+    timerange = (('date', None), test_data[-1][0] / 1000 + 1, None)
+    data, start_ts = load_cached_data_for_updating(test_filename,
+                                                   '1m',
+                                                   timerange)
+    assert data == test_data[:-1]
+    assert test_data[-2][0] < start_ts < test_data[-1][0]
+
+    # same with 'line' timeframe
+    num_lines = 30
+    timerange = ((None, 'line'), None, -num_lines)
+    data, start_ts = load_cached_data_for_updating(test_filename,
+                                                   '1m',
+                                                   timerange)
+    assert data == test_data[:-1]
+    assert test_data[-2][0] < start_ts < test_data[-1][0]
+
+    # no timeframe is set
+    # should return the chached data w/o the last item
+    num_lines = 30
+    timerange = ((None, 'line'), None, -num_lines)
+    data, start_ts = load_cached_data_for_updating(test_filename,
+                                                   '1m',
+                                                   timerange)
+    assert data == test_data[:-1]
+    assert test_data[-2][0] < start_ts < test_data[-1][0]
+
+    # no datafile exist
+    # should return timestamp start time
+    timerange = (('date', None), now_ts - 10000, None)
+    data, start_ts = load_cached_data_for_updating(test_filename + 'unexist',
+                                                   '1m',
+                                                   timerange)
+    assert data == []
+    assert start_ts == (now_ts - 10000) * 1000
+
+    # same with 'line' timeframe
+    num_lines = 30
+    timerange = ((None, 'line'), None, -num_lines)
+    data, start_ts = load_cached_data_for_updating(test_filename + 'unexist',
+                                                   '1m',
+                                                   timerange)
+    assert data == []
+    assert start_ts == (now_ts - num_lines * 60) * 1000
+
+    # no datafile exist, no timeframe is set
+    # should return an empty array and None
+    data, start_ts = load_cached_data_for_updating(test_filename + 'unexist',
+                                                   '1m',
+                                                   None)
+    assert data == []
+    assert start_ts is None
+
+
 def test_download_pairs_exception(ticker_history, mocker, caplog) -> None:
     mocker.patch('freqtrade.optimize.__init__.get_ticker_history', return_value=ticker_history)
     mocker.patch('freqtrade.optimize.__init__.download_backtesting_testdata',
@@ -168,7 +273,7 @@ def test_download_backtesting_testdata(ticker_history, mocker) -> None:
     # Download a 1 min ticker file
     file1 = os.path.join(os.path.dirname(__file__), '..', 'testdata', 'XEL_BTC-1m.json')
     _backup_file(file1)
-    download_backtesting_testdata(None, pair="XEL/BTC", interval='1m')
+    download_backtesting_testdata(None, pair="XEL/BTC", tick_interval='1m')
     assert os.path.isfile(file1) is True
     _clean_test_file(file1)
 
@@ -176,7 +281,7 @@ def test_download_backtesting_testdata(ticker_history, mocker) -> None:
     file2 = os.path.join(os.path.dirname(__file__), '..', 'testdata', 'STORJ_BTC-5m.json')
     _backup_file(file2)
 
-    download_backtesting_testdata(None, pair="STORJ/BTC", interval='5m')
+    download_backtesting_testdata(None, pair="STORJ/BTC", tick_interval='5m')
     assert os.path.isfile(file2) is True
     _clean_test_file(file2)
 
@@ -188,8 +293,8 @@ def test_download_backtesting_testdata2(mocker) -> None:
     ]
     mocker.patch('freqtrade.misc.file_dump_json', return_value=None)
     mocker.patch('freqtrade.optimize.__init__.get_ticker_history', return_value=tick)
-    assert download_backtesting_testdata(None, pair="UNITTEST/BTC", interval='1m')
+    assert download_backtesting_testdata(None, pair="UNITTEST/BTC", tick_interval='1m')
-    assert download_backtesting_testdata(None, pair="UNITTEST/BTC", interval='3m')
+    assert download_backtesting_testdata(None, pair="UNITTEST/BTC", tick_interval='3m')
 
 
 def test_load_tickerdata_file() -> None:
@@ -221,12 +326,12 @@ def test_trim_tickerlist() -> None:
     ticker_list_len = len(ticker_list)
 
     # Test the pattern ^(-\d+)$
-    # This pattern remove X element from the beginning
+    # This pattern uses the latest N elements
-    timerange = ((None, 'line'), None, 5)
+    timerange = ((None, 'line'), None, -5)
     ticker = trim_tickerlist(ticker_list, timerange)
     ticker_len = len(ticker)
 
-    assert ticker_list_len == ticker_len + 5
+    assert ticker_len == 5
     assert ticker_list[0] is not ticker[0]  # The first element should be different
     assert ticker_list[-1] is ticker[-1]  # The last element must be the same
 
@@ -251,6 +356,37 @@ def test_trim_tickerlist() -> None:
     assert ticker_list[5] is ticker[0]  # The list starts at the index 5
     assert ticker_list[9] is ticker[-1]  # The list ends at the index 9 (5 elements)
 
+    # Test the pattern ^(\d{8})-(\d{8})$
+    # This pattern extract a window between the dates
+    timerange = (('date', 'date'), ticker_list[5][0] / 1000, ticker_list[10][0] / 1000 - 1)
+    ticker = trim_tickerlist(ticker_list, timerange)
+    ticker_len = len(ticker)
+
+    assert ticker_len == 5
+    assert ticker_list[0] is not ticker[0]  # The first element should be different
+    assert ticker_list[5] is ticker[0]  # The list starts at the index 5
+    assert ticker_list[9] is ticker[-1]  # The list ends at the index 9 (5 elements)
+
+    # Test the pattern ^-(\d{8})$
+    # This pattern extracts elements from the start to the date
+    timerange = ((None, 'date'), None, ticker_list[10][0] / 1000 - 1)
+    ticker = trim_tickerlist(ticker_list, timerange)
+    ticker_len = len(ticker)
+
+    assert ticker_len == 10
+    assert ticker_list[0] is ticker[0]  # The start of the list is included
+    assert ticker_list[9] is ticker[-1]  # The element 10 is not included
+
+    # Test the pattern ^(\d{8})-$
+    # This pattern extracts elements from the date to now
+    timerange = (('date', None), ticker_list[10][0] / 1000 - 1, None)
+    ticker = trim_tickerlist(ticker_list, timerange)
+    ticker_len = len(ticker)
+
+    assert ticker_len == ticker_list_len - 10
+    assert ticker_list[10] is ticker[0]  # The first element is element #10
+    assert ticker_list[-1] is ticker[-1]  # The last element is the same
+
     # Test a wrong pattern
     # This pattern must return the list unchanged
     timerange = ((None, None), None, 5)

freqtrade/tests/test_arguments.py

@@ -89,6 +89,13 @@ def test_parse_args_dynamic_whitelist_invalid_values() -> None:
 def test_parse_timerange_incorrect() -> None:
     assert ((None, 'line'), None, -200) == Arguments.parse_timerange('-200')
     assert (('line', None), 200, None) == Arguments.parse_timerange('200-')
+    assert (('index', 'index'), 200, 500) == Arguments.parse_timerange('200-500')
+
+    assert (('date', None), 1274486400, None) == Arguments.parse_timerange('20100522-')
+    assert ((None, 'date'), None, 1274486400) == Arguments.parse_timerange('-20100522')
+    timerange = Arguments.parse_timerange('20100522-20150730')
+    assert timerange == (('date', 'date'), 1274486400, 1438214400)
+
     with pytest.raises(Exception, match=r'Incorrect syntax.*'):
         Arguments.parse_timerange('-')
 

scripts/download_backtest_data.py

@@ -4,6 +4,7 @@
 import json
 import sys
 import os
+import arrow
 
 from freqtrade import (exchange, arguments, misc)
 
@@ -25,17 +26,33 @@ dl_path = DEFAULT_DL_PATH
 if args.export and os.path.exists(args.export):
     dl_path = args.export
 
+since_time = None
+if args.days:
+    since_time = arrow.utcnow().shift(days=-args.days).timestamp * 1000
+
+
 print(f'About to download pairs: {PAIRS} to {dl_path}')
 
-# Init Bittrex exchange
+# Init exchange
 exchange._API = exchange.init_ccxt({'key': '',
                                     'secret': '',
-                                    'name': 'bittrex'})
+                                    'name': args.exchange})
+
 
 for pair in PAIRS:
     for tick_interval in TICKER_INTERVALS:
         print(f'downloading pair {pair}, interval {tick_interval}')
-        data = exchange.get_ticker_history(pair, tick_interval)
+
+        data = exchange.get_ticker_history(pair, tick_interval, since_ms=since_time)
+        if not data:
+            print('\tNo data was downloaded')
+            break
+
+        print('\tData was downloaded for period %s - %s' % (
+            arrow.get(data[0][0] / 1000).format(),
+            arrow.get(data[-1][0] / 1000).format()))
+
+        # save data
         pair_print = pair.replace('/', '_')
         filename = f'{pair_print}-{tick_interval}.json'
         misc.file_dump_json(os.path.join(dl_path, filename), data)