Merge pull request #1712 from freqtrade/log/tofile

Allow logging to file

README.md

@@ -68,9 +68,9 @@ For any other type of installation please refer to [Installation doc](https://ww
 ### Bot commands
 
 ```
-usage: freqtrade [-h] [-v] [--version] [-c PATH] [-d PATH] [-s NAME]
-                 [--strategy-path PATH] [--dynamic-whitelist [INT]]
-                 [--db-url PATH]
+usage: freqtrade [-h] [-v] [--logfile FILE] [--version] [-c PATH] [-d PATH]
+                 [-s NAME] [--strategy-path PATH] [--dynamic-whitelist [INT]]
+                 [--db-url PATH] [--sd-notify]
                  {backtesting,edge,hyperopt} ...
 
 Free, open source crypto trading bot
@@ -84,6 +84,7 @@ positional arguments:
 optional arguments:
   -h, --help            show this help message and exit
   -v, --verbose         Verbose mode (-vv for more, -vvv to get all messages).
+  --logfile FILE        Log to the file specified
   --version             show program's version number and exit
   -c PATH, --config PATH
                         Specify configuration file (default: None). Multiple
@@ -100,6 +101,7 @@ optional arguments:
   --db-url PATH         Override trades database URL, this is useful if
                         dry_run is enabled or in custom deployments (default:
                         None).
+  --sd-notify           Notify systemd service manager.
 ```
 
 ### Telegram RPC commands

docs/bot-usage.md

@@ -6,9 +6,9 @@ This page explains the different parameters of the bot and how to run it.
 ## Bot commands
 
 ```
-usage: freqtrade [-h] [-v] [--version] [-c PATH] [-d PATH] [-s NAME]
-                 [--strategy-path PATH] [--dynamic-whitelist [INT]]
-                 [--db-url PATH]
+usage: freqtrade [-h] [-v] [--logfile FILE] [--version] [-c PATH] [-d PATH]
+                 [-s NAME] [--strategy-path PATH] [--dynamic-whitelist [INT]]
+                 [--db-url PATH] [--sd-notify]
                  {backtesting,edge,hyperopt} ...
 
 Free, open source crypto trading bot
@@ -22,6 +22,7 @@ positional arguments:
 optional arguments:
   -h, --help            show this help message and exit
   -v, --verbose         Verbose mode (-vv for more, -vvv to get all messages).
+  --logfile FILE        Log to the file specified
   --version             show program's version number and exit
   -c PATH, --config PATH
                         Specify configuration file (default: None). Multiple

docs/configuration.md

@@ -70,6 +70,7 @@ Mandatory Parameters are marked as **Required**.
 | `strategy` | DefaultStrategy | Defines Strategy class to use.
 | `strategy_path` | null | Adds an additional strategy lookup path (must be a folder).
 | `internals.process_throttle_secs` | 5 | **Required.** Set the process throttle. Value in second.
+| `logfile` | | Specify Logfile. Uses a rolling strategy of 10 files, with 1Mb per file.
 | `internals.sd_notify` | false | Enables use of the sd_notify protocol to tell systemd service manager about changes in the bot state and issue keep-alive pings. See [here](installation.md#7-optional-configure-freqtrade-as-a-systemd-service) for more details.
 
 ### Parameters in the strategy

freqtrade/arguments.py

@@ -71,6 +71,13 @@ class Arguments(object):
             dest='loglevel',
             default=0,
         )
+        self.parser.add_argument(
+            '--logfile',
+            help='Log to the file specified',
+            dest='logfile',
+            type=str,
+            metavar='FILE'
+        )
         self.parser.add_argument(
             '--version',
             action='version',

freqtrade/configuration.py

@@ -4,16 +4,18 @@ This module contains the configuration class
 import json
 import logging
 import os
+import sys
 from argparse import Namespace
-from typing import Any, Dict, Optional
+from logging.handlers import RotatingFileHandler
+from typing import Any, Dict, List, Optional
 
 import ccxt
 from jsonschema import Draft4Validator, validate
 from jsonschema.exceptions import ValidationError, best_match
 
 from freqtrade import OperationalException, constants
-from freqtrade.state import RunMode
 from freqtrade.misc import deep_merge_dicts
+from freqtrade.state import RunMode
 
 logger = logging.getLogger(__name__)
 
@@ -116,9 +118,22 @@ class Configuration(object):
             config.update({'verbosity': self.args.loglevel})
         else:
             config.update({'verbosity': 0})
+
+        # Log to stdout, not stderr
+        log_handlers: List[logging.Handler] = [logging.StreamHandler(sys.stdout)]
+        if 'logfile' in self.args and self.args.logfile:
+            config.update({'logfile': self.args.logfile})
+
+        # Allow setting this as either configuration or argument
+        if 'logfile' in config:
+            log_handlers.append(RotatingFileHandler(config['logfile'],
+                                                    maxBytes=1024 * 1024,  # 1Mb
+                                                    backupCount=10))
+
         logging.basicConfig(
             level=logging.INFO if config['verbosity'] < 1 else logging.DEBUG,
             format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
+            handlers=log_handlers
         )
         set_loggers(config['verbosity'])
         logger.info('Verbosity set to %s', config['verbosity'])

freqtrade/tests/test_configuration.py

@@ -5,6 +5,7 @@ import logging
 from argparse import Namespace
 from copy import deepcopy
 from unittest.mock import MagicMock
+from pathlib import Path
 
 import pytest
 from jsonschema import Draft4Validator, ValidationError, validate
@@ -547,6 +548,23 @@ def test_set_loggers() -> None:
     assert logging.getLogger('telegram').level is logging.INFO
 
 
+def test_set_logfile(default_conf, mocker):
+    mocker.patch('freqtrade.configuration.open',
+                 mocker.mock_open(read_data=json.dumps(default_conf)))
+
+    arglist = [
+        '--logfile', 'test_file.log',
+    ]
+    args = Arguments(arglist, '').get_parsed_arg()
+    configuration = Configuration(args)
+    validated_conf = configuration.load_config()
+
+    assert validated_conf['logfile'] == "test_file.log"
+    f = Path("test_file.log")
+    assert f.is_file()
+    f.unlink()
+
+
 def test_load_config_warn_forcebuy(default_conf, mocker, caplog) -> None:
     default_conf['forcebuy_enable'] = True
     mocker.patch('freqtrade.configuration.open', mocker.mock_open(