Add logging to syslog and journald

freqtrade/loggers.py

@@ -1,9 +1,12 @@
 import logging
 import sys
 
-from logging.handlers import RotatingFileHandler
+from logging import Formatter
+from logging.handlers import RotatingFileHandler, SysLogHandler
 from typing import Any, Dict, List
 
+from freqtrade import OperationalException
+
 
 logger = logging.getLogger(__name__)
 
@@ -36,8 +39,36 @@ def setup_logging(config: Dict[str, Any]) -> None:
     # Log to stdout, not stderr
     log_handlers: List[logging.Handler] = [logging.StreamHandler(sys.stdout)]
 
-    if config.get('logfile'):
-        log_handlers.append(RotatingFileHandler(config['logfile'],
+    logfile = config.get('logfile')
+    if logfile:
+        s = logfile.split(':')
+        if s[0] == 'syslog':
+            # Address can be either a string (socket filename) for Unix domain socket or
+            # a tuple (hostname, port) for UDP socket.
+            # Address can be omitted (i.e. simple 'syslog' used as the value of
+            # config['logfilename']), which defaults to '/dev/log', applicable for most
+            # of the systems.
+            address = (s[1], int(s[2])) if len(s) > 2 else s[1] if len(s) > 1 else '/dev/log'
+            handler = SysLogHandler(address=address)
+            # No datetime field for logging into syslog, to allow syslog
+            # to perform reduction of repeating messages if this is set in the
+            # syslog config. The messages should be equal for this.
+            handler.setFormatter(Formatter('%(name)s - %(levelname)s - %(message)s'))
+            log_handlers.append(handler)
+        elif s[0] == 'journald':
+            try:
+                from systemd.journal import JournaldLogHandler
+            except ImportError:
+                raise OperationalException("You need the systemd python package be installed in "
+                                           "order to use logging to journald.")
+            handler = JournaldLogHandler()
+            # No datetime field for logging into journald, to allow syslog
+            # to perform reduction of repeating messages if this is set in the
+            # syslog config. The messages should be equal for this.
+            handler.setFormatter(Formatter('%(name)s - %(levelname)s - %(message)s'))
+            log_handlers.append(handler)
+        else:
+            log_handlers.append(RotatingFileHandler(logfile,
                                                     maxBytes=1024 * 1024,  # 1Mb
                                                     backupCount=10))