add LOG_FILE env var

relay/logger.py

 import logging
 import os
 
+from pathlib import Path
+
 
 ## Add the verbose logging level
 def verbose(message, *args, **kwargs):
@@ -14,9 +16,15 @@ setattr(logging, 'VERBOSE', 15)
 logging.addLevelName(15, 'VERBOSE')
 
 
-## Get log level from environment if possible
+## Get log level and file from environment if possible
 env_log_level = os.environ.get('LOG_LEVEL', 'INFO').upper()
 
+try:
+	env_log_file = Path(os.environ.get('LOG_FILE')).expanduser().resolve()
+
+except TypeError:
+	env_log_file = None
+
 
 ## Make sure the level from the environment is valid
 try:
@@ -27,8 +35,13 @@ except AttributeError:
 
 
 ## Set logging config
+handlers = [logging.StreamHandler()]
+
+if env_log_file:
+	handlers.append(logging.FileHandler(env_log_file))
+
 logging.basicConfig(
 	level = log_level,
 	format = "[%(asctime)s] %(levelname)s: %(message)s",
-	handlers = [logging.StreamHandler()]
+	handlers = handlers
 )