conf: make config file a CLI parameter

The config file might be stores in an alternate location for several
reasons (i.e. testing different configs or running multiple nodes on the
same host). Make the config file a CLI parameter so that it can be
specified when launching the lbrynet-daemon.

Related to #1039

Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>

lbrynet/conf.py

@@ -56,6 +56,8 @@ settings_encoders = {
     '.yml': yaml.safe_dump
 }
 
+# set by CLI when the user specifies an alternate config file path
+conf_file = None
 
 def _win_path_to_bytes(path):
     """
@@ -476,7 +478,11 @@ class Config(object):
             }
 
     def save_conf_file_settings(self):
-        path = self.get_conf_filename()
+        if conf_file:
+            path = conf_file
+        else:
+            path = self.get_conf_filename()
+
         ext = os.path.splitext(path)[1]
         encoder = settings_encoders.get(ext, False)
         assert encoder is not False, 'Unknown settings format %s' % ext
@@ -484,7 +490,11 @@ class Config(object):
             settings_file.write(encoder(self._data[TYPE_PERSISTED]))
 
     def load_conf_file_settings(self):
-        path = self.get_conf_filename()
+        if conf_file:
+            path = conf_file
+        else:
+            path = self.get_conf_filename()
+
         ext = os.path.splitext(path)[1]
         decoder = settings_decoders.get(ext, False)
         assert decoder is not False, 'Unknown settings format %s' % ext

lbrynet/daemon/DaemonControl.py

@@ -20,9 +20,18 @@ def test_internet_connection():
 
 def start():
     """The primary entry point for launching the daemon."""
-    conf.initialize_settings()
+
+    # postpone loading the config file to after the CLI arguments
+    # have been parsed, as they may contain an alternate config file location
+    conf.initialize_settings(load_conf_file=False)
 
     parser = argparse.ArgumentParser(description="Launch lbrynet-daemon")
+    parser.add_argument(
+        "--conf",
+        help="specify an alternative configuration file",
+        type=str,
+        default=None
+    )
     parser.add_argument(
         "--wallet",
         help="lbryum or ptc for testing, default lbryum",
@@ -49,6 +58,8 @@ def start():
     args = parser.parse_args()
     update_settings_from_args(args)
 
+    conf.settings.load_conf_file_settings()
+
     if args.version:
         version = system_info.get_platform(get_ip=False)
         version['installation_id'] = conf.settings.installation_id
@@ -83,6 +94,8 @@ def update_settings_from_args(args):
         'wallet': args.wallet,
     }, data_types=(conf.TYPE_CLI,))
 
+    conf.conf_file = args.conf
+
 
 @defer.inlineCallbacks
 def start_server_and_listen(use_auth, analytics_manager):