Make Unix sockets writable for user group

README.rst

@@ -82,14 +82,17 @@ The following configuration values are available:
 
 - ``mpd/hostname``:
   Which address the MPD server should bind to.
-  This can be a network address or the path toa Unix socket:
+  This can be a network address or the path to a Unix socket:
 
   - ``127.0.0.1``: Listens only on the IPv4 loopback interface (default).
   - ``::1``: Listens only on the IPv6 loopback interface.
   - ``0.0.0.0``: Listens on all IPv4 interfaces.
   - ``::``: Listens on all interfaces, both IPv4 and IPv6.
-  - ``unix:/path/to/unix/socket.sock``: Listen on the Unix socket at the
+  - ``unix:/var/run/mopidy/mpd.sock``: Listen on the Unix socket at the
     specified path. Must be prefixed with ``unix:``.
+    If `Mopidy is run as a system service <https://docs.mopidy.com/en/latest/running/service/>`_,
+    users must be added to the ``mopidy`` group (``usermod -a -G mopidy user``)
+    to communicate with the MPD server over a Unix socket.
 
 - ``mpd/port``:
   Which TCP port the MPD server should listen to.

mopidy_mpd/network.py

@@ -125,7 +125,9 @@ def create_server_socket(self, host, port):
         socket_path = get_unix_socket_path(host)
         if socket_path is not None:  # host is a path so use unix socket
             sock = create_unix_socket()
+            oldmask = os.umask(0o002) # make socket writable for users in the 'mopidy' group
             sock.bind(socket_path)
+            os.umask(oldmask)
         else:
             # ensure the port is supplied
             if not isinstance(port, int):