From 83f1d00944eaa2d22bffd9fc35ee3a9d990dfe41 Mon Sep 17 00:00:00 2001
From: Stein Magnus Jodal <stein.magnus@jodal.no>
Date: Wed, 9 Jul 2014 23:20:48 +0200
Subject: [PATCH] docs: Add {Backend,Frontend,Mixer}Error guidelines to
 backend/frontend/mixer APIs

---
 docs/api/frontends.rst     | 8 ++++----
 mopidy/backend/__init__.py | 8 ++++++++
 mopidy/mixer.py            | 8 +++++++-
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/docs/api/frontends.rst b/docs/api/frontends.rst
index 5e2f8d6c..b843692d 100644
--- a/docs/api/frontends.rst
+++ b/docs/api/frontends.rst
@@ -29,12 +29,12 @@ The following requirements applies to any frontend implementation:
 - The main actor MUST be able to start and stop the frontend when the main
   actor is started and stopped.
 
-- The frontend MAY require additional settings to be set for it to
-  work.
+- The frontend MAY require additional config values to be set for it to work.
 
-- Such settings MUST be documented.
+- Such config values MUST be documented.
 
-- The main actor MUST stop itself if the defined settings are not adequate for
+- The main actor MUST raise the :exc:`~mopidy.exceptions.FrontendError` with a
+  descriptive error message if the defined config values are not adequate for
   the frontend to work properly.
 
 - Any actor which is part of the frontend MAY implement the
diff --git a/mopidy/backend/__init__.py b/mopidy/backend/__init__.py
index 6f895985..68aad778 100644
--- a/mopidy/backend/__init__.py
+++ b/mopidy/backend/__init__.py
@@ -6,6 +6,14 @@ from mopidy import listener
 
 
 class Backend(object):
+    """Backend API
+
+    If the backend has problems during initialization it should raise
+    :exc:`~mopidy.exceptions.BackendError` with a descriptive error message.
+    This will make Mopidy print the error message and exit so that the user can
+    fix the issue.
+    """
+
     #: Actor proxy to an instance of :class:`mopidy.audio.Audio`.
     #:
     #: Should be passed to the backend constructor as the kwarg ``audio``,
diff --git a/mopidy/mixer.py b/mopidy/mixer.py
index edda8455..01216186 100644
--- a/mopidy/mixer.py
+++ b/mopidy/mixer.py
@@ -2,7 +2,13 @@ from __future__ import unicode_literals
 
 
 class Mixer(object):
-    """Audio mixer API"""
+    """Audio mixer API
+
+    If the mixer has problems during initialization it should raise
+    :exc:`~mopidy.exceptions.MixerError` with a descriptive error message. This
+    will make Mopidy print the error message and exit so that the user can fix
+    the issue.
+    """
 
     name = None
     """Name of the mixer.