Decode messages from IOError before logging them

IOError messages are bytestrings, often in the language of the system, so they
may include non-ASCII characters. Thus, we must decode them using the locale's
preferred encoding to get Unicode objects we safely can pass on for logging
the IOError.

mopidy/backends/local/translator.py

@@ -4,6 +4,7 @@ import os
 logger = logging.getLogger('mopidy.backends.local.translator')
 
 from mopidy.models import Track, Artist, Album
+from mopidy.utils import locale_decode
 from mopidy.utils.path import path_to_uri
 
 def parse_m3u(file_path):
@@ -33,8 +34,8 @@ def parse_m3u(file_path):
     try:
         with open(file_path) as m3u:
             contents = m3u.readlines()
-    except IOError, e:
-        logger.error('Couldn\'t open m3u: %s', e)
+    except IOError as error:
+        logger.error('Couldn\'t open m3u: %s', locale_decode(error))
         return uris
 
     for line in contents:
@@ -61,8 +62,8 @@ def parse_mpd_tag_cache(tag_cache, music_dir=''):
     try:
         with open(tag_cache) as library:
             contents = library.read()
-    except IOError, e:
-        logger.error('Could not open tag cache: %s', e)
+    except IOError as error:
+        logger.error('Could not open tag cache: %s', locale_decode(error))
         return tracks
 
     current = {}

mopidy/frontends/mpd/__init__.py

@@ -5,7 +5,7 @@ from pykka import registry, actor
 
 from mopidy import listeners, settings
 from mopidy.frontends.mpd import dispatcher, protocol
-from mopidy.utils import network, process, log
+from mopidy.utils import locale_decode, log, network, process
 
 logger = logging.getLogger('mopidy.frontends.mpd')
 
@@ -32,8 +32,8 @@ class MpdFrontend(actor.ThreadingActor, listeners.BackendListener):
         try:
             network.Server(hostname, port, protocol=MpdSession,
                 max_connections=settings.MPD_SERVER_MAX_CONNECTIONS)
-        except IOError, e:
-            logger.error(u'MPD server startup failed: %s', e)
+        except IOError as error:
+            logger.error(u'MPD server startup failed: %s', locale_decode(error))
             sys.exit(1)
 
         logger.info(u'MPD server running at [%s]:%s', hostname, port)

mopidy/utils/network.py

@@ -9,6 +9,8 @@ from pykka import ActorDeadError
 from pykka.actor import ThreadingActor
 from pykka.registry import ActorRegistry
 
+from mopidy.utils import locale_decode
+
 logger = logging.getLogger('mopidy.utils.server')
 
 class ShouldRetrySocketCall(Exception):
@@ -21,9 +23,9 @@ def try_ipv6_socket():
     try:
         socket.socket(socket.AF_INET6).close()
         return True
-    except IOError, e:
+    except IOError as error:
         logger.debug(u'Platform supports IPv6, but socket '
-            'creation failed, disabling: %s', e)
+            'creation failed, disabling: %s', locale_decode(error))
     return False
 
 #: Boolean value that indicates if creating an IPv6 socket will succeed.