Increase database resiliance with sqlite WAL mode

resources/lib/itemtypes/common.py

@@ -4,8 +4,8 @@ from __future__ import absolute_import, division, unicode_literals
 from logging import getLogger
 from ntpath import dirname
 
-from ..plex_db import PlexDB
+from ..plex_db import PlexDB, PLEXDB_LOCK
-from ..kodi_db import KodiVideoDB
+from ..kodi_db import KodiVideoDB, KODIDB_LOCK
 from .. import utils, timing
 
 LOG = getLogger('PLEX.itemtypes.common')
@@ -38,8 +38,9 @@ class ItemBase(object):
     Input:
         kodiType:       optional argument; e.g. 'video' or 'music'
     """
-    def __init__(self, last_sync, plexdb=None, kodidb=None):
+    def __init__(self, last_sync, plexdb=None, kodidb=None, lock=True):
         self.last_sync = last_sync
+        self.lock = lock
         self.plexconn = None
         self.plexcursor = plexdb.cursor if plexdb else None
         self.kodiconn = None
@@ -53,13 +54,16 @@ class ItemBase(object):
         """
         Open DB connections and cursors
         """
+        if self.lock:
+            PLEXDB_LOCK.acquire()
+            KODIDB_LOCK.acquire()
         self.plexconn = utils.kodi_sql('plex')
         self.plexcursor = self.plexconn.cursor()
         self.kodiconn = utils.kodi_sql('video')
         self.kodicursor = self.kodiconn.cursor()
         self.artconn = utils.kodi_sql('texture')
         self.artcursor = self.artconn.cursor()
-        self.plexdb = PlexDB(self.plexcursor)
+        self.plexdb = PlexDB(cursor=self.plexcursor)
         self.kodidb = KodiVideoDB(texture_db=True,
                                   cursor=self.kodicursor,
                                   artcursor=self.artcursor)
@@ -69,16 +73,21 @@ class ItemBase(object):
         """
         Make sure DB changes are committed and connection to DB is closed.
         """
+        try:
             if exc_type:
                 # re-raise any exception
                 return False
             self.plexconn.commit()
             self.artconn.commit()
             self.kodiconn.commit()
+            return self
+        finally:
             self.plexconn.close()
             self.kodiconn.close()
             self.artconn.close()
-        return self
+            if self.lock:
+                PLEXDB_LOCK.release()
+                KODIDB_LOCK.release()
 
     def commit(self):
         self.plexconn.commit()

resources/lib/itemtypes/music.py

@@ -5,8 +5,8 @@ from logging import getLogger
 
 from .common import ItemBase
 from ..plex_api import API
-from ..plex_db import PlexDB
+from ..plex_db import PlexDB, PLEXDB_LOCK
-from ..kodi_db import KodiMusicDB
+from ..kodi_db import KodiMusicDB, KODIDB_LOCK
 from .. import plex_functions as PF, utils, timing, app, variables as v
 
 LOG = getLogger('PLEX.music')
@@ -17,6 +17,9 @@ class MusicMixin(object):
         """
         Overwrite to use the Kodi music DB instead of the video DB
         """
+        if self.lock:
+            PLEXDB_LOCK.acquire()
+            KODIDB_LOCK.acquire()
         self.plexconn = utils.kodi_sql('plex')
         self.plexcursor = self.plexconn.cursor()
         self.kodiconn = utils.kodi_sql('music')

resources/lib/kodi_db/__init__.py

@@ -3,6 +3,7 @@
 from __future__ import absolute_import, division, unicode_literals
 from logging import getLogger
 
+from .common import KODIDB_LOCK
 from .video import KodiVideoDB
 from .music import KodiMusicDB
 from .texture import KodiTextureDB

resources/lib/kodi_db/common.py

@@ -1,15 +1,34 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, unicode_literals
+from threading import Lock
+from functools import wraps
 
-from .. import utils, path_ops
+from .. import utils, path_ops, app
+
+KODIDB_LOCK = Lock()
+
+
+def catch_operationalerrors(method):
+    @wraps(method)
+    def wrapped(*args, **kwargs):
+        attempts = 3
+        while True:
+            try:
+                return method(*args, **kwargs)
+            except utils.OperationalError:
+                app.APP.monitor.waitForAbort(0.01)
+                attempts -= 1
+                if attempts == 0:
+                    raise
+    return wrapped
 
 
 class KodiDBBase(object):
     """
     Kodi database methods used for all types of items
     """
-    def __init__(self, texture_db=False, cursor=None, artcursor=None):
+    def __init__(self, texture_db=False, cursor=None, artcursor=None, lock=True):
         """
         Allows direct use with a cursor instead of context mgr
         """
@@ -17,8 +36,11 @@ class KodiDBBase(object):
         self.cursor = cursor
         self.artconn = None
         self.artcursor = artcursor
+        self.lock = lock
 
     def __enter__(self):
+        if self.lock:
+            KODIDB_LOCK.acquire()
         self.kodiconn = utils.kodi_sql(self.db_kind)
         self.cursor = self.kodiconn.cursor()
         if self._texture_db:
@@ -27,14 +49,19 @@ class KodiDBBase(object):
         return self
 
     def __exit__(self, e_typ, e_val, trcbak):
+        try:
             if e_typ:
                 # re-raise any exception
                 return False
             self.kodiconn.commit()
-        self.kodiconn.close()
             if self.artconn:
                 self.artconn.commit()
+        finally:
+            self.kodiconn.close()
+            if self.artconn:
                 self.artconn.close()
+            if self.lock:
+                KODIDB_LOCK.release()
 
     def art_urls(self, kodi_id, kodi_type):
         return (x[0] for x in
@@ -53,6 +80,7 @@ class KodiDBBase(object):
         for kodi_art, url in artworks.iteritems():
             self.add_art(url, kodi_id, kodi_type, kodi_art)
 
+    @catch_operationalerrors
     def add_art(self, url, kodi_id, kodi_type, kodi_art):
         """
         Adds or modifies the artwork of kind kodi_art (e.g. 'poster') in the
@@ -71,6 +99,7 @@ class KodiDBBase(object):
         for kodi_art, url in artworks.iteritems():
             self.modify_art(url, kodi_id, kodi_type, kodi_art)
 
+    @catch_operationalerrors
     def modify_art(self, url, kodi_id, kodi_type, kodi_art):
         """
         Adds or modifies the artwork of kind kodi_art (e.g. 'poster') in the
@@ -102,10 +131,12 @@ class KodiDBBase(object):
             ''', (url, kodi_id, kodi_type, kodi_art))
 
     def delete_artwork(self, kodi_id, kodi_type):
-        for row in self.cursor.execute('SELECT url FROM art WHERE media_id = ? AND media_type = ?',
+        self.cursor.execute('SELECT url FROM art WHERE media_id = ? AND media_type = ?',
-                                       (kodi_id, kodi_type, )):
+                            (kodi_id, kodi_type, ))
+        for row in self.cursor.fetchall():
             self.delete_cached_artwork(row[0])
 
+    @catch_operationalerrors
     def delete_cached_artwork(self, url):
         try:
             self.artcursor.execute("SELECT cachedurl FROM texture WHERE url = ? LIMIT 1",

resources/lib/library_sync/fanart.py

@@ -153,15 +153,7 @@ def process_fanart(plex_id, plex_type, refresh=False):
                                                 setid,
                                                 v.KODI_TYPE_SET)
         done = True
-    except utils.OperationalError:
-        # We were not fast enough when a sync started
-        pass
     finally:
         if done is True and not suspends():
-            try:
             with PlexDB() as plexdb:
-                    plexdb.set_fanart_synced(plex_id,
+                plexdb.set_fanart_synced(plex_id, plex_type)
-                                             plex_type)
-            except utils.OperationalError:
-                # We were not fast enough when a sync started
-                pass

resources/lib/library_sync/websocket.py

@@ -127,27 +127,11 @@ def process_new_item_message(message):
         LOG.error('Could not download metadata for %s', message['plex_id'])
         return False, False, False
     LOG.debug("Processing new/updated PMS item: %s", message['plex_id'])
-    attempts = 3
-    while True:
-        try:
     with itemtypes.ITEMTYPE_FROM_PLEXTYPE[plex_type](timing.unix_timestamp()) as typus:
         typus.add_update(xml[0],
                          section_name=xml.get('librarySectionTitle'),
                          section_id=xml.get('librarySectionID'))
     cache_artwork(message['plex_id'], plex_type)
-        except utils.OperationalError:
-            # Since parallel caching of artwork might invalidade the current
-            # WAL snapshot of the db, sqlite immediatly throws
-            # OperationalError, NOT after waiting for a duraton of timeout
-            # See https://github.com/mattn/go-sqlite3/issues/274#issuecomment-211759641
-            LOG.debug('sqlite OperationalError encountered, trying again')
-            attempts -= 1
-            if attempts == 0:
-                LOG.error('Repeatedly could not process message %s', message)
-                return False, False, False
-            continue
-        else:
-            break
     return True, plex_type in v.PLEX_VIDEOTYPES, plex_type in v.PLEX_AUDIOTYPES
 
 
@@ -349,9 +333,9 @@ def process_playing(data):
         else:
             mark_played = False
         LOG.debug('Update playstate for user %s for %s with plex id %s to '
-                  'viewCount %s, resume %s, mark_played %s',
+                  'viewCount %s, resume %s, mark_played %s for item %s',
                   app.ACCOUNT.plex_username, session['kodi_type'], plex_id,
-                  session['viewCount'], resume, mark_played)
+                  session['viewCount'], resume, mark_played, PLAYSTATE_SESSIONS[session_key])
         func = itemtypes.ITEMTYPE_FROM_KODITYPE[session['kodi_type']]
         with func(None) as fkt:
             fkt.update_playstate(mark_played,

resources/lib/plex_api.py

@@ -929,7 +929,7 @@ class API(object):
                     artworks[kodi_artwork] = art
             if not full_artwork:
                 return artworks
-            with PlexDB() as plexdb:
+            with PlexDB(lock=False) as plexdb:
                 db_item = plexdb.item_by_id(self.plex_id(),
                                             v.PLEX_TYPE_EPISODE)
                 if db_item:
@@ -938,12 +938,12 @@ class API(object):
                 else:
                     return artworks
             # Grab artwork from the season
-            with KodiVideoDB() as kodidb:
+            with KodiVideoDB(lock=False) as kodidb:
                 season_art = kodidb.get_art(season_id, v.KODI_TYPE_SEASON)
             for kodi_art in season_art:
                 artworks['season.%s' % kodi_art] = season_art[kodi_art]
             # Grab more artwork from the show
-            with KodiVideoDB() as kodidb:
+            with KodiVideoDB(lock=False) as kodidb:
                 show_art = kodidb.get_art(show_id, v.KODI_TYPE_SHOW)
             for kodi_art in show_art:
                 artworks['tvshow.%s' % kodi_art] = show_art[kodi_art]
@@ -952,10 +952,10 @@ class API(object):
         if kodi_id:
             # in Kodi database, potentially with additional e.g. clearart
             if self.plex_type() in v.PLEX_VIDEOTYPES:
-                with KodiVideoDB() as kodidb:
+                with KodiVideoDB(lock=False) as kodidb:
                     return kodidb.get_art(kodi_id, kodi_type)
             else:
-                with KodiMusicDB() as kodidb:
+                with KodiMusicDB(lock=False) as kodidb:
                     return kodidb.get_art(kodi_id, kodi_type)
 
         # Grab artwork from Plex

resources/lib/plex_db/__init__.py

@@ -2,7 +2,7 @@
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, unicode_literals
 
-from .common import PlexDBBase, initialize, wipe
+from .common import PlexDBBase, initialize, wipe, PLEXDB_LOCK
 from .tvshows import TVShows
 from .movies import Movies
 from .music import Music

resources/lib/plex_db/common.py

@@ -1,9 +1,12 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
 from __future__ import absolute_import, division, unicode_literals
+from threading import Lock
 
 from .. import utils, variables as v
 
+PLEXDB_LOCK = Lock()
+
 SUPPORTED_KODI_TYPES = (
     v.KODI_TYPE_MOVIE,
     v.KODI_TYPE_SHOW,
@@ -19,21 +22,28 @@ class PlexDBBase(object):
     """
     Plex database methods used for all types of items
     """
-    def __init__(self, cursor=None):
+    def __init__(self, cursor=None, lock=True):
         # Allows us to use this class with a cursor instead of context mgr
         self.cursor = cursor
+        self.lock = lock
 
     def __enter__(self):
+        if self.lock:
+            PLEXDB_LOCK.acquire()
         self.plexconn = utils.kodi_sql('plex')
         self.cursor = self.plexconn.cursor()
         return self
 
     def __exit__(self, e_typ, e_val, trcbak):
+        try:
             if e_typ:
                 # re-raise any exception
                 return False
             self.plexconn.commit()
+        finally:
             self.plexconn.close()
+            if self.lock:
+                PLEXDB_LOCK.release()
 
     def is_recorded(self, plex_id, plex_type):
         """