PlexKodiConnect/resources/lib/db.py
2019-11-15 13:38:41 +01:00

101 lines
3.3 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import sqlite3
from functools import wraps
from . import variables as v, app
DB_WRITE_ATTEMPTS = 100
class LockedDatabase(Exception):
"""
Dedicated class to make sure we're not silently catching locked DBs.
"""
pass
def catch_operationalerrors(method):
"""
sqlite.OperationalError is raised immediately if another DB connection
is open, reading something that we're trying to change
So let's catch it and try again
Also see https://github.com/mattn/go-sqlite3/issues/274
"""
@wraps(method)
def wrapper(self, *args, **kwargs):
attempts = DB_WRITE_ATTEMPTS
while True:
try:
return method(self, *args, **kwargs)
except sqlite3.OperationalError as err:
if 'database is locked' not in err:
# Not an error we want to catch, so reraise it
raise
attempts -= 1
if attempts == 0:
# Reraise in order to NOT catch nested OperationalErrors
raise LockedDatabase('Database is locked')
# Need to close the transactions and begin new ones
self.kodiconn.commit()
if self.artconn:
self.artconn.commit()
if app.APP.monitor.waitForAbort(0.1):
# PKC needs to quit
return
# Start new transactions
self.kodiconn.execute('BEGIN')
if self.artconn:
self.artconn.execute('BEGIN')
return wrapper
def _initial_db_connection_setup(conn, wal_mode):
"""
Set-up DB e.g. for WAL journal mode, if that hasn't already been done
before. Also start a transaction
"""
if wal_mode:
conn.execute('PRAGMA journal_mode=WAL;')
conn.execute('PRAGMA cache_size = -8000;')
conn.execute('PRAGMA synchronous=NORMAL;')
conn.execute('BEGIN')
def connect(media_type=None, wal_mode=True):
"""
Open a connection to the Kodi database.
media_type: 'video' (standard if not passed), 'plex', 'music', 'texture'
Pass wal_mode=False if you want the standard (and slower) sqlite
journal_mode, e.g. when wiping entire tables. Useful if you do NOT want
concurrent access to DB for both PKC and Kodi
"""
if media_type == "plex":
db_path = v.DB_PLEX_PATH
elif media_type == "music":
db_path = v.DB_MUSIC_PATH
elif media_type == "texture":
db_path = v.DB_TEXTURE_PATH
else:
db_path = v.DB_VIDEO_PATH
conn = sqlite3.connect(db_path, timeout=30.0)
attempts = DB_WRITE_ATTEMPTS
while True:
try:
_initial_db_connection_setup(conn, wal_mode)
except sqlite3.OperationalError as err:
if 'database is locked' not in err:
# Not an error we want to catch, so reraise it
raise
attempts -= 1
if attempts == 0:
# Reraise in order to NOT catch nested OperationalErrors
raise LockedDatabase('Database is locked')
if app.APP.monitor.waitForAbort(0.05):
# PKC needs to quit
return
else:
break
return conn