Handle multiple threads writing to the db at the same time

[benoitguigal]

30.08.16 19:19:10 [+0200] File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
30.08.16 19:19:10 [+0200] self.run()
30.08.16 19:19:10 [+0200] File "/usr/lib/python2.7/threading.py", line 763, in run
30.08.16 19:19:10 [+0200] self.__target(*self.__args, **self.__kwargs)
30.08.16 19:19:10 [+0200] File "figureraspbian/photobooth.py", line 375, in update_paper_level
30.08.16 19:19:10 [+0200] paper_level = db.update_paper_level(pixels)
30.08.16 19:19:10 [+0200] File "figureraspbian/db.py", line 354, in update_paper_level
30.08.16 19:19:10 [+0200] photobooth.save()
30.08.16 19:19:10 [+0200] File "/usr/local/lib/python2.7/dist-packages/peewee.py", line 4742, in save
30.08.16 19:19:10 [+0200] rows = self.update(**field_dict).where(self._pk_expr()).execute()
30.08.16 19:19:10 [+0200] File "/usr/local/lib/python2.7/dist-packages/peewee.py", line 3117, in execute
30.08.16 19:19:10 [+0200] return self.database.rows_affected(self._execute())
30.08.16 19:19:10 [+0200] File "/usr/local/lib/python2.7/dist-packages/peewee.py", line 2656, in _execute
30.08.16 19:19:10 [+0200] return self.database.execute_sql(sql, params, self.require_commit)
30.08.16 19:19:10 [+0200] File "/usr/local/lib/python2.7/dist-packages/peewee.py", line 3492, in execute_sql
30.08.16 19:19:10 [+0200] self.commit()
30.08.16 19:19:10 [+0200] File "/usr/local/lib/python2.7/dist-packages/peewee.py", line 3316, in __exit__
30.08.16 19:19:10 [+0200] reraise(new_type, new_type(*exc_args), traceback)
30.08.16 19:19:10 [+0200] File "/usr/local/lib/python2.7/dist-packages/peewee.py", line 3485, in execute_sql
30.08.16 19:19:10 [+0200] cursor.execute(sql, params or ())
30.08.16 19:19:10 [+0200] OperationalError: database is locked

[benoitguigal]

Might help http://stackoverflow.com/questions/3172929/operationalerror-database-is-locked