Thread-Safety and Multiple Databases

If you plan to change the database at run-time in a multi-threaded application, storing the model’s database in a thread-local will prevent race-conditions. This can be accomplished with a custom model Metadata class:

import threading
from peewee import Metadata
class ThreadSafeDatabaseMetadata(Metadata):
    def __init__(self, *args, **kwargs):
        # database attribute is stored in a thread-local.
        self._local = threading.local()
        super(ThreadSafeDatabaseMetadata, self).__init__(*args, **kwargs)
    def _get_db(self):
        return getattr(self._local, 'database', self._database)
    def _set_db(self, db):
        self._local.database = self._database = db
    database = property(_get_db, _set_db)
class BaseModel(Model):
    class Meta:
        # Instruct peewee to use our thread-safe metadata implementation.
        model_metadata_class = ThreadSafeDatabaseMetadata