Fixed SQLite & thread error / warning.

Author: mikeckennedy

apps/py/ch08_db/guitary/app.py

@@ -1,3 +1,9 @@
+import os
+import sys
+
+folder = os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))
+sys.path.insert(0, folder)
+
 import flask
 from guitary.services import catalog_service
 from guitary.data import session_factory

apps/py/ch08_db/guitary/data/context_session.py

@@ -16,3 +16,4 @@ def __exit__(self, exc_type, exc_val, exc_tb):
                 pass
 
         self.session.close()
+        self.session = None

apps/py/ch08_db/guitary/data/session_factory.py

@@ -2,7 +2,7 @@
 
 import sqlalchemy
 import sqlalchemy.orm
-from sqlalchemy.orm import Session
+from sqlalchemy.orm import Session, scoped_session
 
 from guitary.data.context_session import ContextSession
 from guitary.db import db_folder
@@ -19,7 +19,7 @@ def global_init(db_name: str):
 
     conn_str = 'sqlite:///' + db_folder.get_full_path(db_name)
     __engine = sqlalchemy.create_engine(conn_str, echo=False)
-    __factory = sqlalchemy.orm.sessionmaker(bind=__engine)
+    __factory = scoped_session(sqlalchemy.orm.sessionmaker(bind=__engine))
 
 
 def create_tables():

apps/py/ch08_db/guitary/services/catalog_service.py

@@ -7,11 +7,13 @@
 def all_guitars(style: Optional[str]) -> List[Guitar]:
     with session_factory.create_session() as ctx:
         if style is None or style == 'all':
+            # noinspection PyUnresolvedReferences
             guitars = ctx.session.query(Guitar).order_by(Guitar.price.desc())
             return list(guitars)
 
-    filtered_guitars = list(ctx.session.query(Guitar)
-                            .filter(Guitar.style == style)
-                            .order_by(Guitar.price.desc()))
+        # noinspection PyUnresolvedReferences
+        filtered_guitars = list(ctx.session.query(Guitar)
+                                .filter(Guitar.style == style)
+                                .order_by(Guitar.price.desc()))
 
     return filtered_guitars