Add option to defer table creation; allows management of table and sc…

…hema by other tooling (like Flask-Migrate)

src/flask_session/__init__.py

@@ -91,6 +91,9 @@ def _get_interface(self, app):
         SESSION_SQLALCHEMY_TABLE = config.get(
             "SESSION_SQLALCHEMY_TABLE", Defaults.SESSION_SQLALCHEMY_TABLE
         )
+        SESSION_SQLALCHEMY_CREATE_TABLE = config.get(
+            "SESSION_SQLALCHEMY_CREATE_TABLE", Defaults.SESSION_SQLALCHEMY_CREATE_TABLE
+        )
         SESSION_SQLALCHEMY_SEQUENCE = config.get(
             "SESSION_SQLALCHEMY_SEQUENCE", Defaults.SESSION_SQLALCHEMY_SEQUENCE
         )
@@ -182,6 +185,7 @@ def _get_interface(self, app):
                 **common_params,
                 client=SESSION_SQLALCHEMY,
                 table=SESSION_SQLALCHEMY_TABLE,
+                create_table=SESSION_SQLALCHEMY_CREATE_TABLE,
                 sequence=SESSION_SQLALCHEMY_SEQUENCE,
                 schema=SESSION_SQLALCHEMY_SCHEMA,
                 bind_key=SESSION_SQLALCHEMY_BIND_KEY,

src/flask_session/defaults.py

@@ -39,6 +39,7 @@ class Defaults:
     SESSION_SQLALCHEMY_SEQUENCE = None
     SESSION_SQLALCHEMY_SCHEMA = None
     SESSION_SQLALCHEMY_BIND_KEY = None
+    SESSION_SQLALCHEMY_CREATE_TABLE = True
 
     # DynamoDB settings
     SESSION_DYNAMODB = None

src/flask_session/sqlalchemy/sqlalchemy.py

@@ -86,6 +86,7 @@ def __init__(
         sequence: Optional[str] = Defaults.SESSION_SQLALCHEMY_SEQUENCE,
         schema: Optional[str] = Defaults.SESSION_SQLALCHEMY_SCHEMA,
         bind_key: Optional[str] = Defaults.SESSION_SQLALCHEMY_BIND_KEY,
+        create_table: bool = Defaults.SESSION_SQLALCHEMY_CREATE_TABLE,
         cleanup_n_requests: Optional[int] = Defaults.SESSION_CLEANUP_N_REQUESTS,
     ):
         self.app = app
@@ -103,13 +104,15 @@ def __init__(
         self.sql_session_model = create_session_model(
             client, table, schema, bind_key, sequence
         )
-        # Create the table if it does not exist
-        with app.app_context():
-            if bind_key:
-                engine = self.client.get_engine(app, bind=bind_key)
-            else:
-                engine = self.client.engine
-            self.sql_session_model.__table__.create(bind=engine, checkfirst=True)
+
+        # Optionally create the table if it does not exist
+        if create_table:
+            with app.app_context():
+                if bind_key:
+                    engine = self.client.get_engine(app, bind=bind_key)
+                else:
+                    engine = self.client.engine
+                self.sql_session_model.__table__.create(bind=engine, checkfirst=True)
 
         super().__init__(
             app,