--- aurweb/db.py | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/aurweb/db.py b/aurweb/db.py index 1ccd9a07..02aeba38 100644 --- a/aurweb/db.py +++ b/aurweb/db.py @@ -10,6 +10,8 @@ except ImportError: import aurweb.config +engine = None # See get_engine + def get_sqlalchemy_url(): """ @@ -38,6 +40,34 @@ def get_sqlalchemy_url(): raise ValueError('unsupported database backend') +def get_engine(): + """ + Return the global SQLAlchemy engine. + + The engine is created on the first call to get_engine and then stored in the + `engine` global variable for the next calls. + """ + from sqlalchemy import create_engine + global engine + if engine is None: + engine = create_engine(get_sqlalchemy_url(), + # check_same_thread is for a SQLite technicality + # https://fastapi.tiangolo.com/tutorial/sql-databases/#note + connect_args={"check_same_thread": False}) + return engine + + +def connect(): + """ + Return an SQLAlchemy connection. Connections are usually pooled. See + https://docs.sqlalchemy.org/en/13/core/connections.html. + + Since SQLAlchemy connections are context managers too, you should use it + with Python’s `with` operator, or with FastAPI’s dependency injection. + """ + return get_engine().connect() + + class Connection: _conn = None _paramstyle = None -- 2.27.0