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-rw-r--r--aurweb/db.py30
1 files changed, 30 insertions, 0 deletions
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