GH-120: Refresh database connections after 30 mins

As recommended for Cloud SQL:
https://cloud.google.com/sql/docs/postgres/manage-connections#duration

schemes/__init__.py

@@ -137,7 +137,8 @@ def _create_engine(app: Flask) -> Engine:
 @inject.autoparams()
 def _create_capital_schemes_engine(config: Config, engine: Engine) -> Engine:
     database_uri = config.get("CAPITAL_SCHEMES_DATABASE_URI")
-    return create_engine(database_uri) if database_uri else engine
+    engine_options = config["SQLALCHEMY_ENGINE_OPTIONS"]
+    return create_engine(database_uri, **engine_options) if database_uri else engine
 
 
 @inject.params(engine=Engine, capital_schemes_engine=(Engine, CapitalSchemeEntity))

schemes/config.py

@@ -10,6 +10,7 @@ class Config:
 
     # Flask-SQLAlchemy
     SQLALCHEMY_DATABASE_URI = "sqlite+pysqlite:///:memory:"
+    SQLALCHEMY_ENGINE_OPTIONS = {"pool_recycle": int(timedelta(minutes=30).total_seconds())}
 
     # Flask-Session
     SESSION_TYPE = "sqlalchemy"

tests/integration/test_database.py

@@ -0,0 +1,24 @@
+from typing import Any, Mapping
+
+import inject
+import pytest
+from sqlalchemy import Engine
+
+from schemes.infrastructure.database import CapitalSchemeEntity
+
+
+@pytest.mark.usefixtures("client")
+class TestDatabase:
+    @pytest.fixture(name="config", scope="class")
+    def config_fixture(self, config: Mapping[str, Any]) -> Mapping[str, Any]:
+        return dict(config) | {"CAPITAL_SCHEMES_DATABASE_URI": "sqlite+pysqlite:///:memory:"}
+
+    def test_pool_recycles_connections(self) -> None:
+        engine = inject.instance(Engine)
+
+        assert engine.pool._recycle == 1800
+
+    def test_capital_schemes_pool_recycles_connections(self) -> None:
+        engine = inject.instance((Engine, CapitalSchemeEntity))
+
+        assert isinstance(engine, Engine) and engine.pool._recycle == 1800