configuration.rst

Configuration

yaml

A typical SQLAlchemy configuration consists of a single database. At minimum, you only need a connection URL (see the SQLAlchemy documentation for how to construct one). Such a configuration would look something like this:

components:
  sqlalchemy:
    url: postgresql+asyncpg://user:password@10.0.0.8/mydatabase

This will add two static resources and one resource factory, as follows:

• engine (type: sqlalchemy.future.engine.Engine or sqlalchemy.ext.asyncio.AsyncEngine)
• sessionmaker (type: sqlalchemy.orm.sessionmaker)
• session factory (generates ~sqlalchemy.orm.Session or sqlalchemy.ext.asyncio.AsyncSession resources)

You can also pass the URL in separate pieces (e.g. to take advantage of YAML key/value sharing features):

components:
  sqlalchemy:
    url:
      drivername: postgresql+asyncpg
      username: user
      password: password
      host: 10.0.0.8
      database: mydatabase

* sqlalchemy.engine.URL * asphalt.sqlalchemy.component.SQLAlchemyComponent

Setting engine or session options

If you need to adjust the options used for creating new sessions, or pass extra arguments to the engine, you can do so by specifying them in the session option:

components:
  sqlalchemy:
    url: sqlite+aiosqlite:///:memory:
    engine_args:
      encoding: latin1
    session_args:
      info:
        hello: world

Multiple databases

If you need to work with multiple databases, you will need to use multiple instances of the sqlalchemy component:

components:
  sqlalchemy:
    resource_name: db1
    url: postgresql+asyncpg:///mydatabase
  sqlalchemy2:
    type: sqlalchemy
    resource_name: db2
    url: sqlite+aiosqlite:///mydb.sqlite

This will make the appropriate resources available using their respective namespaces (db1 or db2 instead of default).