pyApp - SQLAlchemy

Let us handle the boring stuff!

This extension provides a Connection and Session factory for SQLAlchemy to allow database connections to be configured via pyApp settings.

Engine instances are created from a singleton factory to ensure that connection pooling is utilised.

The extension also provides checks to confirm the settings are correct and that the application is able to connect to the database host.

Installation

Install using pip:

pip install pyapp-sqlalchemy

Install using pipenv:

pipenv install pyapp-sqlalchemy

Add the DATABASE_ENGINES block into your runtime settings file:

DATABASE_ENGINES = {
    "default": {
        "url": "postgres://user:pass@host:port/database",
    },
}

Note

The URI is a defined by SQLAlchemy see the documentation. In addition to the url any argument that can be provided to sqlalchemy.engines.create_engine can be provided.

Usage

The following example creates both Connection and Session instances:

from pyapp_ext.sqlalchemy import get_connection, get_session

# Get connection from default connection pool
cnn = get_connection()

# Get connection from an alternate pool
session = get_session("Alternate")

API

pyapp_ext.sqlalchemy.get_engine(default: str = None) -> Engine

Get named Engine instance (singleton)

pyapp_ext.sqlalchemy.get_connection(default: str = None) -> Connection

Get named Connection instance.

pyapp_ext.sqlalchemy.get_raw_connection(default: str = None)

Get named raw connection, this is the underlying Python DBAPI object.

pyapp_ext.sqlalchemy.get_session(default: str = None) -> Session

Get named Session instance.