Backing services

Treat backing services as attached resources. A backing service is anything the app talks to over the network to do its job: a database, a cache like Redis, a message queue, an SMTP server, an object store.

The rule is that the app makes no distinction between a service you run and one someone else runs. Both are just a URL in the config. Swap one for the other, and the code doesn't change.

#In code

import os
from sqlalchemy import create_engine
import redis
 
engine = create_engine(os.environ["DATABASE_URL"])
cache = redis.Redis.from_url(os.environ["REDIS_URL"])

Nothing in this file knows whether Postgres runs on the same machine, in a container next door, or at a cloud provider.

#What counts as a backing service