splent_feature_redis

Redis infrastructure for SPLENT products (config archetype). It brings a Redis 7.4 container and puts in the app's configuration how to reach it, so other features can use Redis without knowing where it runs or what its password is. Sessions are a separate feature, splent_feature_session_redis, which requires this one.

What it provides

In app.config:

A feature that keeps something in Redis reads the URL for its use and hands it to redis.from_url. Each use has a logical database of its own: a cache may be flushed whenever it is in the way, queued tasks may not, and neither may take the sessions with it.

Docker, one redis:7.4 service named splent_feature_redis with its data in the redis_data volume:

• docker/docker-compose.dev.yml publishes port 6379 on the host as REDIS_HOST_PORT, and runs without a password unless REDIS_PASSWORD sets one, like the rest of the development stack.
• docker/docker-compose.prod.yml publishes no port, so only the product's own containers reach Redis, and always runs with requirepass. It refuses to start until REDIS_PASSWORD is set.

Configuration

Credentials written into REDIS_URL (rediss://user:password@host:6380) win over REDIS_PASSWORD. That is how a product points at a Redis it does not run, such as a managed one with a user of its own. A database in the URL is replaced by the one each use is configured with.

The database settings are declared in [tool.splent.config], so a product changes them there. A value that is not a database number, or one that two uses share, stops the app at start-up rather than quietly putting two uses in one database. A number the server does not have fails at the first connection instead, since only the server knows how many it has: the feature's own has 16, from 0 to 15.

Upgrading from 1.5

• A production deployment needs REDIS_PASSWORD. product:deploy asks for it and offers a random one; on a host without the CLI, set it in deploy/.env before docker compose up.
• Redis is no longer published on the host in production. Anything that reached it through REDIS_HOST_PORT has to run inside the product's network now.
• The data moves to the redis_data volume, which survives docker compose down. The first start of this version begins with it empty, so everyone signs in once more.
• REDIS_WORKER_TIMEOUT is gone. Nothing read it.

Use it in a product

splent feature:add splent_feature_redis

Tests

splent feature:test splent_feature_redis

The unit tests build the URLs against a bare Flask app and parse them with redis-py, which opens no connection, so no server is needed.