pevensie_redis - v1.0.0

Pevensie Redis Driver

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The official Redis-compatible driver for Pevensie. It provides driver implementations for Pevensie modules to be used with Redis-compatible databases.

Currently provides drivers for:

Getting Started

Configure your driver to connect to your database using the RedisConfig type. You can use the default_config function to get a default configuration for connecting to a local Redis database with a timeout of 5000 milliseconds.

import pevensie/redis.{type RedisConfig}

pub fn main() {
  let config = RedisConfig(
    ..redis.default_config(),
    host: "cache.pevensie.dev",
  )
  // ...
}

Create a new driver using one of the new_cache_driver function provided by this module. You can then use the driver with Pevensie Cache.

import pevensie/redis.{type RedisConfig}
import pevensie/cache

pub fn main() {
  let config = RedisConfig(
    ..redis.default_config(),
    host: "cache.pevensie.dev",
  )
  let driver = redis.new_cache_driver(config)
  let pevensie_auth = cache.new(driver:)
  // ...
}

Connection Management

Pevenise Redis uses radish to connect to Redis. Radish works by spawning a Gleam OTP actor to for communication with Redis. As such, the connect function provided by Pevensie Cache will start this actor. This can be called once on boot, and will be reused for the lifetime of the application.

The disconnect function will stop the actor.

Pevensie Redis uses the radish library to connect to Redis. Connection pooling is managed using Bath.

Implementation Details

This driver aims to use Redis in a standard way, and will work with any Redis-compatible database (our own test suite uses Valkey).

Pevensie Cache

Pevensie Cache uses a combination of a custom resource type and key to identify values in the cache. In Redis, this is represented as a single key of the form <resource_type>:<key>.

TTL on SET operations is managed via the EXPIRE and PERSIST commands. When the ttl_seconds argument is not None, an EXPIRE command will be sent after the SET operation. When the ttl_seconds argument is None, a PERSIST command will be sent instead.

Both will use the timeout value provided in the configuration. This means that cache.set, when called with the Redis driver, may take twice the configured timeout to complete.

Development

Tests rely on a local Redis-compatible database running on port 6379. The repo includes a compose.yaml file to start a local Valkey instance for testing, but feel free to use any Redis-compatible database you’d like.

Tests can be run with:

gleam test
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