uxmlib-redis

A binary publish/subscribe bus for fanning a message across the servers sharing one Redis. It is deliberately small: opaque byte[] frames, no relational dependencies, and nothing that knows what a message means.

bus.subscribe("party-updates", frame -> applyUpdate(frame));
bus.publish("party-updates", encode(update));

Why bytes

The bus does not serialize for you. Encoding is yours — protobuf, JSON, a hand-rolled format — and the bus moves the bytes.

That is the right boundary for a primitive: a bus with an opinion about serialization forces every consumer to share it, and a version mismatch between two servers becomes the bus's problem rather than the message's.

Failure behaviour

Publishing is fail-degraded. With Redis unreachable, publish does not throw — the message is lost and the plugin keeps running. A cross-server notification is not worth taking a server down for.

Subscriptions auto-reconnect, per subscription. A Redis restart does not require a server restart, and each subscription recovers independently.

RateLimitedWarner bounds the logging: an unreachable Redis warns once and then goes quiet rather than writing a line per publish.

Lettuce is compile-only

LettuceRedisBus is the implementation, and Lettuce is a compile-only soft dependency. You add it yourself:

implementation("com.github.UXPLIMA.uxmLib:uxmlib-redis:VERSION")
implementation("io.lettuce:lettuce-core:VERSION")

A plugin that shades uxmlib-redis without using it does not carry a Redis client.

No internal dependencies

uxmlib-redis depends on nothing else in the library — not even uxmlib-common. It is usable on its own, and uxmlib-storage's RedisDataSynchronizer builds cache invalidation on top of it without the storage stack and the bus knowing about each other.

When you need it

Only when more than one server node has to agree about something: a party that spans servers, a cache to invalidate, a broadcast to carry.

A single server does not need Redis. uxmlib-storage ships a LocalDataSynchronizer that implements the same interface as a no-op, so the same code runs in both shapes and adding Redis later is a wiring change.