Sticky sessions for spring-session

The spring-session project has an open issue about supporting the concept of sticky sessions, where a load-balancer is configured to send one client always to the same server if possible.

This allows some optimizations like keeping a local cache of sessions, and replicating changes to the centralized session store asynchronously.

This repository aims to provide a reference implementation of this feature, which can ultimately be merged into spring-session upstream.

Configuring StickySessionRepository

This project provides a StickySessionRepository class, which manages a local cache of sessions and delegates to another repository for centralized session management (e.g. RedisIndexedSessionRepository).

The simplest way to configure sticky sessions with a redis backend is by using the @EnableStickyRedisHttpSession annotation:

@Configuration
@EnableStickyRedisHttpSession
public class StickySessionConfig {

  // here could be your redis connection factory

}

For a more advanced configuration, you can use @EnableStickyHttpSession and provide your own adapter, or subclass StickyHttpSessionConfiguration.