Redis client: custom connections manager

Hello,

In case someone else stumbles upon the question, unfortunately, there is no built-in way to dynamically grow the connection pool size in Jedis or JedisConnectionFactory. As you mentioned, the latest version of GenericObjectPool does not have this capability, and JedisConnectionFactory does not provide an option to pass a custom object pool.

However, you can implement your own dynamic connection pool growth logic using a combination of Jedis and some custom code. Here’s an approach you can consider:

1. Create a custom ConnectionPool class that extends JedisPool and adds dynamic pool growth logic. For example, you can override the getResource() method to check if the pool size has reached a certain threshold, and if so, create a new connection and return it instead of one from the pool. You can also implement a check-in method that releases a connection back to the pool and checks if the pool size can be reduced.

2. In your application code, create an instance of your custom ConnectionPool and pass it to JedisConnectionFactory using the setPoolConfig() method. This will configure JedisConnectionFactory to use your custom connection pool.

Here’s an example implementation of a custom ConnectionPool class:

import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;

public class DynamicConnectionPool extends JedisPool {

    private static final int DEFAULT_POOL_SIZE = 10;
    private static final int MAX_POOL_SIZE = 100;

    public DynamicConnectionPool(String host, int port) {
        this(host, port, DEFAULT_POOL_SIZE);
    }

    public DynamicConnectionPool(String host, int port, int poolSize) {
        super(new JedisPoolConfig(), host, port);
        this.internalPool.setMaxTotal(poolSize);
    }

    @Override
    public Jedis getResource() {
        Jedis jedis = null;
        if (this.getNumIdle() == 0 && this.getNumActive() < MAX_POOL_SIZE) {
            jedis = new Jedis(this.getHost(), this.getPort());
        } else {
            jedis = super.getResource();
        }
        return jedis;
    }

    public void checkIn(Jedis jedis) {
        if (this.getNumActive() > this.internalPool.getMaxIdle()) {
            jedis.close();
        } else {
            super.returnResource(jedis);
        }
    }
}

In this example, the DynamicConnectionPool class extends JedisPool and overrides the getResource() method to create a new Jedis instance if the pool size has reached a certain threshold (MAX_POOL_SIZE). The checkIn() method releases a connection back to the pool and checks if the pool size can be reduced.

You can then use the DynamicConnectionPool class in your application code like this:

DynamicConnectionPool pool = new DynamicConnectionPool("localhost", 6379, 20);
JedisConnectionFactory jedisConnectionFactory = new JedisConnectionFactory();
jedisConnectionFactory.setPoolConfig(pool);

This will configure JedisConnectionFactory to use your custom connection pool with a maximum size of 20. You can adjust the pool size and threshold values as needed for your specific use case.

I hope this will help